India's Hydrocarbon Outlook – 2022-2023

154 DGH: 3 DECADES OF UNLOCKING INDIA'S HYDROCARBON POTENTIAL Unconventional resources exist in petroleum accumulations that are pervasive throughout a large area and are not significantly affected by hydrodynamic influences (also called “continuous-type deposit”). Usually, there is not an obvious structural or stratigraphic trap. These include deposits like the coal bed methane (CBM), Shale gas/oil, Gas Hydrates etc. that lack the porosity and permeability of conventional reservoirs required to flow without stimulation at economic rates. Such accumulations require specialized extraction technology (e.g., dewatering of CBM, hydraulic fracturing, horizontal drilling etc.). The target volumes are larger. The Government of India had mooted an array of policies since 1997 for the effective extraction and utilization of these resources. Background of the activities carried out in CBM, Shale Gas/ Oil and Gas Hydrates in India shall be discussed in the subsequent sections. 7.1 Coal Bed Methane Coal is a combustible, heterogeneous organic rock made up of organic and inorganic substances and is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years, the process called Coalification. During the process of coalification or thermal maturation of coal beds, valuable quantities of hydrocarbon gas methane get accumulated, primarily in the adsorbed state. There are four types of terms used to describe the methane emanating from coal beds: a. Coalbed Methane (CBM) or Coal Seam Gas (CSG) - A generic term for the methane- rich gas naturally in coal seams typically comprising 80% to 90% methane with lower proportions of ethane, propane, nitrogen, and carbon dioxide. In international use, Realizing untapped potential of Unconventional Petroleum Resources 7