Co-Production Well Test of the CBS Unit No. 1 Well Mt. Selman Gas Field, Texas

摘要

This project was designed to obtain technical data on the mechanism of co-production of gas and water. Primary production from the Mt. Selman field started in 1956 and extended until 1971, during which a total of 7.7 BCF of natural gas had been produced. Secondary Gas Recovery, Inc. acquired leases to the abandoned field in February 1983. Reentry of one of the old wells indicated that water would need to be pumped to recover the gas by co-production. A second well was reentered for offset well pressure monitoring during the test. Analysis of field test data combined with production projections using several computer models yielded the following results: The presence of about 12 BCF of gas in place, originally calculated from preliminary testing and primary production data, was confirmed. The distribution of gas in the reservoir was quite different than calculated assuming a critical gas saturation of 15% in the invaded reservoir. Specifically, free gas was primarily a dispersed, immobile phase throughout the water-wet rock matrix. No significant ''attic'' gas cap was found in the area near the wellbore investigated during two months of production testing. Pressure drawdown caused by co-producing brine and gas made the dispersed gas phase mobile in the area around the wellbore affected by the test. Thus, the mechanics for enhanced recovery by co-production was confirmed. The reservoir volume capable of being affected by pressure drawdown using existing, unstimulated wells was not large enough to result in a commercial operation without additional expenditures for well workovers, stimulation, etc. to remove larger volumes of brine. 4 refs., 9 figs. (ERA citation 11:019119)