Publications

Exploration in the deepwater Kutei Basin, offshore East Kalimantan has resulted in a number of hydrocarbon discoveries in Pliocene and Late Miocene sediments. A series of depositional models of slope and basin floor sediments have been generated from a study of Recent sediments in this basin (Fowler et al., 2001). The aim of this study was to calibrate these Recent models with drilled Mio- Pliocene examples and then to assess their value as analogues to assist future drilling in the Kutei Basin.The deepwater Kutei Basin contains highly structured and relatively unstructured slope provinces and Mio- Pliocene depositional elements from both structured and unstructured slope and probable basin floor are described and compared to their Recent equivalents. A seismic and biostratigraphically-calibrated sequence stratigraphic framework and 3D seismic techniques such as dip attribute displays, variance cube and amplitude extractions have been employed to visualise and characterise depositional elements. Borehole penetrations allow the identification of lithofacies and diagnostic wireline log motif and the assessment of reservoir quality in each of these depositional elements.Similarities between Recent and Mio-Pliocene deepwater deposits include broad similarity of depositional elements including debrites, slope channels, channel-levee deposits and various fan deposits. Similar stacking patterns are identified and slope gradient appears to similarly influence nature of sedimentation. In all cases, the narrowing and widening of channel belts across changes in slope gradient is clearly seen and toe-of-slope gradient change results in the largest volume of coarse sediment deposition.Differences between the Recent and Mio-Pliocene sediments include the apparent subdued development of pre-Pliocene channel-levees and the identification of Mio-Pliocene backstepping mini-basin fills. Mio- Pliocene fans have been subdivided into those fed by channels and canyons and those fed by leveedchannels rather than the slope and basin floor fan categories used for Recent deposits. The vertical facies succession seen in the Recent sediments, from initial debrites through basin floor fans or channelised complexes to channel levees is only hinted at in the Miocene sediments.These geological models are being used for the prediction of optimum sand-prone facies development and will thus help reduce the risk associated with future exploration and appraisal drilling activity.