Successful High Grading of Coal Bed Methane Prospects with Soil Gas Geochemistry: A Test of Multiple Methods in the Powder River and Raton Basins

By

John V. Fontana and James H. Viellenave

Direct Geochemical, Golden, CO

Soil gas geochemistry can be used to locate better production in coal bed methane prospects. Multiple sampling and analytical methods were used over prospective CBM areas in the Powder River and Raton Basins. Sampling methods included the collection of deep soil gas samples, surface soil samples and deep subsurface soil cores. Analytical methods include the analysis of soil gas hydrocarbons, concentrated soil gas hydrocarbons, soil adsorbed hydrocarbons and acid extracted hydrocarbons. The results of the different sampling and analytical methods are compared. Modeling of the geochemical data over areas of high and low production rates (with greater than an order of magnitude range) results in the prediction of areas with the highest gas production rates. The results of the ongoing drilling will be updated with the most current production data.

AAPG Search and Discovery Article #90004©2002 AAPG Rocky Mountain Section, Laramie, Wyoming