Predicting Resource Potential of Hydrocarbon in the Gulf of Cambay, West Coast of India, by Integrating Rock Physics and Multi-attribute Linear Regression Transform.

The exploration block MB_OSN-2004/1 in the Gulf of Cambay on the western coast of India is an area of interest for oil and gas exploration, as it is surrounded by hydrocarbon-producing fields including a giant field—Bombay High. However, preliminary studies indicate the presence of non-commercial hydrocarbons (mainly gas) in only three wells among the nine wells drilled in the block. We, therefore, propose an approach to reinvestigate the area by integrating rock physics modeling with multi-attribute linear regression transform to predict hydrocarbon potential from the seismic and well log data. The area of interest (~ 200 km²) is carved out of the main full 3D survey area (~ 1441 km²). We first estimated the saturation of gas with depth from the observed sonic velocity by applying rock physics modeling. Then, we applied a model-based inversion algorithm to compute the acoustic impedance volume by inverting the 3D post-stack seismic data. The computed saturation at well locations and 3D acoustic impedance were used in stepwise multi-attribute linear regression to estimate 3D saturation. The estimated gas saturation was in the range of 5–80% of the pore space within the Paleocene, Eocene, and Oligocene sequences in the Tapti, Mahuva, Pipavav, Panna, and Deccan Trap formations of the study area, where porosity varies in the range of 10–40%. This study suggests that gas can be exploited commercially from wells that penetrate sequences with good reservoir quality as so interpreted. [ABSTRACT FROM AUTHOR]