Abstract: Hydrocarbon Prospectivity Assessment of the Southern Pattani Trough, Gulf of Thailand

Neil Mountford

The Pattani Trough is an elongate north to south basin in the Gulf of Thailand offshore area that developed from Oligocene times onward. Numerous hydrocarbon discoveries, mainly gas, have been made within the Tertiary stratigraphic section in areas adjacent to the depocenter of the basin, but only dry holes have been drilled on the extreme basin margins and flanking platform areas. The southern Pattani Trough represents a "transition zone" in terms of potential hydrocarbon prospectivity between the low potential/high exploration risk basin marginal areas, and the high potential/low exploration risk basin depocenter area. The development of hydrocarbon accumulation potential within the southern Pattani Trough can be related to a number of major controlling factors. These include struct re, which on a regional scale shows a marked influence of tectonic regime on depositional system development, and on a more local scale determines trap development; stratigraphy, which determines reservoir geometry and potential hydrocarbon source rock facies distribution; petrology, which exerts a major control on depth related reservoir quality; overpressure development, which controls local migration pathways for generated hydrocarbons, and locally provides very efficient trap seals, geochemical factors, related to potential source facies distribution, hydrocarbon type, and thermal maturation of the section.

The above factors have been combined to define low-, medium-, and high-risk exploration "play fairways" within the prospectivity transition zone of the southern Pattani Trough.

AAPG Search and Discovery Article #90982©1994 AAPG International Conference and Exhibition, Kuala Lumpur, Malaysia, August 21-24, 1994