--> ABSTRACT: Case History of a Geopressured-Geothermal Prospect Test Well: Gladys McCall 1, by Chacko J. John and Donald A. Stevenson; #91030 (2010)

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Case History of a Geopressured-Geothermal Prospect Test Well: Gladys McCall 1

Chacko J. John, Donald A. Stevenson

The Gladys McCall 1 well has been one of the most successful tests conducted by the U.S. Department of Energy in the Gulf Coast area under its geopressured-geothermal program. Since production testing was initiated in November 1983, the well has produced over 26 million bbl of brine and 655 million standard ft3 of associated gas at average brine production rates of 20,000 b/d. Gas-separated brine is injected into shallow sands through a disposal well located nearby. During the early Miocene, the prospect area was located at the shelf-slope boundary. The thickest sands in the area are found in this well, in which 1,150 ft of net sand is present between 14,412 and 16,230 ft. Eleven producing zones, numbered sequentially, have been defined and two have been tested although only zone 8 has been subject to long-term testing. Faults bound the producing reservoir to the north and south; east-west boundaries are poorly defined due to the lack of deep well control. Continuous microseismic recording stations were set up around the test site to help evaluate possible area-wide land subsidence and local growth-fault movement related to well testing, as reflected in microseismic activity. These stations represent the first of their kind in the Gulf Coast region. Many different and curious signal characteristics have been identified in the microseismic data recorded over 6 years. No detrimental environmental effects related to this testing have been observed so far.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.