Fracture densities and fracture azimuths evident in the azimuthal amplitudes from the top of a fractured carbonate oil reservoir

• DOI: 10.1190/segam2014-0393.1
• Publication Date: 2014-08-05T22:07:51Z
• Authors: Heloise Bloxsom Lynn
• Keywords: 01 natural sciences; 0105 earth and related environmental sciences

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. calibration data natural fractures are: 1) logging-while-drilling (LWD) Star Trak™ resistivity image log in horizontal borehole, 2) micro-seismic (m-s) data. were through azimuthal prestack depth migration (PSDM), traveltimes quantified non-sectored analysis then removed into attribute volumes, leaving flat common gathers (CIGs). companion paper presents minimum stress (taken as Instantaneous Shut In Pressure gradients) correlation interval velocity slow. After offset vector tile (OVT) PSDM, four azimuth sectors (0-180 degrees), each angle stacks, enabled AVOaz computation Top/Reservoir, well computations variation incidence. Inversions, both azimuthally-isotropic azimuthally (only VS allowed to change azimuthally), gave estimates rock properties. amplitudes themselves insight results presented this near-offset (7°) best matched Trak data; acceptable, but did not match 7° incidence amplitudes; m-s events most frac stages studied showed NE-SW spatial distribution indicating maximum orientation, consistent VINTfast; 3) at several stage centers, detailed patterns that track density interpreted from amplitudes, specifically, amplitudes. 4) To explain data, knowledge in-situ (azimuthal VINT) amplitudes) must be used.