Fracture-related amplitude variations with offset and azimuth in marine seismic data

摘要: Fractures are of great interest for hydrocarbon production. In particular, they can provide conduits fluid flow, hence knowledge their distribution and orientation be critical, especially horizontal wells. Unfortunately, most fractures relatively small, well beyond the imaging range conventional seismic data. On other hand, it is increasingly recognized that do have a strong influence on shear-wave energy (S waves). Indeed, amplitude variations in stacked (qS2) data successfully been used to identify productive fracture clusters Austin Chalk formation Texas (Mueller 1991). Although information fracturing readily obtained from shear waves, direct measurements require both specialized sources multicomponent receivers, not feasible marine environments, except perhaps at sea floor. Of importance fact an impact entire wavefield, with imprint symmetries leading general azimuthal behaviour. As result, although compressional (P) waves insensitive near offsets, become linked larger effects experienced by shear-waves through mode conversion oblique incidence, also own specific sensitivity. Thus, anisotropic P-wave behaviour way obtaining properties subseismic scales. (MacBeth 1995). This then offers potential means studying distributions orientations areas. this paper we present evidence show presence nature (i>P-wave) using AVO (amplitude variation offset) analysis. our results demonstrate fracture-related has distinct (directional) directly fractures. consistent numerical study Mallick & Frazer (1991), previously observed land variety fractured gas reservoirs (Lynn et al. 1996). However, knowledge, given constitute first example phenomenon dataset.