Opinion ID: 2509156
Heading Depth: 1
Heading Rank: 16

Heading: Coalbed methane compared to conventional natural gas

Text: 1. Coalbed methane is produced from wells that are drilled into coal seams. These wells typically have a center tube through which water is pumped from the coal seam. The act of pumping off water reduces pressure on the coal, which liberates the natural gas from the coal seam. The gas enters an open-hole completion area, and flows to the surface through a production casing that surrounds the center tube. [Transcript Vol. I, pp. 73-74]. 2. Generally speaking, coalbed methane differs from other natural gas produced in Wyoming. It is typically produced at lower pressure. It has lower flow rates per well. Coalbed methane is not complex natural gas, that is, coalbed methane does not contains heavy hydrocarbons and has few impurities. [Transcript Vol. I, pp. 66-70]. Because coalbed methane does not have heavier hydrocarbons, there is no byproduct stream of natural gas liquids that can be used to generate revenue, nor any need to separate out oil or other liquid hydrocarbons. [Transcript Vol. I, pp. 71, 76]. 3. Coalbed methane is in contact with water when produced, so the gas produced from the well is saturated with water. [Transcript Vol. I, p. 76]. The water vapor content of gas from a high pressure conventional well is approximately 100 pounds of water vapor per million cubic standard cubic feet a day of gas. [Transcript Vol. I, pp. 76-77]. The water vapor content of gas from a coalbed methane well is approximately 1000 pounds of water vapor per million standard cubic feet a day of gas, or about ten times more for the same volume of gas. [Transcript Vol. I, p. 77]. 4. No party introduced precise information about industry-wide production of coalbed methane from the Powder River Basin of Wyoming, although such information is available from the Wyoming Oil and Gas Conservation Commission. [Transcript Vol. II, p. 292]. However, the parties agree, and we find, that coalbed methane production was not significant until the latter part of the decade of the 1990's. [Transcript Vol. II, pp. 292-293; Transcript Vol. IV, pp. 679-680]. The Petitioner's expert testified that, 1999 is probably the first year when things started ramping up. [Transcript Vol. II, p. 292].