Publications

South Sumatera Basin is Indonesian Basin which has a large CBM potential of 183 tcf. Several parameters are needed to evaluate the CBM potential, such as geological factors, including coal thickness, depth, quantity and quality of coal, structural geology influences which control fracture permeability from tectonism processes. Methane gas is stored in the natural fractures of coalbeds called cleats. Cleats were produced during coalification and tectonism processes. The aim of this study is to evaluate the influence of structural and tectonism processes towards the CBM potential in a study area. The research methods were done by desciptive and analytical methods. Descriptive methods were done by describing secondary data which contain rock mass data, and an analytical method was done by analyzing subsurface data consisting of seismic and wireline logs. Those data were used to determine the "sweetspot" area in target zone of CBM. Based on geologic structural analyses, the primary orientation trend, which configures geologic structures is northeast-southwest, which is a Compressional Phase from Miocene to Recent. This stress configured synclines, sinistral strike-slip faults, and normal faults in tensional phase. The interesting area of CBM exploration or "sweetspot" area is located in the northeast area, with normal faults, which control the fracture permeability, deliver 12,22 mD, coal thicknesses reach 14 – 18 feet (4,7 – 6 meter), and a CBM target depth of < 6000 feet (2000 meter). Completion techniques for CBM targets in the study area with relatively low permeability are hydraulic fracturing completion and horizontal wells where the direction of the wells are relatively northeast-southwest which are perpendicular with face cleats. Keywords: coalbed methane, secondary permeability, sweetspot area