Coal Bed Methane Enhancement Techniques: A Review

Abstract

Paper investigates the potential impact of Coalbed methane (CBM) in near present and future. CBM is a natural gas that mainly consists of methane present in physically adsorbed state on the surface of porous coal seam under geothermal pressure. CBM is a cleaner fuel which can be used in the transportation industry, conventional power generation, and many other ways. 50–60% of CBM recovery can be obtained under primary operations and enhancement techniques can increase recovery as high as 80%. Recovery enhancement can be made through temperature increase, pressure release or by selective adsorption in which an injection gas displace methane from coal surface. Recovery through the use of CO2, N2, CO2 & N2 mixture is discussed in detail. Underground coal gasification can be used to recover energy from methane depleted, unminable coal reservoirs and has many advantages over surface mining. CBM consists of both thermogenic and biogenic origin. Depleted CBM reservoirs are observed to produce methane even after recovery is done. Native naturally occurring microbes decomposes coal into methane which explains biogenic origin, through a series of reaction. Kinetics of these decomposition reaction could be escalated significantly through the injection of nutrients and genetically enhanced methanogens. These processes has a great potential and could provide a fossil fuel which is almost renewable as large amount of methane can be generated from small amount of coal.

Petrophysical Investigation of Hydrocarbon Generation Potential of Coal from Raniganj Basin, India

“…The petrographic analysis indicates the quantity of organic content, maturity, gas generation, and storage capacity in coal (Kumar, Mendhe et al 2018, Goraya, Rajpoot et al 2019). It's also significantly utilized to determine coal formation and diagenesis (Moore 2012, Gao, Mastalerz et al 2020.…”

“…The macro-micro pores in coal provide extremely massive surface areas for methane, and it accumulate as free, adsorbed, and dissolved state (Kumar, Mendhe et al 2018, Wang, Su et al 2020). The different ranks of coal, maceral composition, and mineral matter significantly influence the methane sorption capacity (Moore, Bowe et al 2014, Goraya, Rajpoot et al 2019. Literature reveals that Fourier transform infrared spectroscopy (FTIR) is extensively employed to characterize various source rock to determine hydrocarbon generation potential (Ganz and Kalkreuth 1991, Mishra, Samad et al 2018, Varma, Mishra et al 2018.…”

Geochemical investigation of hydrocarbon generation potential of coal from Raniganj Basin, India

“…The petrographic analysis indicates the quantity of organic content, maturity, gas generation, and storage capacity in coal (Goraya et al 2019;Kumar et al 2018). It was also significantly utilized to determine coal formation and diagenesis (Gao et al 2014;Moore 2012).…”

“…The macro-micro pores in coal provide extremely massive surface areas for methane, and it accumulates as a free, adsorbed, and dissolved state (Kumar et al 2018;Wang et al 2020). The different ranks of coal, mineral matter and maceral composition significantly influence the methane sorption capacity (Goraya et al 2019;Moore et al 2014). The literature reveals that Fourier transform infrared spectroscopy (FTIR) is extensively employed to characterize various source rocks to determine hydrocarbon generation potential (Ganz and Kalkreuth 1991;Mishra et al 2018;Varma et al 2018).…”

Distribution law of floor stress during mining of the upper protective coal seam

“…Pressure relief is a direct method for realizing permeability enhancement. [15][16][17][18][19] In the past decades, much research has been conducted on mining-induced pressure in protective coal seams. Based on theoretical analysis, Yavuz 20 proposed a method for estimating the distance to return of the cover pressure and the stress distribution in the goaf of flat-lying longwall panels.…”