Integration of 3D-Seismic With Reservoir Simulation for Reservoir Characterization and Assessment of Alternative Exploitation Schemes of Field Development - A Case Study

Abstract

Abstract This paper deals with a study where integration of 3D-seismic survey and reservoir simulation has aided in reservoir characterization which in turn have led to better and effective implementation of reservoir development schemes. Shalmari, one of the major oilfields in Assam-Arakan geological province of North-East India was discovered in 1986 and the initial field development was carried out on the basis of then available 2D-seismic data. During the course of initial field development, the area of major concern was the rapid decline of reservoir pressure. A detailed simulation study was carried out in 1994 for assessment of the pressure maintenance requirements and field development. A 3D-seismic survey was carried out in 1994 in this area to obtain additional information on the reservoir geometry and structural configuration. The processing and interpretation of 3D-seismic data resulted in identification of additional faults thus bringing about a change in the structural configuration of the reservoir. The presence of identified faults was corroborated by pressure transient surveys. This necessitated in carrying out of another detailed reservoir simulation study by building up a geological model based on 3D-seismic data. The basic objective of the study was to carry out a more accurate and reliable reservoir characterization apart from identifying the prominent direction of aquifer support and reassessment of the hitherto planned reservoir development scheme including ongoing pressure maintenance scheme. The results of the study carried out in 1997 also indicated possible increase in gross ultimate recovery as a result of water flooding. The financial analysis of the development schemes envisaged in this study was also found to be attractive. Cross-discipline integration of data expertise and study has helped in accurate mapping of the minor faults and has provided a better insight into fault transmissibilities in the fluid flow simulation.