Petrophysical analysis of Sui upper limestone and Sui main limestone in Qadirpur gas field, middle Indus basin, Pakistan (T-1379) (MFN 3883)

Abstract

Qadirpur gas field is one of the major gas reserves of Pakistan, which is located in the southern portion of the Qadirpur structure of sulaiman sub basin in middle Indus basin.. Gas has been discovered from middle Eocene carbonate reserviors in Qadirpur areas. Sui Main Limestone is the main producer of gas in Qadirpur Gas-field area. The Qadirpur area is operated by Oil and Gas Company Limited, Pakistan. The present tectonic features of the sulaiman sub basin and its structures came into existence during post cretaceous orogenic events. The sub basin is bounded on the east by Indian shield and on the west by the marginal zone of the Indian plate. On the north side, it lies Sargodha high and Pezu uplift and Sukkur rift in south. The petrophysical analysis for Sui Upper limestone and Sui Main limestone of Qadirpur well 14, 15, 16 and 17 in the Qadirpur Gas Field of Middle Indus Basin has been carried out after having the data of wells from Directorate General of Petroleum Concession of Pakistan (DGPC) in the form of wireline logs. Petrophysical analysis involves the study of parameters of shale volume, average porosity, effective porosity, saturation of water, saturation of hydrocarbon, saturation of pore volume of hydrocarbon, saturation of pore volume of water, lithology and thickness of productive zone. The net pay thickness is estimated by applying the cutoff values of petrophysical parameters. The value of volume of shale for the Sui upper limestone ranges from 15.07 to 38.9%. The value of effective porosity ranges from 7.44 to 25.42%. The value for saturation of hydrocarbon ranges from the 35 to 40% and the water saturation ranges up to 60%. The value of volume of shale for the Sui main limestone ranges from 29.9 to 60%. The value of effective porosity ranges from 11.33 to 23.58%. The value for saturation of hydrocarbon ranges from the 35 to 72.73% and the water saturation ranges up to 27.2 to 65 %. The isopach maps of the reservoir formations thickness and Petrophysical parameters are prepared showing the extent of formations in nearby areas. The correlation of reservoir formations is prepared showing that the reservoir is getting shallower in the northward side of Qadirpur Gas field.