Our study documents the shelf, shelf-edge, slope, and basin-floor depositional facies characteristics, stratigraphic variations, and sedimentation trends of the Missourian Canyon Group and Virgilian–Wolfcampian Cisco Group across the southern Eastern Shelf and the adjacent Midland Basin.

Six interlocking regional stratigraphic cross sections of Lower Cretaceous strata (middle Albian-lower Cenomanian) of the Edwards and Stockton Plateaus of West Texas illustrate the vertical and lateral extent of lithostratigraphic units and distribution of facies and facies tracts.

Electrical images in boreholes are becoming increasingly important in interpreting the rock record.

The Leonardian Spraberry Formation is a major oil-producing formation of the Permian Basin, accounting for more than 700 million barrels of oil produced from heterogeneous submarine-fan reservoirs.

Silurian and Devonian carbonate and chert rocks in the Permian Basin constitute a prolific hydrocarbon-bearing succession in West Texas and New Mexico.

The Upper Devonian Woodford Formation is an organic-rich petroleum source rock that extends throughout West Texas and southeastern New Mexico and currently is generating oil or gas in the subsurface.

Unrecovered mobile oil is oil that is movable at reservoir conditions but is prevented from migrating to existing we1 l bores because of geologic complexities or heterogeneities.

Petroleum reservoirs typically yield only a fraction of the oil initially in place because geologic heterogeneity causes incomplete drainage of oil.

More than 350 well logs and core and production data were used to geologically characterize oil reservoirs of the Driver waterflood unit of the Spraberry Trend in the Midland Basin, West Texas, and to assess the relationship between reservoir stratigraphy and oil recovery.

In 1982, the Bureau of Economic Geology initiated a project to characterize the major oil fields of Texas.