Mapping Sweet Spots in a Shale Reservoir through Simultaneous Inversion of 3 D Seismic Data

In contrast to a conventional clastic or carbonate reservoir, where sweet spots for drilling are defined by petrophysical properties like porosity, volume of clay and water saturation, in a shale reservoir the same are characterized by geomechanical properties of the rock such as brittleness, elastic moduli, Young’s modulus, Poisson’s ratio and total organic carbon (TOC). An accurate description of the reservoir and appropriate mapping of the sweet spots are key for an optimized drilling campaign in shale gas reservoirs, The detailed mapping of sweet spots helps in proper planning of well location and completions. Traditionally, such programs are heavily dependent on well logs recorded at pilot wells. ,traditionally, post-stack seismic attributes are used to augment interpretations from the well logs to avoid zones of structural complexities, such as faults etc. Recently, rich information available in seismic gathers in the form of Amplitude Variation with Offset (AVO) has been used to achieve these objectives (Sena et al., 2011; Gabino et al., 2014). We present here the results of simultaneous inversion of multiple offset stacks from a 3D onshore survey over a shale block from the United States to demonstrate that geomechanical properties derived from inversion provide invaluable information to map sweet spots for further use in well planning and designing of hydraulic fractures.