Chapter L National Coal Resource Coal-Bed Methane Gas-In-Place Resource Assessment Estimates Using Sorption Isotherms and Burial History Reconstruction: An Example from the Ferron Sandstone Member Click here to return to Disc 1 Volume Table of Contents of the Mancos Shale, Utah By Todd A. Dallegge1 and Charles E. Barker1 Chapter L of Geologic Assessment of Coal in the Colorado Plateau: Arizona, Colorado, New Mexico, and Utah Edited by M.A. Kirschbaum, L.N.R. Roberts, and L.R.H. Biewick U.S. Geological Survey Professional Paper 1625–B* 1 U.S. Geological Survey, Denver, Colorado 80225 * This report, although in the USGS Professional Paper series, is available only on CD-ROM and is not available separately U.S. Department of the Interior U.S. Geological Survey Contents Overview ...................................................................................................................................................... L1 What Is Coal-Bed Methane? ...................................................................................................................... 2 Importance of Coal-Bed Methane Production ........................................................................................ 2 How Much Coal-Bed Methane is Available?........................................................................................... 3 How Do Coal Beds Generate and Store Methane? ................................................................................ 4 Details About Coal Cleat..................................................................................................................... 5 Production of Coal-Bed Methane .............................................................................................................. 6 Indtroduction to Ferron Sandstone CBM.................................................................................................. 7 Regional Geology.......................................................................................................................................... 8 Structural Setting in the Western United States During the Late Cretaceous.......................... 9 Depositional Environment for the Ferron Sandstone Member ........................................................... 10 Formation of Ferron Coal ........................................................................................................................... 11 Ferron Coals................................................................................................................................................. 12 Characteristics of Lower Ferron Coal at Drunkards Wash......................................................... 13 Characteristics of Upper Ferron Coal at Emery............................................................................ 13 Similarities of Upper and Lower Ferron Coals .............................................................................. 14 Procedures for Estimating Gas-In-Place................................................................................................ 15 Direct Method .................................................................................................................................... 15 Direct Measurements of Coal-Bed Methane Content........................................................ 15 Methods for Determining Sorption Isotherms ............................................................ 15 Experimental Method........................................................................................................................ 16 Experimental Method of Estimating CBM Content.............................................................. 16 Theoretical Method .......................................................................................................................... 17 Theoretical Method of Estimating CBM Content: Burial History Reconstruction.......... 17 Biogenic Gas—An Unknown Quantity.................................................................................................... 19 Estimates of Total Coal Mass for Drunkards Wash Area..................................................................... 20 Method for Determining Gas-In-Place.................................................................................................... 21 Estimating the GIP for Drunkards Wash ........................................................................................ 22 Direct Method ........................................................................................................................... 22 Experimental Method............................................................................................................... 22 Thoeoretical Method................................................................................................................ 22 Summary ...................................................................................................................................................... 23 Caveats................................................................................................................................................ 23 References Cited ........................................................................................................................................ 23 Glossary 24 Figures 1. Photograph of the Ferron Sandstone Member showing thick sandstones and the Sub-A coal zone at the Interstate-70 roadcut south of Emery, Utah ................................................................................................ Frontispiece 2. Photograph of coal-bearing Ferron Sandstone Member of the Mancos Shale and the Marysvale volcanic field............................................................................................. L1 3. Map showing major U.S. coal-bed methane resources ........................................................ 2 4. Graph showing potential future availability of U.S. coal-bed methane............................... 3 5. Coal cleat terminology................................................................................................................. 4 6. Gas generation from sapropelic and humic coals.................................................................. 4 7. Photograph of outcrop showing pyrite filling cleat fracture................................................. 5 8. Photograph of cleats in the A coal horizon at the I-70 roadcut south of Emery, Utah .................................................................................................................... 5 9. Coal-bed methane release process .......................................................................................... 6 10. Measured, calculated, and hypothetical gas production curves for River Gas Corp. 25-7-6 well......................................................................................................... 6 11. Map showing location of Drunkards Wash study area.......................................................... 7 12. Depositional setting for Ferron Sandstone Member of the Mancos Shale........................ 8 13. Block diagram showing depositional environments of Upper Cretaceous rocks in the foreland basin of eastern Utah............................................................................. 8 14. Late Triassic–Late Cretaceous depositional pattern in the Western United States ......... 9 15. Diagrammatic cross section of the Sevier foreland basin .................................................... 9 16. Generalized cross section showing Ferron Sandstone Member stratigraphy ................ 10 17. Diagram showing depositional environment for Ferron Sandstone Member of the Mancos Shale.................................................................................................................. 10 18. Diagram showing peat environments and preservation of peat by a transgressive event ........................................................................................................... 11 19. Location map for coal-bed methane development in eastern Utah .................................. 11 20. Generalized cross section from the Wasatch Plateau to the San Rafael Swell showing position of Ferron coals............................................................................................. 12 21. Surface outcrop pattern of the Ferron Sandstone Member ............................................... 12 22. Photomicrograph of an upper Ferron coal showing vitrinite, the major gas-sorbing component of a coal............................................................................................ 13 23. Map showing vitrinite reflectance values for the Ferron Sandstone Member................ 13 24. Adsorption isotherm of lower Ferron coal from Utah 25-9-1 well ...................................... 15 25. Diagram of upper Ferron experimental gas-in-place estimate .......................................... 16 26. Drunkards Wash burial history reconstruction ..................................................................... 17 27. Muddy Creek (Emery) burial history reconstruction ............................................................ 18 28. Map showing isopachs of total coal for Drunkards Wash area......................................... 20 Table 1. Average analyses of Ferron coals ......................................................................................... L14 Figure 1 (Frontispiece). Photograph of the Ferron Sandstone Member of the Mancos Shale