Arizona carbon dioxide accumulation may extend into New Mexico

A Canadian operator is delineating what appears to be a large carbon dioxide/helium accumulation in the Holbrook salt basin in East Central Arizona.

The operator, Ridgeway Petroleum Corp., Calgary, opened the area with two initial wells in 1994 (see map, OGJ, Sept. 5, 1994, p. 42). It began a 10 well delineation program earlier this year and plans to drill two exploratory wells soon, including one in Catron County, N.M.

The delineation program is designed to establish reserve estimates for a 600,000 acre project, of which 200,000 acres are now considered proved and probable based on the two main zones, the Fort Apache and Amos Wash members of Permian Supai.

Several wells have encountered three new zones found to contain CO2 and nitrogen, and production tests are pending. Those zones are the deeper Granite Wash, Raven, and Oak Creek members of Supai.

Ridgway's working interest in the project is 98%. It holds a total of 429,000 acres, including about 23,000 acres of New Mexico state lands leased in January 1997 and about 81,000 acres of federal leases acquired Apr. 16.

Drilling in New Mexico is to start in June. Ridgeway's leases extend as far as 10 miles into Catron County from the state line.

It is about 500 miles from the Arizona-New Mexico line to oil fields in Kern County, Calif., where markets for CO2 exist in enhanced oil recovery and other uses.

Well test program

Ridgeway's two most distant wells, the 1 Plateau Cattle Co. (Alpine Federal), in 15-12n-29e, and the 9-21 Ridgeway-State, in 21-9n-31e, Apache County, are 24 miles apart.

Early gas analyses indicated recoveries of 90% CO2 and 6-9% nitrogen.

The operator is conducting all tests and completions with the assistance of Dowell/Schlumberger.

As a result of core analysis, drill stem testing, and a sophisticated logging suite, Ridgeway has assigned various total pay thicknesses to three wells being production tested in late April ( see table [10888 bytes]).

Ridgeway plans to complete the well in 21-9n-31e from Granite Wash at about 2,600 ft. The zone flowed CO2 to surface during a DST and had a relatively high shut-in reservoir pressure of 680 psi. Completion tests of Fort Apache and Amos Wash are to follow.

The well in 22-10n-30e flowed CO2 to surface during a DST of Amos Wash. Shut-in reservoir pressure is 410 psi.

Fort Apache and Amos Wash are significantly well developed in the well in 22-9n-29e, in the southwest part of the leasehold.

The results indicate that Fort Apache and Amos Wash continue into New Mexico.

Ridgeway has also drilled wells this year in 16-10n-31e, 21-11n-30e, and 22-12n-29e, Petroleum Information/Dwights reported. It has permits to drill in 2-, 10-, and 11-11n-29e, 35-12n-29e, and 15-12n-30e, all in Apache County, Ariz.