San Andres and Grayburg reservoirs have yielded about 42 percent (9.8 billion barrels) of the total cumulative production of oil from the Permian Basin of West Texas. However, recovery efficiencies have been low, and significant quantities of mobile oil remain after primary and conventional secondary recovery. Major San Andres and Grayburg reservoirs, each of which has produced more than 10 million barrels, are estimated to contain 8.7 billion barrels of unrecovered mobile oil.

Data from five drainage basins in the Texas Panhandle and northeastern New Mexico characterize the recent history of regional drainage basin formation and landscape development around the margins of the Southern High Plains. Because stream flow records for most streams in the area are only available for the last 15 yr, morphometric (shape) measurements are used to obtain a long-term, basinwide view of the geomorphic history of these watersheds.

Permeability in a vuggy carbonate sequence can be related to particle size, separate-vug porosity, and interparticle porosity. Total porosity can be determined from neutron, acoustic, and density logs, but the distinction made between interparticle and separate-vug porosity using log responses has never been quantifiable. As a result, such distinction has never been integrated into permeability estimates drawn from log analysis.