Characterization of naturally fractured basement reservoir and its play concept, South Pattani Basin, Gulf of Thailand

Abstract

Structural development and complex basin forming mechanism in Pattani Basin may have formed naturally fractured basement reservoirs. The basement of the South Pattani Basin is poorly understood, as a result of low seismic resolution in its deeper part and lack of wells that reach the basement. Hence, seismic interpretation may improve the understanding of South Pattani Basin basement fracture systems. This paper aims to investigate the geological and seismic characteristics of the fractured basement reservoir, identify the relation between basin evolution and fracture network and development, and proposed a play concept for naturally fractured basement reservoir. Seismic attributes exhibit prominent N-S fault and fracture trends in the study area. Three basement high areas revealed that open fractures distribution identified using seismic ant-tracking technology has good correlation with regional maximum horizontal stress direction (N-S), but the intra-basement (central) area exhibits strong alignment with pre-existing fabrics (NW-SE). Open fracture networks in Zone A and B developed around major fault swarm features. Integrated qualitative and quantitative seismic analysis suggests that the three basement high areas have the potential for fractured basement reservoirs, with a complex fracture configuration and development due to poly-phase deformations.