Hydrologic Characterization of Coal Seams for Methane Recovery--Activity 1 Topical Report: Hydrologic Data Base for Piceance, San Juan, and Warrior Basins

摘要

Attempts to produce methane from coal seams have frequently encountered large volumes of water which must be removed to reduce reservoir pressure and improve permeability to gas, and hence allow methane drainage. Knowledge of the hydrologic properties of a target coal seam will enable selection of favorable sites for field testing and final methane recovery, and will provide information needed to design an effective dewatering program. The objective of the study is to characterize the hydrologic properties of coal seams in selected basins by collecting and analyzing data from available sources. A lack of hydrologic information for all the basins studied was encountered. The information available showed a general correlation between depth of burial and permeability in which the formation tightens with increasing depth. Permeability contour maps were constructed based on the individual correlations for each basin. Caution is recommended when using these correlations, since geologic structure (e.g., folding) may cause localized variations in permeability. No trends were noted for the occurrence of water in coal seams or for variations in reservoir pressure.