Slip Potential and Seismogenic Association of Basement-Rooted Faults in the Delaware Basin, West Texas
Abstract
The Delaware Basin of west Texas and southeastern New Mexico is now one of the world's most productive petroleum provinces. Within the basin the earthquake rate has accelerated significantly alongside recent petroleum development. Many of these earthquakes have been spatiotemporally linked to petroleum operations. However, the linkage of earthquakes to known faults to better characterize the hazard regionally and to develop strategies for mitigation has been not been possible previously because of limitations of existing fault maps resulting in an incomplete assessment of fault reactivation potential.
We integrate a new fault interpretation of the region, an analysis of fault slip potential (FSP, expressed as the pore-pressure required for fault criticality, Ppcrit), and a well-located TexNet Earthquake Catalog to assess which faults have been recently seismogenic and to determine the sensitivity of other faults to reactivation. Our new fault map includes 650 basement-rooted faults that we classify by interpretation confidence. Our analysis of fault slip potential uses faults of high- and moderate-confidence. We employ a probabilistic spatial assessment to determine the likelihood that earthquakes are located on specific fault segments. We use a published stress interpretation for the region but our analysis benefits from an important improvement to the existing FSP approach. Due to the large north to south systematic rotation of the SHmax azimuth (~150°), we discretize the FSP calculation by applying the appropriate local SHmax azimuth to each fault segment utilizing the progressively varying continuous stress field. In doing this we are able to better honor the deterministic variation in SHmax azimuth and reduce the uncertainty of that important parameter in the FSP analysis. We assess the native state of the faults without consideration of changes in pore pressure that may stem from injection or fluid withdrawal. In the application of our results we show the distribution of FSP and Ppcrit throughout the region for seismogenic and non-seismogenic faults. We assess the characteristics of each of those fault populations and provide an estimation of minimum FSP and Ppcrit associated with faults to assess the reactivation hazard for mapped faults, and faults that might be mapped in the future.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMS013.0011H
- Keywords:
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- 1822 Geomechanics;
- HYDROLOGY;
- 7212 Earthquake ground motions and engineering seismology;
- SEISMOLOGY;
- 7223 Earthquake interaction;
- forecasting;
- and prediction;
- SEISMOLOGY;
- 8010 Fractures and faults;
- STRUCTURAL GEOLOGY