Abstract

The U.S. Department of Energy (DOE) Gladys McCall well in Cameron Pariah, Louisiana, was drilled in 1981 and subsequently tested as part of the DOE Geopressured- Geothermal Energy Program. The well produced geopressured brine containing dissolved natural gas from the Lower Miocene sands at a depth of 15,150 to 16,650 feet (4 618 to 5 075 m). More than 25 million barrels of brine(4 (E+06) m) and 727 million standard cubic feet of natural gas (20.6 (E+06)m) were produced in a series of flow tests between December 1982 and October 1987 at various brine flow rates up to 28,000 barrels per day (4 452 m /d).Short-term flow tests for the Number 9 Sand found the size of the reservoir to be too small for long-term production, so it was plugged off. Initial short-term flow tests of the Number 8 Sand found a suitably large reservoir with a permeability of 113 to 132 millidarcies (md) (111 to 130 (E-03) um) and an indicated volume of 430 to 550 million barrels of brine (68.4 to 87.5 (E+06)m). The long-term flow and buildup test found that the reservoir was much larger than was measured by the short-term flow test. Test data and numerical simulation of the flow and buildup tests through 1990 required the initial reservoir volume, as measured by the short-term tests, to be connected to additional reservoir volume with lower permeability. A total reservoir volume of about 7.8 billion barrels (1.2 (E+09) m) was determined with an effective permeability of the distal parts of the reservoir in permeability of the distal parts of the reservoir in the range of 0.2 to 20 md (0.2 to 20 (E-03) um).Detailed chemical analysis of the brine and gas found the brine to be slightly undersaturated with gas at about 29 SCF/STB (5.16 m /m). The produced gas/brine ratio was invariant with product ion time and flow rate. Calcium carbonate scale format ion in the well tubing and separator equipment was controlled by the injection of a scale inhibitor into the flow line and by twice successfully injecting inhibitor "pills" directly into the reservoir. Corrosion and/or erosion of piping and equipment was also significant.

Introduction

The Gladys Mccall well was one of the Design Wells tested in the U.S. Department of Energy's Geopressured-Geothermal Energy Program. The objective of the program was to evaluate the geopressured-geothermal resource as a possible source of energy for the nation. The possible energy sources from these wells include heat, pressure, and recoverable hydrocarbons. The McCall test focused on the evaluation of the reservoir and the recoverable hydrocarbons, primarily methane.

This paper focuses on the data obtained from the well-test program and the analysis of the data as per formed by several organizations. A report covering the test program at the McCall site from 1982 to 1985 was program at the McCallsite from 1982 to 1985 was previously prepared by Technadril-Fenix and Scisson when previously prepared by Technadril-Fenix and Scisson when they were the site operator. This previous report sets forth the program objectives and describes the well drilling and facilities installation in detail; therefore these items are only briefly summarized in this paper.

SUMMARY OF GEOLOGY

The location of the Gladys Mccall well is in southwestern Louisiana. The site is in the coastal marsh about 3 miles (5 km) southeast of Grand Chenier, Louisiana, in the coastal wet lands. The geology of the site and surrounding area was originally described by Bebout and others. The most recent work was by C. J. John.

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