Abstract: Petroleum Geology of Tembungo Area, Sabah Basin

Muhamad Abdul Jalil, Ibrahim Komoo

Tembungo area, located in the central part of the Sabah Basin, is a highly prolific hydrocarbon play. This is reflected by the discovery of Tembungo field in 1971, which has been producing oil for more than 19 yr. Petronas (PRSS) has recently reassessed the remaining potential of the area by undertaking an integrated study to determine structural and stratigraphic evolution, reservoir characteristic, source rock potential, entrapment styles, and hydrocarbon potential.

The results indicate that Tembungo oil has been generated from dominantly terrigenous organic matter derived from coastal and inland vegetation. The reservoir sandstones, which were deposited during middle to upper Miocene, were evidently transported

from a shallow coastal region into a bathyal environment by turbidity current. These sandy sediments entered the basin from the south and southeast through canyons and channels, and spread into the basin in the form of deep-water fan complexes. Shales that dominated the sedimentary sequences in the basin formed an effective cap rock.

Integrated study of Tembungo area reveals the presence of a number of structural and stratigraphic prospects significant for hydrocarbon exploration. Some stratigraphic prospects include wedge-out and pinch-out. Paleochannel distribution pattern is an important factor in controlling the highly potential prospects as it provides clue to the presence or absence of reservoir rocks. Combined with structural and stratigraphic features, several new prospects have been identified and ranked.

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