Characterization of selected petroleum source rocks and reservoir rocks of Bengal Basin (Bangladesh) based on geochemical, petrographical and petrophysical methods / Md. Farhaduzzaman

Nine gas fields and two coal fields of Bengal Basin, Bangladesh are studied in the current research based on geochemical, petrographical and petrophysical methods. The Surma Group of Bengal Basin is composed of the Bhuban and Boka Bil Formations. Both formations are composed of sandstones and shales interpreted to have been deposited in a deltaic to shallow-marine environment. This is the most important geological unit of the basin since the entire hydrocarbon accumulations so far discovered in Bangladesh is found within these sandstones. These two formations also contain shale intervals with important source rock potential. Together with coal and coaly samples, shales and sandstones of the Surma Group are the key subjects of the present study. Around 151 core samples of shale, sandstone and coal were investigated for this project. Shale and sandstone cores were chosen from ten wells of respective nine gas fields. Five bore holes of the Barapukuria and Dighipara Basins were selected for coal, carbargillite and mudstone sampling. All shale, coal and coaly samples are subjected to a Source Rock Analyzer (SRA). After SRA screening, different standard geochemical methods (e.g., PyGC, GC, GCMS, AAS, TGDTA, EA and proximate analysis) were employed for the current study. Many shale and coal and coaly samples are examined with UV-facilitated microscope for maceral and vitrinite reflectance analyses. Poor to fair quality source rock potential is estimated for the studied Bhuban and Boka Bil shales. The organic matter found in both formations is thermally immature to early mature for hydrocarbon generation. The organic matters of the analyzed shales are derived from land plants of terrestrial environmental settings with minor contribution from marine sources. The siliciclastic sandstone samples are studied using both petrographic microscope, SEM and XRD for reservoir quality and diagenetic control analysis. Very good to excellent reservoir quality is evaluated by the present study. Together with petrography, petrophysical analysis is also carried out for one well (Rashidpur 4) and four potential hydrocarbon bearing zones are identified.The depositional environment and hydrocarbon generation potential is another focus of the present study, emphasizing the biomarker characteristics of Permian coals of the Barapukuria and Dighipara half-graben basins. In this project, organic facies distributions within the Permian succession are investigated focusing on coals, carbargillites and mudstones in the half-graben basins. The studied bituminous B rank coal consists dominantly of inertinite macerals followed by vitrinite and liptinite. The various facies models used commonly indicate forest swamps with mixed oxic-anoxic conditions under terrestrial settings with periodic flooding. Organic facies characteristics suggest that the coals are dominantly terrestrial with minor contributions from marine sources. The carbargillites correspond to a mixture of terrestrial and marine sources, whereby the mudstones being terrestrial with no marine influences. Very good hydrocarbon generation potential is estimated for the analyzed coal and coaly samples, ranging from fair to excellent. The carbargillites possess good potential for both oil and gas and followed by coals (mainly gas with minor oil) and mudstones (predominantly gas). Along with %Ro and Tmax, the presence of exsudatinite, fluorinite and solid bitumen suggests the analyzed coal and coaly samples have already expelled hydrocarbons

Petroleum source rock properties of the Neogene Bhuban shales,Bengal Basin, Bangladesh

The present study evaluates the petroleum source rock generation potential of the Neogene Bhuban shales from Bangladesh. Organic geochemical and organic petrological methods were used for analyzing 11 drill core samples from 4 gas fields in the basin. Source rock potential, maceral composition, organic matter abundance, biomarker distribution, thermal maturity, hydrocarbon generation and depositional environment were evaluated. Kerogen in the studied shale samples is classified mainly as Type III with lesser amounts of Type II. Vitrinite is the dominant maceral group observed in the analyzed Bhuban samples followed by liptinite and inertinite. Vitrinite reflectance, Tmax and biomarker parameters indicate the thermal maturity ranges from just pre-oil window to mid-oil window. Based on its total organic carbon (TOC), extractable organic matter (EOM) and hydrogen index (HI), the analyzed Bhuban shales are ranked as mainly poor to fair source rocks but with good gas generation potential. The dominant terrestrial environment prevailed during the deposition of the studied Bhuban shales while the condition was sub-oxic as indicated by cross-plots of pristane versus phytane and sterane versus pristane/phytane ratios

Progress of seabass, Lates calcarifer (Bloch, 1970) culture in Bangladesh: Field-level updates from the Bhola and Satkhira Districts

Since the high market value of seabass, Lates calcarifer (Bloch, 1970), mainly found in Bangladesh's coastal waters and tidal rivers of Bangladesh, farmers in those areas cultivate it alongside carp fish in ponds and shrimp farms. Even though farming began many years ago, progress in overcoming obstacles of only natural sources for hatchlings, supplemental feeding, and knowledge on advanced farming management in seabass farming at the field level has been prolonged. This study discusses the current farming and trading of seabass in Bangladesh's coastal districts. Seabass fry is collected from rivers and estuarine areas, grown in hatcheries or ponds, and sold to farmers in large sizes. Some farmers cultivate this fry in mixed fish culture ponds in the extensive method; some farmers cultivate them with carp fish in a semi-intensive method. Seabass feeds only live feed (Tilapia and carp fishes fry); continuous supply is difficult and expensive. In these ponds, seabass is cultivated in the traditional method in 18–20 months, weighing 7-8 kg, and in the advanced traditional method in 1 year, weighing 2-3 kg. The profit percentage of seabass farming with the semi-intensive method is 77.42%. To expand this profitable fish farming, it is crucial to acclimate the fish to induced breeding and supplemental food. The institutions involved should not work in isolation but rather collaborate on developing induced breeding techniques and expanding seabass farming. In this case, prosperous seabass farming countries' experience can be applied.Int. J. Agril. Res. Innov. Tech. 12(2): 117-125, December 202

Progress of seabass, Lates calcarifer (Bloch, 1970) culture in Bangladesh: Field-level updates from the Bhola and Satkhira Districts

Since the high market value of seabass, Lates calcarifer (Bloch, 1970), mainly found in Bangladesh's coastal waters and tidal rivers of Bangladesh, farmers in those areas cultivate it alongside carp fish in ponds and shrimp farms. Even though farming began many years ago, progress in overcoming obstacles of only natural sources for hatchlings, supplemental feeding, and knowledge on advanced farming management in seabass farming at the field level has been prolonged. This study discusses the current farming and trading of seabass in Bangladesh's coastal districts. Seabass fry is collected from rivers and estuarine areas, grown in hatcheries or ponds, and sold to farmers in large sizes. Some farmers cultivate this fry in mixed fish culture ponds in the extensive method; some farmers cultivate them with carp fish in a semi-intensive method. Seabass feeds only live feed (Tilapia and carp fishes fry); continuous supply is difficult and expensive. In these ponds, seabass is cultivated in the traditional method in 18–20 months, weighing 7-8 kg, and in the advanced traditional method in 1 year, weighing 2-3 kg. The profit percentage of seabass farming with the semi-intensive method is 77.42%. To expand this profitable fish farming, it is crucial to acclimate the fish to induced breeding and supplemental food. The institutions involved should not work in isolation but rather collaborate on developing induced breeding techniques and expanding seabass farming. In this case, prosperous seabass farming countries' experience can be applied