Azimuthal pre-stack depth migration for in-situ stress evaluation in a fractured carbonate oil reservoir: Predrill prediction of instantaneous shut-in pressure gradients

• DOI: 10.1190/segam2014-0392.1
• Publication Date: 2014-08-05T18:07:51Z
• Authors: Heloise B. Lynn*; Walter Lynn; Justin Obilo; Vinod Agarwal
• Keywords: Pressure gradient; Directional Drilling

A high-fold full-azimuth, full-offset 3D P-P reflection survey was acquired and processed for the purpose of characterizing a naturally fractured carbonate reservoir. The reservoir is thick carbonate, overlain by shale, which will flow oil with sufficient fracture network. on-going drilling completion program horizontal wells plus hydraulic stimulation. azimuthal seismic attributes were compared to ISIP (instantaneous shut-in pressure) gradients, taken as indicating minimum stress, other calibration data discussed in companion papers presenting amplitude results. Azimuthal interval velocities derived from prestack depth migrated provide insight into in-situ stress field. success stimulations depended upon having low presence natural fractures that oil. results this study are: 1) magnitude slow velocity (VINTslow) showed local proportional sensitivity estimated gradients. 2) anisotropy (VINTfast-slow) seen be locally inversely gradients throughout much survey. 3) Based on observations first two results, pre-drill qualitative predictions corroborated well drilled after we had finished processing interpretation