Publications

Maximizing reserves in a mature field is a classic challenge within the oil and gas industry. Petapahan Field, Central Sumatera Basin of PT Chevron Pacific Indonesia was discovered in 1971 with peak production over 48,000 BOPD in 1973. By 2006 the production had declined to 2,900 BOPD. From this point forward, steps were taken to increase reserves in the Petapahan Field by exploiting bypassed oil in structural and stratigraphic traps increasing oil production by improving recovery and water cut of existing wells. The first step to boost the fields performance was to reprocess existing 3D seismic acquired in 1995 to enhance the subsurface image. Interpretation of the re-processed 3D seismic identified new faults across the field that were previously hidden in the noise of the old processed data. Fault seal analysis was completed to understand the fault behavior and to determine reservoir compartmentalization. Concurrently, it was decided to reactivate existing wells by reopening sand intervals that had been closed for an extended period of time (8-10 years) due to water coning. This reactivation of sands increased production more than expected. Integrating the results of 1) the seismic interpretation, 2) fault seal analysis and 3) production of the reactivated wells, unearthed stratigraphic and structural compartmentalization of potential by-passed oil not recoverable by existing wells. An infill drilling project was then conducted to develop these opportunities. The infill drilling project was very successful as the four (4) infill wells produced about 4,900 BOPD initial production rates in a field that was producing 3,100 BOPD. The drilling project was also an excellent economic success, with total cumulative production 463,000 bbl during the first ten months production period (January to October 2008). Assuming an average oil price of $70 US/bbl, the project generated more that $32 million US revenue while capital and operating costs for the project were about $5.2 million US. Additional locations have been developed for future drilling projects based on the updated geologic model and 2008 drilling results.