Shale gas potential of the Ranikot group, lower Indus basin, Pakistan

Abstract

Natural gas production from tight and impermeable shale formations can be recognized as shale gas and has developed into a significant source of natural gas globally. With the development of modern technology, natural gas prices are likely to rise rapidly in response to substantial supply and demand pressures. The gross thickness of the Ranikot Group in the Lower Indus Basin ranges from 100 m to 400 m. The Ranikot Group is nearly 300 meters thick in the studied area having a depth of more than 1000 m to 2000 m. Geochemical studies indicate that the TOC content analyzed in specimens varies in range from 0.69-8.5 wt. % and the average value is about 2.30 wt%. Hydrogen Index ranges from 40-250 mg HC/g, hence, exhibiting the type III kerogen, which is also corroborated by the Van Krevelen diagram and shows a tendency to generate the gaseous hydrocarbons. The studied samples' Production Index (PI.) is between 0.02-26.2, averaging2.41 mg HC/g rock. T_max varies from 420 to 444 ^oC, and Vitrinite Reflectance (R _o) is between 0.4-0.8%, indicating that the organic matter in the shales of RaniKot Group is immature to early mature. In the studied shale intervals of the Ranikot Group, the clay (ductile mineral) content ranges from 20-30%, while brittle mineral content (quartz) ranges from 70-80%. High Brittleness Index, value (0.6 -Average), lesser values of Poison Raito, and higher values of Young's Modulus reveal that Ranikot Group's shales are within the brittle region. Studied samples of Ranikot Group were mostly brittle. Therefore, it is suggested that the formation is suitable for hydraulic fracturing.