--> Abstract: Exploration Potential in Toe Thrust Area of Block F Sarawak Deep Water - Malaysia, by Theresia Kuswardhany, Robert Wong, M. Irwani Sadi, and Barry James Boyce; #90072 (2007)

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Exploration Potential in Toe Thrust Area of Block F Sarawak Deep Water - Malaysia

Theresia Kuswardhany1, Robert Wong2, M. Irwani Sadi2, and Barry James Boyce2
1Petronas Nasional Berhad, Kualalumpur city, Malaysia
2PETRONAS, Kuala Lumpur, Malaysia

Block F, located within the Sarawak deep water basin in 500–2000 meters water depth, has one well, viz. Jelawat-1/st drilled June 2004. Mapping of 2,360 sq. km 3D seismic shot in 2002 revealed new untested Rajang Delta reservoir types in the toe thrusts previously unevaluated. These Rajang Delta Late Miocene – Pliocene turbidites were deposited in a variety of settings.
Clastics accumulated in slope and basin floor during Late Miocene to Late Pliocene. Late Pliocene aged listric faulting and toe thrusting, which ramp above the 10.5 Ma aged carbonate horst blocks, caused ponded turbidites above basal detachments. Mobilized shales above these horsts allowed plastic deformation of younger reservoirs.
Project objectives are to delineate best quality turbidite reservoir sands in shelf, slope and basin floor. The types of turbidites in the catchments areas are ponded, channel, channel lobe and channel levee. Risk and resource estimates prove this is an attractive area.
Late Miocene and older anoxic shales, considered potential source rocks, matured during early Pleistocene. Shallow gases accumulated at the end of the compression phase are indicated by the numerous gas chimneys.
Reservoir distribution using amplitude extraction delineates moderate continuous amplitudes characteristic of sheet like distal turbidite facies near the well; but Jelawat -1/st was poorly located to evaluate any good reservoir types and consequently was abandoned. High amplitudes west of the well indicate the presence of high porosity sand. Amplitude extraction maps indicate low amplitudes in the vicinity of the well outside any channel belts. Gamma ray log and cuttings indicate a lack of reservoir, but gas isotope data in the C1-C5 range indicates the presence of hydrocarbons.

 

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece