A Review on Hydrocarbon Prospectivity in Chittagong Hill Tracts and Adjacent Area

Abstract

Bangladesh is a country with limited sources of energy and since 1990 natural gas has been its main source of energy. Most of the exploration approaches had been conducted onshore especially in the central and eastern part of Bangladesh, particularly in northeastern Sylhet basin. Among the hydrocarbon provinces, the East Delta Hill Tract province is an under explored petroleum province in Bangladesh. An exploratory well drilled in Sitakund anticline was found dry but no reasonable cause was perceived why that well went dry. Although many works had been carried out in Chittagong Hill Tracts but none of them was cumulative and descriptive. In this study, the overall hydrocarbon prospect of the Chittagong Hill Tracts was analyzed by mapping of potential zones on the basis of the evaluation of regional structure and construction of lithocolumn of the prospective zones. The five elements of the petroleum system discussed thoroughly to find overall petroleum prospect of the study area. Source rocks of Chittagong Hill Tracts are mainly Bhuban shale, reservoir rock is sandstone from Bhuban-Bokabil formation, the way of migration path is both through longitudinal and cross fault. The data of source rock and seal is collected from previous researches. Multiple types of traps have been found there. Conventional anticlinal traps which are highly disturbed due to tectonic instability & the core part are shale diapirism. Most of the anticlines are plunging and the nose or plunge area might be prospective to HC for being comparatively less faulted. Broad synclinal areas between tight narrow anticlines are another prospective area for HC. These similar types of synclines are also found in Tripura, India which is a highly prospective area for petroleum and their small anticlinal hums within syncline are also prospective. Some stratigraphic traps have also been found in Tripura from where production has been started already. Both Chittagong Hill Tracts and Tripura Fold Belts are parts of great Arakan Fold Belts, so similar type of structures might be prospective here. Apart from these, Bangladesh is a deltaic country. So stratigraphic trapment like channel sand, pinch-outs is possible. Considering all the elements of petroleum prospectivity of the area and

Evaluation of the Reservoir Characteristics of Exposed Sandstone Facies of the Bhuban Formation in Sitakund Anticline, Chittagong

“…The Chittagong Tripura Fold Belt (CTFB) in Bangladesh holds considerable potential for hydrocarbon extraction. Alongside conventional prospects, unconventional targets within this region can be explored for petroleum, including zones beneath broader synclinal valleys, channel sands, clay dippers with overpressure shale in deeper subsurface zones, thinly bedded plays, and similar areas (Islam and Lupin, 2020). The Surma Group (Bhuban and Bokabil formations) is the principal reservoir for hydrocarbons.…”

Exploring Structural Geology and Their Implications in the Kaptai – Sitapahar Anticline

“…The goal of this study is to interpret the geology and active tectonics of the Kaptai-Rangamati road cut section which runs across the Sitapahar anticline (Figure 1). The area has experienced neotectonics activity, as evidenced by fault scarps, incised streams, landslides, and earthquakes in the recent past (Islam and Lupin, 2020). To better understand the structural evolution of the area, this research aims to combine surface structural geology and geomorphology with structural data.…”

Landslide Risk Assessment and Preventive Measures of Selected Locations in the Rangamati District, Bangladesh

“…The natural reasons behind landslides are soil characteristics, slope gradient, land cover, and groundwater table (G.W.T), where earthquakes and rainfall are the triggering factors. Again, different human activities such as massive deforestation of hills, unplanned development in the hills that includes hill cutting, land cover change, and soil excavation change in slope profile play an important role in slope deformation [6,7].…”

“…of Bangladesh, the number of fatalities and structural damage brought on by landslides has grown in recent days [11]. Over 350 individuals have died due to slides in the past 30 years [6,7]. A landslide inventory of Chittagong hill zones is included in [12].…”