Design and interpretation of injection/falloff tests for coalbed methane wells

This paper presents the results of a study undertaken to investigate the reasons why data from injection/falloff tests of coalbed methane wells were not interpretable using conventional well test analysis techniques and the results of a field study to investigate completion effectiveness during injection tests. The pressure transient test data obtained using the old injection/falloff test design were found to be interpretable only by history matching analysis. A modified test design is presented. A field example is presented which illustrates how application of the modified test design resulted in easily interpretable data using conventional well test analysis techniques. Spinner surveys run during injection tests showed that breakdown/ballout treatments are required prior to simultaneous testing of multiple coals in cased-hole completions to ensure adequate communication between the well and all target coal seams.

Design and interpretation of injection/falloff tests for coalbed methane wells Conference Paper