Preliminary Test Results of the First Geopressured-Geothermal Design Well, Brazoria County, Texas

The Pleasant Bayou #2 Geopressured-Geothermal test well was completed in the summer of 1979. The C sand of the Frio formation was selected for completion on the basis of core analysis, well logs, and drill stem tests. The purpose of this paper is to summarize the results of the short term production tests run on the Pleasant Bayou #2 well during 1979 and the Fall of 1980. These tests were analyzed using conventional transient pressure test analysis methods. The most significant test run during 1979 was a ten day drawdown test from December 3 to December 14 followed by a 20 day buildup period, during which reservoir pressure response was observed. After a hiatus of nine months, a second production test was conducted over a period of 45 days beginning on September 16, 1980. The well was shut in on October 31, 1980. Pressure buildup data continues to be monitered. Both production tests indicate a formation permeability of 200 millidarcies. The presence of a permeability interruption located approximately 3700 feet from the wellbore is also suggested by these tests. During the last production test, a producing gas-water ratio of 20 standard cubic feet per barrel of produced water was observed. An additional 9-12 standard cubic feet of gas per barrel was found in the water downstream of the separator. The total more » gas-water ratio of 29-32 SCF/bbl is in reasonable agreement with laboratory data and correlations for this produced brine. The major growth fault which forms the reservoir boundary to the northwest of the well is evident from the pressure drawdown data obtained during the last production period. The last production test also indicates an apparent rate dependent skin effect. « less