Coalbed methane development in Colorado. September 1990 (a talk presented at the AAPG Section Meeting in Denver, Colorado). 35 pages. 29 figures. 5 tables. Digital PDF download. IS-32D
Excerpted from the introduction:
As coal undergoes the coalification process from peat to anthracite, it emits methane, the principle component of natural gas. Much of this gas is lost to the atmosphere; some remains trapped in the coal. The trapped gas is both a coal mine explosion hazard and an unconventional natural gas resource.
In Colorado, gas is found in Cretaceous and Paleocene coals deposited in back barrier bar to fluvial environments that existed adjacent to the Cretaceous epeiric seaway. Most of the gas occurs in high-volatile B to medium-volatile rank coals with the highest gas content in the higher rank coals. At the time of this report, there were over 700 producing or shut-in coalbed methane wells in Colorado in four basins in the southeastern and western part of the state: the Raton, San Juan, Piceance, and Sand Wash. This report summarizes and compares the coalbed methane activity in each basin.