Coal – A Potential Source of Hydrocarbon Reservoir and Source

Abstract

Coal, as we all know, has been used since ancient times as a source of energy, primarily burned for the production of electricity and/or heat, and is also used for industrial purposes, such as refining metal. With developments in technology, natural gas has also been derived from coal beds. Natural gas also acts as an energy resource. Both natural gas and crude oil have the common origin. Both are formed from the remains of small animals and plants buried inside the earth crust under the application of intense heat and pressure from the earth layers above it. Since we have already established the production of Natural gas from coal (generally known as coal bed methane), can we find out if coal reserves have oil bearing potential? With the dwindling oil reserves all over the world and the demand for oil so high, it is essential to find out new reserves. Already work has been done to find crude oil in shale reservoirs or tight reservoirs. But can coal also serve as a crude oil reserve? This project is aimed to find that. For the research, various tests have been done on the coal samples acquired. First of all, XRD and FTIR were conducted on the samples. These tests established the various elements and chemical bonds present in the samples Then, Rock Eval Pyrolysis and Elemental Analysis were conducted to understand the inner molecular structure of the samples. Various cross plots between parameters were drawn to derive the conclusions. These tests helped to understand the potential oil bearing capacity of the coal and how the amount of hydrocarbons varies in the coal sample with variation in coal maturity. Vitrinite reflectance studies were done to determine the rank of coal. It further confirmed by the Bomb Calorimeter values, which also established the variation of calorific value according to the rank of the coal. From all the tests, it can be said that the three samples belong to the bituminous range of coal, with no or very little potential for oil generation and good potential for gas generation. It was also established that as rank increases, calorific value of coal increases.