Publications

A detailed depositional facies mapping has been conducted in recent Bodri Delta in the north coast of Central Java. This study suggests that sedimentation processes and hydrodynamically controlled facies of Bodri Delta could be identified. Bodri Delta is a wave-dominated delta that has three main facies: delta plain, delta front and prodelta. The delta plain comprises meandering channel, swamp, beach ridge terrace, and tide-dominated estuaries. The delta front comprises detached mouth bar with bar crest and wave sand spit. The prodelta comprises muddy facies. One interesting point encountered in the study was a large amount of organic matter accumulation in the tide-dominated estuaries (TDE) facies. This suggested a new idea to produce biogenic methane from this facies. This paper aims to prove the idea by conducting laboratory analyses. Five TDE mud samples had been analyzed using rumen as a source of methanogenic bacteria in connate water condition. These samples were incubated in isolated tubes at room temperature (natural condition) for 22 days. The results show there are changing of pH value, from 6.38-6.77 to 6.95-7.05 and also producing methane 5.81 ppm. These data show the physico-chemical characteristics of TDE deposit is a suitable condition for methanogenic bacteria to grow and to produce methane gas. Based on these laboratory results, it is recognized that bacteria injection could be applied in the subsurface analysis of ancient TDE deposits (a new play). For the implementation, exploration of ancient TDE of Bodri Delta must be focused southward, because Bodri Delta has been prograding ±8.6 km northward during the Holocene. It could be concluded that this is a promising method for shallow biogenic gas to be developed as future unconventional resources.