Exploratory interest renewed in Otero County, N.M.

The Harvey E. Yates 1Y Bennett Ranch well (Fig. 1 [215,682 bytes]) has been recently drilled in sparsely explored southern Otero County, N.M. The well, in 14-26s-12e, was spudded in July 1997 and drilled to a reported total depth of 8,400 ft by Aug. 10, 1997.

Aug. 3, 1998

5 min read

Ronald F. Broadhead
Bureau of Mines and Mineral Resources
Socorro, N.M.

The operator has not released details of what the well encountered. The well was drilled as a replacement for the Harvey E. Yates 1 Bennett Ranch well, which was drilled in June 1997 at a location 25 ft east of the 1Y well. The 1 Bennett Ranch well was junked and abandoned at a total depth of 2,643 ft in reported Permian strata. Ten miles southwest of the Bennett Ranch wells, H.L. Brown Jr. recently announced plans to drill the 1 University A-3 well in northern Hudspeth County, Tex. (Fig. 1).

No commercial oil or gas production has occurred on the Otero platform.

Regional geology

The Harvey E. Yates 1Y Bennett Ranch well is located on the Otero platform (Fig. 1), a wide, stable area covered by Permian-age strata of the Hueco, Abo, Yeso, and San Andres formations.

The Otero platform is bordered on the west by the Tularosa basin, on the southwest by the Hueco Mountains, on the east by the Salt Basin graben, and on the north by the Sacramento Mountains (Fig. 1). The prolifically productive Permian Basin lies more than 60 miles to the east.

The Otero platform appears to be structurally simple at the surface. The most prominent structural features are north- to northwest-trending anticlines and synclines that have been mapped by Black.¹ These structures are probably Laramide in age. However, several large structures of Pennsylvanian age are concealed within the subsurface of the Otero platform.

The southern terminus of the late Paleozoic Pedernal uplift has been buried by Permian strata underneath the eastern part of the platform. The Pedernal uplift has a north-south trend and its axis is located approximately 15 miles east of the 1Y Bennett Ranch well. In the Otero County area, the Pedernal uplift is bordered on the west by the Pennsylvanian-Early Permian Orogrande basin.^{2 3}

The 1Y Bennett Ranch well was drilled 2 miles northwest of Alamo Mountain. Alamo Mountain is formed by Tertiary age intrusive bodies of phonolite and nepheline syenite.⁴ It is the westernmost of the Cornudas Mountains, all of which are formed by Tertiary-age igneous intrusive rocks in southern Otero County and adjoining areas of Texas (Fig. 1).

Some idea of the stratigraphy encountered in the Harvey E. Yates 1Y Bennett Ranch well may be gleaned from the strata encountered by the Transocean Oil 1 George J. Ablah well. The Transocean well was drilled in 1978 approximately 7 miles northeast of the 1Y Bennett Ranch well.

The Transocean well was drilled to a total depth of 5,305 ft in Precambrian granite. It penetrated thick sections of carbonate rocks in the Permian, Pennsylvanian, Mississippian, Silurian, and Ordovician (Fig. 2 [59,227 bytes]). That the 1Y Bennett Ranch well was drilled almost 3,100 ft deeper is perhaps indicative that it was located in a deeper part of the old Orogrande basin and therefore perhaps encountered a thickened Pennsylvanian section. Most of the Paleozoic section is absent 15 miles to the east where redbeds of the Abo formation (Permian) rest on Precambrian along the axis of the Pedernal uplift. To the west, Ordovician through Permian strata are exposed in the Hueco Mountains uplift. Stratigraphy in the area has been most recently discussed by Black,¹ Greenwood et al.,⁵ and King and Harder.⁶

The H.L. Brown 1 University A-3 well is expected to be drilled to a total depth of 3,750 ft. The well may encounter Lower Permian or Upper Pennsylvanian strata at that depth.

References

Black, B.A., Geology of the northern and eastern parts of the Otero platform, Otero and Chaves counties, New Mexico, PhD dissertation, University of New Mexico, 1973, 158 pp.
Kottlowski, F.E., Depositional features of the Pennsylvanian of south-central New Mexico, in Guidebook for field trip, northern Franklin Mountains and southern San Andres Mountains with emphasis on Pennsylvanian stratigraphy: Roswell Geological Society, 1960, pp. 96-130.
Kottlowski, F.E., Paleozoic and Mesozoic strata of southwestern and south-central New Mexico: New Mexico Bureau of Mines and Mineral Resources Bull. 79, 1963, 100 pp.
McLemore, V.T., and Guilinger, J.R., Geology and mineral resources of the Cornudas Mountains, Otero County, New Mexico, and Hudspeth County, Texas, New Mexico Geological Society, Guidebook to 44th field conference, 1993, pp. 145-153.
Greenwood, E., Kottlowski, F.E., and Thompson, S. III, Petroleum potential and stratigraphy of the Pedregosa basin: comparison with the Permian and Orogrande Basins, AAPG Bull., Vol. 61, 1977, pp. 448-469.
King, W.E., and Harder, V.M., Oil and gas potential of the Tularosa basin-Otero platform-Salt Basin graben area, New Mexico and Texas, New Mexico Bureau of Mines and Mineral Resources, Circular 198, 1985, 36 pp.

The Author

Ronald F. Broadhead is senior petroleum geologist and assistant director at the New Mexico Bureau of Mines & Mineral Resources, a division of New Mexico Tech. He has worked as a petroleum geologist with the former Cities Service Oil Co. His recent work has included the petroleum geology of the San Juan, Permian, Tucumcari, and Estancia basins as well as the carbon dioxide fields of Northeast New Mexico. He has a BS degree in geology from New Mexico Tech and an MS degree in geology from the University of Cincinnati.