A_rock Properties and Saturation 1-6-04

8/11/2019 A_rock Properties and Saturation 1-6-04

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Rock Propertiesand In-Situ Saturation

Copyright 2003 Schlumberger. Unpublished work. All rights reserved. This work contains con idential and proprietary trade secrets o Schlumberger and may

not be copied or stored in an in ormational retrieval system! trans erred! used! distr ibuted! translated or retransmitted in any orm or by any means! electronic or

mechanical! in whole or part! without the e"press written permission o the copyright owner.


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Outline

Importance to SchlumbergerRocks properties Porosity

Primary and Secondary Permeability Matrix

Fluid SaturationsPressure


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Objecti es

State the importance to you and Schlumberger!escribe " rocks properties!escribe " types o# permeability

!escribe !arcy$s la% #or oil and gas %ells!escribe primary and secondary porosity&xplain the applications o# a perm s' porosityplot'

!escribe and calculate (uid saturations')hat is the *ing +ubbert e,uation


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Importance to Schlumberger)ell logging)ell testing

.reatment designProduction prediction


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Rock Properties

Rocks are described by threeproperties/

Porosity - ,uantity o# pore space

Permeability - ability o# a #ormation to (o%

Matrix - major constituent o# the rock


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Reser oir RocksReser oir rocks need t%o properties to be success#ul/

Pore spaces able to retain hydrocarbon' Permeability %hich allo%s the (uid to mo e'


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b

mab

b

pV

VVVVPorosity =

Porosity/ .he #raction o# total olumethat is a ailable #or the storage o#(uids


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Porosity

Porosity depends on grain packing0 not grain si1e

Rocks %ith di2erent grain si1es can ha e the samepercentage porosity but di2erent permeability'

# Rhombohedral packing# Pore space = 26 % of total volume

# Cubic packing# Pore space = 4 % of total volume


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Pore-Space 3lassi4cation .otal porosity0 t 5

&2ecti e porosity0 e 5

6 ery clean sandstones / t 5 e

Poorly to moderately %ell -cemented intergranular materials/t e

+ighly cemented materials and most carbonates/ e 7 t

Volume Bulk Space PoreTotal

Volume Bulk Space Porected Interconne


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Rock Matrix and Pore Space

Rock matri!

Pore space


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3arbonate Porosity

Intergranular porosity is called 8primaryporosity8'

Porosity created a#ter deposition iscalled 8secondary porosity8'

Fissures 9not Fractures: 6ugs


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3arbonate Porosity/ Primary

"nterparticle porosity# $ach grain isseparated! giving a similar pore spacearrangement as sandstone.

"ntragranular porosity# %ore space iscreated inside the individual grains whichare interconnected.

3arbonate porosity is ery heterogeneous' It is classi4ed into a number o# types/


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Fissures 9Fractures:/Secondary Porosity

Fissures are caused %hen a rigid rock is strainedbeyond its elastic limit - it cracks'

.he #orces causing it to break are in a constantdirection0 hence all the 4ssures are also aligned'Fissures are an important source o# permeability in

lo% porosity carbonate reser oirs' )hat is the perm o# a ;'< in %ide 4ssure

$issures

atri!

3&'0()( af w**.)ftmd(wk =


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3hannel Porosity/ Secondary

3hannel porosity/ Similar to #ractureporosity but larger '


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%ermeability is a property o the porous medium and is a measure o thecapacity o the medium to transmit luids

Absolute %erm* +hen the medium is completely saturated with one luid!then the permeability measurement is o ten re erred to as speci ic or absolutepermeability

$ ective %erm* +hen the rock pore spaces contain more than one luid!then the permeability to a particular luid is called the effective permeability.

$ ective permeability is a measure o the luid conductance capacity o aporous medium to a particular luid when the medium is saturated with morethan one luid

,elative %erm* -e ined as the ratio o the e ective permeability to a luid at agiven saturation to the e ective permeability to that luid at '00 saturation

%ermeability


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Oil

)ater

=as

k

kk eoro =

k

kk e&r&

k

kk egrg =

Calculating !lati"! #!$m!a%iliti!&


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Relati e Permeability 3ur es

0

0.2

0.(

0./

0.)

'

0 0.' 0.2 0.3 0.( 0. 0./ 0.1 0.) 0.& '00

'&

k r

krwkrg


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!arcy$s >a%

> 5 length

, 5 (o% ratep 1 0 p2 5 pressures? 5 area perpendicular to (o% 5 iscosity

(

)irection of flo&*

p 2 p +,

)( 21 p p

L

A

qk

=

k = permeability-measured indarcies.

k kh


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!arcy$s >a%/ Radial Flo%

h 5 height o# the cylinder 91one:P 5 pressure at rP

w 5 pressure at the %ellbore

rw / r ln

) Pw P ( khq

= 2

. $ $ w


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=

s/01r

r ln

pphk+1310(

&

eoo

&f 5

=

s/01r r ln67

pphk+13150(

&

eg

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!arcy$s >a%/ PseudosteadyState &,uations

>i,uid (o% in >aminar Flo% through apermeable medium/

.he beha ior o# gas (o%ing in laminar (o%through a porous medium/

g Dq s s +='


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Permeability and RocksIn #ormations %ith large grains0 the permeability is high and the (o% rate larger'

In a rock %ith small grains the permeability is less and the (o% lo%er'

=rain si1e has no bearing on porosity0 but has a large e2ect on permeability'

k md @ 9 : A

k

k


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Permeability B Porosity3rossplot

+11

+1

+

10+

101+ 101+

10+

+

+1

+11

+111

2 6 +1 +4 2 6 +1 +4 +

P e r m e a

b i l i t y - m d .

Porosity -%.

,imestone *+ 'andstone *+


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Fluid SaturationsCasic concepts o# hydrocarbon accumulation

Initially0 pore space 4lled


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Saturation

?mount o# %ater per unit olume 5 S %?mount o# hydrocarbon per unit olume 5 9< - S % :5 S h

atri!1

8ater 9ydrocarbon -+:' &.

' &


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In-Situ Saturation

Rock matri! 8ater ;il and


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Summary/Reser oir Rock Properties

Porosity to retain fuidPermeability to allow the fuid to movePermeability is a dynamic property

unconnectedpore spaces

flo& path


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Reser oir Pressure

>ithostatic pressure is caused by thepressure o# rock0 transmitted bygrain-to-grain contact'

Fluid pressure is caused by %eight o#column o# (uids in the pore spaces'? erage 5 ;' GH psi #t 9saline %ater:'

O erburden pressure is the sum o#the lithostatic and (uid pressures'

k d


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&xercise/ aJRock Properties and Saturation

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A_rock Properties and Saturation 1-6-04