Geophysical Imaging for Characterization
Published:December 01, 2006
2006. "Geophysical Imaging for Characterization", Reservoir Characterization: Integrating Technology and Business Practices, Roger M. Slatt, Norman c. Rosen, Michael Bowman, John Castagna, Timothy Good, Robert Loucks, Rebecca Latimer, Mark Scheihing, Hu Smith
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The east coast of India represents a passive Atlantic-type peri-cratonic margin setup. The Krishna-Godavari basin along the east coast of India covers the deltaic and inter-deltaic areas of Krishna and Godavari rivers and extends into the offshore; it has an area of 1,45,000 sq. km. The basin evolved through crustal rifting and subsequent drifting during Mesozoic time, followed by major fluvial and marine Tertiary sedimentation.
A geologic model has been constructed for Neogene deep-water depositional systems in the Krishna-Godavari basin to conceptualize the reservoir architecture of complex channel-levee, overbank, and lobes on the shelf-slope geologic setting. While the channel-levee deposits are dominated by siltstone/sandstone prone facies assemblages, the lobes are predominantly fine-grained sandstone/siltstone/mudstone facies. High quality 3D seismic imaging and interpretation techniques, integrated with wire-line logs, litho-cut-tings and cores have been followed in characterizing the complex deep-water reservoirs. The study integrates different data sets and methodologies such as (1) high quality 3D seismic with rigorous quality control in acquisition and processing using interactive geological input; (2) imaging enhancement through pre-stack depth migration of selective areas; (3) extensive use of rock-physics attributes through inversion and AVO studies; (4) detailing of depositional architecture through stratal-amplitude attribute, spectral decomposition, and coherency slices; (5) high resolution wire-line logs and analysis; (6) detailed petrophysical and petro-logical evaluation of conventional cores, and (vii) quantitative computation of reservoir properties and improving bed resolution through simultaneous angle dependent inversion.