Abstract:
For the exploration of hydrocarbons, petrophysical analysis has been done in Garhi-01 well in Basal block Upper Indus Basin Pakistan. In Garhi-01 drilling has been done from Murree Formation of Miocene age up to Lockhart Formation of Paleocene age which is acting as a reservoir. Logging suits including caliper log, spontaneous potential log, spectral gamma ray log, computed gamma ray log, dual laterolog, microspherically focused log, neutron log, density log and sonic log have been run from depth of 4625 m to 5267 m. A reservoir zone having thickness of 60 meters (5120 m – 5180 m) in Lockhart Formation has been marked on the basis of certain petrophysical parameters i.e. low SGR log values, high LLd values and neutron-density crossover. Marked zone have low volume shale, low effective porosity and low hydrocarbon saturation that is why it is showing low hydrocarbon potential. Identification of lithology and mineralogical composition have been done with the help of M-N, neutron-density, neutron-sonic and thorium-potassium cross plots and it was found that the lithology of Lockhart Formation is limestone having calcite and some dolomite minerals. SGR log is indicating the lithology of the formation is pure limestone at upper part having no organic matter and showing oxidizing environment of deposition, whereas shaly to pure limestone at lower part, having the organic matter and reducing environment of deposition.
