Cased_Hole_summary.pdf

8/10/2019 Cased_Hole_summary.pdf

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12004 NExT All Rights Reserved

Variable Density Log (5 receiver)

- Full waveform rectified & color coded

casing then formation (P or P&S)

- qualify cement to formation bond- BP no casing, strong P(S) arrivals

- FP only strong casing arrivals

-annulus, channel casing & P(S)

Repeat with 500kpsi or Ultrasonic

1) Evaluate cementing job efficiency to place right quality cement (Zc) over

right depth interval, without channel & good bonds (casing to cement &cement to formation) to minimise risk of communication between zones

2) Evaluate eventual need for squeeze& possibility to squeeze (annulus)

3) Have a reference for eventual futur cement reevaluation

Cement Bond Log (3 receiver)

- First casing arrival : BP < E1 < FP casing to cement Bond Index

B.I=(LogFPLogE1)/(Log FP-LogBP)E1 single averaged value affected byexcentralisation, concentric casings,fast formation, parameters as well asannulus, channel, Zc

annulus = Channel = Contaminated

Cement Placement Evaluation 1 of 2Cement Placement Evaluation 1 of 2

Monopole Sonic Tools (SDT, SLS, SCMT, Sonic Scanner) with 3 & 5 receivers


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Pulse-echo technique uses rotating (7.5rps) transducer emitting abroadband ultrasonic wave to :

- excite casing into its resonance mode depending on casing thickness &

- analyse resonance decay depending on Zmud

& Zcement

- compute 72 Zcement & casing reflectiv ities, internal radii & thicknesses

- sor ts Zc into Gas (ZcZTCM) or liquid USBI

Identi fies channel down to 5,

Insensitive to microannulus smaller than 100

10 of dry annulus or 300 of wet annulus behave like free pipe

difficult differentiation between lite Crete & liquid of similar Z

attenuative muds (12 dB/m/MHz) WBM < 1.9g/cc OBM < 1.4 g/cc

Cement Placement Evaluation 2 of 2Cement Placement Evaluation 2 of 2

Ultra Sonic Imager Tool


3/13


CBL LQC

1) Check TT is constant and correct (TT2 ~ 300s for 7 & 340s for 9 5/8 ),

) Check NMSG = TT210s, CBLG=35s, AMSG=TT2-120s, SGW=80s

) TT=TTSL (apart opposite fast formation where TT>TT2>TTSL) 2 ok

) Check CBL = FP (52mv in 9 5/8, 62mv in 7, ..) above Top Of Cement else

) Adjust CBAF to read CBL = FP above TOC

) If BI is presented check MSA corresponds to BP value for Zcement from UC

) Correlation (or anticorrelation) of GR with CBL indicates interference ofcasing to cement bond & formation confirms cement behind casing

) If CBL increases at concentric casing shoe repeat with shorter CBLG

Cement Placement EvaluationCement Placement Evaluation -- LQCLQC

VDL LQC

1) Opposite high CBL reading late, low frequency S formation arrival can be

the only proof of large annulus rather than FP


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USIT LQC

1) Check FPM versus DFVL & ZMUD used to compute radii & Zcement

2) check internal radii versus casing nominal I.D else change DFVL

3) check that ECCE is smaller than 0.02 * casing OD

4) use ZMUD = 304.8 * mud densi ty / DFVL

5) check ZTCM = ZMUD + 0.5 MRayl

Cement Placement EvaluationCement Placement Evaluation LQC & QLLQC & QL

USBI=BI=100%

USBI=BI=0%

USBI=BI=75%

Perfect cement placement Channel (25% or 90) Wetannulus < 100

USBI = 100%

20% < BI < 80%

Wetannulus > 300

USBI = 0%0% < BI < 5%VDL S arrival

fast formation

Dry annulus < 10

USBI = 0%

60%< BI


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Reservoir Saturation Tool

RST*

1

RST Pulsing Modes

capture

Energy

Time

Time

GAMMARAYSIGNAL

inelastic

IC

CS/Sigma

WFL

MODE

100 s

1500 s

0.3 s ~ 60 s

NEUTRONPULSE

thermal neutroncapture cross section

oxygen activation

Saline saturationBH Yw, TPHI

MEASUREMENT

I NTERPRETATION

inelasticC,O,Si,Ca,Fe

C/O saturation

captureH,Cl,Si,Ca,S,Fe,Gd... lithology

water velocity & flow


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Chlorine has high thermalneutron Capture cross

Section :

~ Sw

Works in any borehole fluids

GOC, H2O entry points

So independant of salinity offormation water

Spectrolith from C spectrum

No quantitative Sw in low-salinity H2O < 35 kppm

Gas filled boreholes need

AIRB = YES

Principles

Advantages

& other

appications

Limitations

Sigma mode Inelastic Capture mode

Inelastic spectrum analysis

near & far Carbon/Oxygen

COR ~ (1-Sw)

Cannot differentiate Oil & gas

Work best with gas < 10%

Slow logging speed

only for porosity > 12%

Reservoir Saturation ToolReservoir Saturation Tool


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Water entry @ 425

No production below 425

Oil entry @ 380 => SIBH decreases water velocity increases =>

FBAC decreases

GR increases

Compare Shut in &

Flowing passes

GR w/o minitron is GR reference

Shut in pass is FBAC reference

FBAC & GR in flowing show H2O

& . 407


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GHOST and PS Platform Overview

Flow-Caliper Imaging tool

Combinations

Gradiomanometer tool GHOST tool

Telemetry, gamma ray,

CCL, pressure,temperature

Density, deviation Gas holdup, gas/liquid

bubble count, one-armcaliper, relative bearing

Velocity, X-Y caliper, water

holdup, water/hydrocarbonbubble count, relative

bearing


9/13


GHOST Log Output

Single PassRate INTerpretation

Real-TimeInterpretation


10/13


SinglePassRate INTerpretation 2.0

bubble

size

Frict.Corr.

3

Flow.

Added:

- Selection of hold-up

sensorsFloView & GHOST

GHOST & GradioFloView & GradioFloView

GHOSTGradio

3 Phase

Spinner Pitch 2.14 IN

Spinner Threshold 4 FT/MN

Spinner Efficiency 1

E probe Stand Alone Bubble size 0.06 IN

O probe Stand Alone Bubble size 0.04 IN

Water Density 1.0 GR/CC

Oil Density 0.7 GR/CC

Gas Density 0.15 GR/CC

Hold-up Selector *

- O probe bubble size

- Adjustment factor forFloView & GHOST

- Correction factor forInverted Gradio


11/13


Flow Rate Calculation

Cable velocity

Rotation

al

velocity

Fluid velocity

Readings at a given depth

Multiple Passes

Single Pass

Pitch

Vm = ( RPS . P + T Cs ) E

- SPRINT recommended values

for efficiency E :

0.9 in monophasic flows

1.0 in multiphasic flows


12/13


Flagship Tool String: PSP Architecture

RSTThree Phase Hold-upHoldups from Sigma

PFCSTotal flowrateHole diameter

PVLWater velocityOil velocity

DEFT, GHOSTFlow regimeWater hold-upGas hold-up

WFLWater velocityWater flowrateindex

Pressure/TemperatureGamma Ray/CCL


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Flow Scan Imager (FSI)

FSISonde

(11)

(+Welldi

ameter&

Toolorientatio

n)

4MS

5Op/5Ep

1MS/1O

p/1Ep

FSI Specifications: 1-1/16, ~16 150oC, 15 kpsi CT and tractorconveyance

PSP, RST combinability

Fluid local velocity

Optical

Probe

Gas holdup & Bc

Electrical

Probes

Water holdup & Bc

FSI Sonde Structure

Documents

Cased_Hole_summary.pdf