Bulletin  29—Pre-San Andres stratigraphy and oil-producing zones in southeatern NM—a progress report

By E. R. Lloyd, 1949, 79 pp., 7 figs., 10 plates, 1 index.

The first discovery of commercial oil or gas in NM in rocks older than the San Andres actually took place late in 1943 with the drilling of R. Olsen Oil Company's Langlie well in Lea County. Gas was discovered in what was later called the Justis pool, but the well was not officially completed until April 18, 1944. Late in 1944 the Dublin, Drinkard, and Cass pools were discovered, and the search for older pays has been active since that time. In 1945 the NM Bureau of Mines and Mineral Resources published Bulletin 23, which was a preliminary report of the present work. This present work is designed as a progress report to supplement the work contained in Bulletin 23 in the light of numerous wells that have been drilled since 1945.

Southeastern NM is an indefinite area. The accompanying base map covers the part of the state south and east of Albuquerque. Present interest, however, is largely in the southeastern counties, Lea, Eddy, Chaves, and Roosevelt, and actual production of oil or gas from pre-San Andres Formations is confined to Lea County. Most of the producing formations are exposed in the Sacramento, San Andres, and other mountains where they have been studied and described in more or less detail. A comparison of these described surface sections with the correlative sections in producing areas and in numerous exploratory wells has been one of the primary objects of the present studies. Much is yet to be learned, and future studies and data to be revealed by future wells will undoubtedly necessitate important revisions and additions to correlations and interpretations herein presented.

The report is primarily an attempt at regional stratigraphic interpretation. Some consideration of the major structural features is necessary in an interpretation of the stratigraphy, but no detailed structural studies have been undertaken. The stratigraphic settings of the several oil and gas pools producing from rocks of pre-San Andres age are presented, and some general structural features are shown by outline cross sections.