Hydrologic characterization of coal seams for methane recovery--Activities 5 and 7 progress report: review of single-phase hydrologic testing in coalbeds and development of unsaturated-flow well-test procedures. Topical report, June 1983-December 1984

Activities 5 and 7 are part of a program to hydrologically characterize coal seams for designing effective dewatering schemes. Activity 5 evaluated the single-phase well testing methods that are used in analyzing coal seams and assessed the effectiveness of dewatering designs. Activity 7 examined stress-dependent permeability effects and discovered an intermediate, unsaturated flow regime (between single-phase flow of water and two-phase flow of gas and water), and developed appropriate testing and data analysis procedures. Examination of five cases in which single-phase test methods were used in coal seams proved that instantaneous and constant-rate methods are useful when appropriate precautions are observed. A model of a stress-sensitive aquifer was developed and used to show that stress sensitivity is apparently insignificant in the case available for application. The method was applied to a drawdown test in which unsaturated flow was observed.