Recommendations on Testing Procedures at the Gladys McCall and Pleasant Bayou GeoPressured Test Wells

Abstract

Nine possible testing procedures for the Gladys McCall and Pleasant Bayou geopressured fields are listed. Evidence is presented that shows that reduction in salinity due to shale water addition to Gladys McCall formation waters can be measured over a 2-year period, but water analyses will need to be done under strictly controlled laboratory conditions. Sidetrack coring of geopressured reservoirs after production appears to be the most effective way of estimating total volumes of compaction and shale water recharge of geopressured formations. Sidetrack coring of the Andrau ('C') sandstone in the Pleasant Bayou No. 2 well will provide the maximum amount of information on post-production changes in shales and sandstones. Three preferred testing procedures are suggested in order of decreasing scientific payback and cost. The best testing procedure is to continue testing the Gladys McCall well for 2 years, then to cut a sidetrack core and plug and abandon the well. At the same time, a sidetrack core must be cut in the Pleasant Bayou well and then plugged and abandoned. The total cost of these tests will be several million dollars. The next best testing procedure that will provide a large scientific payback is to cut sidetrack cores and then plug and abandon both the Gladys McCall and Pleasant Bayou wells at a cost of about $1.1 million. The last testing procedure, which will also provide a large scientific payback, is to cut a sidetrack core and plug and abandon Pleasant Bayou, and then plug and abandon Gladys McCall at a cost of about$600,000.Bureau of Economic Geolog