Diagnostic fracture injection test (DFIT) is a means of obtaining important reservoir and treatment parameters ahead of the main frac treatment. However, in tight-gas sand the shut-in time required to obtain closure can be excessive. A rapid injection, falloff-analysis has been used successfully in the Granite Wash formation of the central mid-continent US to give estimations of:

  • Maximum prop concentration for created fracture network

  • Maximum job time before net pressure maximum

  • Estimated fracture leakoff rate in bbl/min

Using a modified version of the injection procedure and analysis developed by Shelley and McGowen (1986), prediction of fracture parameters can be made in as little as a 20-min shut-in. The results from this modified injection test correlate well to formation productivity.

This paper describes the stimulation chronology of the Granite Wash, the use of modified injection tests to quickly determine stimulation parameters, and the injection/production connection.

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