Integration of Geology, Rock-Physics, Logs, and Pre-stack Seismic for Reservoir Porosity Estimation

Abstract

The main objective of this paper is to obtain reservoir properties, such as porosity, both at the well locations and in the inter-well regions from seismic data and well logs. The seismic and well-log datasets are from an oil field in eastern Saudi Arabia, and the main target is a Jurassic carbonate reservoir. The geology of carbonate reservoirs in Saudi Arabia is well understood. However, reservoir porosity estimation is essential and needs to be determined for flow simulation and reservoir management. One of the main components of this project is establishing the relation between the Pimpedance and porosity using well log data. An amplitude-versus-angle (AVA) seismic inversion algorithm was employed to invert for the 3-D impedance volumes (i.e., Pimpedance and S-impedance) given partial angle stacks of seismic traces representing reflection amplitude variations with angle of incidence. These impedance volumes were used to estimate porosity between the well locations. The seismic and log data provided a priori information (i.e., the initial starting model and source wavelet estimate) to obtain geologically consistent results.