Petroleum geology of Pennsylvanian and Lower Permian strata, Tucumcari Basin, east-central New Mexico

Abstract

The Tucumcari Basin of east-central New Mexico is an asymmetric structural depression that existed as a depositional basin from Strawn (Middle Pennsylvanian) until late Wolfcampian (Early Permian) time. Depth to Precambrian ranges from 6,500 ft in the southern part of the basin to more than 9,000 ft in the northern part of the basin. High-angle faults form the northern, western, and eastern margins of the basin. Faults cut Pennsylvanian and Wolfcampian strata but do not generally offset post-Wolfcampian strata. To the north and west, the basin is bounded by the Sierra Grande and Pedernal Uplifts. To the east, the Frio Uplift separates the Tucumcari Basin from the Palo Duro Basin of the Texas panhandle. No major structural discontinuities separate the basin from a shallow shelf to the south.Correlations between fusulinid biostratigraphic data, geophysical logs, cores, and drill cuttings indicate the facies and thickness patterns of Pennsylvanian and Wolfcampian strata are structurally controlled. Coarse-grained arkosic sandstones that were deposited in the northern and western parts of the basin were derived from the highlands of Precambrian granitic rocks that formed the northern and western margins of the basin. These sandstones are good reservoirs and exhibit both primary and secondary porosities. High-energy limestones of Pennsylvanian through Wolfcampian age were deposited in the southern part of the basin and are possible reservoirs. Dissolution porosity may have developed in the limestones that are truncated by a basin-wide unconformity at the top of the Pennsylvanian. Porous dolostones of Wolfcampian age cover the Frio Uplift on the eastern side of the basin and are good reservoirs.Thermally mature oil-and-gas source rocks are Pennsylvanian and Wolfcampian marine shales that were deposited throughout the Tucumcari Basin. Post-Wolfcampian strata are thermally immature.Two presently noncommercial to marginally commercial pools of oil and gas, the Latigo Ranch and the T-4 Cattle Company pools, have been discovered in Strawn sandstones in the northern part of the basin. Oil generated in upper Paleozoic strata has migrated vertically through faults into Triassic strata; two accumulations of heavy oil, the Santa Rosa tar sands and the Newkirk oil pool, are in Triassic sandstones and have combined reserves of 153 million bbls of oil.

Energy and Mineral Resources of New Mexico: Overview of the Valles Caldera (Baca) Geothermal System

“…The Chester shallow marine limestones are productive primarily from oolitic shoals, although associated grainstones may also be productive (Hamilton and Asquith, 2000). Reservoir porosity ranges from less than 10% up to 18%, and the permeability generally appears to be relatively high (Broadhead, 2009b). In general, Chester reservoirs are more fully developed than other Mississippian reservoirs.…”

“…It is also absent from large parts of the Central Basin Platform where it was removed by erosion during the Pennsylvanian. The lower Mississippian limestone consists primarily of dark-colored lime mudstones although siliciclastic shales and dark-colored cherts are locally present (Broadhead, 2009b). Production from the lower Mississippian limestone is from small scattered reservoirs in northern Lea and eastern Chaves Counties (Fig.…”

Energy and Mineral Resources of New Mexico: Metallic Mineral Deposits

“…The Upper Mississippian section consists of the Barnett Shale in the basinal area to the south and the Meramec and Chester units on the shelf to the north. Four poorly developed oil and gas plays have been identified in Mississippian strata of southeastern New Mexico (Broadhead, 2009b): 1) Chester shallow marine limestone play, 2) the Upper Mississippian limestone interbedded with Barnett shale play, 3) Barnett shale play, and 4) lower Mississippian limestone play.…”

“…South of the shelf margin, thin Mississippian limestones are interbedded with the Upper Mississippian Barnett Shale. Production is obtained from one to two well reservoirs in these limestones with the interbedded Barnett Shales acting as vertical seals as well as source rocks (Broadhead, 2009b). It is unknown if the limestone reservoirs are progradational tongues of the shelf margin, debris flows of carbonate material that originated on the shelf margin, or microbial mounds deposited on the promargin slope.…”

“…Present-day, post-maturation total organic carbon (TOC) ranges from 0.85-4.9% and kerogens are dominantly gas prone. In most areas of southeastern New Mexico, the Barnett is within the oil window, but a gas exploration fairway of higher thermal maturity lies along a depth-independent northwest-southeast trend in Eddy County (Broadhead, 2009b). Shows along this maturity trend are dry gas.…”