New Mexico Geological Society Annual Spring Meeting — Abstracts

The Permian Basin is currently seeing an oil boom of historic proportions. This oil boom is in large part due to technological advances, namely horizontal drilling and hydraulic fracturing that enable petroleum recovery from low porosity and low permeability formations such as shale. However, this type of production relies on large quantities of water: millions of gallons are required to drill and complete these wells. While there is increasing use of produced water to help meet this need, the oil well boom has been matched by a fresh water well boom. The number of applications for both new groundwater appropriations and wells has been rapidly increasing in the past few years, as have the quantities being requested. This has created management challenges for the Office of the State Engineer, in part because no administrative groundwater model exists for a large portion of this region. Having a better 3-dimensional understanding of the geology and, ultimately, the hydrology of the basin will allow for the construction of an administrative numerical model for the Capitan Basin and greatly improve management and decision making.

The New Mexico Bureau of Geology & Mineral Resources Aquifer Mapping Program and the Office of the State Engineer Hydrology Bureau are jointly funding this project to review gamma logs from oil and gas wells at a target density of one gamma log per section to map the tops of the Rustler, Dewey Lake, Santa Rosa and Tecovas Formations. The New Mexico Oil Conservation Division (NM OCD) collects and maintains gamma logs in their online imaging system. Distinctive gamma signatures of these lithologies are known, but can be difficult to discern in many gamma logs. A process for correlating these lithologies across multiple logs was developed using ArcGIS. The results of this work will generate subsurface geology and eventually be used to create layers for an administrative groundwater model. There have been other attempts at mapping the subsurface in this region using gamma logs, but not at the density pursued by this project. The 3-dimensional data generated will be made available to the public.