ABSTRACT: Deep Water Exploration Potential of the Neogene Sandakan Basin, South Sulu Sea, The Philippines
Samsu, Dharmawan H.1, I. Wayan Darma2, Kristian
Meisling3, Daniel T. Boyd1, Stephen Hertig4,
and Charles T.
(1) ARCO International Oil and Gas Co, Plano, TX
(2) ARCO Indonesia Inc, Jakarta, Indonesia
(3) ARCO Exploration & Production Technology, Plano, TX
(4) Vastar Resources Inc, Houston, TX
An integrated evaluation of 8000 km of 2D seismic data and regional wells indicates the presence of active, and potentially prolific, petroleum systems within several distinct structural domains that comprise the under-explored Miocene Sandakan basin. The 90 km wide Sandakan basin is filled with 6,500 meters of highly-prospective deltaic and correlative deep-water slope to bathyal section that overlies volcanic basement and spans most of the Miocene epoch.
Within the region with water depth exceeding 600 meters, regional mapping defines three key structural domains from west to east. These are a large system of northwest-trending detached listric normal growth faults as a result of deltaic collapse, a buckled zone of slope basins underlain by shale ridges caused by Miocene slope failure and sediment loading, and a compressional toe-thrust belt located in the most distal portion of the delta subparallel to the growth fault. The toe-thrust belt forms a large anticlinorium which is kinematically coupled to the northwest-trending growth fault by a detachment near acoustic basement.
Both seismic AVO effect and paleogeographic maps constructed from sequence analysis of the Miocene section, suggest correlative turbidite sands occurs eastward of the growth-fault domain. Predominantly marine lowstand or pro-delta units source rock in the deep-water area is unproven, but suggested by paleogeographic analyses. Integration of source rock, heat flow and transformation ratio modeling within the Middle to Late Miocene section suggests that 2,900 to 4300 meters deep oil window have excellent potential to expel hydrocarbons where peak kerogen transformation occurred in the last 5 Ma.
AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia