Geochemical Studies of Black Shales for Shale Gas Prospects of the Semri Group, Vindhyan Basin, Exposed around Maihar Area

Abstract

Summary The Proterozoic basins from different parts of the world viz. Lena Tunguska, Siberia; Amadeus and McArthur basins, Australia; Sichuan and Tarim basins, China and Huqf basin, Oman etc. have reported commercial production of oil and gas. The Vindhyan basin of India has all the favorable geological conditions which were conducive for generation and accumulation of Hydrocarbon within the basin. It is one of the several “Purana” (ancient) sedimentary basins of the Indian. It is a sickle-shaped basin, outcropping between the Archaean Aravalli-Bundelkhand province to the north and east and the Cretaceous Deccan Traps to the south and by the Great Boundary Fault to the west. The TOC is varies from 0.1% to 4% in the study area. The black shales unit of the Rohtasgarh Limestone has higher TOC. The HI values are ranging, 0 to 51 mg HC/g TOC. A Tmax higher than 470° C represents the wet-gas zone to over maturation of organic matter. The HI vs. Tmax values show Type I and Type II (gas prone) kerogen field. Also, Oxygen Index (OI) vs. Hydrogen Index (HI) diagram indicates type II kerogen. The light gaseous hydrocarbon compositions are showing higher concentration of C1, C2 and C3 gases in the shales.