The Roosevelt positive is bounded on the south by the petroliferous Northwest Shelf province; the Tucumcari basin lies to the north.

The current Fusselman-Cisco play was ignited in June 1978, by discovery of South Peterson-Fusselman field by Enserch in T5S, R33E. The discovery well had produced over 560,000 bbl of oil to January 1, 1984. In 1981, Energy Reserves Group extended Cisco production into T6S, discovering the East Tanneyhill-Cisco field, now part of South Peterson-Penn (Associated) field.

Present structural trends in the southern Roosevelt positive are northerly and contain all presently discovered oil and gas fields. Structures in the northern province trend westerly where shows have been encountered in the San Andres and Cisco. A paleostructural high projecting from the ancestral Central Basin platform trends across Roosevelt County to the northwestern part of Curry County. All known major fields producing from units below the San Andres are on the crest or flank of this paleo-high.

Pre-Pennsylvanian Paleozoic rocks are truncated around the edge of Precambrian knobs by an Early Pennsylvanian unconformity. Primary objectives are Fusselman Dolomite and Cisco limestone. Fusselman reservoirs in intercrystalline and vuggy porosity produce from truncation or anticlinal traps. Secondary porosity in the Cisco is created by leaching of forams and algal plates. Traps have been found on flanks and crests of anticlinal trends.

The province is considered a good seismic recording area. Although objective formations are relatively thin, high resolution seismic, synthetics, and modeling make reasonable stratigraphic interpretations possible.

End_of_Article - Last_Page 259------------