Finding New Exploration Targets in the ‘Mature’ Petroleum Basins Offshore Thailand: All About Nuance

Abstract

Thailand's offshore Tertiary basins have yielded nearly 5 BBOE. Exploration initiated in the 70s and peaked by mid 90s. Volumetrically the discoveries are dominantly gas (∼80%). Some important discoveries within the northern Pattani Basin have significant oil reserves e.g. Jasmine 60 MMBO. Basins offshore Thailand consist of Eocene-Oligocene NW-SE grabens, overprinted by narrow N-S fault depocenters developed during Miocene back-arc stretching of continental Sundaland crust. These are filled by lower synrift lake/fluvial deposits, post rift fluvial sequences and drowning brackish intertidal to marine succession. Hydrocarbons are sourced from synrift lacustrine shales. Internally the basins are heavily dissected and compartmentalized by faulting generating numerous traps; consequently exploration targets have consisted primarily of structural traps. With the exception of the disputed boundary zone straddling Thailand / Cambodian waters exploration offshore Thailand is considered to be in a mature stage of exploration. Nevertheless, fields currently being developed reveal a level of complexity that suggest significant additional exploration upside: complex trapping mechanisms related to combined structural and stratigraphic elements rarely targeted in past ventures. We present a rejuvenated play portfolio for offshore Thailand, within the context of a regional structural and biostratigraphic recalibration. In addition we illustrate examples of several complex play-trap systems that we consider still worth significant exploration potential. Our view is that Thailand's perception of exploration maturity may be more related to the operational approach taken till now to finding hydrocarbons, rather than actual depletion of the resource. Current “exploration maturity” is related to old ideas and innovative complex / subtle trapping models and play-types as presented here should generate a step-change in the gulf of Thailand creaming curve.

AAPG Datapages/Search and Discovery Article #90194 © 2014 International Conference & Exhibition, Istanbul, Turkey, September 14-17, 2014