Feasibility of estimating vertical transverse isotropy from microseismic data recorded by surface monitoring arrays

• DOI: 10.1190/geo2011-0028.1
• Publication Date: 2011-12-31T23:01:51Z
• Authors: Davide Gei; Leo Eisner; Peter Suhadolc
• Keywords: Transverse isotropy; Overburden; Microseism; Normal moveout

Microseismic data recorded by surface monitoring arrays can be used to estimate the effective anisotropy of overburden and reservoir. In this study we inversion picked P-wave arrival times Thomsen parameter [Formula: see text] anellipticity coefficient text]. This employs an analytic equation traveltimes as a function offset in homogeneous, transversely isotropic media with vertical axis symmetry. We considered star-like distribution receivers and, for geometry, analyzed sensitivity method picking noise uncertainties velocity source depth. Long offsets, well high number per line, improve estimation from noisy times. However, if do not use correct value or depth, long-offset may increase inaccuracy anisotropic parameters. Such cannot detected time residuals. also applied field acquired during hydraulic fracturing gas shale reservoir compared results parameters estimated synthetic computed layered medium. The explained layering only is partially due intrinsic and/or overburden. emphasizes importance using accurate values depth estimating passive seismic data.