Facies Analysis And Reservoir Characterization Of The Kawagarh Formation (Late Cretaceous) Based On Outcrop Analogue And Petrophysical Data, In The Nizampur And Kohat Basin (Kpk), Pakistan

Abstract

The present study deals with the facies analysis and reservoir characterization of the outcrop analogue and well data of the Kawagarh Formation (middle Jurassic) in Nizampur and Kohat Basin (KPK) Pakistan. Nizampur Basin is situated in the north direction of Kala Chitta Range whereas Kohat Basin is located on north-west of Kala Chitta Range. The Kawagarh Formation in the study area is composed of limestone, Silt, Sandstone and Shale. A petrographic and paleo environmental study basses on thin section was done and subsequently used in the microfacies analysis. Three microfacies were identified in three depositional environments, including peritidal, restricted lagoon, and high-energy shoal present on the inner to outer part of a homoclinal carbonate ramp utilizing conventional facies model for ramps and facies assessments. The wire line logs data of wells (Manzali-01, Manzali-02, Makori-01) from Kohat Basin was used for petro physical studies and four limestone electrofacies were identified. These facies are vacillated from clean limestone to marly/argillaceous limestone, which is sandwiched by dominant shale and traces of silt/sandstone in some places. Lithological correlation showed that limestone facies were slightly pinched out from north east to south west direction, with GR values between 30 and 70 API. The results of wire line logs showed no hydrocarbons presence in the Kawagarh Formation in Manzalai -1 and Manzalai-2 wells. However, the logs were encouraging in the Sumari Deep-01 well; clean limestone is developed in the upper most part of the Kawagarh Formation and having considerable porosities (1.5-4.5) %. The wire line logs data represented the Kawagarh Formation having good reservoir qualities in the eastern side of the Kohat Basin whereas the western part of the basin is less prospective. Whereas the study area of Nizampur Basin is located toward north eastern side of the Kohat Basin, thin section studies showed the presence of dolomitization and other porosity behaviours which may indicate the development of secondary porosities. Based on available data interpretation The Kawagarh Formation can be a potential future exploration target in the Nizampur Basin.