Analysis of diagnostic testing of Gladys McCall Well No. 1

Gladys McCall Well No. 1 was flow tested from 1983 to 1987, underwent long-term pressure buildup testing from October 1987 to October 1991, and has recently been re-entered for final diagnostic testing. The combination of a very large, poorly defined reservoir with data from only a single well has required that the testing be carried out over an unusually long time period for an understanding of the pressure maintenance mechanisms to be developed. Ongoing diagnostic testing of the well has been undertaken by DOE to help resolve questions that arose during the analysis of the test data from the eight year depletion and recovery testing. A rather complete summary of the synthesis, correlation and analysis of the earlier test data has recently been published (Riney, 1991.) and is included in this report as an Appendix. Figure 1 (an update of Figure 9 in the Appendix) includes the final pressure buildup data in the comparison with the earlier reservoir simulation model. During October 1991 the Gladys McCall well was flowed twice as part of the diagnostic testing. On October 1 flow was started to clean out the well and to perform a spinner survey to determine the fluid entry distribution across the perforated interval of Sand 8. The spinner log was run on October 2 with the well producing at a constant rate of {approx} 4800 stb/d. Total production during the October 1-2 test period was 5954 stb. The second flow was from October 10 to 14 to obtain downhole pressure transient data to determine if the transmissivity (kh product) of Sand 8 had changed during the four-year shutin period (October 1987 to October 1991). The total production during the four day constant-rate (5958 stb/d) drawdown test of October 10-14 was 23,850 stb. Eaton Operating Co. and Institute of Gas Technology are continuing with the diagnostic testing; entry and pressure measurements in two overlaying sands (2 and 4) are planned. Since neither time nor funds are sufficient to complete the Gladys McCall analysis under S-Cubed's FY 1991 Subcontract, this is a preliminary report. It is anticipated that the work will continue under a new FY1992 Subcontract to LBL