Date(s) - 02/09/2021
11:30 am - 1:00 pm
Old rocks, new ways: A preview of the Spring 2021 WTGS field trip to the Precambrian through Devonian of far West Texas and southeast New Mexico
Andy Roark – 2020/21 WTGS Field Trip Chair
Precambrian through Devonian strata exposed in the Franklin, Organ, and Sacramento Mountains are nearly identical in thickness and lithology to the equivalent subsurface interval in the Permian Basin. WTGS’s planned off-cycle field trip for Spring 2021 will visit these areas, each of which provides unique insights to deep saltwater disposal zones, conventional reservoirs, and unconventional target zones. This talk will preview the stops and key learnings – with abundant outcrop photos! First, the Franklin Mountains near El Paso, Texas, offer a complete section of the Ordovician El Paso Group (Ellenberger equivalent), as well as the type sections of the Montoya and Fusselman Formations. These strata are saltwater disposal zones and conventional reservoirs in different parts of the Permian Basin. We will reconstruct measured sections from literature, learn about matrix porosity and permeability systems, and view spectacular examples of karstic porosity and collapse features. Secondly, we will visit the southern Organ Mountains to learn about the response of these formations to tectonic fracturing. Multiple shallow abandoned fluorite mine shafts penetrate seismic-scale faults cutting the Fusselman, revealing the associated natural fracture networks in three dimensions. Finally, continuous exposure and minimal vegetation in Alamo Canyon in the Sacramento Mountains permit tracing of individual beds of over half a mile, and show truncation along the low-angle Montoya-Fusselman unconformity. At each stop along the transect, we will observe distinct characteristics reflecting changes in environment of deposition in the Devonian Percha Shale (Woodford equivalent)
More information will be available for the field trip on the website very soon.