Abstract

Seismic characterization of naturally occurring faults and fractures is one of the main goals in unconventional reservoirs. It is crucial in understanding the geological history; identify optimal locations for development drilling and to maximize production in these tight reservoirs. The objective of this paper is to discuss and compare the application of unconventional fracture attributes with respect to conventional geometric attributes to enhance fault detection within the tight volcanic reservoirs of Raageshwari Deep Gas field, Barmer Basin. Seismic data is first filtered with a structurally oriented filter to reduce random noise and improve the imaging quality. As a second step, traditional geometric attributes such as semblance and curvature were applied. These attributes successfully identified fault and fracture geometries. Additionally new unconventional fault attribute known as Fault Likelihood, defined as a power of semblance, was then used to capture and delineate faults and fractures in the same area. This attribute scans for a range of fault dips and provides maximum likelihood of fault presence in the value ranging 0 and 1. Further 'thinning filter is applied to obtain sharper fault plane geometries. In comparison with the conventional geometric attributes, the faults and fractures are better visualized by the new method. In addition, the new 'Thinned Fault Likelihood' attribute can further be used for characterizing faults. by extracting fracture attributes known as Fracture Proximity, Fracture Density and analyzing their connectivity. Results of this study will be used for optimal placement of development wells for enhanced field productivity.