Routine Core Analyses

7/24/2019 Routine Core Analyses

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Petrophysical CorePetrophysical Core

AnalysesAnalysesProf. Bassem S. NabawyProf. Bassem S. Nabawy

National Research CentreNational Research Centre

1



2



Sampling & Coring Process

Surface Samples Sub-Surface

Samples

Ditch Samples Core Samples3



4



5



6



7



Coring bitsCoring bits

8

R Sid ll C iR t Sid ll C i



Takes actual samplesTakes actual samples

from the formationfrom the formation

surrounding the boreholesurrounding the borehole

A caliper is deployed A caliper is deployed

to press the RSCT upto press the RSCT upagainst the side ofagainst the side of

the borehole at thethe borehole at the

desired sampledesired sample

locationlocation A rotating diamond A rotating diamond

bit cuts the samplebit cuts the sample

from the formationfrom the formation

Rotary Sidewall CoringRotary Sidewall Coring

ToolTool

9

t



otary ewa or ngo ary ewa or ngToolTool

10



11



12



13

(ethods o) Core(ethods o) Core



Use an aluminized bag as an efective O2 barrier.Use an aluminized bag as an efective O2 barrier.

Flush bag with Flush bag with 22! add O! add O22 "ac#! and core section."ac#! and core section. $eat seal bag.$eat seal bag.

%acuum Sealing! %acuum Sealing! no &luminized bags! no no &luminized bags! no 22

'ushing or O'ushing or O22 "ac#s"ac#s

(ethods o) Core(ethods o) Core

*reservation*reservation

14

The core section beingThe core section being



The core section beingThe core section being wra""ed wra""ed

15

e core sec on en ers e



e core sec on en ers eheat tunnelheat tunnel

16

e wra""ee wra""e



e wra""ee wra""esectionsection

17

+ tube storage rac#s at the+ tube storage rac#s at the



+,tube storage rac#s at the+,tube storage rac#s at the-CR -CR

18

+e"th+e"th



+e"th+e"th(atching(atching

19



The value of the given either formation or an ore-bearing rock is

efine b! its areal e"tent# thickness an its $etro$h!sical $ro$erties%

The $etro$h!sical $ro$erties inclue&

1' (oli $hase $ro$erties )bulk an grain ensit!'*

2' (torage ca$acit! $ro$erties )$orosit!# $ermeabilit!# an irreucible

+ater saturation'*

3' ,lectric $ro$erties )a$$arent electric resistivit! .o/# formation

resistivit! factor /# an true electric resistivit! .t/'*

4' coustic $ro$erties* an

5' Thermal $ro$erties%

20



ow to get Roc! Properties "

21



oring nal!sis .outine core anal!sis )rcal'%

orosit!# $ermeabilit!# saturation# litholog!# grain ensit!%

($ecial core anal!sis )scal'%

a$illar! $ressure# relative $ermeabilit!# acoustic velocit!#

+ater sensitivit!%

22

T f R i C A l i



1- onventional core anal!sis&

se in anal!sis for homogeneous sanan selecte carbonates%

2- ull iameter core anal!sis&

or heterogeneous reservoir incluing

carbonates an those +ith seconar!

$orosit!%

3- (ie+all core anal!sis&

or relativel! homogeneous# $oorl!

consoliate sans%

23

Types of Routine Core Analysis

&d t )&dvantages o) core



&dvantages o) core &dvantages o) core

&nalysis &nalysis orosit!# ermeabilit!# a$illar! ressure an lui

(aturation can in turn assist in&

etermine net $a! an reserves estimate%

ssessing flui an rock t!$e%

nerstaning +ell reservoir $erformance%

,stimate $robable flui $rouction%

,stablishing contacts bet+een reservoir fluis an various rock

units%

,stimating reserves an initial $rouction%

24

&dvantages o) core&dvantages o) core



&dvantages o) core &dvantages o) core

&nalysis &nalysis efining the limits of the fiel%

,stablishing structural an stratigra$hic correlation +ith +ire line

logs%

nter$reting an calibrating +ire-line logs%

esigning rilling an +ell com$letion $rograms%

(electing intervals for testing# that ai in the inter$retation of

$ressure transient anal!sis%

reating a reservoir engineering management strategies%

25



Roc# *hasesRoc# *hases

PorePhase

Grain

Phase

Fluid

Migration

Path

26

-rain *ore and Fluid-rain *ore and Fluid



orosit!

.ockatri"

Total :olume ; :.<ΦT;1

:.;1-ΦT

:olume of

.ock atri"

:=2

>; (?ΦT

:olume

of ?ater

:=; )1-(?'ΦT

:olume of

=!rocarbons

-rain! *ore and Fluid-rain! *ore and Fluid"hases"hases

27

H d b Cl i &



Hydrocarbons Cleaning &

Soxhlet Apparatus

28



Routine Core Analyses

Porosity & ensity Per!eability"The percentage of pore spaces in

the total #olu!e of the roc$%

"The eight of the unit #olu!e

of the roc$%

"The ability of the porous

roc$s to trans!it fluids

under certain pressure

gradient%

29

i* i



*orosity *orosity lassification of orosit! @ccoring to the time of e$ositionA&

'( Pri!ary )*riginal+ Porosity

refers to the $orosit! that evelo$e at the time of

e$osition )sanstone $orosit!'%

,( Secondary )-nduced+ Porosity refers to the $orosit! that forme after e$osition%

fracturing# Bointing# issolution# re-cr!stallisation or a

combination%

olomite ma! be forme b! re$lacing the calcium

carbonate in limestone rock +ith magnesium%

30



0

31

/asic *orosity Ty"es/asic *orosity Ty"es



/asic *orosity Ty"es/asic *orosity Ty"es abric (elective&

nter$article& voi s$ace bet+een $articles ntra$article& voi s$ace insie $articles

ntercr!stal& voi s$ace bet+een cr!stals olic& $orosit! ue to selective removal of a former fossilgrain enestral& bir/s-e!e/ $ores usuall! associate +ith algal mats (helter& sheltering effect of large $articles $revent infilling the $ores b! finer

$articles Cro+th-frame+ork& ue to the in$lace gro+th of a carbonate rock frame+ork

abric (elective& racture& ue to tectonic shocks an ifferent $ressures hannel& issolution enlarge fracture# ue to issolution :ug& irregular-sha$e $ores# ue to issolution avern& irregular-sha$e human-siDe caves# ue to issolution

abric (elective&

Ereccia& ue to brecciation Eoring& making or enlarging a hole as a c!linrical hole b! boring or igging a+a Eurro+& irregular vugs surrouning casts of burro+s or roots (hrinkage& n irregular $ore forme in mu! seiment b! shrinkage%

32



.ffect of #arious factors enhancing or reducing the

effecti#e porosity(


effecti#e porosity(

Reducing factors Reducing factors Enhancing factors Enhancing factors

Selling clay !ineralsSelling clay !inerals

Meta!orphis! Meta!orphis!

Pac$ing and co!paction Pac$ing and co!paction

Ce!entationCe!entation

SilicificationSilicification

Sphericity F RoundnessSphericity F Roundness

issolution and /eaching outissolution and /eaching out

0eathering & Fracturing0eathering & Fracturing

olo!iti1ationolo!iti1ation

Grain sorting & orientation Grain sorting & orientation

2olu!e changes 2olu!e changes

33

*orosity Controls



*orosity Controls

Roundness and S"hericity

S P H . R . C - T 3

34

*orosity Controls



*orosity Controls-rain,Size Sorting in Sandstone

:er! ?ell(orte

?ell(orte

oeratel!(orte

oorl!(orte

:er! oorl!(orte

S*RT-4G

35

*orosity Controls



*orosity Controls+issolution and

leaching out

36

*orosity Controls



o os ty Co t o s

Fracturing

37

Fissures 0Fractures1



0 1 Fissures are caused when a rigid rock is strained

beyond its elastic limit - it cracks.

The forces causing it to break are in a constantdirection, hence all the ssures are also aligned.

Fissures are an im"ortant source o) "ermeabilityin low porosity carbonate reseroirs.

38

%ugs



ugs

%ugs are dened as non,connected "ore s"ace. They do not contribute to the "roducible 'uid total. %ugs are caused by the dissolution o) soluble material

such as shell )ragments a)ter the roc# has been )ormed They usually have irregular sha"es.

39

*orosity Controls



y+olomitization

!abawy, "#$%, & Arabian 'eosciences, ol40

*orosity Controls



*orosity ControlsCementation

41

*orosity Controls



*orosity ControlsCementation

42

*orosity Controls



*orosity ControlsSwelling Clay

distribution

43

*orosity Controls



ySorting and

*ac#ing

Porosity depends on grain pac$ing5

not grain si1e

Roc$s ith different grain si1es can

ha#e the sa!e percentage porosity

but different per!eability(

*orosity Controls



Com"action

45

*ore,S"ace Classication



" lassification of orosit!&

1% Total orosit!

is the ratio of the total $ore volume to bulk volume regarless the

continuit! of the $ores%

2% ,ffective orosit!

is the ratio of interconnecte $ore volume to the bulk volume%

46

*ore,S"ace Classication



o e S"ace C ass cat o

Total "orosity! ∅t 3

4fective "orosity! ∅e 3

VolumeBulkSpacePore Total

VolumeBulk

SpacesPorectedInterconne

%b 3 %" 5 %g47

*orosity



*orosity

.ffecti#e5 isolated and total porosity

Total5 effecti#e5 isolated per!eable anddead end pore space

48

Total and 4fective *orosity



ccoring to the $etroleum geological stuies# $orosit!

coul be classifie as*

'+ Total porosity )∅t+6 is all vois +ithin the rock# regarless of

+hether the $ore s$aces are interconnecte or not*

,+ .ffecti#e porosity )∅e+6 is that $art of total $orosit! +hich is

accessible to free fluis# e"cluing non-connecting $orosit!

an the volume occu$ie b! the s+elle cla!s# an hence

is smaller than the total $orosit!%

49

Total and 4fective *orosity



y

ery clean sandstones / ∅t 0 ∅e

1oorly to moderately well -cementedintergranular materials/ ∅t ≈ ∅e

2ighly cemented materials and most

carbonates/ ∅e 3 ∅t

50

*orosity*orosity



*orosity *orosity '(7ul$ 2olu!e

n all $orosit! methos a bulk core sam$le volume

has to be etermine an this ma! be carrie out b!&

is$lacement of liGui )rchimees mercur! immersion

a$$aratus'%

:b ; )(aturate ?t H mmerse ?t' ensit! of immerse flui

rchimees mercur! immersion a$$aratus :olumetric mercur! is$lacement $um$ 51

*orosity



y 2% Crain :olume )Eo!leIs la+ $orosimeter'

nvolves the com$ression of a gas into the $ore s$ace or the

e"$ansion of gas from the $ores of a $re$are (am$le%

The gas )usuall! =elium' is amitte into a $re-calibrate

reference cell of kno+n volume @:rA at a reference $ressure @1A%

The reference cell gas is then vente into a connecte chamber

+ith a volume @:cA containing a core sam$le +ith grain volume@:gA%

This venting results in a lo+er eGuilibrium $ressure @2A# from

+hich the grain volume is calculate&

:r % 1 ; ):c-:g' % 2 :g ; :c H ):r%1 2'

52

*orosity



#ent 8 ay #al#e

Shut off #al#e

Fro! gas source

Reference

cha!ber

2r Pressure

transducer

sa!ple

cha!ber

2c

sa!ple

2g

Eo!leIs la+ $orosimeter

$elium *ycnomete53

*orosity



3% ore :olume

(im$l!# the $ore volume is calculate b! subtracting the Crain

:olume @:gA from the Eulk :olume @:bA% :$ ; :b H :g

There are other +a!s to measure the $ore volume +hich can be

summariDe as follo+s&

3%1% (ummation of fluis

This metho involves the ine$enent etermination of oil# gas

an $ure +ater volumes of a fresh core sam$le%

The oil an +ater can be obtaine by retort%

The gas can be obtaine b! mercur! inBection%

The $ore volume is etermine b! summing the three

ine$enent volumes%54

orosty



ty

*#en retort

55

*#en retort

*orosity



8(,( 0ashburn Porosi!eter

nvolves the vacuum e"traction an collection of the gas

containe in the $ores of a $re$are sam$le%

The metho measures $ore volume%

8(8( /i9uid resaturation

The $ores of a $re$are sam$le are fille +ith a liGui of akno+n ensit!%

The increase in +eight of the sam$le ivie b! the flui

ensit! is a measure of the $ore volume%

56

*orosity



y 4% Total orosit!

Total $orosit! is etermine b! this metho as com$are +ith

effective $orosit!%

The sam$le is reuce to grain siDe after the r! +eight an bulk

volume are etermine%

Crain volume is etermine an subtracte from the bulk volume

to !iel the total $ore volume%

57

*ermeability



#$t is the ability of the porous me%ia to transmit a single flui% through it

interconnecte% pores.

6. Single *hase System 0absolute "ermeability1

#it is the con%ucti'ity of each phase at a specific saturation( when

secon% or thir% phase is present) the obtaine% permeability of each phase a

a specific saturation is calle% effecti'e permeability) hence) %epen%s upothe flui% ratio an% its %istribution within the pore spaces. *lui% %istributio

in turn %epen%s upon the saturation history an% wettability of the roc!.

2. (ulti "hase system2.6 4fective "ermeability

#it is the ability of the roc! to transmit a flui% when there are two or

three phases within the pore spaces

2.2 Relative "ermeability

Relati'e Permeability +tyPermeabilispecifc

tyPermeabilieective

58

Darcy,s aw i t d d d l d i i l l ti hi f th



k : per!eability5 !illidarcies

q : flo rate5 c!8 ;sec

µ : fluid #iscosity5 cp

L : syste! length5 c!

A : syste! cross sectional area5 c!,

∆p : differential pressure )p'<p,+5 at!(

L

p Ak q

µ

)(∆=

arcy experi!ented and de#eloped an e!pirical relationship for th

flo of fluid through a pac$ed sand 5 $non as arcy=s lo>

GG

J

$1$2

µ

*ne darcy is defined as>

"the ability of the porous roc$ to trans!it fluid of one centipoise #iscosity ) + a rate )9+ of ' c!8 ;s through a cross sectional area )A+ of 'c!, he

the pressure gradient ) P ; /+ is ' at!;c!% 59


per!eability


per!eability



per!eabilityper!eability

Reducing factors Reducing factors Enhancing factors Enhancing factors

Selling clay !ineralsSelling clay !inerals

Meta!orphis! Meta!orphis!

Pac$ing and co!paction Pac$ing and co!paction

Ce!entationCe!entation

SilicificationSilicification

Porosity percent and typePorosity percent and type

issolutionissolution

0eathering & Fracturing0eathering & Fracturing

olo!iti1ationolo!iti1ation

Grain sorting & orientation Grain sorting & orientation

2olu!e changes 2olu!e changes Tortuosity of channelsTortuosity of channels

Co!plexity of pore throatsCo!plexity of pore throats

-rreducible 0ater Saturation-rreducible 0ater Saturation

Roundness & sphericity Roundness & sphericity

Channel dia!eter Channel dia!eter 60

*etrogra"hy and S4(studies la! inerals



llite(mectiteKaolinite

studies la! inerals

61

Clay Minerals in Sandstone Reser#oirs

Authigenic ?aolinite



(econar! ,lectron icrogra$h

arter (anstoneLorth Elo+horn reek >il nitElack ?arrior Easin# labama# (

(ignificant ermeabilit!.euction

=igh rreucible ?ater (aturation

igration of inesroblem

)hotogra$h b! .%J% Kugler' 62



63



64



65

Porosity-permeability cross plot



P e r ! e a b i l i t y

F r a c

t u r e d

r o c

$

C r y s

t a l l i n e

c e ! e

n t e d s

a n d s t o

n e

C l e a n s a n d

s t o n e

Cla y ce!en ted sands tone & ch

al $ F i n e

l y C r y s t

a l l i n e c a

r b o n a t e

s & i t h # u g

s

Coarsely Crystalline

carbonates

Porosity

Generali1ed per!eability<porosity cross plots5

co!!on trends are noted according to roc$ type 66

Porosity-permeability cross plot



Porosity-Permeability Relationships



ermeabilit! can be estimate from $orosit!# resistivit!# (+ an h!rocarbon

ensit! ata% =o+ever# (+ must eGual (+irr# the irreucible +ater

saturation%There are t+o sim$le formulas for meium gravit! oil an r! gas )i%e

h!rocarbon ensit! is assume%

@ Ti!ur .9uation )'B+>

@ For !ediu! gra#ity oil> ?!llie an .ose )1950'

@ For ry Gas> ?!llie an .ose )1950'

23

250

∅∗=

wirr S

K

23

79

∅∗=

wirr S K

2

4.4

)(*3!.0

wirr S

K ∅

=

68

Porosity-Permeability Relationships

@ For !ediu! gra#ity oil>



( )"#

PP$%& 2 −=

g y

69

ffect of stresses on basic roc! properties



MThe effect of the stress is clearly illustrated in the figure( The change in the

per!eability as net effecti#e stress is increased as a function of roc

consolidation and !echanical properties such as Poison=s ration5 and

3oung=s !odulus( For co!pacted roc$5 the percentage change i

per!eability is s!all as net effecti#e stress is increased(

-n unconsolidated sands5

the losses in per!eability

as net effecti#e stress

increase can be dra!atic

unconsolidated roc$

Co!pacted roc$

-nter!ediate roc$

stress

P e r c e n t p e r ! e a b i l i t y l o s

s

70

/as Permeameter



0.0 md ' 7000 md 0.0 md ' 7000 md71



72

Porosity and Per!eability Scales

@ Porosity Scale



@ Per!eability Scale

air & 1 N K ≤ 10 m%*

Coo & 10 N K ≤ 100 m%* an

:er! goo & 100 N K ≤ 1000 m% )Jevorsen# 1967'

,"cellent & 1000 N K )Le+ .ank# Laba+! et al%# 2009'

Legligible & 0 N ∅ ≤ 5 O#

oor & 5 N ∅ ≤ 10 O#

air & 10 N ∅ ≤ 15 O#

Coo & 15 N ∅ ≤ 20O* an

:er! goo & 20 N ∅ ≤ 25O% )Jevorsen# 1967'

,"cellent & 25 O N ∅ )Le+ .ank# Laba+! et al%# 2009'

73

$lnken*er+ (94) stated t,at permea*lt- to +as s relatel-

1lin!enberg ffect



+ ( ) p - + -

,+,er t,an t,at to /ater. e attr*uted t,s p,enomenon to a slip flow

*et/een t,e +as molecules and t,e sold /alls. 1,e error ntroduced s

significant for 'alues less than 0 m%.

/,ere'

k s t,e apparent permea*lt- calculated rom +as lo/ tests md

k # s t,e true a*solute permea*lt- measured rom lud lo/ tests mdPm s t,e mean lo/ pressure o t,e +as n t,e lo/ s-stem atm and

* s t,e $lnken*er+6s actor or a +en +as n a partcular porous medu74

Permeability

0. Single phase system 2absolute permeability3



0. Single phase system 2absolute permeability3

$n perfectly homogenous reser'oir) permeability is e4ual in all %irections. 5hile in real

reser'oirs) permeability 'aries with %irection.

6easurement of flui% flow in a gi'en %irection is an a'erage of the permeability in a

certain plane.

?x

?y

?1

y z v

x z v

y xh

k k k k k k

k k k

.

.

.

=

=

=

irectional per!eability is particular i!portant in

assessing the sedi!entological e#aluation of

per!eability5 fracture porosity5 reser#oir coningpotential5 opti!u! ell direction and orientation and

ell co!pletion design(75

Permeability

7. 6ulti Phase System



7.0 ffecti'e Permeability

"-t is the per!eability to a particular fluid 5 i(e( oil5 gas5 or ater )$ o5 $g5

or $+ in the presence of any other phase%(

y

D E $o5 $g5 $ E $

Where:

k : absolute per!eability

k o : oil effecti#e per!eability

$ : ater effecti#e per!eability

$g : gas effecti#e per!eability

ater capillary all

76

Permeability




"-t is the fractional ratio of the effecti#e per!eability of certain phase tothe absolute per!eability%(

D E $ro5 $rg5 $r E '

Where:

k : absolute per!eability

k ro : oil relati#e per!eability

$r : ater relati#e per!eability

$rg : gas relati#e per!eability

?ro : $o ;$5

$r : $ ;$5

$rg : $g ;$

7.7 Relati'e Permeability

y

77

Permeability




aboratory measurement of en% points'( Clean the core6 e#acuate all fluids(

,( Saturate ith ater6 then S : ' and ?r : ? and absolute per!eability

can be !easured(

8( -nect oil 5 )non<etting5 drainage+ until no further 0ater is produced5

ater saturation no : Sirr 5 at this point ?o could be !easured (

( 4o inect ater )etting5 i!bibition+ until no further oil is produced5

oil saturation is e9ual Sor )the e9uilibriu! point+5 at this point ? could

be !easured ((


78

ysteresis effect Relati'e Permeability



79

oiloil

kA )(∆





+ater +ater

+

∆=+=

w

rw

o

rowot

k k

L

pkAqqq

µ µ .)(

ro

o

o k L

pkAq

µ

)(∆=

rw

w

w k L

pkAq µ

)(∆=

[ ]wo

w

w

o

ot M M

L p Ak k

L p Aq +∆=

+∆= .)(.)(

µ µ

Where:

M o = oil mobilit

M ! = !ater mobilit

$o : effecti#e per!eability to oil : $ro@$

$ : effecti#e per!eability to ater : $r@$

(+ < (o ; 1

80

Fluid saturations

*actors Affecting Relati'e Permeability



'eometry of the pore spaces and pore si4e

distribution 5ettability

Fluid saturation history )i.e., imbibition or drainage*

Characteristics of Relati'e Permeability Relatie permeability is uni6ue for di7erent rocks

and 8uids

Relatie permeability a7ects the 8ow

characteristics of reseroir 8uids.

Relatie permeability a7ects the recoery81

&""lications o) Relative *ermeability Functions



y

Reservoir simulation

Flow calculations that involve multi,"hase

'ow in reservoirs 4stimation o) residual oil 0and7or gas1

saturation

82

$s there another metho% to measure the permeability"

Absolute per!eability



'( C*R.S

Absolute per!eability

.ffecti#e per!eability

Relati#e per!eability

,( T.ST-4G .ffecti#e per!eability

8( /*GS Absolute per!eability

83

8ettability 8ettability 5 tt bilit5 tt bilit



5ettability/5ettability/

: :it is the tendency of one 8uid to spread on or adhereit is the tendency of one 8uid to spread on or adhere

to a solid surface in the presence of other immiscibleto a solid surface in the presence of other immiscible8uids;.8uids;.

5ettability refers to interaction between 8uid and solid5ettability refers to interaction between 8uid and solidphases.phases.

<nterfacial )boundary* tension/:it is the energy per unit area )force per unit

distance* at the surface between phases;.

Commonly e=pressed in dynes9cm.

84

ature o) 8ettability



S4( microgra"h o) oi wetting nature o) a clay illitematerials.

S4( microgra"h o) water wetting o) an illite rich 9uartzsandstone reservoir roc#.

85

Documents

Routine Core Analyses