GEOLOGICAL INSIGHTS INTO UNCONVENTIONAL HYDROCARBON DEPOSITS OF THE EASTERN FOLDED BELT, BANGLADESH

The thin-bed reservoir units of the Eastern Folded Belt are medium to fine-grained and well sorted, with frequent alteration of sand shale with the prevalence of parallel bedded sandstone. The samples collected from the field are studied in the laboratory to characterize the reservoirs more precisely. The overall workflow of laboratory analysis has been categorized into three sorts. In the petrographic study, the thin section of the samples is studied to determine their textural properties thoroughly. The porosity and permeability have been determined by analysing textural characteristics and diagenetic changes. This microscopic section evaluates the effects of diagenetic processes on reservoir quality. A scanning electron microscope was utilized to complement the inconclusive results. The most crucial finding from this study is that the thin bed of the unconventional reservoir and the conventional reservoir are in close proximity in the context of reservoir quality. The average porosity in a thin bed reservoir is 4 to 12%, and pore spaces are interconnected. So, the permeability rate is good enough to flow the hydrocarbon through these pore spaces. The thickness of the thin bed and tight reservoir (average porosity 2 to 8%, but pore spaces are not interconnected) is only as prominent as 1 or 2 meters. Subsequently, though the vertical thickness is not so high, they keep up a momentous tirelessness of horizontal progression. With advanced technology, the gas production rate from unconventional reservoirs in Bangladesh can be expanded significantly, and thus, the energy crisis might be reduced. At the same time, the dependency on LNG could be reduced, and the economy of Bangladesh could be sustainable