In the last three years, two significant commercial hydrocarbon accumulations in Indonesia deep waters of the Makassar Strait were discovered. These fields are located approximately 16 miles northeast of the giant Attaka Field in 1400 ft to 3400 ft of water.
To date more than 40 exploration and appraisal wells have been drilled in both fields and extensive pressure data has been collected by formation tester tool and drillstem testing tool. The pressure data, used with other data such as seismic and well logs, has enabled Unocal Indonesia to characterize deepwater turbidite sand reservoirs.
In this deepwater environment, DST is used selectively and only with strong justification due to its prohibitive cost. Instead, the use of the pressure testing tool is pushed to its limit in order to gain extensive pressure, rock and fluid properties data, conventionally obtained by DST.
This paper will show the experience of Unocal Indonesia to characterize deepwater reservoirs by means of pressure data from the formation tester tool and DST's to complement geological and seismic data interpretations. Reservoir characteristics such as fluid type, fluid contacts, reservoir connectivity and sand geometry can be inferred from the pressure gradients and pressure transients. These data are used in constructing reservoir fluid flow models for field development plan.