a study of coalbed methane water quality analysis and its effects on environment of rajhara coal field region of palamu district jharkhand

Abstract

Natural gas produced from coal beds (coal bed methane, (CBM)) accounts for about 7.5 percent of the total natural gas production in United States. Along with this gas, water is also brought to the surface. newlineThe amount of water produced from most CBM Wells is relatively high compared to conventional natural gas wells because coal beds contain many fractures and pores that can contain and transmit large volumes of water. In some areas, coal beds many function as regional or local aquifers and important sources of groundwater. Coal bed Methane (CBM) Recovery is associated with the production of large quantities of groundwater. The coal seams are depressurised by water pumping for regular and consistent gas production. Usually, CBM operators need to pump [10m3 of water per day] from one well, which depends on the aquifer characteristics, drainage and recharge pattern. In India, 32 CBM blocks have been awarded for exploration and production, out of which six blocks are commercially producing Methane gas at 0.5 Million metric standard cubic feet per day. A large amount of water is being produced from CBM-producing blocks, but no specific information or data are available for the geochemical properties of CBM-produced water and its suitable disposal or utilization options for better management. CBM operators are in fancy searching for suitable solutions for optimal management of produced water. CBM and mine-produced water needs to be handled considering its physical and geochemical assessment, because it may have environmental as well as long-term impact on aquifers. newlineInvestigations were carried out to evaluate the geochemical and hydrogeological conditions of CBM blocks in Rajhara Colliery. The Chemical signature of produced water reveals high sodium and bicarbonate concentrations with low calcium and magnesium, and very low sulphate in CBM water. It is comprehended that CBM water is mainly of Na-HCO3 type and coal mine water is of Ca-Mg-SO4 and HCO3-Cl SO4 type. newline