PENGARUH STRUKTUR DAN TEKTONIK DALAM PREDIKSI POTENSI COALBED METHANE SEAM PANGADANG-A, DI LAPANGAN “DIPA”, CEKUNGAN SUMATERA SELATAN, KABUPATEN MUSI BANYUASIN, PROVINSI SUMATERA SELATAN

Abstract

The increasing of oil and gas and energy crisis nowadays has been causing the explorationist look for
the new energy sources such as gas in shale and coal which more environmentally friendly. South
Sumatera Basin is one of Indonesian Basin which has a large potency with 183 tcf. Methane gas is
stored in natural fracture of coalbeds called cleat. Cleat was produced during coalification and
tectonism process.

The aim of this study is to evaluate the influence of structures and tectonism processes towards the
CBM potency in an area. The research methods were done by desciptive and analysis methods.
Descriptive method was done by describing secondary data which contain rock mass data, and
analyzing method was done by analyzing subsurface data consist of seismic and wireline log. Those
data were used to determine the sweetspot area and calculate gas in place in target zone of CBM.

Based on geologic structure analysis, primary orientation trends which configure geologic structures
is northeast-southwest, it is a Compression Phase of Miocene-Recent. This stress configured sincline,
sinistral strike-slip fault, and normal faults in tensional phase. The interesting area of CBM
exploration or sweetspot area located in the northeast area, with normal faults which control fracture
permeability reach 12,22 mD, high thickness reach 14 – 18 feet (4,7 – 6 meter), and CBM target
depth of < 6000 feet (2000 meter), and gas in place calculation reach 0,742 tcf. Completion
techniques for CBM target in study area with relatively low permability are hydraulic fracturing
completion and horizontal well with direction of well is relatively northeast-southwest which
perpendicular with face cleat.