A project to model the hydrogeology of the Delaware basin of southeastern New Mexico, where shallow groundwater aquifers overlie some of the world’s most prolific oil and gas reservoirs, was completed through funding from the NM Energy Minerals and Natural Resources Oil Conservation Divison.. The study area encompasses roughly 4,200 square miles in New Mexico’s Eddy and Lea counties. The western boundary of the study area coincides with the western side of the Guadalupe Mountains; the northern boundary coincides with the southern boundary of the previously completed Pecos Slope/Southern High Plains 3D hydrogeologic model. The eastern and southern boundaries extend to the New Mexico-Texas state line. The main population centers include Carlsbad, Hobbs, Lovington and Jal, together with the smaller communities of Loving and Malaga located along the Pecos River. The Guadalupe Mountains are a significant recharge area for groundwater resources in the Carlsbad area, and for the southernmost reach of the Pecos River in New Mexico. Oil and gas production and associated salt-water injection activities are strikingly conspicuous throughout the project area, and underground mines southeast of Carlsbad are an important source of the nation’s potash supply. Additionally, the Waste Isolation Pilot Plant radioactive-waste repository is located in the north-central portion of the study area. The amount and variety of subsurface activity highlights the need for digital 3D hydrogeologic data suitable for efforts to manage subsurface resources in this region.
We are developed digital elevation models (geologic-structure maps) for the basal contacts of the following lithologic units (formations or groups, in ascending order): the Permian-age Capitan Formation, Artesia Group, Castile Formation, Rustler Formation, and Dewey Lake Formation, the Triassic Dockum Group, and undivided Cenozoic deposits including the Ogallala Formation and Quaternary alluvial and piedmont deposits. Aquifer systems are delineated using lithologic boundaries and inferred hydrologic connectivity between lithologic units, resulting in three distinct aquifer systems referred to as the Delaware Basin Aquifer System (DBAS), the Capitan Reef Aquifer System (CRAS), and the Intermittent Alluvial Aquifer System (IAAS). The DBAS is comprised of the Rustler Formation at its base and overlying Permian- through Triassic-age formations and extends from the Pecos River south and east to the New Mexico-Texas state line. The CRAS includes the Capitan Formation and Artesia Group strata and surrounds the Delaware structural basin. The IAAS is discontinuously present across the study area, largely extending eastward from the Pecos River but also including piedmont deposits west of the Guadalupe Mountains. We developed digital maps of aquifer extent and base elevation, potentiometric surface, depth-to-water, maximum saturated thickness, and water quality for the DBAS and CRAS. We did not delineate aquifer extent and base elevation for the IAAS due to sparse data and the irregular thickness of the aquifer system. Water-level elevations, depth-to-water, and well-depth point data are included for the IAAS.
Results
Geologic Model - Open File Geologic Report 303. 3D Geologic Model of Aquifer-Bearing Units of the Delaware Basin, New Mexico. 2022
Hydrologic Model - Open File Report 623 - Three-Dimensional Hydrogeologic Framework of Aquifer Units in the Delaware Basin, Southeastern NM, 2024