In 1990 Texaco Exploration and Production Inc. drilled and completed the first horizontal wells ever drilled in the Gulf of Mexico. The wells, East Cameron Block 278 "B" Platform Wells B-12 and B-14, are about 195 nautical miles southwest of New Orleans, Louisiana in 173 feet of water. The wells are completed in a shallow gas sand at a depth of about 1700 feet TVDSS.

The B-14 well was tested in April 1991. The primary objective of the test was to obtain data for a reservoir simulation study to compare the ultimate recovery of a horizontal and a vertical well in the same reservoir. Other objectives were to use the simulation model to optimize production rates; to characterize inflow performance; to evaluate the slotted liner/prepack gravel pack completion; and to use the data to optimize the length of the horizontal section in future wells. To meet the test objectives, five high resolution quartz memory pressure gauges were placed throughout 380 feet of the horizontal section.

Based on the analysis of the test data the following conclusions were reached: the horizontal well will recover nearly twice as much gas as a conventional well completed in the same reservoir; the optimum rate for each well is about 20 MMSCFD; the reservoir is contributing flow along the entire length of the horizontal section; and that gas flowed outside the prepack gravel pack completion during the test. Test data also indicate that the common assumptions of infinite conductivity and uniform flux are not valid for this well.

This paper describes the test objectives, design, operational aspects, alternatives evaluated, test data, interpretation and application of results, and the ultimate recovery of a horizontal well versus a conventional well.

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