SUCCESSFUL CBM CORING ACTIVITY INTEGRATED WITH CONVENTIONAL WELL DRILLING IN SANGA SANGA BLOCK, MAHAKAM DELTA, EAST KALIMANTAN, INDONESIA

摘要

The Sanga Sanga Production Sharing Contract (PSC) which is known as a very large conventional gas producer in East Kalimantan, is now developing another opportunity; coal bed methane (CBM). In November 2009, the Sanga Sanga PSC contractors secured the CBM rights in the PSC. Having both the conventional and CBM rights allowed the Sanga Sanga operator (VICO) to explore opportunities to combine the CBM initial appraisal program with the conventional development well drilling, by having CBM coring in oil and gas development wells in areas where there may be CBM potential. Coring of the coal is normally the first step in determining whether a CBM project can be successful. Analysis of the cores allows calculation of gas content, gas composition, gas saturation, and also coal properties. The Sanga Sanga CBM coring campaign started in early 2010 and so far 18 wells have been cored which 10 of those was cores obtained in the conventional well drilling. To comply with the conventional well drilling objectives and also to get good data, a CBM Coring Operation Decision Tree was created. CBM coring requires the use of wireline system to minimize the retrieval time of the cores. A quick and accurate core retrieving and handling processes is essential to minimize the lost gas measurement of the total gas content (lost gas, measured gas, residual gas). CBM wireline coring operations in Sanga Sanga project brought up some issues to be resolved. However overall there was a very good result with a very high core recovery in average of 85% with a total of 434 feet of coal recovered. The key point of this article is that it is possible to accelerate a CBM project evaluation in a double PSC area such as Sanga Sanga area with good efficiency.