Petrophysical evaluation of reservoir rocks of Rajian-01, Daiwal-01, and Kal-01 by well log data, Potwar Plateau, upper Indus basin, Pakistan

The present study is an integrated approach to derive reservoir characteristics from well log data. The studied wells, Rajian-01, Daiwal-01, and Kal-01, have been drilled by the Oil and Gas Development Company Limited in the south-eastern part of Potwar Plateau. The petrophysical analysis of these three wells has been done on the basis of well logs (Gamma-ray log, resistivity log, density log, sonic log, and neutron log) which helps to evaluate the hydrocarbon saturations, water saturations, volume of shale, net pay, porosity, and permeability. Rajian-01 gives approximately 65% hydrocarbon saturation in the reservoir rocks. The most promising reservoir rocks of this well are Khewra Sandstone and Jutana Dolomite; the Tobra Formation, however thinly bedded, also acts as a reservoir. Daiwal-01 is an abandoned well and Khewra Sandstone, Jutana Dolomite, and Dandot Formation act as reservoir rocks, whereas the reservoir rocks in well Kal-01 comprises 68% hydrocarbon saturation. The best reservoir rocks in the Kal-01 are Khewra Sandstone, Jutana Dolomite, and Warchha Sandstone (poor to moderate reservoir intervals). The overall petrophysical analysis shows that Rajian-01 and Kal-01 have significant hydrocarbon potential, whereas Daiwal-01 well is uneconomical due to the structural complexity. The Khewra Sandstone and Jutana Formation in Rajian-01 and Kal-01 have favorable petrophysical characteristics for commercial hydrocarbon accumulation. The effective porosity in the Jutana Formation can be increased by induced fracturing. Fracturing work in the Jutana Formation can increase oil recovery. The detailed subsurface studies (including subsurface structure) will enable a better understanding of the hydrocarbon potential in the Potwar Plateau.