Abstract: Hydrocarbon Charge Modeling, Balingian Province, Sarawak, Malaysia

Peter Swinburn, Heinz Burgisser, Jamlus Yassin

Geochemical analyses of source-rock samples and oils strongly indicate that oils in the Balingian province are sourced by coals and coaly shales found in the Oligocene and early Miocene coastal plain sequences. For these source rocks the main phase of oil generation is in the maturity range 0.8-1.1% VR equivalent. The burial history is well constrained by mapping regionally dated horizons and erosional surfaces. The temperature history suggests that from the late Oligocene to present, the heat flow was basically constant and fairly high due to sustained wrenching.

Results of the expulsion and migration modeling suggest that in the Balingian area oil has been flushed out of many traps by the excessive gas generated. Although the source rock distribution is imprecisely known, the estimated total amounts of oil and gas expelled far exceed the quantity in existing accumulations. A high oil:gas ratio can be expected in closures only where either gas flushing has not occurred or a large amount of gas has preferentially leaked.

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