Why Mining Coal-Bed Methane Gas Is So Polluting?
The ability of coalbed reservoirs to store methane depends upon reservoir pressure, composition and rank of the coal, micropore structure, molecular properties of the adsorbed gas constituents, and reservoir temperature. CBM wells are drilled using techniques similar to those used for drilling conventional wells, but completion practices and the method of reservoir evaluation are different. Because the methods used (“cavitation,” hydraulic fracturing, and removing “production water”) all can result in increased mixing of hydrocarbons with aquifer water, “the BLM has adopted COGCC order No. 112-61, which requires that the production casing of all coal-bed methane wells be cemented from producing horizon to surface by grout circulation methods.” This is done in order to attempt to minimize or preclude the inter-zonal flow of fluids between producing horizons and aquifers within the casing annulus. Again, both enhancement methods of mining CBM gas involve moving fluids or gases through ta
