← Back to Sessions

WITHDRAWN Roles of Shallow and Deep Saltwater Disposal in Triggering Deep Seismicity in the Northern Delaware Basin, Southeast New Mexico, and West Texas

Description: 

WITHDRAWN The Northern Delaware Basin (NDB) in Southeast New Mexico and West Texas has hosted shallow and deep saltwater disposal (SWD) for decades and is now one of the most seismically active areas in North America. A high-precision earthquake catalog indicates that most events in the region occur at depths within the deep disposal zone (DDZ) and the upper basement. While deep seismicity is commonly associated with deep SWD, two recent studies argue that in parts of the NDB, deep seismicity is driven primarily by shallow SWD. In this study, we assess the roles of shallow and deep SWD in triggering deep seismicity at two seismogenic depths: within the DDZ (depth I) and near the top of the basement (depth II). To this end, we develop methods to model multi-decadal changes in in-zone pore pressure and pressure-induced stress everywhere. To address uncertainties in hydraulic diffusivity, we consider values of 0.15 m²/s and 1 m²/s for the shallow disposal zone and 0.2 m²/s, 1 m²/s, and 5 m²/s for the DDZ. To compute Coulomb stress (CS), we use the focal plane of the 2023-11 M5.2 Coalson Draw event. Our results at depth I show that CS changes in the NDB are mainly driven by deep SWD, except for an area in West Texas where shallow SWD dominates. This area, centered around Northern Reeves County, expands under low diffusivities but diminishes otherwise. At depth II, CS changes are sourced primarily from deep SWD in Southeast New Mexico; however, they seem to be always dominated by shallow SWD in the eastern half of the Culberson - Reeves Seismic Response Area and to the east in West Texas, regardless of tested diffusivities. Specifically for the 2023-11 M5.2 event, if triggered from within the DDZ, then shallow SWD contributes to the overall CS by ~100% to 20%, depending on the scenario; if triggered directly within the basement, then shallow SWD accounts for nearly all CS changes in all scenarios. Together, these findings suggest that shallow and deep SWD play varying roles in triggering deep seismicity in the NDB, depending on the location, depth, and diffusivity, and can inform the design of future SWD curtailment strategies.

Session: Induced Earthquakes: Source Characteristics, Mechanisms, Stress Field Modeling and Hazards [Poster Session]

Type: Poster

Date: 5/1/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Lei

Student Presenter: No

Invited Presentation: 

Authors