Publications

The Tarakan Basin in Indonesia has significant, potential coal bed methane (CBM) resources. One coal bearing formation in the Tarakan Basin has already been shown to contain CBM: the Tarakan Formation. This formation is indicated to be the prime CBM target in the Kuncring area. The Tarakan Formation is composed of sand, shale, and coal interbeds that belong to a Pliocene delta system. They mainly developed in the Tidung Sub basin and the western part of the Tarakan Sub basin and were deposited as delta front–delta plain sediments. The maximum coal thickness of the Tarakan Formation is about 3 m at a depth of 861 m (based on the Ciyus-3X well). According to the Hinira-3X well, the maximum coal thickness is about 10 m at a depth of 1330 m. There are ten coal seams in the interval of 1156–1700 m depth within the Hinira-3X well and nine coal seams in the interval 772–1262 m depth within the Ciyus-3X well. The objectives of this evaluation are to identify and to map the CBM potential in the Kuncring area by integrating all available geological and geophysical data consisting of well data (Ciyus-3X and Hinira- 3X wells), two-dimensional seismic data, and surface geology and other data, both published and unpublished. The scope of the evaluation is aimed to put the captured acreage into proper subsurface configuration, identifying its coal zone by well logs and its continuity by seismic inversion, and to estimate the CBM resources in the Kuncring area. Based on well log analysis, the Tarakan coalbed in the Kuncring area can be divided into three coal * Patra Nusa Data zones.Moreover, lateral continuity of the Tarakan coalbed in this area distributes from NW to SE with estimated gas resources at more than 2 TCF. Keywords: Tarakan Formation, Coal Distribution, CBM Resources