17-1 Discovering the Permian Basin from Top to Bottom: A Century-Plus of Geologic Exploration

Session: One Century of Oil and Gas in the Permian Basin

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Abstract:

            Our understanding of the ‘Permian Basin’ (West Texas Basin) is the product of over a century of geologic study, including the limited outcrop areas as well as hundreds of thousands of wells drilled to find and produce hydrocarbons. The basin has little surface indication, due to Triassic, Cretaceous and Cenozoic cover; this delayed its recognition until the 1920s.

The first wave of drilling discovered the world’s thickest Permian section (over 2 km), with abundant oil in structural and stratigraphic traps. The Permian paleogeography, with deep basins and thick shelf-slope clinoforms, was not fully worked out until the 1960s (using exposures in the Guadalupe Mountains, and seismic data).

Deeper drilling in the 1940s discovered Lower Paleozoic reservoirs on large, faulted structures along a central basin axis (CBA). These complex structures that developed in Pennsylvanian and early Permian time, and the deep Delaware basin to the west, formed as part of the regional Ancestral Rocky Mountains orogeny, likely related to NE-directed compression and related strike-slip faulting. Debate continues on the origins and nature of this structural episode.

The deeper drilling also found an earlier ‘Tobosa’ phase of subsidence in the Ordovician-Devonian, that preserved thick Lower Paleozoic sediments. Below are poorly defined (nearly undrilled) zones of Cambrian faulting, volcanism and sedimentation in the southern part of the basin, and a complex Proterozoic basement.

Understanding of the petroleum systems developed more recently, and continues today. Late Paleozoic silled basins formed in the composite basin during the closing of Pangea, yielding km-thick sections of organic-rich sediment. Subsequent burial, sealing by salt and sediment, and modest later uplift matured the organic rocks into the oil-generating window. Some oil migrated onto the CBA and into shelf-edge clinoforms; most of it stayed put in the organic rock and is now being targeted by horizontal wells and hydraulic fracturing.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10684

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