ML for Dummies Total

TEP/DEG/CEF/SUB. . . Natters Around Field . . .

October 1998

MUDLOGGINGMUDLOGGING ... for dummiesCONTENTS

TOOLBOX

module 6.1

s GENERALITIES: PAST & FUTURE PRESENTATION

s SUMMARYs Introduction: AIMS & PURPOSESs SENSORS, DATUM & DATAs GAS: DEFINITION, ORIGIN,

MEASUREMENTS, INTERPRETATION

s PRESSURE: GENERALITIES: Hydrost., Overburden, Pore Pressure

FORMATION: SOBG, ’d’exp, ...WELL MEASUREMENTS: LOT, FIT, SBT, Csg Test

s SAMPLING: PROCESSING and DESCRIPTION

s LABORATORY: PREPARATION and ANALYSIS

s CORING: EQUIPMENTS and OPERATIVE TECHNICS

s REPORTING: DGR, GWR and DDR

s ANNEXESs CONCLUSION


GENERAL PRESENTATION

S U M M A R Y

MUDLOGGING: «on the road again ...»from ... STONE AGE BIBLESto ... 21st century BIBLES => TOOLBOX module 6.1)THEMATIC RESEARCHALPHABETIC RESEARCHTECHNICAL DATA SHEETS: examples (Toolbox module 5.2)GEOLOGICAL WELL REPORT (Toolbox module 7.0)MUDLOGGING AUDIT (Toolbox module 2.1)


TESTING

CIRCULATING FISHING

CORINGLOGGING

DRILLINGD R

I L L

I N G

R

E G

U L

A T

I O N

S

DATAENGINEER

MUDLOGGER

SAMPLECATCHER

WELLSITEGEOLOGIST

DATA ACQUISITION

EVALUATING

DRILLING EVENTS

MUD PARAMETERS

LITHOLOGICAL & GAS DATA

HT

DATA MANAGEMENT

WELL FOLLOW-UP

REPORTING PREPARINGRECORDING

WELL MONITORING

DATA DISPATCHINGINTERPRETATION

DATADISPATCHING

D R I L L I N G P R O P O S A L

LOTFITHP

GWR

S A

F E

T Y

R

E G U

L A

T I O

N S

M U D L O G G I N G


’STONE AGE’ BIBLES ...

USEFUL, BUT:- DIFFICULT TO MANAGE (heavy, huge, ...)- BORING RESEARCH & READING

Md iu L ngo g

g


... 21st century BIBLES

FILES:- STRICKLY A4 SIZE- MAINLY VISUAL- ESSENTIAL TEXT- FAST CONSULTATION- EASY TO UPDATE

THEMATIC RESEARCHALPHABETIC RESEARCHLINKAGE between FILES

WEB siteINTRANETM

UD L O G

I NG

G

SENSORS

GAS

PRESSURE

LABO

RATO

RY

SAMPLINGCORING

RE

PO

RT

ING

ANNEXES

CDWSG AIMS ...

THE TRICKS OF THE TRADE

TOOLBOXmodule 6.1

… JOB PURPOSES


THEMATIC RESEARCH

INTRODUCTION: AIMS

CORING

DATUM, SENSORS & DATA

SAMPLING

ANNEXES

GAS

PRESSURE

LABORATORY

REPORTING

KEYWORDS INDEX RESEARCH

CONVERSIONS & EQUIVALENTS

UNIT CONVERTER

BASIC WELLSITE GLOSSARY

International SPELLING CODE

. . .

TOOLBOX - module 6.1


Mudlogging KEYWORDS index research


EASY RESEARCH … Press to

BASICGLOSSARY

(GB - F - E)

KEYWORDGENERAL INDEX

OIL FIELDABBREVIATIONS

TECHNICALDATA SHEETS

UNITCONVERTER

More … ?

OPEN

CUTTINGDESCRIPTION

SHEET

MUDLOGGINGAUDIT

GEOLOGICALWELL REPORT


TECHNICAL DATA SHEETS

Geoservices

DRILLING SENSORS


sensor type & model

DRAWWORKS

MEASUREð Aim: To measure the rotation of the Drawworks drum and so the hook

movement.

� Features & Benefits:n Can easily be rigged up, does not normally require maintenance.n True real-time measurement.n Pipe velocity is actually calculated allowing real surge and swab calculations.

� Principle: A notched wheel with teeth rotates with the cable drum and twoproximity sensors detect the movement of the wheel which send pulses to the ALSsystem. The pulses are computed in hook movement knowing initial characteristics ofthe drum and the line.

� Manufacturer: Turck � Unit: Si 3.5 K 10 Y0

� Certification: EEx ia IIC T6

CHARACTERISTICS� Type of Output: Pulses. 3 to 8 V � Range: 48 pulses/turn

� Sensitivity: 1/48th of the DRW drum revolution. � Alarm: YES (HI/LOW)

� Accuracy: +/- 1cm � Repeatability: +/- 1 pulse

� Dimens.: N/A � Weight: N/A

MAINTENANCE� Calibration & frequency: By physical comparison of actual vertical movement of

the travelling block.

� Check & frequency:n Check of the agreement with the Driller’s depth with the pipe tally.n During each trip or every 5 days: physical inspection of the sensor.n Recalibrate each time the cable is changed.

OPERATING MODE� Power: � Voltage: 8V DC

� Sensor location: On the shaft of the drawworks.

� Operating limits: -25 -> +70 °C

CONTRACTOR Reference :-TOTAL Experience :-

Geoservices

MUD SENSORS


sensor type & model

PIT LEVELULTRASONIC

MEASUREð Aim: To measure the mud level in the pits and to know the pit volumes.

� Features & Benefits:n Light and compact.n Accurate, intrinsically safe.

� Principle: The sensor emits an ultrasonic wave which is reflected at the surface ofthe fluid. An accurate measurement of the time taken to the wave to return gives thedistance to the level of mud.

� Manufacturer: Milltronics � Unit: «The Probe»

� Certification: EEx ia IIC T4

CHARACTERISTICS� Type of Output: Analogic. 4 - 20 mA � Range: 0.3 - 5 m

� Sensitivity: 3 mm � Alarm: YES (HI/LOW)

� Accuracy: +/- 5% of Full Scale � Repeatability:

� Dimens.: N/A � Weight: 1.5 kg

MAINTENANCE� Calibration & frequency: With a tape measurer.

� Check & frequency:n Once per shift: check levels of pits, clean sensor if necessary.

OPERATING MODE� Power: � Voltage: 12 to 30 V DC

� Sensor location: Over the pit, at least 0.3m over the maximum mud level.

� Operating limits: -40 -> + 60 °C

CONTRACTOR Reference :--TOTAL Experience :--

Geoservices

GAS EQUIPMENTS


equipment & model

GZGDEGASSER

for GASLOGGERand

for RESERVAL

MEASUREð Aim: To extract gases from mud at a constant rate with equal performances on

light and heavy gases.

� Features & Benefits:n Independant of mud level variations in the mud return circuit.n High efficiency of degassing and constant performances quite independant of mud

parameters (density, viscosity, solids content,etc).n Good extraction of gases from the mud (85%) with equal performances on heavy

and light gases.

� Principle: The mud is pumped into a degasser tank where an agitator extracts thehydrocarbon gas.

� Manufacturer: Geoservices � Unit: GZG

CHARACTERISTICS� Type of Output: N/A � Range: N/A� Sensitivity: N/A � Alarm: NO� Accuracy: N/A � Repeatability: N/A

� Dimens.: 79x57x24 cm. � Weight: 38 kg

MAINTENANCE� Calibration & frequency: No calibration.

� Check & frequency:n Several time per shift: check for steady mud flow from outlet.n Once per shift: Check gas line air tightness.n Every 5 days: Check gas transit time, lubricate pump diaphragm, inspect screen

assembly and blade for wear.

OPERATING MODE� Power: 120/140 W � Voltage: 220/380 V AC

� Purpose 1: Gas Out ð location: Flow Line.� Purpose 2: Gas In ð location: Suction pit.

� Operating limits:CONTRACTOR Reference :--TOTAL Experience :--

Geoservices

LABORATORY EQUIPMENTS


equipment & model

AUTOCALCIMETER

MEASUREð Aim: To measure and record the amount of carbonates contained in rock

samples and quantify Calcite and Dolomite.

� Features & Benefits:n Compensation of sample weight between 0.90 and 1.10 g.n Memory capacity up to 800 calcimetries.

� Principle: A corrosive attack of a known amount of rock using hydrochloric acid,some carbon dioxide is produced. A sensor records the pressure increase and amicroprocesseur calculates the percentage of carbonates contained in rock samples.

� Manufacturer: � Unit:

� Certification:

CHARACTERISTICS

� Type of Output: � Range: 0-100%

� Sensitivity: 0.1 % � Alarm: NO

� Accuracy: 1 % � Repeatibility:

� Dimens.: 240x270x300 mm � Weight: 11 kg

MAINTENANCE� Calibration frequency: With pure CaCO3 as reference.

� Check & frequency: Every 5 days and before a new section check the calibrationand adjust if necessary.

OPERATING MODE� Power: � Voltage: 220V AC

� Accessories: Electronical balance. Printer.

� Operating limits: 0 -> 50 °C.

CONTRACTOR Reference:--TOTAL Experience:--

SENSORS EQUIPMENTS

DRILLING MUD GAS LABORATORY



Geological Well Report


TEXT.doc

PRESSURE MEASUREMENTS

SAMPLING SEQUENCE

MUDLOG

PORE PRESSURE

DATA TRANSFER (ASCII)


MUDLOGGING AUDITMUDLOGGING AUDIT

C O N T E N TS

AUDIT SUMMARY Sum-1

CONCLUSIONS and RECOMMENDATIONS Rec-1

EQUIPMENT and SAFETY AUDIT Eq&S

Environment§ RIG CHARACTERISTICS Eq&S-1/5§ SENSORS REVIEW Eq&S-2/5

Mudlogging§ UNIT Eq&S-3/5

§ LABORATORY 1/2 Eq&S-4/5§ LABORATORY 2/2 Eq&S-5/5

TECHNICAL and CREW AUDIT Tech

§ SENSORS accuracy Tech-1/8

§ GAS • combustible - Degaser Tech-2/8- Detector Tech-3/8- Analyser Tech-4/8

• non combustible - Detector &Analyser Tech-5/8

§ COMPUTER 1/2: Data acquisition and processing Tech-6/8§ COMPUTER 2/2: Networking and softwares Tech-7/8

§ CREW (Awareness and performance) Tech-8/8

ANNEXES: Gas flow-charts: - Degaser Ann-1- Detector Ann-2- Analyser Ann-3

ANNEXES: Nominal gas values for Detectors & Analysers§ BAKER HUGHES INTEQ (BHI Ann-4 a-b§ GEOSERVICES Ann-5 a-b§ HALLIBURTON Ann-6 a-b§ SPERRY-SUN (SSDS) Ann-7 a-b

TOOLBOX

SUBTOTAL

DIRECTION EXPLORATION GISEMENTDépartment Subsurface

SUB TOOLBOX

MODULE 2.1

MUDLOGGING AUDITD. GARDETTE

REF : DG/970606-1

PREDEFINED CHECKLISTSTAG SUGGESTED ANSWERSand ADD YOUR COMMENTS ...

June 1997

TOOLBOXmodule 2.1


I N T R O D U C T I O NS U M M A R Y

- Rigsite CONTRACTORS- Rigsite RESPONSIBILITIES- MUDLOGGING CREW: Householder- MUDLOGGING AIMS (1): scope of work, data ... what for?- MUDLOGGING AIMS (2): how?, and Conclusions- MUDLOGGING JOB PURPOSES- ML & well behavior: WASH OUT examples- ML & well behavior: FLOW-CHECK & CIRCULATION- WELLSITE GEOLOGIST JOB PURPOSES- WELLSITE GEOLOGIST AIMS- WELLSITE GEOLOGIST: JOB SPIRIT


TOOLPUSHERGEOLOGIST

CO- MANMUDLOGGING

LOGGING(WL & LWD)

DIRECTIONALDEVIATION

POSITIONINGCORING

MWD

DRILLINGMUD

CEMENTCASINGROV, ...

DRILLING&

RIGMAINTENANCE

RIGSITE CONTRACTORS


RIGSITE RESPONSIBILITIES

Rigsite

role

TOOLPUSHERCO-MANGEOLOGISTMUDLOGGING

Rigsite

position

ACQUISITION

EVALUATION

DECISION

EXECUTION


MUDLOGGING «Householder»

DATAENGINEER

MUDLOGGERSAMPLE-CATCHER

OUR TEAM

YOURBOSS?

MY BOSSYEAH!

WELLSITEGEOLOGIST

MUDLOGGINGCREW


MUDLOGGING: AIMS (1)

MONITOR & EVALUATE OIL & GAS SHOWS

CONFIRM or ADJUST FORMATION PRESSURE ESTIMATION

ESTABLISH ACCURATE & COMPREHENSIVE DOCUMENTS, REPORTS, ...

INFORM ( IN REAL TIME) PEOPLE INVOLVED IN WELL MONITORING

OF ALL PLANNED EVENTS .... or .... IN CASE OF UNFORECASTED EVENTS => ALERT

Provide Oil Companies with validated measurements /samples related togeological, drilling and mud parameters, as per Client specifications.

DATA ... WHAT FOR?

STOREPARAMETERS

DISPATCHDATA ON REQUEST

MANAGE DATA

COLLECT WELL INFORMATION

GAS

DRLG MUD

SCOPE OF WORK


MUDLOGGING: AIMS (2)

HOW?

INSTALL ALL REQUIRED SENSORSCONTROL SENSORS RELIABILITY and ACCURACY

RECORD CONTINUOUSLY ALL MEASURED PARAMETERSNOTIFY ANY EVENTS OBSERVED

PREPARE SAMPLES FOR DESCRIPTION & ANALYSISASSIST, when needed , FOR CORE RECOVERY, TESTING OPERATIONS, ...

MUDLOGGING is a HIGHLY VALUABLE SERVICEat LOW PRICE (only 2-3% of well cost: 1500-2000 USD/d)

... M ONITOR SECURE O BSERVE but should ASSISTANT for N EVER VISUALIZING & for E NSURE EVALUATING Y OURSELF RESERVOIR

but it is a ...

CONCLUSION: the MUDLOGGING ...


MUDLOGGING : JOB PURPOSES

MONITORING&

DETECTION

QUICKUNDERSTANDING

& FASTREACTING

RECORDING REPORTING

PARAMETERS EVENTS

DATAACQUISITION DOCUMENTS

WELL FOLLOW UP ...

?

... ON A ROUTINE BASIS

BS


ML & well behavior examples: WASH OUTDRILLING GEOLOGY

• Possible ORIGIN:. very abrasive formations (hd SLST, Pyrite, ...). and/or deviated wells (Drillpipe along casing)

• PHENOMENA:Abnormal friction/wear along Drill-pipe / BHAupto create a hole along pipe => Wash pipe

• Surface DETECTION in Mudlogging unit:Injection Pressure (SPP) slowly reducing to fastdropping (=> Flow-Rate may increases)

• Final Consequence => FISHING! (if not detected)• How to solve the situation?

POOH with ‘heavy slug’ inside pipesand check every stand prior breakingthe strings: then locate the WASH-OUT

• Other: TWIST-OFF, but no forewarning signs! Lost nozzles on bit (check hydraulic report)

Mudlogging crew => INFORMDrlg Supervisor => DECIDE & ACT: WOO

. formations poorly cemented, indurated, ... . and/or inappropriate drilling fluid (mud)

Mudlogging crew=> DECIDE & ACTthen ... INFORM=> Drlg Supervisor

Possible origin:

Refer to chapterSAMPLING


ML & well behavior: FLOW-CHECK & CIRCULATION

• WHEN? . after a fast DRILLING BREAK ( unexpected event)

. after breaking a core, prior POH (no slug pumped)

. to check possible swabbing, ( while pulling out at shoe depth), ...

• WHY? to check if well is still in equilibriumin static conditions; observed if anyGain or Losses ... and report rate (vol/ time)

• HOW? Stop circulating (Pumps OFF)Stop adding mud into Active sum ( transferring, mixing, diluting, ...)

• Duration : at least 15 min ... fct(depth, OH length)

Requested by . . . DRILLING SUPERVISOR

Water Oil Gas

time - +ACTIVEPITS - + - +ACTIVE

PITSACTIVE

PITS

15 min

5

0 EVENT

AIM OBSERVATION of WELL ANNULAR LEVEL AIM WELL CONTROL

• WHEN? . prior performing SBT, LOT, FIT, ... (=> drilling circulation: code F) . to check lithology at TD (=> geological circulation: code G) . for mud and/or well conditioning ( prior possible rising MW) . After a positive ‘Flow-Check’: gain ...

( circulate through Choke Manifold)• WHY? to clean out annular volume

( gas cut mud, cuttings)to homogenize mud properties (U tube)to determine coring point depth (code G)to set casing shoe depth, ...(to wait on weather, orders, contractors, ...)

• HOW? Stop drilling ... ‘Flow-Check’; then... Resume circulating (Pumps ON)

• Duration : at least ONE ‘Bottom-up’ depending on... LAG TIME / LAG STROKE

Requested by . . . DRILLING SUPERVISOR WELLSITE GEOLOGIST


WELLSITE GEOLOGIST: JOB PURPOSES

LOGGING: wireline , LWD MUDLOGGING

MWD & MUD CORING & TESTING

LITHOLOGICAL IDENTIFICATION

& CORRELATIONS(FACIES)

SAFETY: HP/HTRISK EVALUATION

RESERVOIR & FLUIDSCHARACTERIZATIONGAS & SHOWS

INTERPRETATION

DRILLING

REPORTING:MUDLOG, GWR, ...

GEOLOGICAL INTERFACE

INPUT

OUTPUT

WELL FOLLOW UP ...

... ON A ROUTINE BASIS


SAFETY FIRST(people, equipments & RIG)

WELLSITE GEOLOGIST AIMS

SAVE MONEY

ANTICIPATE

Casing depthCoring depth

Pressure regimeRISKS, ...

REACH TARGETS

OIL

GAS

WATER

FIND RESERVOIRS&

IDENTIFY FLUIDS(CONTACTS

QUANTIFY Hcb)

EVALUATE

Phi K

Sw PpPf

FOLLOWDRILLING

PROPOSAL(Casing,(Mud,...)

REACTto hazardous &

unexpected events

...


WELLSITE GEOLOGIST: Job spirit

COMPETENT

AVAILABLE 24h/day

AUTHORITYACCURATE

PROMPT TO REACT FAST TO DECIDE

CONVIVIALin any circumstances

SECURE

(IRON FIST) (VELVET GLOVE)


DATUM, SENSORS & D A T A

S U M M A R Y

- REFERENCE DEPTHS: Onshore & Offshore- Well PROFILES- Well PROJECTION: horizontal & vertical views- HORIZONTAL DRAIN NOMENCLATURE- RIGSITE SENSORS LOCATION (simplified)- DATA: real time & delayed- LAG TIME: definition & control- LAG TIME: interpretation & consequences- DRILLING SENSORS- MUD SENSORS- Technical Data Sheets: TOOLBOX module 5.2


REFERENCE DEPTHS

MSL(Annual)Mean

Sea Level

Sea Bed or

(Sea Floor)

GroundLevel

RTE / (KB)

TMDBRT(Below Rotary Table)

ZERO reference«SUB-SEA depth»

riser

RTE / KB(+)

(-)

0

TV

DB

RT

ori

gine 0

TV

DM

SL

orig

ine

TD(Terminal Depth)

WaterDepth

PILOTHOLE(+)

ONSHORE OFFSHORE

Rotary Table Elevation(Kelly Bushing)

PERMANENT DATUM


WELL PROFILES

ONSHORE OFFSHORE

TMDBRT(Below Rotary Table)

KOP(Kick Off Point)

Landingphase

PILOT HOLE

DOP(Drop Off

Point)

BU(Build Upsection)

iiJii wellSLANT

well

VERTICALwell

HORIZONTALwell/drain

E R W wellextended reach well

ULTRADEEPWELL

LAND RIG SWAMP-BARGEJACK-UP SEMISUB’

DRILLSHIP(0 - 20m)(20 - 100m)

(80 - 2000m)

GO ON THEGAME, GUY!

ROV(Remote

OperatingVehicule)

BOP’s+PGB


WELL PROJECTIONS

WELLHEAD

N

S

W E

-

+

delta X

HORIZONTAL VIEW

well profileCURRENT

DEPTH

delta

Y

Departure 2= +(deltaX) (deltaY)2

DEPARTURE atCURRENT DEPTH

AzimuthN140°

VERTICAL VIEW

TVDDEPTH

DISTANCE

PROJECTION PLANE:AZIMUTH N140°

well profile

WELLHEAD

VERTICAL SECTION at CURRENT DEPTH

ANGLE(inclinaison)

CURRENTDEPTH


HORIZONTAL DRAIN NOMENCLATURE

TMDBRT(Below Rotary Table)PILOT HOLE

VERTICALwell

WELL TRAJECTORY

TST

Layer follow-upalong azimuth drain

TST: True Stratigraphic Thickness(Reference Thickness inside drain)

Layer identificationTVD: True Vertical Depth

TVD

DrilledThicknessbetween

TOP-BTMApparentVertical

Thickness

TOP

BTM

AIM dip calculation depends on TST, Drilled Thickn. and on Apparent Vert. Thickn.


SENSORS: SIMPLIFIED RIGSITE VIEW

Pit levelTemp° INResist.INDens.IN SUCTION PIT Mixing pit

(hoopers)

mud Pumpand SPM

desanders & desilters

(to sand trap)RETURN PIT

Degaser, Dens.OUTResist.OUT, H2S

Pit level

Temp° OUTWell headWHP, CP

BOP’sCAVEH2S

WOH ondead line(=>WOB)

DRILL FLOOR(DRUM missing)

Kelly BushingRotary TableRPM, TRQ

ROP => DepthHKPos, H2S

SPP

swivel

Stand Pipe

Flowmeteron Flowline

hoose

ChokeManifold

TRIP TANK

to RIG DEGASER

Notezoological nomenclature missing:DOG HOUSE MONKEY DECKGOOSE NECK MOUSE HOLECAT WALK WIDOW MAKER! … POOR BOY !!

SAND TRAP

POSSUM BELLY&

SHALE SHAKER

Crown BlockTravelling Block

& Hook (old)=> TOP DRIVE

RESERVE PIT

H2S


DATA : REAL TIME or DELAYED?

GEOLOGICALMUDDRILLING

REAL TIMEDATA

downhole eventsvisible on surface

=> instantaneous data

DELAYED DATA

downhole events , carriedby mud, after LAG TIME

=> immediate data

Depth ROPTRQ WOBRPM SPPSPM WHP

PITS & FLOW(gain & losses)

GAS & CUTTINGS (analysis & observation)

MW data: Temp° OUT

Density OUT Resistivity OUT

DATA TYPE

ACQUISITIONMODE


LAG TIME => ELAPSED TIME (BY MUD) FROM BOTTOM TO REACH SURFACE

Note:

. if riser (offshore) => Take into account booster pump to improve FR in riser annulus

. short cycle => (Surface -> Bit) + (Bit -> surface)

. long cycle => (short cycle) + (transit time on surface: from return pit to succion pit)

. LAG CHECKS, to be performed during pipe connection (short cycle): . Calcium Carbide lag (CaC2) => Acetylene peak (C2H2) on chromato. (WBM mud only) . Crushed brick lag => First arrival easily seen on Shakers screen (reddish grained) . Rice lag => Not expensive, but not easy to check on Shakers (milky-whitish-light tan) . Eventually Mica => in case of LWD (warning: possible effect on WL response)

L a g T im e A n n u lar Vo lum eF l o w R a t e

m in= ⇒

Lag Stroke Annular VolumeStroke vol eff

stroke nb= ⇒( ) * (Pump .)

with AV = (OH vol + IDCSG vol) - (OD IRON vol in hole) FR = (Stroke vol) * (Pump efficiency %) * (SPM)


LT Interpretation & Consequences

LTobserved > LTtheoritical LTobserved < LTtheoritical

Cuttings arrive « late» regarding to ROPHole Enlarged=> CAVINGS

reducing hole cleaning efficiencyShale shape & size (poping, propeller,...)

Cuttings arrive «early» regarding to ROPTight Hole

=> STICKY HOLEShale hydration (Monmorillonite)

in both casesDRILLING PROBLEMS

INVIEW ... as delta P

=> Carefully check lithologyon all sieves

BUT, IT MAY ALSO BE DUE TO:- Wrong Pump efficiency (Toolpusher data) and/or false adjustment (Data Engineer)- Incomplete or erroneous pipes dimensions (OD & ID) and volumes, ...


DRILLING SENSORS SENSORS

WOH Weight On Hook ................................... Dead line or Hook Load=> WOB Weight On Bit computed from Archimees law

(or buoyancy effect)

SPP Stand Pipe Pressure ....................... Stand pipe Manifold

CP Casing Pressure ..................................... Diverter Manifold and WHP Well Head Pressure

ROP Rate Of Penetration & Depth ... Drawwork axleHKPos Hook Position / Travelling Block

RPM Revolution or ........................................... Rotary Table Rotation Per Minute or Top Drive

SPM Strokes Per Minute .................................... Pump piston

PRESSURE TRANSDUCERSmeasuring strainon force triangle

(klbs or tons)

measuring variationsof steel diaphragm

(psi or bars)measuring capacitanceof detecting diaphragm

(psi or bar)

PROXIMITY SWITCHmeasuring crown sensor

counter(logic condition: 0 or 1)

HYDRAULIC

ELECTRIC

Hydraulic system

TRQ Torque ................rotary table (RT)

Electrical lineCURRENT TRANSDUCER

HALL effect: measuring electrical fieldflowing in motor cable (Amp)

items mounting on

MEASUREMENT

method principle


MUD SENSORS SENSORS

Flow Rate .......................................................flow line

Potentiometer (floater)

Potentiometer (paddle)

Platinium resistance

HYDRAULIC

ELECTRIC

items mounting on

MEASUREMENT

method principle

Echo pulse (ultrasonic) ACOUSTIC above mud tank

PITS Volume ..............................

in mud tank

IN ........suction pitTEMP° ................................... OUT .......possum belly

IN ........suction pitCOND. / RESIST................... OUT .......possum belly

Toroidal induction coil

Differential pressure

Gamma ray absorption (NUCLEAR)

IN ........suction pit

OUT .....gas trapMud Weight / DENSITY..... IN ....... stand pipe OUT .......possum belly


SENSORS MEASUREMENT & SPECIFICATIONP

R I

N C

I P

L E

WOH / WOBSPP

CP / WHPTRQ (diaphragm)

DENS. / MWTRQ (Hall effect)

PITS Volume(ultrasonic)

(DENS. / MW )

MUD &DRILLINGsensors

HYDRAULIC ELECTRIC ACOUSTIC NUCLEARM E T H O D

RADIOACTIVE

RESISTIVITY

Pressure

CurrentTRANSDUCER

T

10PROXIMITY switch

(counter)

POTENTIOMETER

ULTRASONIC

ROP / DepthHKPos

RPMSPM

COND. / RESIST.TEMP°

PITS Vol. (floaters)FR (paddle)


G A S : DEFINITION & MEASUREMENT S U M M A R Y (1/2)DEFINITION

- GAS SAMPLING HISTORY- GAS TYPES RECORDED- GAS SHOWS: Definition

Origin … or sourcesSwab & SurgeGas Events vs … warning!Main ranges

- MUD DEGASSING ON SURFACE

MEASUREMENT- GAS MEASUREMENT CHAIN- DEGASSER TYPES- GAS LINES:efficiency

main & back-up- DETECTOR:principles- DETECTORS for ACID GASES- H2S: HYDROGEN SULPHIDE => the Killer gas- CHROMATOGRAPHY: problems to solve

principles & efficiency- FID: total gas & chromatography- TCD: total gas & chromatography


G A S : INTERPRETATION

S U M M A R Y (2/2)

INTERPRETATION

- LOG/LOG DIAGRAM (SNPA)

- PIXLER PLOT (BAROID)

- TRIANGLE METHOD (GEOSERVICES)

- Wh, Bh, Ch RATIOS (EXLOG)

- LIGHT HYDROCARBON RATIOS: interpretation

- RATIOS ACCURACY

- GAS NORMALISATION: AIM

- GAS NORMALISATION: magic! or bluff?


GAS Sampling: HISTORY

< 1930’s > 1930’s (1980’s) -> PRESENT FUTURE

«rule of thumb method»

Based on . shows estimation . depth levels uncertainty

oily appearance, petroleum odor, ...Qualitative method: => Identification by. centrifugation (oil). ignition (gases)

=> no quantitative evaluation

«Mudlogging Blooming»

Lagged depths with associated lithology (off-line Cabin)

=>Degaser calibration: Steam Still analysis (VMS 1950’s, constant vol)

=>«Hot Wire» systems:(Thermal Conductivity Detector)(Catalytic Combustion Detector).total gas detection and.components identification

Combustibles: C1...C4, H2 .Other gases: H2S,CO2,N2,

«R & D»

Micro-indiceson surface: . detection. analysis

(geochemistry)

borehole &fluid travel

contamination?

Downholemeasurements. in-situ data(?)

&. horiz. wells(geosteering)

« Fast & Accurate ...»

Integrated services

(on-line Unit)

=> Degasser efficiencyimprovement

(constant flow & vol)

=> FID system:(Flame Ionisation Detector)

from > 5 min to < 1 minonly for

combustible gases(C1 ... C5)

and optional «hot wire»for other gases


GAS TYPES RECORDED

HYDROCARBON Gas NON-HYDROCARBON Gas

N2 NitrogeneH2 HydrogenHe ? Helium(Rn Radon)

Inert gas

H2S Hydrogen SulfidCO2 Carbon Dioxide

Polar gas or «acid gas»

C1 MethaneC2 EthaneC3 PropaneiC4 iso -ButanenC4 normal-ButaneiC5 iso -PentanenC5 normal- Pentane(C6 Hexanes )

alkanes series(CnH2n+2)

DRY

HUMID

POLAR

INERT


GAS SHOWS: definitions

GAS SHOWS on surface is reflecting a combination of:

LIBERATED Gas

from formationWHILE drilling

by breaking the

rock pore space

PRODUCED Gas

from formationAFTER drillingConnection Gas

(air slug)Swab Gas / LCT

Trip Gas, ...=> short duration

CONTAMINATED Gas

from other sourcesthan formation itself

asmud additives

(chemical reacting), bit, turbine effects, ...

RECYCLED Gas

Remaining in themud (whatever origin),then recirculating

downholedue to

imperfect degassingon surface

minimun gas value(almost constant):

BACKGROUND Gas (BKG)

FORMATIONGas (FG)


ORIGIN of GAS SHOWS

. GAS from Gas

. GAS from Oil

. GAS from Water ( Dissolved)

GAS from CUTTINGS

GAS from SHALE(cavings)

GAS from Fault

GAS RECORDED on surface

NON DRILLED GASNON DRILLED GASRECYCLED(R)PRODUCED (P)

&CONTAMINATED(C)

DRILLED GASDRILLED GASLIBERATED (L)

Surface mixingNew additives

Downhole chemicalreactions

...

affecting

BACKGROUND GASL

L

L

P

P

P

Other Produced GAS: Pipe Connection, Swabbing/LCT, Trip Gas, ...

R

C


SWAB & SURGEPOOH

SWAB & SURGEfunction of:

- pipe velocity- annulus diameter (hole, pipes)- mud rheology (MW, Visc)

imbalance between mud pressure and formation fluid pressureand possible KICK

finalCONSEQUENCE

on both cases

EMW

RIH

delta Pmud LOSSES

delta Pmud GAINS

suctioninjection


SAFETY: GAS EVENTS … WARNING!. . . based on gas observations

when circulation stopped

INFORM and Precise :• Change to new baseline (based on MW)• Lithology (Phi-K) associated to peaks• Gas observed= BKG + ‘Gas event’ origin

Phenomena emphasized IF:• cumulative gas events• recycled gas• rig degasser OFF(‘Poor Boy’)

Initi

al B

asel

ine

Peak heights increase=> back to baselinebetween each gas event

(peaks becoming wider)

BKG increase=> back to new baseline

- shifted between each gas event

- increased between each gas event

nil

traces

ASYM

MET

RIC

peak

sSY

MM

ETRI

CAL p

eaks

Qualitative ALERTQualitative ALERT method method

GAS EVENTS reflect

Pressure Regime and/orFormation fluid content

∆P> 0

∆P< 0

∆P≈0

IDENTIFY Origin of gas observed INDICATORS (possible gas origin)

- PIPE CONNECTIONS- SWAB GAS TEST- LCT (Long Connection Test)- TRIP GAS- BACKGROUND GAS (BKG)

Miscell: surveyfalse connectionscarbide (Lag-Time check)

FORMATION Gas

Total Gas (TG)

1 std

BKG

BKG


GAS SHOWS: scale range

-50 0 50 100delta P (bars) influence

too late!-> Life jacket

0

20

40

60

80

100

Delta P > 0

Delta P < 0

Spectacular => Muster point

Exceptional to Dramatic

Risky to Hasardous

Daring to Lucky

Questionable

Delightful to Interesting

Promising

Nice (or Lovely)

Fair to Slightly

Weak to Poor

Disappointing

Nil

=> Blow-out => Kick

?

Gas (%)observed


MUD DEGASSING on surface

DEGASSER

Drill String

Bell Nipple

MUD PIT(s)

ShaleShakers

GASBUBBLES

andCUTTINGS

GAS LINE to Unit

GasTrap

PossumBelly

loss of free gas

Flow line

loss of free gas(=> recycled in part)

AIRinlet

(Air + Gas)

Decanting tube(water)


GAS MEASUREMENT CHAIN

CARRIER OBSERVEREXTRACTOR ANALYSER

1 2 3 4

DEGASSER GAS LINE

TOTAL GASdetection

&H2S, CO2, ...

(FID burner with H2 flowand/or TCD based onWheatstone bridge)

CALIBRATION ?SENSITIVITY ?

CHROMATOGRAPHYcombustible gas

(FID, TCD)non-combustible gas

(TCD)

CALIBRATIONS ?ACCURACY ?

REPEATABILITY ?

«Gas + Air»mixture

toMudlogging

cabin(mini 2 gas lines)

PLUGGING ?LEAKING ?

Located in possum belly:(shale shaker header box)

either immersed: mud levelnon-constant & agitatoror degassing at constantmud volume & flow via

a suction probe

EFFICIENCY ?PLUGGING ?

gaselution YesNo

DETECTORS


DEGASSER TYPES

GAS TRAPEFFICIENCY (%)

(50) -

(100) -

SUCTION PROBEConstant mud flow &

Constant volumeQantitative Gas

Trap Measurement

Constantmud flow

BASICVariable mud flow

STEAM STILLConstant mud volume

(reference degasser )

ContinuousDiscontinuousGAS EXTRACTING

MODE

EFFICIENCY = fct ( degasser location, chamber volume vs degassing time, mud type, ...)

THE LONGER THE MUDUNDER AGITATOR,

THE GREATER THE EFFICIENCY

immersedtypes


DEGASSER

DETECTOR

DEGASSER

DETECTOR

GAS LINES EFFICIENCYDEGASSER DETECTOR

NEITHER TOO LONG ...(C3+ analysis)

LENGTH

NEITHER TOO FAST ... ... NOR TOO SLOW

FLOW RATE

APPROPRIATE GAS LINES LENGTH => TRANSIT TIME TO UNIT < 100 sec

depending on «AIR + GAS» mixture flow rate through Monoflexand on motor pump suction efficiency

... NOR TOO SHORT(safety reasons)


GAS LINES: main & back-up

AT LEAST, 2 INDEPENDANT GAS LINES per DEGASSER

MAIN GAS LINE

SPARE GAS LINE

GAS LINE


DETECTORS: principles TOTAL GAS

CONTINUOUS PROCESSfor

UNDIFFERENTIATED GASES

QUANTITATIVE measure

CHROMATOGRAPHY

BATCH PROCESSfor

INDIVIDUAL COMPONENTS

QUALITATIVE measure

CCDCATALYTIC COMBUSTION

(NO LONG EXISTS)

Low threshold detection(100ppm)

Poor detection fornon-combustible

C6+ cause breakdown offilament (Platinum)

High T° filament (800°C)

ADVANTAGES

+

DISADVANTAGES

-

FIDFLAME IONISATION

Very low threshold(5-20ppm)

High repeatability

Accurate only forcombustible gases

Need continuousH2 supply

TCDTHERMAL CONDUCTIVITY

No combustionDetection of

non-combustible gases

High threshold (>500ppm)

Very high sensitivity to H2Low sensitivity to Hcb

other than Methane


ACID GASES DETECTORS

Infra-Red ABSORPTION principle

CO2 ATTENUATES the «IR» RADIATIONEMITTED BY THE SOURCE (IR beam)

Voltage proportional to CO2 content=> accuracy: 1000 ppm (0.1%)

warning: CO2 highly absorbed by basicwater contained in WBM and also

in OBM (water phase)

CO2

1- SEMICONDUCTOR principleH2S REDUCES THE METAL OXIDE COATING

TO METALLIC SULPHIDESConductivity proportional to H2S content

=> accuracy: 1 ppm (0.0001%)warning: humidity reduces sensor sensibility

2- DELPHIAN MUD DUCKIDENTIFY SOLUBLE SULPHIDES IN THE MUD

related to mud pH (>10) & temperaturewarning: operating ONLY in water base mud

H2S<= QUANTITATIVE RESULTS =>

DRAEGER hand-held (QUALITATIVE RESULTS)

graduated tube filled withsilicagel impregnatedwith LEAD ACETATE

... turning to DARK-BROWN( +/- 10 ppm)

graduated tube filled withHYDRAZINE

(N2H4)... turning to BLUE-PURPLE

( +/- 10 %)

** DETECTOR AVAILABLE FOR ALL GASES (various reactants) with various SENSITIVITY RANGES **

CO2 H2S


Hydrogen Sulfide (H2S) SAFETY

odourROTTEN EGGS

0.1 1000

0.001 10

0.01 100

0.05 500

0.07 700

0.02 200

0.002 20

H 2S

conc

entr

atio

n

H2S effects

% ppm

’safe’for 8 hours

STINGS EYES & THROATwithin 3-5 min

HEADACHE

KILL SMELL

DIZZINESS

UNCONSCIOUSNESS

breathing ceases after 30 min

DEATH => 15 minDEATH => 1 min

H2SACID GAS

COLORLESS DEADLY GAS

FLAMMABLE ( blue flame ) sg=1.18 (heavier than air)Highly CORROSIVE to certain metals

permanent cerebral injury

=> prompt artificial respiration

THETHE KILLER GASKILLER GAS

ROTTEN EGGSodour


CHROMATOGRAPHY: problems to solve

Question: HOW TO BE FAST AND ACCURATE FORSEPARATING GASEOUS COMPONENTS MIXTURE (AT A MAXIMUM MUD FLOW)

and forAVOIDING CONTAMINATION BY SUCCESSIVE & REPEATING MEASURES ?

Heu!it depends ...

IF THERE IS WIND,IF IT’S HOT ...

hey, guys!

SAMPLING RATE

(TEMPERATURE& PRESSURE)

PROCESS ACCURACY

(COLUMNS and/orCAPILLARY TUBES)

Answer: yes, absolutely right, Mr O’NURB,IT DEPENDS ON ANALYSIS SYSTEMEFFICIENCY ... mainly BASED ON ...

andon


CHROMATOGRAPHY: principles & efficiency

=> DIFFERENTIAL DISTRIBUTIONS OF THESAMPLE COMPONENTS BETWEEN 2 PHASES:

ONE STATIONARYsolid phase

asSILICAGEL,

SQUALANE, ...packing (coatingfilm thickness)

ONE MOBILEliquid phase

withGAS SAMPLE+CARRIER

(Air, He)percolating through

or over the solid phase

stainlessor

aluminiummade

COLUMNS

Length: 6-20 ftID: 0.125 - 0.25 inch

CAPILLARY TUBES

Length > 300 ftID < 0.03 inch

=> bent or coiledfor compactness

TEMPERATURE & PRESSURE EFFECTS

Temp° & Press. Temp° & Press.

QUICK and POOR ELUTION

C1C2 C3 C4 C 5

SLOW and GOOD ELUTION

C1 C 2 C 3 C 4 C 5

1 2

3


total gas & chromatography : FID

ionisationchamberiC5

C1

C2nC4iC4

C3

iC5nC5peak

area

BASELINERetentiontime for C1

response (mV)

timeanalysis

# 300 sec

SCHEMATIC CHROMATOGRAM(after Geoservices)

(*) Backflush starts only when compounds of interest have passed through the PRECUT column (depending on selection of cycles)

Gas line

manualinjection

TOTAL GAS detection line

GAS «in»(mixture)

wasteeffluent

H2Air

C1

C2C5 C3

C4Precutelution

Main elution(separation)

backflush(*)

P2 > P1

P1

signal

purge speed up

C1C2 C5C3

C4C6+


total gas & chromatography : TCD

TOTAL GAS detection line

Gas line

manualinjection

GAS «in»(mixture)

SI(slow)

2 columns withdifferent characteristics

SQ(fast)

C1C2 C5C3

C4C6+ C1

C2C3C4H2

thermalconductivity

chamber

WHEATSTONEBRIDGE

SQ column(SQUALANE)

SCHEMATIC ANALYSIS CHROMATOGRAM(after Geoservices)

deflection

time(short cycle)

(long cycle)# 120 sec

# 120 sec# 250sec

C1

C2 C3iC4

H2nC4

composite peak(H2/C1)

SI column(SILICAGEL)

CO

MM

UT

AT

ION

BASELINE BASELINE

peaklength

RTC1

C1C2

C3C4 H2

commutation valve

signal

wasteeffluent

Air


LOG/LOG Diagram (SNPA)

S.N.P.A. (1950’s), now ELF

developed over Lacq gas & oil field (France)

gas ratios used:(C2/C1) x 103

(C3/C1) x 103

… based on production gas data (DST)

1 10 100 1000 10000 1000001

10

100

1000

10000

100000

(C2/C1)x103

(C3/C1)x103

3

4

1

2

4

3

2

1 DRY GAS dissolved in water

GAS with CONDENSATE

GAS with OIL

... grading to TARS & BITUMEN


PIXLER PLOT (Baroid)

PIXLER (1969) modified FERRIE (1981)

gas ratios used: C1/C2 C1/C3 C1/(iC4+nC4) C1/(iC5+nC5)

=> LINES ARE DRAWN BY CONNECTING INDIVIDUAL RATIOS

Comments:- Plot basically based on C1/C2 ratio (see ratios accuracy)- Steep slopes are usually a «tight reservoir» criteria- Negative slope might be a «water zone»

Texas and Louisiana experiences

Non-productive Gas

Productive Gas

Non-productive Oil

Productive Oil

(wet gas)

(dry gas)

(volatile oil)

(heavy oil)

(tars, bitumen)

(no free gas)

C1/C2 C1/C3 C1/C4+ C1/C5+

… based on productiongas data (DST)


TRIANGLE METHOD (Geoservices)

so-called «POTATO PLOT» (early 1970’s)

developed in Middle-East, extended to Europe & Africa

gas ratios used:C2 / (C1+ C2+C3+C4+C5)C3 / (C1+ C2+C3+C4+C5)C4 / (C1+ C2+C3+C4+C5)

1 - TRIANGLE (size & orientation) defines FLUID TYPE:

2 - HOMOTHETIC CENTER defines PRODUCTIVE ZONES:by drawing 3 lines from «initial plot apexes (A,B,C)»

to «sample ratios apexes (a, b, c)»IF HOMOTHETIC POINT IS INSIDE «brown POTATO»

C2/C(1-5)

C 4/C

(1-5

)

C3 /C

(1-5)

A

B Cupward

«a» apex

downward

GAS

OIL

drywet

high GOR:Condensate

low GOR:Tars

a

b c

a

c b

… based on productiongas data (DST)


Wh, Bh and Ch ratios (EXLOG)EXLOG (1985), now BHI

gas ratios used … based on drilling:

1 - WETNESS

2 - BALANCE

3 - CHARACTER

W h C C C CC C C C C

= + + ++ + + +

( )( )

*2 3 4 5

1 2 3 4 51 0 0

B hC C

C C C= +

+ +( )

( )1 2

3 4 5

C h C CC

= +( )4 5

3

(*) N/A => incompatible

Wh < 0.5 0.5 - 17.5 17.5 - 40 > 40

Fluid DRY GAS GAS OIL Residual Oil

Bh Fluid

> 100 dry Gas

> Wh GAS

Bh Fluid

>>Wh coal bed

> Wh GAS

= Wh lt G / Cond

Bh Fluid

> Wh coal-N/A*

< Wh OIL

<<Wh heavy OIL

Bh Fluid

> Wh N/A*

heavy to<< Wh residual OIL

1001 10 0 1 2 3

VERY LIGHTDRY GAS

LIGHT GAS

GAS &LIGHT OIL

COAL-BEDEFFECT

MEDIUMGRAVITY OIL

RESIDUALOIL

Wh ratio

Bh ratioCh ratio

0.54017.5

< 0.5 GAS or COAL COAL or N/A* Ch > 0.5 N/A* OIL

CONT

INUO

US PL

OTTIN

G


LIGHT HYDROCARBONS ratios INTERPRETATION

1001 10 0 1 2 3VERY LIGHT

DRY GAS

LIGHT GAS

GAS &LIGHT OIL

COAL-BEDEFFECT

MEDIUMGRAVITY OIL

RESIDUALOIL

Wh ratioBh ratio

Ch ratio

Non-productive Gas

Productive Gas

Non-productive Oil

Productive Oil

1 10 100 1000 10000 1000001

10

100

1000

10000

100000

(C2/C1)x103

(C3/C1)x103

C2/C(1-5)

C 4/C

(1-5

)

C3 /C

(1-5)

WHICH PLOTto trust ?

NONE or ALL !

NO MIRACLE METHOD

WHY ?

... based onRATIOS ACCURACY

CALIBRATED IN SPECIFIC AREAS


RATIOS ACCURACYDEPEND ON . . .

- Fluids pre-identification & characteristics - Detection & Monitoring HP wells- Geosteering (warning: recycling?) and ... GAS DATA RELIABILITY!

SELECTED GAS RATIOS REMAIN HIGHLY HELPFUL for:

NEVER FORGET «ROP vs Cycle time analysis vs Reservoir thickness»

DEGASSER: location efficiency?

GAS LINE: Flow pressure pre-elution? Ambiant Temp° (Atmosph. Press.) DETECTORS: «windows» calibration? ... for each component sensitivity? thus, better use «C1+C2» overlap? (instead of «C2/C1» or «C1/C2» ratios)

... GAS MEASUREMENT CHAIN

Rate Of Penetration Drilling modes (rotary, sliding) Mud Flow Rate Bit types Mud weight Mud type (WBM, OBM, ...)

Help for GAS NORMALISATION

... DRILLING PARAMETERS


GAS NORMALISATION: AIM

It normally ONLY represents the LIBERATED GAS content per volume of rock drilled warning IF: GAS RECYCLED (from surace) IF: GAS CONTAMINATION ( from mud, bit, ...) => BACKGROUND GAS

IF: GAS PRODUCED ( from Open Hole)

SEVERE LIMITATIONS: sources of gas, Temperature & Pressure effectson mud gas composition while gas migration , ...

CGI

VGN

SPI

CGS

Corrected Gas Index

Volumetric Gas Normalisation

Surface Potential Index

Calculated Gas Saturation

attempts forGAS

NORMALISATION

A I M :TO ELIMINATE CHANGES IN DRILLING PARAMETERS AND IN MEASURING CONDITIONS BASED ON TOTAL GAS Measurement (TG)

APPROACH remains empirical (surface cond.) and/or approximate (downhole cond.)


GAS NORMALISATION: magic!CGI (Corrected Gas Index)

CGI Gas FRHV ft ROP ft

(%) (%)* (bbl / min)(bbl / ) * ( / min)

=

approximate normalisation for changesof flow rate (FR), of hole volume (HV) and of ROP

(equivalent to SPI)

Recommended DEGASSERS: steam still (Cst volume) and/or suction probe (Cst flow)

SPI (Surface Potential Index)

SPI Gas FR l ROP minches

= 197100 2. * (%) * ( / min) * (min/ )

* (BS )( )

SPI estimates, at SURFACE CONDITIONS,the m3 of gas per m3 of rock

(dimensionless value)THE MOST REALISTIC INDEX

FOR FAST & EASY COMPARISONS

BS: bit size

CGS (Calculated Gas Saturation)

CGS SPIPaPu

TuTa

Zkg cm

kg cm

K

K= °

°100

2

2* * * *

( / )

( / )

( )

( )

Pa: ambiant surface pressure=1 Ta: ambiant surf. temp° (AMST)Pu: estimated fluid pressure Tu: estimated bottom temp (BHT)Z: deviation coefficient from Ideal Gas Law («gas compressibility»)

CGS estimates, at BOTTOM CONDITIONS,the m3 of gas per m3 of rock (dimensionless value)

Gas saturation affected bydrilling conditions (flushing)

VGN (Volumetric Gas Normalisation)

VGN GasROPROP

HVHV

FRFR E

normal

actual

normal

actual

actual

normal(%) (%) * * * *= 1

(ROP in m/hr HV in bbl/ft E=degasser efficiency in decimal %)

«normal» conditions derived froma specific field, basin or region (!)

Similar to CGI, more rigorousbut incomprehensible!

MAGIC!

tremendously


S U M M A R Y (1/2)

GENERALITIESConceptsPressure Regime statusHYDROSTATIC PressureOVERBURDEN: DefinitionOVERBURDEN: CalculationOVERBURDEN: EvaluationPORE Pressure: DefinitionOverburden and Pore PressureCOMPACTION: Normal & AbnormalLUCKY & UNLUCKY: examples

FORMATION PRESSUREAcquisitionIndicatorsEvaluationSwab Gas Test & LCTDrilling pressure evolution‘ROP’ normalized … storyAdvanced ‘ d ’ exp ./.

Generality & Formation PRESSURES


S U M M A R Y (2/2)

FORMATION PRESSURE (suite)Normal Compaction Trend ‘dCn’Rock bit types vs ROP curve vs ’d’ expCompaction vs Drilling parametersCompaction vs LithologyCompaction Trend Observed ’dCo’Shale Pore Pressure computed: Eaton methodPore Pressure: Eaton formula (dC, ∆tcl, Rcl) and OverlaysEATON Overlays: isodensity (EMW)’dCo’ OVERLAYS example: Excel worksheetFracturation pressure evaluation

WELL PRESSURE MEASUREMENTSTHEORETICAL TESTS: CSG, SBT, LOT, FIT

(Casing, Shoe Bond Test, Leak Off Test, Formation Integrity Test)PRESSURE RECORDING PLOTEquivalent Mud Weight (EMW)CHARACTERISTIC PROFILESANALYSES & INTERPRETATIONS

Formation & Well PRESSURES


PRESSURE CONCEPTS HYDROSTATIC

pressure OVERBURDEN

pressure PORE

pressure

beurk!

H2O Matrix+

Fluidinto pores

Fluidin pore


PRESSURE REGIME STATUS

ABNORMALpressureHYDROSTATIC

LITHOSTATICpressure

GEOSTATICSUBNORMALpressure

0 200 400 600 800 1000

0

1000

2000

3000

4000

5000

0 2000 4000 6000 8000 10000 12000 14000

0

2500

5000

7500

10000

12500

15000

De

pth

(m

ete

rs)

De

pth

(fe

et)

Pressure (psi)

Pressure (kg/cm2)

Eq.Dens= 2.31 g/cc (1 psi/ft)

Eq.Dens = 1.00 g/cc (0.433 psi/ft)

Eq.Dens= 1.08 g/cc (0.468 psi/ft)


HYDROSTATIC PRESSURE Pressure exerted by a static fluid at a given point in a column

MW g/cm 3

TVD meter HP = 1850 psi

theoreticallyPh = (d . h) / 10

practicallyHP = (MW x TVD) x 1.422

1000m TVDmud

weight: 1.30g/cm3

TMDh

waterdensity: 1.00g/cm3

0 m

1000m

1300m

Pressure depends on vertical height (1) and on fluid density (2)

Note: 130 kg/cm2 = 1850 psi Ph = 130 kg/cm2

d g/cm 3

h meter(1)

(2)

FLUID


OVERBURDEN PRESSUREOBG Pressure exerted by the total weight of overlying sediments

(sea water + matrix + fluids into porous medium)

EMW

Cumulative Geostatic pressure

( ) i

n

iii

iOBG ZZ

ZS ρ**

1

11∑

=−−=

( )Z Z erval usually m TVDi i− = ≈− 1 50int

( )ρi average density litho y

along erval

= ∀ log

int

SOBG expressed in EMW TVDTVD

EMW

cumulative

SOBG

air gap

ρi

Zi

Zi - 1 cumulative

SOBG

sea water


OVERBURDEN CALCULATION

Air gap

Sea water

Litho 1

Litho 2

0m RTE

25m AMSL

125m Sea bed

pb= 0

pb= 1.03

pb= 1.65

S1= (0 x 25) / 25 = 0.000 EMW

S2= [(0 x 25) + (100 x 1.03)] / 125 = 0.824 EMW

S3= [(0 x 25) + (100 x 1.03) + (175 x 1.65) ] / 300 = 1.306 EMW

S4= [(0 x 25) + (100 x 1.03) + (175 x 1.65) + (150 x 1.75)] / 450 = 1.454 EMW

300m Unit 1

pb= 1.75

450m Unit 2

and so on ...


OVERBURDEN EVALUATIONBULK DENSITY EVALUATION

directly from DENSITY log:average value along constant interval => NOT ACCURATE in case ofheterogeneous formations

OVERBURDEN EVALUATION• known regionally, ie from logs ( ∆t )

• unknown (ie exploration: wildcat) => rough approximation:

=> parabolic equation

with

in feet A B Csoft 0.01304 -0.017314 1.4335hard 0.01447 -0.018350 1.4846

in meters A B Csoft 0.01304 -0.014215 1.2462hard 0.01447 -0.014912 1.2870

=> or regional equation/parameters

( ) i

n

iii

iOBG ZZ

ZS ρ**1

11∑

=−−=

( ) CZBZAS TVDBRTTVDBRTOBG ++= ln*ln* 2

derived from SONIC log:

Sonic velocity (µsec/ft), computedwhatever formations: AGIP formula

• If SOFT form. ( > 70 µsec/ft)

• If HARD form. ( < 70 µsec/ft)

( )( )200

50*11.275.2

+∆−∆−=

tt

bρ

8928.3

tb

∆−=ρ

( )( )

( ) 3.28*ZZ1000*TTI

? t1ii

msecµsec/ft

−−=

50m)Z(Zinterval:note 1ii ≈− −


PORE PRESSURE Po Pressure exerted by fluids density into pore space

Po

SUBNORMAL

Po < PhNORMAL

Po = PhABNORMAL

Po > Ph

- for SHALE => Po corresponds to Pp (d’exp, Sigmalog) - for RESERVOIR => Po corresponds to Pf (formation testers)

EQUILIBRIUM GAINSLOSSES


OVERBURDEN and Pore Pressure

PorePressure

effectiveStressOVERBURDEN = + PPS += σ (TERZAGHI law)

σPP

Pressuresupported

onlyby matrix

Pressuresupported

by FLUIDS and MATRIX

Pore Fluid

pressure

PRESSURE

S

DEPT

H


COMPACTION

pore

pore

pore

pore

... ONLYBY

GRAIN TO GRAIN CONTACT

... BY GRAIN CONTACT AND

... BY PORE FLUIDS

NORMAL

He-he!

WEIGHTTRANSMITTED

...

Oooh

ABNORMAL


LUCKY and UNLUCKY ?(NORMAL and ABNORMAL PRESSURES)

weight

H20H20

H20H20

sponge+

H20

weight

NORMAL COMPACTION UNDERCOMPACTION <=> OVERPRESSURE

plastic bagsponge+ H2O

weight

weight

H20

H2O H 2O

H 2O KICK


Formation Pressure ACQUISITION1 - CONTRACTORS INVOLVED vs DATA MODES

REAL TIME DRILLING POST DRILLING

RECORDING

MUD LOGGINGCREW

controlled (DST)uncontrolled (FFT)

On SURFACE

DOWNHOLE(transmitted to surface)

ACQUISITION

LOGGING WHILE DRILLINGCREW

andWIRELINE LOGGING

CREW

DATA


Formation Pressure INDICATORS2 - DATA INVOLVED and RESULTS

RESULTSTHROUGH

GASDRILLINGCUTTINGSWell Temp°NUCLEARELECTRICACOUSTIC

BKG, LCT, SwG, PCG, Ratio, …ROP, WOB, Bit type, TRQ, DragShape, Size, Density (shale)Thermal gradient: (T°IN, T°OUT)

nonenonenone

noneROP, CAL, Rotary/Sliding modes

noneBHT, Mud T°, Tool T°GR, Density (RhobCL), Neutron (PhiNCL)Resistivity (RCL)SONIC Transit Time (deltaTCL)

PARAMETERS

COMPACTION TREND SOBGPORE PRESSURE(PP) Psh, Pf ’d’ exp, Sigmalog, Form. testers

Empirical formula or laws Direct physical measurements


Formation Pressure EVALUATION3 - DATA RESPONSES versus SHALE POROSITY INCREASE EFFECTS

GAS BKG PCG LCTDRILLING ROP WOB TRQCUTTINGS Cavings Size ShapeWell Temp° Thermal gradientNUCLEAR RHObCL PHINCLELECTRIC ResCLACOUSTIC DeltaTCL

NORMAL ABNORMAL

WHOLE CRITERIA MAY or MAY NOT REACTand IF ONLY 1 => ALERT

(diversity)


Swab Gas Test & Long Connection Test

AIM ANTICIPATE the ARRIVAL OF the TRANSITION ZONE with the lowest MW

PC

PC

1 std (Top Drive)1 single (Kelly)

time

Hook height

SPMSwGT• Stop drilling• Stop circulating• ‘Off Bottom’ 3-5mswabbing time < 1min• Resume circulation• Back to drillingTotal DURATION: 5-10min

PSWB << PFORM < PECD

PC

PCtime

Hook height

SPM LCT• Stop drilling• ‘Off Bottom’ 2-3m• Circulating ~10min• Stop circulating LCT time ~10min• Resume circul’ ~5min• Back to drillingTotal DURATION <30min

PLCT < PFORM < PECD

Better ’PFORM ’ follow-up with LCT than SwGT (PSWAB < PLCT)PROCEDURE

Mudlogging crew records gas on surface(and checks associated lithology),

then informs WSG and Co-Man for actions:

• Keep on drilling … to next gas test• Increase MW step by step (5 points= 0.05sg)• Logging & Set casing (depending on LOT, FIT)

FormGBKG

SwG

TG laggedFormG

BKG

LCT

TG lagged

SwG


z

DRILLING PRESSURE EVOLUTIONDE

PTH

PRESSURE (EMW)

OVERBURDENFRACMW

Hydrostatic Press.

PP ECD

2

3

43

5 5

1too early (?) for- setting Casing- rising MW(possible LOSSES)

too late (?) forrising MW => KICK(if porous reservoir)

PP = MW, but still < ECDUnsafe drilling … => well in equilibrium (in static conditions)

ECD > PFRAC ( or ≥ PLOT)=> LOSSES(slow pump rate: reduce ECD and pump LCM)

2

1

4• drilling conditions => LOSSES (ECD > PFRAC)• static conditions (PP > MW) => GAIN to KICK… depending on permeability

THE WORST SITUATION!

What to do?


’ROP’ NORMALIZED … STORY!

• BINGHAM (1964, Gulf coast): relationships between LITHOLOGY and DRILLING PARAMETERS

’d’ exponent empirical formula

=

BS inches

WOB lbsK

RPMROP hrft

)(

)(.)/(

BSWOBRPM

ROP

inches

lbs

*

hrft

d

* )(

* )(

10

)/(

10

6

''

1012log60log

=

• JORDEN & SHIRLEY (1966) solved this equation for a constant lithology (K=1 for shale)

with d = compaction exponent (=> ‘ d ’ exp) and K = lithological constant

Any decrease in ‘ d ’ exp(expressed in EMW)

when drilling a shaly sequenceis a function of the degree

of undercompaction

• REHM & McCLENDON (1971): ‘ d ’ exp corrected for mud weight (∆P function of Shale pore presure)

ECDPhydro

EMW

EMWddc)(

)('.''' =Parameters not taken into account:

- ∆P, not known accurately - bit type and bit wear- mud hydraulics when drilling with jetting (unconsolidated Clay)

Why only forSHALE?

)*(exp*@ ZCstsurfacedepthCLAY Z −=φφ

RUBEY & HUBBERT law (1959)

φ

Ζ

CLST

SST

easy,Man?

Yeah!

Fair enough?NO !

d


UPGRADED or ADVANCED ’d ’ exp

How to restitute an almost true normalized ROP ?

)(

)(

)(

)(

)(min/ **026469.0

log

**3048.0log

EMW

EMW

inches

T

m

p

c ECDPhRPMc

BSWOB

ROPa

d =corrected for ROCK BITS

as new onesfor each depth drilled

)(*

8

1*3*31.0

18

*38

*31.0

)(?0.0)(2.01.0)(5.03.01*6*93.0

)09.1*10*8(2

2

2

4

drilledIntervaldepthBitdepthBitBWx

and

RPMRPMandxx

BWBW

Z

with

bitPDCbitinsertbitteethpandZZa

where

INOUT

RPMcorrected

−=

=++

++=

−−=++=

+− −

WELLSITE GEOLOGIST& MUDLOGGING Crew

MUDLOGGING UnitCOMPUTER

dCndCo

YES!

HELP!

è … and ‘dCn’ still not drawn !


NORMAL COMPACTION TREND ’dCn’• RUBEY & HUBBERT ⇒ log(φ ) = -c.Z + log(φo) => linear relationship between Depth (Z) and Porosity (φ )

• ZAMORA: the ‘ d ’exp (proportional to porosity), follows the same law for claystone/shale:

Slope A( )

12

12 /logDepthDepth

ddA CnCn

−= [ ]DepthAdCn

Cn

B

DepthAdB*)log(10

*)log()log(−=⇒−=

Intercept B

Example:@ 1500m dCn= 1

@ 4500m dCn= 2

slope A= 1.003*10-4

intercept B= 0.707Computer job(MUDLOGGING CREW)

Geologist job

log(dCn) = A.(DEPTHTVDBRT) + B

0

1000

2000

3000

4000

5000

3 5 2 31.00

*

*

SLOPEINTERCEPT

dCn

dCo

dc(EMW)

Dep

th(T

VD

BR

T)

[ ])log(*10 BDepthACnd +=⇒ At any depth:


ROCK BIT types vs ROP curve vs ’d’ exp

Cone bitsNOZZLES3 x ??/32’’

Fixed head bitsNOZZLES or

TOTAL FLOW AREA

TEETH bit INSERT bit Polycrystalline Diamond Compact

Rock is SHATTERED by pressure Formation is CUT with cutters• ROP curve CONTRASTED: drilling parameters relatively steady• Cuttings shape & size generally well representative of rock compaction

• ROP curve SMOOTHED: parameters adjusted vs lithology • Cuttings shape & size fairly to non representative of rock compaction

NOZZLES

3 x … /32’’

TFA inch2

convertedto equiv.nozzles

+ -


COMPACTION TREND and Drilling param ’s

COMPACTION TRENDassumed to reflect a normalized ROP

with constant (!) DRILLING & MUD

parameters

WOBRPMBit typeBit size

OBMWBMMWECD

è ADJUST ‘END to END’ SHIFTSè WITHOUT CHANGING SLOPE(S)

Fast ROP (min/m) Slow

Depth

OBM effectWBM effectDCn

TEETHtricone bit

èPDC bit

ç Core bit

Worn bit

è

ç

çINSERTtricone bit

IT WORKS!


COMPACTION TREND and LITHOLOGY

è check LITHOLOGYè check CALCIMETRY

Fast ROP (min/m) Slow

DCn

Sandbaseline

DCo

SILT effect CO3 effect

Depth

Shalebaseline

Dco => OBSERVED

COMPACTION TRENDassumed to reflect a normalized ROP

based on pure (!)CLAYSTONE / SHALE

Dcn => NORMAL


COMPACTION TREND OBSERVED ’dCo’

’dCo’reflects a ‘Normalized ROP’

corresponding to:

normalcompaction

dCo= dCn

0

1000

2000

3000

4000

5000

3 5 2 31.00

dCn

d(EMW)

Dep

th

dCoabnormal

compactiondCo < dCn

porepore

porepore

The increase in pressure isproportional to the difference

dCn and dCo

PRESSURE


SHALEPore Pressure COMPUTED

Shale Pore Pressure (PP)EATON method

( )2.1

trend)(normal

trend)(observed(EMW) chydrostatiOBGOBG

−−=

Cn

CoP

ddPSSP

0

1000

2000

3000

4000

5000

3 5 2 31.00

dCn

d(EMW)

Dep

th

dCoExample at 4000m: dCo = 1.50 g/cc (EMW)

Ph = 1.00 g/cc (function of water salinity)

dCn = 10(1.003*10-4*4000 + log(0.7)) = 1.76 g/cc (EMW) at 4000mSOBG = 0.01447*(ln4000)2 + (-0.014912*ln4000) + 1.287 = 2.16 g/cc

PP = 2.16 - (2.16-1.00)(1.50/1.76)1.2 = 1.20 g/cc (EMW)


Pore Pressure & Overlays

EATON formulas

While drilling

During logging

Overlaysisodensity EMW

( )2.1

trend)(normal

trend)(observedhydro

−−=

Cn

CoP

ddPSSP

( )3

trend)(observedl

trend)(normalhydro

∆∆−−=

o

nP

ttPSSP 3*

p

hno PS

PStt−−∆=∆

2.1*h

pnCnCo

PSPSdd

−−=

(Pp sucessively taken to 1.00, 120, 1.40, … )

( )5.1

)(observedl

)(normalhydro

−−=

o

n

clay

clayP

RRPSSP

’d’ exp

∆t clay

Resclay 5.1*h

pno

PSPSRclRcl

−−=


EATON Overlays: isodensity (EMW)

0

1000

2000

3000

4000

5000

2 3 5 2 31.00d (EMW)

dept

h

1.00

1.20

1.40 dCn

dCo

2.00

1.80

1.60

Isodensity lines for ’d’ exp

1 - Determine the ’dCn’ trend: ( slope & intercept)

2 - Compute at each depth, knowing- the SOBG (regional or recomputed)- the Ph hydrostatic gradient (1.00 to 1.08)

the theoritical values of the ’dCo’ for different pressure gradients (1.20, 1.40, 1.60, … )

⇒ using Eaton ’s formula:

2.1*h

pnCnCo

PSPS

dd−−=

Quick look method for Shale Pp

Note: Eaton exponents may vary (1.1 - 1.5)


’dCo’ OVERLAYS example (Excel worksheet)NORMAL TREND dcn:

log(dcn)=A*depth+B A=(log(dcn2/dcn1))/(depth2-depth1) OVERBURDEN:dcn1 = 0.75 sgEMW 0.00010557 => slope S=a*(ln(depth))^2+(b*(ln(depth))+cdcn2 = 0.9 sgEMW B=10^(log(dcn1)-A*depth1) depth in meter

depth1 = 250 m 0.70577702 => intercept a => 0.01447depth2 = 1000 m => dcn at depth: b => -0.01491

dcn=10^(A*(depth)+log(B)) c => 1.28700 Pr.hydr. = 1.01 sgEMW => OVERLAY at depth: or enter new coefficientsEATON exp'= 1.2 dco= dcn*[(S-Pp)/(S-Ph)]^(1/Eaton exp') or enter local OBG formula

SHALE PORE PRESSURE at depth: S = 2.129 SHPP= S-(S-Ph)*[dco/dcn]^1.2dco = 1.35 dcn = 1.65 => 1.249 sgEMW

DEPTH dcn= 1,00 SOBG OVERLAYS (sgEMW)(mTVDBRT) 1.00 (EMW) 1.20 1.40 1.60 1.80 2.00 2.20

100 0.723 1.525 0.493 0.222 #NOMBRE! #NOMBRE! #NOMBRE! #NOMBRE!250 0.750 1.646 0.558 0.340 0.084 #NOMBRE! #NOMBRE! #NOMBRE!500 0.797 1.753 0.623 0.429 0.214 #NOMBRE! #NOMBRE! #NOMBRE!750 0.847 1.822 0.678 0.491 0.288 0.043 #NOMBRE! #NOMBRE!1000 0.900 1.874 0.732 0.546 0.346 0.117 #NOMBRE! #NOMBRE!1250 0.956 1.916 0.786 0.598 0.398 0.173 #NOMBRE! #NOMBRE!1500 1.016 1.952 0.842 0.651 0.447 0.222 #NOMBRE! #NOMBRE!1750 1.080 1.983 0.901 0.705 0.496 0.268 #NOMBRE! #NOMBRE!2000 1.148 2.010 0.963 0.760 0.546 0.312 0.024 #NOMBRE!2250 1.220 2.034 1.028 0.818 0.596 0.356 0.071 #NOMBRE!2500 1.296 2.056 1.097 0.879 0.649 0.401 0.113 #NOMBRE!2750 1.377 2.076 1.169 0.942 0.704 0.447 0.153 #NOMBRE!3000 1.463 2.095 1.247 1.010 0.761 0.495 0.193 #NOMBRE!3250 1.555 2.113 1.328 1.081 0.821 0.544 0.232 #NOMBRE!3500 1.653 2.129 1.415 1.156 0.885 0.596 0.273 #NOMBRE!3750 1.756 2.144 1.507 1.236 0.952 0.650 0.315 #NOMBRE!4000 1.866 2.159 1.605 1.321 1.024 0.708 0.359 #NOMBRE!4250 1.983 2.172 1.709 1.411 1.099 0.768 0.404 #NOMBRE!4500 2.107 2.185 1.819 1.506 1.179 0.832 0.452 #NOMBRE!4750 2.239 2.198 1.937 1.607 1.264 0.900 0.503 #NOMBRE!

OPENFILE


FRACTURATION evaluation

WHY ?TO DETERMINE the MAXIMUM:

- Mud Weight (ECD) permitted during drilling- Annular surface pressure allowed during kick- Casing shoe settings

FRACTURE gradients depend on:- stress conditions in the wellbore (σx, σy, σz)- Hole geometry & orientation (FRACHORIZ. WELL << FRACVERT. WELL)- FRACOFFSHORE < FRAC ONSHORE- Mud Weight, wellbore Temp°, Lithology, ...

NUMEROUS ATTEMPTS …ALL METHODS ARE APPROXIMATIONS

The ’less worse’: EATON

( ) LOTPP PPPSFRAC ≤+−

−= *

1 ννFRAC ≤ PLOT

POISSON ’s RATIO => Kwith 0.33 < ν < 0.45

ln(K) = a * ln(depth) + b

equation equivalent to SOBG

DEFAULT COEFFICIENTS with depth in feet

a bsoft fm 0.226 -2.667hard fm 0.354 -3.607

FRAC

SOBG

0.50 1.00 1.50 2.00 2.50

0

1000

2000

3000

4000

5000

depth

sg (EMW)


WELL PRESSURE MEASUREMENTS

Theoretical Pressure tests types

TO CHECKpossible leaks

along casing or linerequipments

beforedrilling out

cement

Casing and/orLiner Test

TO CHECKpossible leaksat casing shoe

(cement: presenceand hardness)

after drilling outcasing shoe

SBTShoe Bond Test

TO DETERMINEthe maximun pressureup to ‘‘leak off’’ = PLOT

which can be appliedat the first

permeable level

below the shoe(or no more than 50m)

LOTLeak Off Test

FITForm. Integrity T.

Equivalent to LOT,TO CONFIRM

the validity of formerLOT at shoe

with cracking theformation PFIT PLOT

while drillingthe new section

≤

DRILLER interest DRILLER & GEOLOGIST interest

PracticallyPERFORM IN A ROW (‘RAT HOLE’ DRILLED)

UP TO FRACTURATION/INJECTIVITY THROUGH THE FORMATIONOR at a LOWER PRESSURE (assumed to be valid as PLOT),

DEPENDING ON EXPECTED FORM. PRESS. ALONG THE SECTION


PRESSURE RECORDING PLOTMeasurements for the determination of the maximun mud weight

permitted for drilling (ECD) without loss of circulation

METHOD: Increasing the mud pressure,generally using Cement Unit pump(s),by shut-in-well (well closed)

Pre

ssur

e (p

si)

Volume (bbl) Time (min)

THEORITICAL

PUMPING BLEED OFF

11

LINEAR INCREASE IN ANNULAR PRESSURE,PROPORTIONAL TO THE VOLUME PUMPED,AT CONSTANT MUD FLOW RATE

PLOT

2

2DEPARTURE FROM LINEAR SLOPE: START OF ‘LEAK OFF’ => PLOT => AS PUMPING CONTINUES, MUDPENETRATING/INJECTING THE FORMATION

PINJECTIVITY

3a

3a CRACKING and INJECTIVITY THROUGHTHE FORMATION => STOP PUMPING

3b

3b END OF INJECTIVITY (fracture propagation)WELL STILL CLOSED (TIME > 15 min)

4

4END OF TEST: PRESSURE PURGE=> COMPARE VolPUMPED vs VolRETURNED

paper print

screen plot

computer

MUDLOGGING UNIT

+++

CEMENT UNIT

+--

Pressure outputs


EQUIVALENT MUD WEIGHT: EMWP

ress

ure

(psi

)

Time (min)Volume (bbl)

PUMPING

PLOT

PINJECTIVITY

FRACTUREPROPAGATION

BLEED OFF

In OBM well, the ‘pumping phase’might be smoothly curved,

due to fair oil compressibility

EMW PTVDBRT

MWLOT= +* .07032(g/cc) (g/cc)

(m)

(psi)

(conversionfactor)

examplePLOT = 1250 psiShoe = 1820 mTVDBRTMW = 1.22 g/ccVolPUMPED = 5.50 bblVolRECOV = 4.25 bbl

CONVERSION: 1 14 2210

14 220 7032

1 42 160

2psi kg cm

bbl gal liters

= =

≈ ≈

. / (.

. )

EMW = 1.70 g/cc

Injected through formation: => 1.25 bbl = 200 liters


CHARACTERISTIC PROFILES

Csg Test1 SBT2

CASINGSHOE

LOT3

Permeable bed

FIT4

Permeable bed

Permeable bed

SOB !

P (psi)

V (bbl) T (min)

(15 min)

VOLRECOV = VOLPUMPED

P (psi)

V (bbl) T (min)

VOLRECOV VOLPUMPED≅

P (psi)


FRACTUREPROPAGATION

VOLRECOV < VOLPUMPED

P (psi)


FRACTUREPROPAGATION

VOLRECOV<< VOLPUMPED


PRESSURE ANALYSES

CEMENT

RAT HOLE

CASINGSHOE

FRACTUREPROPAGATION

P (psi)


BA

PLOT > Ppropag.1

VOLRECOV << VOLPUMPED

P (psi)


AB FRACTURE

PROPAGATION

PLOT = Ppropag.2

VOLRECOV < VOLPUMPED

SBTPOOR or WEAK CEMENT JOBPOSSIBLE REMEDIAL JOB?

GOOD CEMENT JOB,SAFE in case of KICK CONTROL(CIRCULATION through CHOKES)

LOTHIGH PROPAGATION INTOre-OPENED FRACTURES,

LIMITED ‘ECD’ WHILE DRILLINGFORMATION NOT DAMMAGED

BELOW THE SHOE

+

SOB !

? ?


S U M M A R YSAMPLING PROCESS:

- SAMPLES: Why? and Types?- SAMPLES: Preservation ... what for?

SAMPLING: BASIC RULESCUTTING PREPARATIONWASH OUT SAMPLE EVALUATIONCUTTING PERCENTAGE ACCURACY and VISUAL ESTIMATIONDESCRIPTION and Order Standardization:

General RECOMMENDATIONS1 - ROCK NAME2 - COLOUR3 - HARDNESS / INDURATION4 - TEXTURE: General

SummarySEDIMENTARY PARTICLESCARBONATE DESCRIPTION

5 - MATRIX and CEMENT6 - FOSSILS and ACCESSORIES7 - Apparent POROSITY8 - OIL SHOWS: Generalities

ObservationComments

SAMPLE PROCESSING


SAMPLING PROCESS (1)

AIM OBSERVATION and EVALUATION OF FORMATION DRILLED,SUMMARIZED IN MUDLOG DOCUMENT, ON RIGSITE

SOLIDS samples FLUIDS samples

=> to rebuiltlithological

column

=> to visualisereservoir

characterisation

=> to identifytrue

formation fluids

=> to preciserheology

(drilling fluid)

CUTTINGSUnwashed (UNW)

Washed & Wet (W&W)Washed & Dried (W&D)

( + spot samples)

CORES+

wax preservedsamples

FORMATION SAMPLES MUD SAMPLES

Prior logging job,New mud type

(per Drlg phase)...

WHY?

SAMPLES

TYPES?LiquidsCond

OilWater

Gas


SAMPLING PROCESS (2)

PRESERVATIONMODE

SAMPLES

LABORATORYSTUDIES

measurement(on rigsite)

&

analysis(in town)

BAGScotton, paper,

plastic,aluminium,glass pills

CORESCUTTINGS

BOXESwooden

(preferably)or plastic

W&DW&W

UNW

=>Accurate DESCRIPTIONLithology

CALCIM., FLUO.,Shale density

Thin sections, ...

HCb extraction, TOC (W&W)Heavy Mals identification

Microfauna, ...

=> Rough descriptionCHIPS observationCALCIM., FLUO.

(thin sections)

PETROPHYS. on PlugsSCAL (Phi-K, matrix, Sw)

SEDIMENTOLOGYon slabbed core

MUDSAMPLES

Liquidsjerricansbottles

GasPVT cellschamber

FORMATIONSAMPLES

CANSJerricans

Quick lookDensity (API),

Pour Point,Resistivity

& Salinity, ...

ComponentC1 ... C5

CO2, H2S

same analysis more accurate+ Volume Factor (Bo, Bg)+ Gravity, Finger prints, ...

Mud weightOBM: Elect. stability

O/W ratio, ...WBM: Rm, Rmf, Rmc

Visc, Gels, ...

rarely to none

SOLIDS samples FLUIDS samples


SAMPLING: BASIC RULES«UNFORESEEN EVENTS OCCUR ONLY ONCE DURING WELL DURATION»

NEVER MISS OPPORTUNITY TO COLLECT SAMPLES

S

OTHERWISE

YOU CAN BE TRAPPED !AND LOOSE SOME IMPORTANT WELL DATA

SOLID SAMPLES LIQUID SAMPLES

=> WHILE TRIPPING/FISHING ...

rock samples remainingstuck on BHA:

- bit (tricone)- stabilizers- junk basket- ...

Bigger cuttings fornicer thin sections

=> WHILE TESTING ...

no flow on surface ornothing while reverse circulation

(but test «technically successful !»)

CHECK below DST string

=> WHILE DRILLING ...

... Oil on Shale-Shakers(fractures indicator ?)

THUS

. . .


CUTTINGS PREPARATION

UNWASHED sample WASHED sampleDEPTH

COARSEsieve

MEDIUMsieve

FINEsieve

WRITTEN WITH PENCIL THROUGH SIEVES COLUMNFROM SHALE SHAKERS SIEVES

RAW & MIXED CUTTINGSEMBEDDED

WITH MUD includingADDITIVE PRODUCTS(Polymers, LCM, ...)

• FOR CHECKING POSSIBLE CAVINGS• BIGGER CUTTINGS MAY BE USED for:

- SELECTIVE CALCIMETRY- THIN SECTIONS

FOR PERCENTAGE EVALUATION& FOR DESCRIPTION

(Medium and Fine granulometric sizesmay be mixed)SUCK EXTRA WATER

with towel,sponge,paper filter, ...

STEEL / INOX

flat area

GLASS-WATCH

curved

ALUMINIUM DISH

undulatedarea

SAMPLE TRAYS

RECOMMENDED . . . . . . . . . . . . IF NOTHING ELSE


GEOLOGICAL WASH OUT

WASH OUT EVALUATION

• Possible ORIGIN:. formations poorly cemented, indurated, ... . and/or inappropriate drilling fluid (mud)

• PHENOMENA:Drilling with almost no WOB (‘jetting’) => vf-f SD/SSTWashable CL/CLST, SLST, ...

• Surface DETECTION in Mudlogging unit:Samples do not reflect the expected lithologyVolume cuttings recovered << Volume drilled

• Final Consequences => Miss DATA, borehole instability

• How to solve the situation?Wash samples yourself & check residue inside sinkLook for ‘lost’ samples: flow-line, sand-trap, ...Washed out evaluation:

• Other: unexpected SALT, drilled ... with WBM not saturated

Mudlogging crew => DECIDE & ACTthen ... INFORM => Drlg Supervisor %606.02.0

%404.08.0

=>=

−+

=

=>=

=

HhH

Hh

xCLAY

HhxSAND

H

Height BEFORE ...

h

Height AFTER ...

WASHINGsieves set

coarse

medium

fine

Raw percentageafter washing:

SAND: 80%CLAY: 20%


ACCURACYEXPECTED ?

±1000

remember:5% TRACES

CUTTING PERCENTAGE ACCURACY


CUTTING PERCENTAGE ESTIMATION


WELLSITE GEOLOGIST

=> EXAMINE SEVERAL SAMPLES IN A ROW ... for updating theinterpretated lithological column ... and KEEP LAST SIGNIFICANT ONES

BUT AVOID TO «fill up volume» for the base Geologist!

OBSERVE under«same conditions»

TIME => hardnessLIGHT => colourFOCUS => texture

. . .

USE«usual codification»

STANDARD

ABBREVIATIONS

REPORTMAIN

ROCK

FEATURES

RECOGNIZE andDISREGARD

CAVINGS and«other

contaminants»

BE CONSISTANT BE HOMOGENEOUS BE ACCURATEBE SELECTIVE BE CONCISE

NOTEDOMINANT

SIGNIFICANT

DETAILS

limestoneLMST

LST LS Lime-stone

SAMPLE DESCRIPTION (1):GENERAL RECOMMENDATIONS


1 - ROCK NAME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . and abundance (estim.%)

2 - COLOUR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . under Cst lighting

3 - HARDNESS / INDURATION . . . . . . . . . . . . . . . . subjective appreciation

4 - TEXTURE: rock’s components . . . . . . . . . . . . characteristic elements

5 - MATRIX and/or CEMENT . . . . . . . . . . . . . mechanical/chemical process

6 - FOSSILS & ACCESSORIES . . . . . . . . . . . . . . secondary rock particles

7 - POROSITY (apparent) . . . . . . . . . . . . . . . . . . . . . . qualitative evaluation

8 - OIL SHOWS . . . . . . . . . . . . . . . . . . . . ephemeral approach fct(rock Phi,K)

DESCRIPTION ORDER

SAMPLE DESCRIPTION (2):BASIC RULES or STANDARDISATION


SAMPLE DESCRIPTION (3): 1 - ROCK NAME

Six (6) BASICCATEGORIES OF ROCKS

ARGILLACEOUSSH ShaleCLST ClaystoneMRL Marl

CARBONATESLS/LMST LimestoneDOL DolomiteCHK Chalk

SILICEOUSSLST SilstoneSD SandSST SandstoneCHT Chert

ANH AnhydriteGYP GypsumSA or HAL Salt

EVAPORITES

COAL CoalLIG LigniteBIT Bitumen

ORGANICS

BM BasementBAS BasaltGRT Granite SSDD - SXSTMiscellaneous

NOTE: DIATOMITE and RADIOLARITE may be encountered, but «FORAMINIFERITE» generally corresponds to an intensive washing of Argillaceous deposits !

PERCENTAGE QUALIFIERSLess than 5 = TRACES


SAMPLE DESCRIPTION (4): 2 - COLOUR

SAMPLE TRAY: a- MUSHROOMS, TOMATO, ...b- CHEESE, NODDLES, ...c- MEAT, PAPRIKA, ... , Oil

ROCK COLOUR DEPENDS ON:

a- CONSTITUENT GRAINSb- MATRIX and/or CEMENTc- STAINING (mud products, iron, ... , OIL) STRESS ON PREDOMINANT COLOURSTRESS ON PREDOMINANT COLOURREDDISH to LIGHT BROWN

(rdsh-lt brn)

BROWNISH to ORANGE(brnsh-or)

TRAFFIC LIGHTSfor

COLOUR BLIND WSG

for more details, see theROCK COLOR CHART

(The Geological Society of America)representing the:

U.S. Geological Survey, AAPG, ...


SAMPLE DESCRIPTION (5): 3 - HARDNESS / INDURATION

MOH’s scale (standard Mineral and Qualifying terms)

1 - TALC loose, uncons. lse, uncons 2 - GYPSUM friable fri 3 - CALCITE soft sft 4 - FLUORINE plastic plas 5 - APATITE firm frm 6 - ORTHOCLASE brittle (as coal) brit 7 - QUARTZ moderately hard mod hd 8 - TOPAZ hard hd 9 - CORUNDUM very hard v hd 10- DIAMOND very hard v hd

French scale

Ta your

Grosse huge

Concierge caretaker

Follement madly

Amoureuse in love

Ose dares

Quémander asking

Tes your

Caresses divine

Divines caresses

(brittle)

(very hard)(friable)

(soft)

ROP WBM OBM

ANHYDRITE v slow pasty, soft mod hd

SALT v fast «lost» firm

NAIL: 2.5

GLASS: 5.5

STEEL: 6.5


SAMPLE DESCRIPTION (6): 4 - TEXTURE: GENERAL

ORGANISATION of the COMPONENT ELEMENTS of the ROCK

(simplified WENTWORTH scale)

SIZE ARRANGEMENT

extr wl srt

v wl srt

wl srt

mod srt

pr srt

v pr srt

mono-modal

poly-modal

ROUNDNESS:edges sharpness

v angang

sbangsbrnd

rndwl rnd

v elongelong

sli elongsli spher

spherv spher

SHAPE

SPHERICITY:shape of the grain(ratio width/length)

CLASTICS size of CARBONATESGrains element Crystals

Mud - Clay < 20µ crpXln - mXln

Silt 20 - 63µ extrXln

vf - f 63 - 250µ vfXln - fXln

med - v crs 250µ - 2mm medXln - vcrsXln

Granule-Boulder 2 - 256mm extrcrsXln

SORTING:grains range size

pr gdfr


SAMPLE DESCRIPTION (7): 4 bis - TEXTURE summary

ROCK GRAINS / CRYSTALS ORGANISATION

SIZE SORTING

SHAPE

ROUNDNESS

SPHERICITY


TEXTURE: SEDIMENTARY PARTICULES

very coarse

coarse

medium

fine

very fine


CLASSIFICATION according to DEPOSITIONAL TEXTURE

Structures of ELEMENTS

CARBONATE DESCRIPTION


SAMPLE DESCRIPTION (8): 5 - MATRIX and/or CEMENT

M A T R I X C E M E N T

OF SMALL INDIVIDUAL GRAINS,BETWEEN LARGER GRAINS,

FILLING INTERSTICES

AROUND GRAINS or CRYSTALS,OFTEN BOUNDED TO THE SEDIMENT ,FILLING INTERSTICES and/or VOIDS

Silica, Calcite, Dolomite,Pyrite, Salt, ...

MECHANICALDEPOSIT

CHEMICALPRECIPITATE

Silt, Clay

BOTH REDUCINGPOROSITY


F O S S I L S A C C E S S O R I E S

EASY TO RECOGNISE, DIFFICULT TO IDENTIFYMINOR ROCK PARTICLES ARE USEFUL

FOR CORRELATIONS and FOR ENVIRONMENT INDICATORSeven if it is A SPECIALIST ’S job

=> INFORMATION on ORIGIN and HISTORY of the SEDIMENT

FORAMINIFERAGASTROPODS

PELECYPODS

CORALS

ALGAE

OSTRACODS

BRYOZOA

. . .

(crystal, framboid) PYRITE => DIAGENETIC, CONFINED DEPOSITS

GLAUCONITE => MARINE: EXTERNAL SHELF

CALCITE => FAULT, RECRYSTALL

(BIOT, MUSC => detrit acid rocks) MICA (CHLORITE => fluvio -marine)SCATTERED GRAINS (Org.Mat, Coal, Gyps., ...l

HEAVY MINERALS (APATITE: detritic, PO4 deposits)

«lithics rock fragments»magnet => Fe-Mg minerals

. . .

MINERALSORGANISMS

PERCENTAGE QUALIFIERS

> 10 % Abundant 5-10 % Minor 1-5 % Rare < 1 % Trace

and COLOUR

DON’T FORGET

SAMPLE DESCRIPTION (9):6 - FOSSILS & ACCESSORIES


softsedimentssolid or liquid ?

0 - 5% negligable visual porosity (n vis por: nvp)

5 - 10% poor porosity (p vis por)

10 - 15% fair/medium visual porosity (fr/med vis por)

15 - 20% good visual porosity (g vis por)

20 - 25% very good visual porosity (vg vis por)

PERCENTAGE QUALIFIERS

INTERGRANULAR

INTRAGRANULAR

MOLDIC

VUGGYINTERCRYSTALLINE

FRACTURE

CONNECTED or ISOLATED network ?

cuttings?CORE => OK

SAMPLE DESCRIPTION (10):7 - APPARENT POROSITY


STRONGEST SHOWSDO NOT NECESSARILY REFLECT

THE BEST RESERVOIR

- mud weight flushed while drillingmud types (WBM, OBM) samples washing- bits used cuttings size

SHOWS ARE FUNCTION OF:DESCRIPTION ORDER

FLUORESCENCE (direct)ODOUR & COLOUR: intensity

DISTRIBUTION: staining & bleedingFLUORESCENCE

(cut, residual)

ONE OF THE MAIN INTEREST OF A WELLknowing that:

SHOWS AREEPHEMERAL

(highly volatile)

SAMPLE DESCRIPTION (11):8 - OIL SHOWS: Generalities


SAMPLE DESCRIPTION (12):8bis - OIL SHOWS: Observation

SOLVENT FLUORESCENCE (crushed sample)

OIL ODOUR & OIL COLOURthe stronger, the darker (dk brnsh), the lower °API

the fainter, the lighter (lt yelsh), the higher °API

3

OIL STAINING & BLEEDING

DISTRIBUTIONEVENMOTTLED very good >40%PATCHY good 20-40%SPOTTY fair 10-20%SPECKLED poor 1-10%PINPOINT very poor 1-2 grainsNIL

(RATING roughly= 1/permeability)

2

BRIGHT => DULL => PALE => FAINT (strong to weak)

INTENSITY+ -

CUT 1 SPEED flash: instant. fast: < 5sec slow: 5-10sec crush:‘needle’

2 STRENGTH strong weak faint

3 FORM blooming streaming (sl, mod, ...)

4 COLOR brown, gold, ...

4a 4bTEST TUBES PAPER FILTER

solventreference

solventreference

sample

EASY STORAGE forlater comparisons

RIGSITE COMPARISONS(test tubes or white porcelaine)

RING FLUORESCENCE or RESIDUAL

FLUORESCENCE DIRECT SOLVENT

Minerals (calcite, ...) YES NO Bitumen ‘Dead Oil’ NO YES Crude Oil YES YES 41

RING

DEPTH


‘CUT FLUORESCENCE’

PERFORM ON

DRY POWDERED SAMPLE

(before calcimetry analysis)

+++ CHLOROTHEN (fairly toxic ... only!)

++ ACETONE (satisfactory for heavy Hcb)

+ ETHER (volatile, for light soluble Hcb)

- TETRACHLORID (poison very toxic!)

SOLVENTS DIR CUT 3 2 1 1 2 3

VENTILATEDAREA

MUDPRODUCTS

&ADDITIVES

DIRECT FLUO OIL Gravity

main COLOUR deg API g/cc

Brownish <15° >0.97

Orange 15-25° 0.97-0.90

Gold yel-grnsh 25-35° 0.90-0.85

White-Milky 35-40° 0.85-0.80

Whitish-Blueish >45° <0.80

SAMPLE DESCRIPTION (13):8ter - OIL SHOWS: Comments


LABORATORY: ANALYSIS & MEASUREMENTS

L A B O R A T O R Y S U M M A R Y

MEASUREMENTS:- CALCIMETRY- SHALE DENSITY

ANALYSIS:- CHEMICAL TEST (Sulfates, Cement, Chlorides, Coal & Lignite)- OIL «POUR POINT» Temperature- THIN SECTIONS

STAINING:- CALCITE COLORATION- OTHERS: Carbonates and Feldspars


CALCIMETRY Measurement

CALCIMETER CARBONATE CONTENT(mechanical or electronic)

CORROSIVE ATTACK USING HYDROCHLORIC ACID (HCl 50%)ON WASHED & DRY CRUSHED / POWDERED ROCK (1 g),

either RAW and/or SELECTED samplesTHE APPARATUS RECORDS

THE CO2 PRESSURE PRODUCED (BOURDON tube)

COMPLETE REACTION achieved after 1 30 +min,depending on LST-DOL content ( ...dolomimetry)

Report values after ‘1 min’ AND after ‘stabilization’(NEVER CHANGE CALCIMETRY SCALE ON MASTERLOG)

0 10 20 30 40 50 60 70 80 90 100%

PERCENTAGE

TIM

E (m

in)

0

10

20

LEAK

a

b

c

d

BLEED OFF

e

1mn CHECK:

- On Chart: depth and curve readings- Under microscope / binoccular: residue (Qz, clay, other Minerals, Org. matter, ...)


SHALE DENSITY Measurement

soapyWATER

d1displacement in AIR

d2displacement in WATER

ccgdd

ddSH /

211

−=

ApparentSHALE DENSITY

MICROSOL METHOD(Geoservices)

VARIABLE-DENSITYCOLUMN METHOD

Calibration Chart

FAIR RESULTS IN OBM(Oil Base Mud)

VAPORS HIGHLY TOXIC(Bromoform 2.85sg,

Trichloroethane, 1.47sg ...)

WASHED & HUMID samples and at least 3 MEASUREMENTS per level

ACCURACY & RELIABILITYNOT EFFICIENT


QUALITATIVE CHEMICAL TESTS

remember: Always add acid to water, not the opposite way round

BaCl2

WHITEPRECIPITATE

BaSO4

HEAT(destroy CO3)

DECANT(filter paper)

SULPHATES(GYPSUM, ANHYDRITE)

HCl (10%) ‘‘SST, tan-gy, vf-f,w cmtd, p calc,

rare Glauco, ... ‘‘

CEMENT

TURNING to REDDISH-PURPLE with

PHENOLPHTALEIN (pH 8.3)‘‘CEMENT components are a BASE»

(Sandstones are not)

CHLORIDES

+filter

AgNO3[N/10]

whiteprecipitate

distilledwater

CHECK withMud Engineer

forquantitative test

COAL & LIGNITE

HNO3 (10%)

SHAKEand

DECANT

brownishLIGNITE

transparentCOAL

CHECK yourfingers if notconvinced !


THIN SECTIONS

glass slide

ARKA

NSO

N s

tick

‘ARKANSON’ MOLTEN(MUST NOT BOILED)

HOT PLATE

PLACE the SAMPLES

frosted glass

RUD DOWN UNIFORMYwith ABRASIVE POWDERS

(300 => 600)

HELP TO IDENTIFY ROCK TYPES (mainly eruptives, ...) on SELECTED SAMPLES

6

21

5

43

7 8

300

600

REVERSE (B) OVER (A)

REMOVE (B)

MAINTAIN ‘SAMPLES’ with needles to eliminate air bubbles

PLACE some QUARTZ grains at slide corners

(A)

(B)

Qz

RE-HEAT GLASS SLIDE (A) WITH ‘SAMPLES’

HEAT NEW GLASS SLIDE (B) WITH ‘ARKANSON’

RUB DOWN SAMPLESwith thinner

Abrasive Powders

TOAPPROPRIATE

THICKNESS

Put a COVER SLIDE or not (=> see ‘stain tests’)

‘rolling’ yellow

too thick

‘rolling’ grey

OK


OIL «POUR POINT» TEMPERATURE

OILphase

behaviourSOLIDstate

LIQUIDstate

TEMPERATURE

POURPOINT(°C / °F)

intoFRIDGE

ambiantTemp°

FIRST DROPLIQUID

AIM RAW OIL CHARACTERISTICS during SAMPLING(°API, viscosity, ...)

1

2

5 °C

40 °C

METHODOLOGY

COOL DOWN the OIL sample to the COMPLETE SOLID state

REPORT the POUR POINT Temp° at the FIRST OCCURRENCE of LIQUID phase

note: NEVER DO IT from LIQUID to SOLID state

2

1


STAINING TEST: CALCITE COLORATION

HELP TO IDENTIFY CARBONATE ROCKS COMPONENTS on Cores & Cuttings

REAGENT1 gram ALIZARIN RED ‘S’1 liter distilled water (998cc)5 drops HCl [N] (2cc)

CALCITE

DOLOMITE PROCEDURE

APPLY 1-2 DROPS of SOLUTIONLEAVE TO DRYOBSERVE under Microscope

SAMPLES (Core chips, Drill cuttings)

MUST BE ‘CLEAN & DRY’


OTHER (advanced) STAINING TESTS

1 ml HCl1 ml Alizarin red1 ml saturated Potassium Ferricyanide8 ml distilled water

Dip 1 min on polished sample, Let stand until dry

RED pure CALCITEPURPLE ferrugineous (Fe++) CALCITELIGHT BLUE ferrug. DOLOMITE Ca,Mg/Fe(CO3)2

DARK BLUE ANKERITE Ca,Fe(CO3)2

CARBONATES

A

B

* Etch polished surface in close vessel of HF ( hydrofluoric acid) vapor for 5 min

* Dip sample (quickly 2 times ‘in & out’ into 5% BaCl2 solution; then, rinse

* Place sample for 1 min into saturated Sodium Cobaltrinitrate solution (40g in 100 ml water)

YELLOW Potassium FELDSPAR (Alkali)

* Cover etch with rhodizonate reagent; then, rinse(reagent: 0.2g rhodizonic acid potassium salt in 30ml water)

RED Plagioclase FELDSPAR (Na, Ca)

ALWAYS WORKUNDER HOOD

+ RUBBER GLOVES+ GOGGLES

(dangerous acid fumes)

HYDROFLUORIC ACIDor HIGH FREQUENCY

Damned! HF ?

FELDSPARS

PRECIPITATE of SILVER CHROMATE ON CALCITE(no stain on Dolomite)

Dip in solution AgNO3 at 60°C for 3 sec ( rinse with water to eliminate excess)Dip in solution K2CrO4 at 10% for 30 sec ( rinse & leave to dry)


CORES & CORINGS U M M A R Y

- GENERALITIES. POLICY ‘AGREEMENT’. WHY CORING?. WHEN CORING?. WHAT FOR?

- EQUIPMENT and TECHNICS. CORE BARREL and CORE BIT. AXIAL and LATERAL CORING

- CORING OPERATION. MUDLOGGING ASSISTANCE. CORE RECOVERY: general

- METHODOLOGY. UNSLEEVED CORE. SLEEVED CORE. CORE ORIENTATION and LABELLING. PRESERVED SAMPLE: S.C.A.L.

- LABORATORY. PLUGS and SLABBED SECTIONS. ORIENTATION: Dip & Deviated wells

- Finally: ‘‘CORING: it’s good ...’’


CORING: POLICY ‘AGREEMENT’

CORE with CARE

CARE with CORE

CONTRACT’sOWNER ...

... CONTRASTEDRESULTS

CORING IS EXPENSIVE and IT CAN BE A CONTINGENCY OPERATION


WHY CORING ?

BRING TO SURFACE

A COLUMNOF THE DRILLED FORMATION


WHEN to cut a CORE?

EXPLORATIONEXPLORATIONWELLSWELLS

- -

WHEN THE FORMATION EXHIBITS SHOWSCHARACTERISTICS of POTENTIAL RESERVOIR

CORING

WHEN UNKNOWN or UNEXPECTEDGEOLOGICAL CONTEXT

FOR BASEMENT IDENTIFICATION (TD CORING) . . .

DELINEATION &DELINEATION &DEVELOPMENT WELLSDEVELOPMENT WELLS

FOR RESERVOIR DESCRIPTION PURPOSESOF KNOWN RESERVOIR and THEIR BOUNDARIES

CORING

FOR PRODUCTIVITY ANALYSIS

FOR GEOLOGICAL MODELLING ,. . .


CORING: WHAT FOR? (AIMS)GEOLOGICAL

ENVIRONMENTRESERVOIR CHARACTERIZATION

STATIC parameters DYNAMIC

• Facies deposition• Sedimentary sequences• Fracturation network• Dip (apparent, structural)• Thin sections: microfossils, mineralogy, petrography• ...

SEDIMENTOLOGIST, PALEONTOLOGIST,

...

• Matrix: Rhoma, Phie ‘m’, ‘n’ & ‘a’ coeff.• Water Saturation Sw• Shaliness distribution => barriers• Correlations• ...

LOG ANALYST

• PLUGS (surface cond.): - Phi, K (horiz. and vert.)• SCAL (downhole cond.): - Irreducible Swirr - Relative permeabilities - Kro, Krw, => wettability• ...

RESERVOIR Eng.

ARE THESE ENOUGH PURPOSESand/or REASONS TO TAKE GREAT CAREDURING & AFTER CORING ? in view of

... the GEOLOGICAL MODEL

YES,. . . almost!


CORING EQUIPMENT

CORE BARREL(DBS)

CORE BITS(DBS)

IMPREGNATED(DIAMOND type)

CUTTERS(PDC type)


CORING TECHNIQUES

AXIAL CORING

CORE BARREL

ADVANTAGES

LIMITATIONS

• ‘CONTINUOUS’ RECORD• Possible ORIENTATED (Dip, Azimuth)• PETROPHYSICAL PROPERTIES

minimally disturbed• Various INNER TUBES:

. Aluminium, Fiberglass

. Rubber sleeve, Sponge, ...

• SLOW and EXPENSIVE• Possible POOR RECOVERY along:

. FRACTURED zones

. UNCONSOLIDATED formations

SIDEWALL

LATERAL CORING

• WIRELINE ACQUISITION• FAST & CHEAP• RUN at ANYTIME (preferably at TD)• SELECTED SAMPLES (after logging)• PERCUSSION or MECHANICAL bullets• Mineralogy studies, ...

• DISCONTINUOUS RECORD• MODERATE RECOVERY

(flushed zone)• NO ‘Phi-K’ ANALYSES

DRILLING Departments ‘prefer not to core; but, they want: «high ROP, long footage, not too many trips, no twist-off, not to be stuck, ...»’ (BHI Coring Seminar)


... UNDER ‘WELLSITE GEOLOGIST’ RESPONSIBILITY

CORING OPERATION & MUDLOGGING ASSISTANCE

TBnb

1 - BEFORE Coring. CHECK (or prepare) CORE TRAYS on rig floor and/or CORE BOXES:

=> Quantity (length cored + 10%), Order (numbering & labelling). DATABASE: INCREASE SAMPLING RATE => every 0.5m, instead of 1m. CHECK ‘SPP & FR’:

- before dropping the ball: mud circulates through the inner tube- after dropping the ball: mud circulates in annulus, between ‘outer barrel-inner tube’

?

2 - WHILE Coring. ADJUST coring param’ (reduced compared to drilling phase) according to Core-man,. RECORD & MONITOR, as usual, all parameters (including lithological control),. DETECT eventual troubleshootings: core jammed/broken, connections, worn bit, ...

... in order to stop coring, if necessary.

3 - STOP Coring. BREAK the core by pulling up (the core catcher retains the core in the inner tube)

when the core barrel is full or if no more penetration is observed,. PULLING OUT the core assembly WITHOUT CIRCULATING at TD


CORING OPERATION: RECOVERYUNSLEEVED CORE

B1

Top

T1

Tn Bn

Bottom

LAY DOWNon

DRILL-FLOOR

BETTER OBSERVATIONS ON RIGSITE

CORE-BARREL

CATCHINGCORE BOXES

SLEEVED CORE

LAY DOWNon

PIPE-RACK / WALKWAYHammer,Plastic bags

Electric saw + caps & clipsto seal each section

=> inner tubes: => main use:RUBBER SLEEVE: soft / unconsol. FmFIBER GLASS: more and more usedALUMINIUM: high Temp° FmORIENTED CORING dip, fractur., direct.K, ...Sponge: Fluid recovery (?)

BETTER PRESERVATION for TRANSPORTATION ... ALWAYS UNDER ‘WELLSITE GEOLOGIST’ RESPONSIBILITY

BottomTop

B1Tn

CONVENTIONAL PRACTICE


UNSLEEVED CORECORE RECOVERY

CONVENTIONAL PRACTICE

LAY DOWNon

DRILL-FLOOR

CORE-BARREL

B1

Top

T1

Tn Bn

Bottom

CATCHINGCORE BOXES

Hammer,Plastic bags

BETTER OBSERVATIONS ON RIGSITE

CORE MARKING

CORE EXAMINATION

CORE TRANSPORTATION

CORE PACKAGING

METHODOLOGY

1 - CATCHING CORE BOXES to ‘ML Unit’2 - Rough SHOWS Observation: => Oil staining & bleeding + UV light: Dir.Fluo.

3 - Soft washing with RAGS, BRUSH, Humid Sponge4 - Pieces MATCHING & ORIENTING from Top to Btm into ‘‘DEFINITIVE CORE BOXES’’5 - DRAW ‘Orientation lines’ from TOP to BOTTOM6 - Measuring core & mark depths7 - % recovery= (Recov.Length / Interv.cored) x 100

8 - Detailled SHOWS9 - Litho. description, including sedimentary features, ...10-Labo analyses: calcim., Cut fluo, thin sections, ...

11-Subsidiary, Well Name, Core Nb, Box nb, T B => note: Never write depths outside boxes


SLEEVED CORECORE RECOVERY

=> inner tubes: => main use:RUBBER SLEEVE: soft / unconsol. FmFIBER GLASS: more and more usedALUMINIUM: high Temp° FmORIENTED dip, fractu., direct.K, ...Sponge: Fluid recovery (?)

LAY DOWNon

PIPE-RACK / WALKWAY

CORE-BARREL

BottomTop

Electric saw + caps & clipsto seal each section

BnT1

BETTER PRESERVATION for TRANSPORTATION

METHODOLOGY

CORE MARKING

CHIPS EXAMINATION

CORE TRANSPORTATION

CORE PACKAGING

1 - CLEAR a.s.a.p. pipe-rack area, and move ...2 - DEFINITIVE CORE BOXES to ‘ML Unit’3 - COLLECT core chips every meter and place chips inside plastic bags for examination

4 - DRAW / underlined ‘Orientation lines’ T => B5 - NOTCH up with saw each segment / inner tube => for orientation inside ‘inner tubes’6 - Clean with rags & mark depths on tubes7 - % recovery= (Recov.Length / Interv.cored) x 100

8 - SEAL with caps and clip each segments ends9 - Subsidiary, Core Nb, Well Name, Box nb

note: Never write depths outside boxes

10 - A/A ... and fill in ‘Core Description Sheet’


CORING: ORIENTING & LABELLING

4

3

2

1

Piecesmatching

3 - 4Good fit

2 - 3Poor fit(one lineeach sideof break)

1 - 2No fit

(two lineseach sideof break)

Orientationlines

LEFT: BLUEor BLACK

RIGHT:RED


PRESERVED SAMPLE for SCAL => PHANTOM

… alongGOOD

andPOORfacies

ououHououH

SCAL#1

Btm

SCAL#1

OUCH !

ALUMINIUM FOIL

SCAL

#119

98.5

0-19

98.2

5m

HOOOUU ...!

Btm

CORE

#1

-

box

5/7

TOTA

L O

WL

Lm

td -

well

GHO

ST#1

WAX or PARAFFIN

HOT Bath

Btm

MiaouH

Woou!

SCAL#11998.50 -1998.25m

well: GHOST#1

25 cm


CORING & LABORATORYPLUGS

CORE

VPLUG

VERTICALH

PLUG

HORIZONTAL

PREFERABLYCUT AT THE

SAME DEPTH

CHIPS USEDFOR

THIN SECTIONS

SMALL CORES CUTINSIDE ‘MAIN CORE’

STRUCTURAL DIP and/or HOLE DEVIATIONNOT TAKEN INTO ACCOUNT

SLABBED SECTIONS

LONGITUDINALCROSS SECTIONS

(for partners, ref., ...)

3 SCRATCHES FORORIENTED CORING


CORING ORIENTATION: DIP & DEVIATED WELL

αSTRUCTURAL DIP

TMD TVDHORIZONTALSECTION

βDEVIATION

ANGLE

DEVIATION AZIMUTH

γβ

α

( )γ α β= °− +90


C O R I N G

IT’S GOODIN ANYCASE,

MY DEARCOLLEAGUE !


Reporting ‘DGR’ & Coding ‘DDR’

R E P O R T I N G S U M M A R Y

- GEOLOGY:

. REPORTING ... through AGES!

. CURRENT REPORTING: when? & what to report?

. DGR: Daily Geological Report => CEF/SUB form

- GWR: Geological Well Report

- DRILLING:

. OPERATIONS CODING

. OPERATIONS TIMING: planned & unscheduled

. DDR:Daily Drilling Report => FPL/OPS form (‘DAISY’)


GEOLOGICAL REPORTING through AGES

AIM

DAILY INFORM the SUBSURFACE OPERATIONS GEOLOGIST in BASE

HOW ?

YESTERDAY TODAY

Quantity ofdata

transmitted

Datatransfer

equipment

INFO-RIG

RADIO TELEXPHONE

DOCUMENTS

FAX

e-mail


CURRENT GEOLOGICAL REPORTING

INFO-RIG DOCUMENTS

WHEN ?

WHAT ?

• ON A BASIS ROUTINE=> TWICE A DAY... on pre-scheduled time

• ON UNUSUAL OPERATION=> AT ANY TIMETD, Logging, Coring point, ...

CURRENT SITUATION• DEPTH (TMD/TVD)• OPERATION IN PROGRESS

with details ... if requested(ROP, litho, intervals shows, ...)

• Possible Contractors failures, ...• Oper. planned ... w/ expect. timing• Miscellaneous:

- job: equipm. transp. <=> base- perso: booking ...if any return ticket

afternoon reportingRUSH PRINTS

=> provisional data• MASTERLOG ... if requested• Deviation data ( detailled outprint )• Main ‘LOG’• Raw Pressure & Sampling data• Rush ‘Core description’• ...

morning reportingUPDATED FILES & PRINTS

=> previous day: 00:00 => 24:00

• DAILY GEOLOGICAL REPORT• MASTERLOG• LOGGING files (ie):

- Logg. Supervision Report- Press./ Samples / Temp°, ...

• Core sheets• ...


DAILY GEOLOGICAL REPORTTOTAL "Subsidiary" DAILY GEOLOGICAL REPORT Well Name

Report: Nb Date: dd/mm/yyyy (abbrev.)

COUNTRY: LICENCE: FIELD: Platform: Slot: Off./OnshoreOperator: Partners: Well Type: Well status:

Rig Name "XXXxx" Contractors Drilling: Mud: Mud Logging: Logging: Other

Coring: MWD: LWD: Testing:

OPERATION SUMMARYSURVEY DATA UNIT m/ft TMDBRT TVDMSL

TMDBRT(m/ft) Angle Azimuth Survey Type TVDBRT(m/ft) delta X(m/ft) delta Y(m/ft) V section(m/ft) RTE MSL 907.4 907.4GL/WD 900 900 PREVIOUS DEPTH 800 107.4

MIDNIGHT DEPTH 1200 -292.6DAILY PROGRESS 400 400Last Casing Shoe : 13 3/8" 310 597OPEN HOLE : 12 1/4" 890 890 MUD type: WBM sg (g/cc, ppg) 1.04

Operation SUMMARY

LAST FORMATION TOPS / LAST MARKERS LAST FORMATION TOPS/LAST MARKERS Delta TVD MSL

TMD BRT(m/ft) TVD MSL(m/ft) Delta X (m/ft) Delta Y(m/ft) (m/ft) TMD BRT(m/ft) TVD MSL(m/ft) Delta X (m/ft) Delta Y(m/ft)Driller/LoggerDriller/Logger

Driller/Logger

LITHOLOGYFrom (TMD) To (TMD) Main Litho LITHOLOGY and DESCRIPTION Fluorescence Formation

(m/ft) (m/ft) Direct Cut

PROGNOSED ACTUAL

GAS SHOWS Gas Analyser Type: BKG:background gas, FG:formation gas, TpG:trip gas, SWG: swabbed gas, PCG: pipe connexion gas, ..

From (TMD) To (TMD) NATURE TG C1 C2 C3 iC4 nC4 iC5 nC5 Remarks(m/ft) (m/ft) (ppm / %) (ppm / %) (ppm / %) (ppm / %) (ppm / %) (ppm / %) (ppm / %) (ppm / %)

OTHER (LOGGING, CORING, SWC, RFT, DST, Remarks)

Status @ 06.00hr: Operations planned:

GEOLOGIST :

=> strictly one A4 sized page=> Expansible item boxes according to operations in progress (ie LOGGING)

1 HEADER:- well data: Name, location, status, type, contractors- daily data: Report nb & Date ... as per DDR

4 DON’T re-COPY the Drilling report (DDR)

2 Focus on main data ... and ‘dog-leg’

3 Midnight depth & Mud data ... as DDR(casing diam & size, ... precise units used)

5 Intervals depth - See ‘lithological description order’

6 Fluorescence summary, Remarks (ROP, calcim.)

7 Interval depths for each gas types (Nature)

8 Unusual operations results (summerized)and ‘mail box’ (equipm. failure, Subsidiary requirem.,Geologist’s Contractors crew change, ...)

9 Morning situation & planned operations for the day

Wellsite Geologist(s) name10

1

32

4

5 6

7

8

9 10

ROCK name, colour, hardness,texture, matrix & cement, fossils &accessories, porosity, Oil shows


Geological Well ReportTEXT.doc

PRESSURE MEASUREMENTS

SAMPLING SEQUENCE

MUDLOG

PORE PRESSURE

DATA TRANSFER (ASCII)


UOY

ASCII files


MUDLOG Basic wellsite document

MANUAL ’’ bi-hecto ’’ AUTOMATIC ’’ GWR ’’


CORING: Description sheet

GWRCORE SHEET

computer aided designdeliberately

not developed


Operations CODING and TIMING (1)

AIM FOR REFERENCING and FILING EACH INTERVENTION & OPERATIONDURING WELL DURATION INTO THE ‘DAILY DRILLING REPORT’

MOVING & RIG UP

A

DRILLING OPERATION

F

CASING & CEMENT C

SIDE-TRACKS

GEOLOGY EVALUATION

G RESERVOIR EVALUATIONW

PRODUCTION:WORK-OVER & COMPLETIONP

PLUG & ABANDON

B


TIMINGDDR => DECIMAL TIME 2.50(GWR => SEXAGESIMAL 02:30)

00h00 - 24h00

G W

P

F

S

C

PLANNEDOPERATIONS

PRODUCTIVE TIME(PT)

Operations CODING and TIMING (2)

UNSCHEDULEDEVENTS

(DOWNTIME)

NON-PRODUCTIVE TIME(NPT)


DAILY DRILLING REPORTTOTAL ‘subsidiary’

Well NAME RIG NAME

Geological remarks:- TOP FORMATIONS- Main GAS peaks- ...

DEVIATION SURVEYS

OPERATIONS DESCRIPTION

SUMMARY of OPERATIONS

WELL STATUS at:

OPERATIONS PLANNED

drilling PARAMETERS average

MUD data

Mud PRODUCTS

REMARKS

COMPANY’S REPRESENTATIVE


ANNEXES

S U M M A R Y

Easy RESEARCH …

Mudlogging KEYWORDS index

Usual CONVERSIONS and EQUIVALENTS

UNIT CONVERTER (general)

Basic Wellsite GLOSSARY(English-Français-Español)

Standard LITHOLOGICAL ABBREVIATIONS: A => K

Standard LITHOLOGICAL ABBREVIATIONS: L => Z

CUTTING DESCRIPTION worksheet (TOTAL & Geoservices forms)

Simplified GEOLOGICAL SRTATIGRAPHIC SCALE



EASY RESEARCH … Press to

BASICGLOSSARY

(GB - F - E)

KEYWORDGENERAL INDEX

OIL FIELDABBREVIATIONS

TECHNICALDATA SHEETS

UNITCONVERTER

More … ?

OPEN

CUTTINGDESCRIPTION

SHEET

MUDLOGGINGAUDIT

GEOLOGICALWELL REPORT


Mudlogging KEYWORDS index research


CONVERSIONS & EQUIVALENTS

VOLUME1 bbl = 159 lit

= 42 gal= 5.61 cuft

1 gal = 3.786 lit1 m3 = 35.31 cuft

= 6.29 bbl1 cuft = 7.48 gal

= 28.32 lit

Gallon expressed in ‘US gal’ (Imperial gal = 1.2 US gal) ppg => pound (lb) per gallon psi => pound per square inch

SPECIFIC GRAVITY1 g/cc = 0.12 ppg1 ppg = 8.345 g/cc

PRESSURE1 kg/cm2 = 14.22 psi1 bar = 14.50 psi1 atm = 14.70 psi1 bar = 1.02 kg/cm2

1 g/cc = 2.31 psi1 psi = 0.433 g/cc1 psia = 1 psig - 14.7

LENGTH1 m = 3.28 ft1 ft = 30.48 cm1 in = 2.54 cm

MASS1 lb = 0.454 kg1 kg= 2.2 lb

TEMPERATURE°C = (°F-32)*5/9°F = (°C*9/5)-32

GRADIENT Pressure:1 psi/100 ft = 2.262 bar/10m1 bar/10m = 44.21 psi /100 ft Temperature:1°C/100m = 0.549°F/100 ft1°F/100 ft = 1.82 °C/100 m

AREA1 acre = 4047 m 2

320 acres = 1.295 km2

1 ha = 10000 m2= 0.1 km2

1 ha = 2.47 acres

°API vs DENSITY(g/cc)

° = −°°

APIsg g cc

FF

@@

.( / )

.6060

14151315


UNIT CONVERTER

ANGLEAREACONCENTRATION (mass/mass)CONCENTRATION (vol/vol)DIAMETERELECTRIC POWERENGINE SPEEDFLUID LOSS CoefficientFORCEFRACTURE CONDUCTIVITYFRACTURE TOUGHNESSINVERSE PRESSUREINVERSE TEMPERATUREINVERSE TIMEK PRIMELENGTHMASSMASS GRADIENTPERCENT

38 CATEGORIES INCLUDING MORE THAN 170 UNITS

PERMEABILITYPOWERPRESSUREPRESSURE GRADIENTRATE (mass/time)RATE (vol/time)SPECIFIC HEATSPURT LOSS CoefficientTEMPERATURETHERMAL CONDUCTIVITYTHERMAL GRADIENTTIME TIME RELATIVEVELOCITYVOLUMEVOLUME GRADIENTVOLUME per COUPLINGVOLUME RATIOYIELD (vol/mass)

CLICK HEREto open

UNIT Converter


BASIC WELLSITE GLOSSARY

3 SHEETS => 3 sorting keys

CLICK HEREto open

GLOSSARY


STANDARD ABBREVIATIONS (non exhautive ) 1/2

Aabout abtabove abvabundant abdaltered altalternating altgamorphous amorand &angular angapproximate apprxarenaceous arenargillaceous argas above a.a., a/aassociated assocat @average av

after SAMPLE EXAMINATION MANUAL - AAPG, 1981

Bbecome/ing bcmbed bdbioclastic bioclblack bkblocky blkyblue blbottom btmbreak brkbright brtbrittle britbrown brn

Ccalcareous calccarbonaceous carbcaving cvgcement cmtchocolate choccirculate/ion circclastic clasclean clnclear clrcoarse crscommon comcompact cpctconchoidal conchconglomerate cglconsolidated consolcream crmcross-bebbed X-bdcross-lamin. X-lamcuttings ctgs Ddark dkdebris debdetrital detrdecrease/ing decrdisseminated dissemdominant/ ly domdirty dty

Eearthy eaelongate elongequivalent equivexcellent exextremely extr

Ffair frferruginous ferrfibrous fibrfine ffissile fisflake:y flkfluorescence fluorforaminifer foramfossil fossfracture:d fracfragment fragfriable fri Ggenerally genglass/y glasglauconite/ic glaucgood gdgrading gradgrey gygreen gn

Hhard hdheavy hvyhigh/ly hihomogenenous homhorizontal horhour/s hrhydrocarbon hc

Iinclusion inclincrease/ing incrindurated indin part i/pinterbedded intbdintercalated intercalintergranylar intgraninterval intvlintrisive intriron Feirregular/ly irr

Jjoint jn

Kkaolin / itic kao


STANDARD ABBREVIATIONS (non exhautive ) 2/2

after SAMPLE EXAMINATION MANUAL - AAPG, 1981

Llamina/ tion/ted lamlarge lgelayer lyrlight ltlimy lmylithic litlithology litholittle ltlloose lse

Mmarl/ly mrlmassive massmaterial matmatrix mtrxmilky mkymineral minmoderate modmost/ly mstmud md

Nno sample NSnodule/ar nodno show n/sno visible poro nvpnumerous num

Ooccasional/ly occolive olvoff-white offwhopaque oporange orngorganic org

Pparticle parpatch/y pchpebble pblpellet pelpermeability k, permpetroleum petpink pkplastic plaspour point ppporosity porpredominant/ly predprimary primprobable/bly probpseudo- pspurple purppyroclastic pyrcl

Qquartz qtzquartzite/ic qtzt

Rrare rrecovery/red recred rdremains remrock rkround/ed rnd Ssaccharoid/al saccsame as above aasample splscarse scsscattered scatsecondary secsediment/ary sedshow shwsilica/iceous silsilt/y slt/ysize szslight/ly sli/lysmall smlsoft sftsorted srtstain stnsticky stkystructure strsub- sbsucrosic suc

Uunconsolidated uncons Vvery vvisible visvitreous vitvug/gy vug Wwaxy wxyweathered wthdweak wkwell wlwhite whwith w/without w/owood wd Yyellow yel

Ttan tntexture texthick thkthin thntop tptrace trtranslucent trnsltransparent trnsp


CUTTING DESCRIPTION Worksheet

Booklet out of print

Bookletfrom ML

Contractor

A4 size

GWR


STRATIGRAPHIC SCALEMESOZOIC PALEOZOICANTHROPOZOIC

HOLOCENE

PLEISTOCENE

CENOZOIC

NEOGENEPLIOCENE

MIOCENE

PALEOGENEOLIGOCENE

EOCENE

PALEOCENE

CRET

ACEO

USJU

RASS

ICTR

IAS

DANIANSENONIANTURONIANCENOMANIAN

ALBIANAPTIANBARREMIANHAUTERIVIANVALANGINIAN

PORTLANDIANKIMMERIDGIANOXFORDIAN

CALLOVIANBATHONIANBAJOCIAN AALENIAN

TOARCIANPLIENSBACHIANSINEMURIANHETTANGIAN

RHETIANKEUPERMUSCHELKALKBUNTSANDSTEIN

LIAS

D

OGGE

R M

ALM

EOCR

ET. N

EOCR

ET.

my

2

4

25

65

my70

95

130

150

180

200

250

my

PERMIAN 250

CARBONIFEROUS 290

DEVONIAN 360

SILURIAN 400

ORDOVICIAN 440

CAMBRIAN 600

PROTEROZOIC

ALGONKIAN 600ARCHEAN... 4500



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N NOVEMBERO OSCARP PAPAQ QUEBECR ROMEOS SIERRAT TANGOU UNIFORMV VICTORW WISKYX X-RAYY YANKEEZ ZOULOU


MUDLOGGING CONCLUSION

Documents

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