Petro-physical evaluation and identifying possible resource plays using the porosity and resistivity logs, Lower Indus Basin, Pakistan

The complex pore network in gas shale may result in the inaccurate evaluation of petro-physical properties with the different models. Therefore, in the current research, we proposed a new methodology of ∆ log R separation method that can be used to distinguish the mature source zone and reservoir zone. When this technique is used together with Thomas Bowman cross-plot, it signifies shaly resource in the study area. The different mature source rock units were recognized based on resistivity log and sonic log by new techniques of models. In the study area, the Goru Formation is marked as source rock, and it is separated by two intervals B and C which shows signs of maturity or reservoir shale. The potential and probable maturity of Lower Goru Formation shale is identified by using the ΔLogR and also the cross-plot techniques of modified ΔLogR. The result shows that the B-interval shale indicates high probable maturity as compared to the C-interval shale. Petro-elastic analysis shows good potential shale gas zone in the B-interval shale as compared to C-interval shale based on other parameters high Young’s modulus, low Poisson’s ratio, high brittleness index, and high total organic carbon content. To check the result acquired from these models, TOC and R˳ were calculated by using well log data. The result obtained from these models indicated that the source rocks encountered in the studied wells having TOC exceeded the kerogen type II for the generation of hydrocarbon and R˳ calculated shows that the source is compensated wet gas in the area. Additional confirmation takes place based on petro-physical properties, i.e., brittleness, so the high brittleness indicates the high rate of hydraulic fracturation.