Prospectivity and Resource Potential of the Malaysia-Thailand Joint Development Area JDA: Results from an Integrated Play Based Exploration Project
Authors: Ali M. F. , Hernandez J. , Brink G. , Koronful N. , Xue F. , Jiang L. , Bencomo J. , Ishak A. Z. , Skulsangjuntr J. 
Published: March 2018

The study area of this paper is located in the mature North Malay Basin, within the offshore Malaysia-Thailand Joint Development Area (MTJDA). Exploration activities have been conducted since 1971 and several gas fields have been developed, mostly at relatively shallow stratigraphic levels of Late Miocene sequences. The study area covers 7250 km2, which includes exploration and production areas covered by approximately 300 wells, 6400 km2 of 3D surveys and 10664 km of 2D seismic line. The multi-disciplinary team was tasked to establish the overall hydrocarbon potential of the area, including potential new play-openers and covering the area outside of existing PSC acreages.

The workflow initially focused on post drill analysis of the existing wells whereby new complete petrophysical analyses for 74 exploration and appraisal wells were incorporated. Geological and geophysical interpretation focused on delineation of regional structural setting and development of a seismic sequence stratigraphic framework. This comprised of interpretation of key selected surfaces at wells and on seismic in the Oligocene and Miocene succession of the North Malay Basin. Upon completion of the tectono-stratigraphic interpretation, litho- and chrono-stratigraphy, sedimentology and sequence stratigraphy, analyses of seismic attributes and gross depositional environments (GDE), velocity model construction, depth conversion, isopach maps, regional overpressure trends; hydrocarbon play analyses could then proceed as supported by comprehensive petroleum system modelling and a regional CO2 study. Source rock hydrocarbon generation and migration timing are favourable throughout the Oligocene to Pliocene at all prospect levels. At lead and prospect scales, work on seismic inversion, AVO analyses and pore pressure modelling were undertaken preceding prospect volumetrics, risking and ranking. Primary target play types are predominantly comprised of stacked, stratigraphic structural combination traps of tidedominated estuarine reservoirs, deposited within a high frequency 4th-order sequence.

This comprehensive play based evaluation approach has successfully identified remaining hydrocarbon prospectivity, not only at deeper undrilled stratigraphic levels, but also at current producing shallow sequences. Several potential drillable prospects were further analyzed for future exploration, often with strong stratigraphic elements, as well as unconventional new play-types enabled by conceptual geological models and supported by existing data analysis and interpretation. Furthermore, a robust petroleum system modeling has enhanced and supported prospective plays in this basin, facilitating realistic yet-to-find resource estimates over the entire area, with good future prospectivity remaining in the area. Apart from the various collaborative technical studies carried out during the project, the imperative factor behind the success of this project was the synergy and co-operation among the team members, with regular technical and management reviews.