Abstract

The first biogenic gas discovery of AndamanNicobar Basin is an offshore well located in the Diligent strait, near the Andaman and Nicobar Islands. The carbonate reservoir of the well has been evaluated through seismic wedge modelling, which is a technique used to analyze the geological structures of any region by examining the reflection and refraction of seismic waves. The study aims to understand the reservoir properties and seismic response of the gasbearing limestone formation for effective exploration and development of the hydrocarbon resources in the Andaman-Nicobar Basin. The analysis involves integrating well log data and seismic data to characterize the rock properties and model the seismic response. Rock physics helps in understanding the relationship between petrophysical properties and elastic properties of the rocks and is therefore essential to validate the inferences made from seismic amplitude measurements. Rock physics analysis helped to establish relationships between the reservoir properties, such as porosity and the observed seismic attributes. Well log data, including gamma ray, resistivity, density, and sonic logs, are also used to estimate the rock properties. Well log da ta cross-plot analysis helps predict the nature of lithology and possible fluid content in the formation. The seismic wedge model of the discovery provides insights into the geological features of the region, such as the distribution of rock layers. These valuable insights have significantly contributed to our understanding of the potential reasons for the limited presence of hydrocarbons in five other wells drilled near the discovery. Moreover, they have greatly improved our comprehension of the diverse characteristics and distribution of the reservoir rocks. Overall, seismic wedge modelling and integration of rock physics has enhanced insight and new dimension of understanding in Andaman-Nicobar basin.