Abstract

South Peterson Field, Roosevelt County, New Mexico: The Southern Edge of a Frontier Province

Will Green
Green Energy Resources

The prolific oil discovery in Fusselman dolomite by Enserch Exploration in June, 1978 ignited an exploration play on the Roosevelt Positive in Roosevelt County, New Mexico. Lambirth No. 1 flowed 638 BOPD on ¼” choke on potential test and has produced nearly 2 MMBO and 1.5 BCFG. Energy Reserves Group (ERG) was poised to enter the play and started acquiring leases between the Enserch discovery and the known updip “granite knob” to the south based solely on subsurface geology.

South Peterson is on one of several generally north-trending anticlinal structural axes on the Northwest Shelf of the Permian Basin and the Roosevelt Positive. The South Peterson area has about 170 feet of closure on top of the Cisco limestone. All wells that penetrated the top of the Cisco above -3300 feet are productive from the Cisco/Canyon where sufficient secondary porosity is present. Cisco/Canyon traps are interpreted to be created by a combination of structure, stratigraphy and digenesis.

The Fuselman has been removed from part of the south Peterson area by pre-Pennsylvanian uplift and erosion. This uplift may be the western portion of the late Mississippian - early Pennsylvanian uplift that formed the Matador Arch. South Peterson field is on a northwest plunging anticlinal nose where the trapping mechanism was created by up dip truncation of the reservoir rock on the north flank of a “granite knob.”

The thickness of the sedimentary section in the South Peterson area ranges from 7600 to 8000 feet. The Permian section consists of red shale, sandstone, evaporates and dolomite. The primary producing formations are the Cisco/Canyon limestone and Fusselman dolomite. The Cisco/Canyon consists of alternating units of lime wackestone, packstone, grainstone and mudstone. Secondary leaching of skeletal material, mainly fusulinids, small forams and algal plates, creates the better reservoir in the formation.

The Fusselman formation in the South Peterson area is divided into “Upper” and “Lower”. The Upper Fusselman is primarily a fine crystalline lime mudstone with thin zones of dolomitic limestone and dolomite with limited porosity. Oil shows have been documented in the Upper Fusselman but no commercial production has been established. The Lower Fusselman, which may actually be Montoya, is the producing zone in the South Peterson Fusselman field. The section is a fine to coarsely crystalline dolomite mudstone with vugular porosity and a fine grained sucrosic dolomite in the productive interval near the top of the formation.

ERG’s first well, Bledsoe No. 1, was drilled in March, 1980 and found the Fusselman truncated, but it was completed initially in a fractured granite zone that produced 3,334 BO. The well was plugged back to the Cisco limestone and recompleted as a gas producer. Vugular porosity in the Cisco/Canyon limestone is quite variable and is a significant factor in reservoir quality within the anticlinal trap. The best Cisco/Canyon well is the ERG, El Paso-State No. 2 and it has produced over 6 BCFG and nearly 200,000 BO. ERG completed a total of 11 Cisco/Canyon wells in the South Peterson Penn field. Cumulative production from 23 producers in the field is 610 MBO and 13.4 BCFG.

ERG completed three Fusselman producers in South Peterson Fusselman field. Two of these wells, Miller 10 Nos. 1 and 2 have produced 390,000 BO and appear to be in a Fusselman truncation trap separated from the rest of South Peterson Fusselman field. Reported cumulative production from the entire field is 4 MMBO and 3.5 BCFG from 13 producers.

Fusselman discoveries were completed in 2011 on another north trending structural axis about five miles east of the South Peterson field. Perhaps the future will bring more significant discoveries to the Roosevelt Positive.

AAPG Search and Discovery Article #90164©2013 AAPG Southwest Section Meeting, Fredericksburg, Texas, April 6-10, 2013