Exceeding the compressive strength

Failure envelope with a compaction cap


Mechanisms of Compaction
 

Pore collapse - plastic deformations



Numerical Methods
 

Numerical extensions of the nucleus of strain method

Early models based on uniaxial compaction in reservoir simulator and C_m coefficient

Coupled geomechanical and flow models - incorporate more complex behavior

Constitution Models for Compaction
 

Elastic models with hysteresis

Elasto - plastic models - cap models

Simple 3-D Case

Porosity (Reservoir Embedded in Geomechanical Grid)


1/4 Element of Symmetry
Pseudo - well in the center
A simplified "Ekofisk" model:
3 reservoir layers, Φ = 35,40,35%
3100m of overburden

GOM Simple 2-D Case
                                                                                     
7 layer reservoir, 3 pay layers separated by shale's                                                   
Linear elastic compaction moduli E = 20,000 psia,                       
ν = 0.3                                                                                                                   
Variable linear elastic moduli for over, under and side burden     



Effect of Salt Canopy on Subsidence - Another GOM Model

Effect of soft salt canopy on vertical deformations, shale E = 4.13E5 kPa




Top - no salt canopy







Bottom - soft salt canopy E = 3E6 kPa





Please refer to our publications for more details.