comp action drive semifinal

8/8/2019 Comp Action Drive Semifinal

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PRESENTERS

y REHAN MANSOOR 2008-PET-14y DANISH MUHAMMAD 2008-PET-45

y SALMAN ZAHEER 2008-PET-14

y EYAD BADARDIN 2008-PET-48



REHAN MANSOOR2008-PET-47



COMPACTION DRIVEy INTRODUCTION

y LABORTARY MEASUREMENT OF COMPACTION

y MATERIAL BALANCE EQUATION FOR COPACTIONDRIVE RESERVOIRS

y PHENOMENON OF COMPACTION

y ADVANTAGES&DISADVANTAGES

y CONCLUSION



INTRODUCTIONy The withdrawal of liquid or gas results in a

reduction in the fluid pressure and consequently

an increase in grain pressurey The increased pressure between the grains will

cause the reservoir to compact

y This compaction can lead to subsidence at the

surface



y Compaction depends the difference betweenthe vertical applied stress and the internalstress

y Compaction drive is the expulsion of reservoirfluids due to dynamic reduction of the pore volume and will only be significant as a drivemechanism if the pore compressibility Cf is large

y

If Vb is the bulk is volume of a rock sample of thickness h, then the uniaxial compaction will beV b/V b=h/h



CAUSESy Overburden pressure

y Disturbance in subsurface

y Extraction of hydrocarbons from subsurfacey Rock compressibility



DANISH MUHAMMAD

2008-PET-45



Laboratory Measurement of

Compactiony Compaction can conveniently be measured in

laboratory by using triaxial compaction cell

y The core sample is completely saturated with water, which has permeable cap and base plateand a cylinder, flexible sleeve surrounding it

y Vertical stress is applied while the fluid pressure ismaintained at one atmosphere.



Triaxial compaction cell



y The pressure in the fluid surrounding the flexiblesleeve can be increased independently so as to

maintain the condition of zero lateral strain on thesample.

y This pressure is continually adjusted so that any change in vertical thickness of the sample del h is

uniformly related to the measured water expelledfrom the porous rock



graph



The equipment used for rock

compressibility tests



y If the reservoir rock consist of well cementedgrains in a rigid rock frame then the compaction,

over a limited pressure range, will beapproximately elastic and reversible

y In loose unconsolidated sand , however ,compaction is both inelastic and irreversible



SALMAN ZAHEER2008-PET-14



GENERAL MATERIAL BALANCE

EQUATION



(1)



Therefore above Material Balance Equation becomes as:

(2)



FOR VOLUMETRIC COMPACTION

DRIVE RESERVOIRS

Because for volumetric reservoir water influx ,water

injection and gas injection becomes zero.

Material balance equation can be written as;

(3)



(3) We have

(4)

Therefore equation (4) can be written as;

(3) We have

(4)

Therefore equation (4) can be written as;



PHENOMENON OF COMPACTIONy The effect of compaction

in a reservoir through itsgeological history is shown

in this figure

y Taken from L.P Dake



A: Depositional timeB: Rock burried more

deeper after deposition After reaching point Bfollowing events may occur

1. Uplifting of reservoir

2. Erosion of the surface layers3. Overpressuring of fluids in

reservoirC : If inelastic deformationC : If elastic deformation

D : As a result of production



EYAD BADARDIN2008-PET-48



ADVANTAGES&DISADVANTAGESy Besides providing the additional drive energy for

production compaction has important effects both

inside and outside of the reservoiry The most obvious is the surface/seafloor subsidence

y Reduction in permeability leading to loss of productivity

y Effect of deformation on overlying shales orfreshwater aquifers

y Inaccurate estimate of the compaction effect can leadto over or underestimation of reserves



y Subsidence occur in case when the reservoir liesbeneath any populated area may cause a lot of

problems



CONCLUSION We have to get the knowledge of the compactionearly in the life of the field to optimize and manage

production.

comp action drive semifinal

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