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Fault Re-activation and Fluid Flow in the Paleogene in Deepwater Gulf of Mexico: A Geomechanics Perspective

Brown, Jeremy A.*1; Zoback, Mark 1; Mallman, Ellen 2; Hornby, Brian 2
(1) Geophysics, Stanford University, Stanford, CA.
(2) BP America, Houston, TX.

The Paleogene play in the Gulf of Mexico is a prolific asset that is located in ultra deepwater Gulf of Mexico. The water depth to the seafloor and subsea depth of the reservoir makes this play one of the deepest and most challenging environments to ever face the industry. Understanding the geomechanics of the Paleogene is crucial in order to optimally and effectively produce the formation. Changes in the in situ stress state as a consequence of depletion can have implications for drilling, production and facilities management. Fault re-activation can not only lead to well shearing and damage and the creation of microearthquakes but also can create a conduit for hydrocarbons to flow out of the reservoir. Fault activity has a large effect on fluid flow and reservoir permeability. This work studies the potential for fault re-activation and subsequent leakage given large depletion in the Gulf of Mexico; and, if fault re-activation occurs, the possibility of passively monitoring the acoustic signals using boreholes instrumented with seismic sensors. A coupled reservoir-geomechanical simulator approach is taken in order to quantify the changes in stress with spatially-variable fluid flow. Due to poroelastic effects and stressing, fault re-activation can occur during depletion depending on the stress path taken and the amount of depletion. Fault re-activation is unlikely to occur for faults within a reservoir.

 

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California