Publications

Deepwater sandstones are prolific reservoirs offshore East Kalimantan and in other deepwater basins around the world. In East Kalimantan, porosities average between 25% and 30% down to depths of over 10,000 feet and wells have tested at rates above 10,000 BOPD. The challenge, after discovery, is to characterize the extent, connectivity, flow units and depositional model of the reservoir sands in order to optimize the development plan. Amplitude data, from 3D seismic, can generally be used to characterize the high porosity reservoir sands due to a large drop in acoustic impedance relative to the surrounding shales. However, in the offshore East Kalimantan area, the seismic resolution at reservoir level is not always optimal for detailed interpretation.We use models developed from interpretation of high frequency, well imaged seismic data at the seabed and in the shallow subsurface to help us characterize the depositional packages deeper in the subsurface. We predict deposition of sandy deposits in the basin and in slope embayments during lowstands from debris flows and turbidity flows. Canyons scoured during the lowstands may be filled with shales or sands, and areas adjacent to the canyons are interpreted to be dominantly shales deposited by muddy hemipelagic rain. Muddy debris flows are thought to be the predominant deposits in the basin and slope embayments from slumping of the canyon walls during high and low sealevel times. Interesting “wavy bedforms which migrate updip with time are observed at the seabed, in the shallow subsurface, and are preserved in some areas of the deep subsurface. Although it is possible that the “wavy bedforms are slumping and plastic flow, we believe the bulk of the evidence supports an interpretation of contourites on the slope. Regardless of their depositional origin, they can be used to predict areas of mostly muddy deposition where they are preserved and imaged at reservoir depths.