Porosity Assessment of Gas Reservoir Using Wireline Log Data: A Case Study of Bokabil Formation, Bangladesh☆

Abstract Shale volume and porosity are the most important rock properties for petrophysical analysis, formation evaluation and estimation of hydrocarbon reserve in the oil and gas fields. This research shows how to shale volume and porosity estimation of Titas gas field (T-11) using wireline log data of Bokabil Formation in Bangladesh. Shale volume has been estimated from Gamma Ray, Self-Potential logs and True resistivity method. Porosity estimated from single log method as well as from Neutron-Density and sonic logs. Lithology is mainly sand and shale where sand is the dominant fraction. In A 2 sand interval of T-11, sand and shaly sand appeared as alternating units. The shales are laminated. Shale volume percentage is ranges from 3.82 to 17.52 averaging 9.23 using Gamma Ray log which is optimistic and more reliable than other two methods. The total porosity (average) percentage is 25.09 based on sonic log which is over estimated but Neutron-density combination formula with clay corrected gives better results as averaging 18.17% which is more reliable for estimation of water saturation, formation evaluation and reserve estimation and similar as core porosity. The porosity quality is good of A 2 gas sand which is potential hydrocarbon reservoir.