Publications

Usually the paradigm in producing hydrocarbons from the basement reservoir is focused on fracture zones. If there are no massive fault and fracture zone at the basement, it is believed that the basement reservoir has no hydrocarbon potential. Jabung Block is a proven example of new method for recognizing and producing hydrocarbon potential from basement reservoir. This study does not only focus on fractured zone, but also focus on weathered zone. The weathered zone is characterized by high gamma ray and resistivity, which is as fresh basement zone, but the density value is lower than the fresh basement zone. In the previous method, the weathered basement reservoir was considered to be a basement part and does not have an intensive fracture in Jabung Block. DST results from several wells obtained a small rate, than it was decided not to continue producing from basement and moved to the deltaic reservoir that has better reservoir property. Based on the new concept, weathered basement can be separated from fresh basement. The weathered basement has better matrix property than fresh basement. It was decided to try fracturing at this zone. The result of fracturing at HS-1 well obtained gas rate of 3 MMSCFD, which is significantly increase compare with previous conventional perforation 0.6 MMSCFD gas rate. Through flow channel fracturing on oil well HS-2 and HS-3 at the neighbor structure, gives oil rate 146 BOPD and 300 BOPD, respectively. Following those results, more detailed evaluation of electric logs, mud logs, and seismic attributes using AVO have been done to know hydrocarbon potential in weathered basement for 35 development wells that have not been develop yet. This new method is continued to be used for other structures in Jabung Block. It is believed that this reservoir potential also occurred at other structures in the Jabung Block, even in other oil companies that operates in South Sumatera Basin.