Publications

Biogenic Gas has become an economic target of exploration and exploitation, due to the high demand for gas. Its geological occurrence is easily interpreted, it is significantly widespread, shallow and gas is of good quality of gas with >98% content of CH4, low S and CO2 content. Production tests from this blocks resulted in a production rate peak of 50 MMscfd at Segat field. This paper presents a summary of Geology, Geochemistry and Geophysical aspects, to assess Biogenic Gas accumulation in Bentu Block.Biogenic gas origins were shown by carbon isotope analysis to be of d13C CH4 value -62 to -66 . The main gas-bearing reservoir is a 7-25 foot thick sand layer over a Late Miocene to Pliocene Binio Formation, at a depth of 600-2000 feet below sea level. The Binio formation was deposited in a coastal environment that reflects the onset of marine regression. The gas is trapped along a NW-SE anticlinal system, related to a reverse fault.Seismically, existing data clearly exhibits strong amplitude anomalies or a “bright spot as a Direct Hydrocarbon Indicator. Furthermore, advanced geophysical analysis: AVO, seismic attribute and LMR methods, were carried out to confirm gas presence. The result of this analysis has been helpful to distinguish between coal and gas bearing reservoirs, where coal revealed a similar appearance in the seismic data. Seismic data were also important to delineate lateral gas distribution and to explore prospects & leads in Bentu Block.Growing interest in gas exploration and development, and also a high demand for gas supplies, encourage the study of Biogenic gas, which has nowadays become important.Biogenic Gas characteristically occurs at a shallow depth and in high quality, which makes this gas economically attractive for production. Bentu area, as one of the proven and potential Biogenic gas targets, provides a typical integration of Geological, Geochemical and also Geophysical aspects to assess gas accumulation.Keywords: Biogenic gas, shallow, good quality, exploration, development, economic