Mississippi gets new deep Knox gas flow

G. Alan Petzet
Exploration Editor

Where Fina, Devon are finding deep gas [140,107 bytes]

Sustained, economic gas production from Cambrian or Ordovician zones at nearly 15,000 ft in the Black Warrior basin would present U.S. explorers with several hundred miles of potentially prospective territory.

That might be what FINA Oil & Chemical Co. and Devon Energy Corp. have established at an exploratory well in Oktibbeha County, Miss. The well is only the second producer in Maben field. The other well there has produced for more than 25 years.

The operator, FINA, has not released information. The best indication of its intentions was the recent spudding of a 15,500 ft test about 3 miles southwest of the new producer, 1 Sanders.

Maben field is 350 miles east-southeast of Wilburton field in the Arkoma basin of Latimer County, Okla., where ARCO opened deep Arbuckle (Knox equivalent) gas production in 1987.

It is about 200 miles southwest of where Tengasco Inc., Knoxville, Tenn., is developing gas and oil in several zones including Knox at less than 5,000 ft in Hancock County, Tenn.

What effect FINA's pending merger with Total SA of France might have on this play is not known.

Maben's latest chapter

FINA's Sanders joins the Maben field discovery well, on production since the early 1970s.

Reports filed with the state show that the Sanders produced 97.173 MMcf during 30 days in September 1998, averaging about 3.2 MMcfd. It did even better in October, making 143.226 MMcf and 18 bbl of water in 31 days, an average of 4.62 MMcfd.

These rates are well above the 1.537 MMcfd reported earlier this year during a test with 150 psi flowing tubing pressure on a 48/64 in. choke.

The producing interval is at 14,224-667 ft, reported to be in Cambro-Ordovician Knox, in a sidetrack hole. The early test included small amounts of hydrogen sulfide, and a scrubber operates at the site.

Devon noted in mid-1997 that it held a 50% working interest in 9,500 acres in the area and said that as many as 10 more wells could be required for full development.

FINA spudded the Sanders in November 1997. It is said to have drilled the last 1,000 ft of the hole with salt water to minimize formation damage. It set 75/8 in. liner at 14,035 ft, leaving open hole across the producing interval, and ran a light acid frac job.

Joining an old one

FINA's wellsite is about 12 miles west of Starkville and across a fault from the Clyde Q. Sheely well.

Maben field was named in 1970 after Texaco tested the Sheely. Now operated by Energy Properties Inc., Metairie, La., the well has recovered a cumulative 1.16 bcf from early 1971 through yearend 1997 and is still on line. Over 27 years that is an average flow rate of 117 Mcfd.

Production came from the "Snow zone," a vuggy dolomite. Dorothy Raymond, Geological Survey of Alabama, wrote in these pages that "recent studies of conodonts" from the Magnolia 1 Pierce well in Monroe County, Miss., "indicate that the 'Snow zone' is actually Middle Ordovician in age and is therefore not the top of the Knox Group as originally thought" (OGJ, May 20, 1991, p. 58).

Knox is said to have been nearly 7,000 ft thick in the Exxon 1 Fulgham, TD 21,376 ft in granite. Exxon tested through liner run to TD and abandoned the hole in February 1973.