A potential giant gas field has been discovered in the very mature exploration province of south Louisiana, by Transco Exploration Partners (TXP) and Exxon Company U.S.A. The West Chalkley prospect is located in Cameron Parish, Louisiana, and is productive in the upper Oligocene Miogypsinoides (Miogyp) sands. This discovery is in the same producing trend as the prolific South Lake Arthur field, where the Miogyp sands have gas reserves on the order of 1.0 tcf.

The West Chalkley prospect was generated by a combination of trend analysis, subsurface well control, and reflection seismic data. The feature appears to be a faulted anticline separate from the nearest production in the area, Chalkley field, which is located about 1 mi (1.6 km) to the east and was discovered in 1938.

Both TXP and Exxon, working independently, recognized the potential prospect and pursued leasing activities in the area. TXP initiated discussions with the landowner in February 1988 and acquired a 960-ac (3.9-km²) lease in June. Exxon leased approximately 2100 ac (8.5 km²) surrounding the TXP lease about one month later. TXP subsequently sold the prospect to Exxon on October 12, 1988. The Exxon #1 Sweet Lake Land & Oil Company was spudded on March 16, 1989, and reached a total depth of 15,600 ft (4755 m) on July 4, 1989. Log analysis indicated a net gas pay zone of nearly 500 ft (152 m) in the 805-ft (245-m) gross productive interval. Testing through perforations near the base of the pay zone yielded flow rates as high as 21.028 MMCFGD and 330 BCPD.

The well was put on production in March 1990 and has produced at rates as high as 45.4 MMCFGD and 740 BCPD. Two successful offsets have been logged, and a third is drilling. At least three more wells are scheduled, with one being a deeper pool wildcat.

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