Tracking Induced Seismicity in the Fort Worth Basin: A Summary of the 2008–2018 North Texas Earthquake Study Catalog

2019 ◽  
Vol 109 (4) ◽  
pp. 1203-1216 ◽  
Author(s):  
Louis Quinones ◽  
Heather R. DeShon ◽  
SeongJu Jeong ◽  
Paul Ogwari ◽  
Oner Sufri ◽  
...  
Keyword(s):  
Induced Seismicity ◽  
Fluid Injection ◽  
Well Log ◽  
Fort Worth ◽  
North Texas ◽  
Wastewater Disposal ◽  
Fort Worth Basin ◽  
Stress Changes ◽  
Seismic Networks ◽  
Earthquake Sequences

Abstract Since 2008, earthquake sequences within the Fort Worth basin (FWB), north Texas, have been linked to wastewater disposal activities related to unconventional shale‐gas production. The North Texas Earthquake Study (NTXES) catalog (2008–2018), described and included herein, uses a combination of local and regional seismic networks to track significant seismic sequences in the basin. The FWB earthquakes occur along discrete faults that are relatively far apart (>30  km), allowing for more detailed study of individual sequence development. The three largest sequences (magnitude 3.6+) are monitored by local seismic networks (<15  km epicentral distances), whereas basinwide seismicity outside these three sequences is monitored using regional distance stations. A regional 1D velocity model for the FWB reflects basinwide well log, receiver function, and regional crustal structure studies and is modified for the larger individual earthquake sequences using local well‐log and geology data. Here, we present an mb_Lg relationship appropriate for Texas and a basin‐specific ML relationship, both calculated using attenuation curves developed with the NTXES catalog. Analysis of the catalog reveals that the earthquakes generally occur within the Precambrian basement formation along steeply dipping normal faults, and although overall seismicity rates have decreased since 2016, new faults have become active. Between 2006 and 2018, more than 2 billion barrels of fluids were injected into the Ellenburger formation within the FWB. We observe strong spatial and temporal correlations between the earthquake locations and wastewater disposal well locations and injection volumes, implying that fluid injection activities may be the main driving force of seismicity in the basin. In addition, we observe seismicity occurring at greater distances from injection wells (>10  km) over time, implying that far‐field stress changes associated with fluid injection activities may be an important component to understanding the seismic hazard of induced seismicity sequences.

Injection‐Induced Seismicity and Fault‐Slip Potential in the Fort Worth Basin, Texas

2019 ◽  
Vol 109 (5) ◽  
pp. 1615-1634 ◽  
Author(s):  
Peter H. Hennings ◽  
Jens‐Erik Lund Snee ◽  
Johnathon L. Osmond ◽  
Heather R. DeShon ◽  
Robin Dommisse ◽  
...  
Keyword(s):  
Induced Seismicity ◽  
Fault Slip ◽  
Normal Faults ◽  
Fort Worth ◽  
Fort Worth Basin ◽  
Reflection Seismic ◽  
The North ◽  
Deep Aquifers ◽  
Central Texas ◽  
Earthquake Sequences

Abstract The rate of seismicity in the hydrocarbon‐producing Fort Worth Basin of north‐central Texas, which underlies the Dallas–Fort Worth metropolitan area, increased markedly from 2008 through 2015, coinciding spatiotemporally with injection of 2 billion barrels of wastewater into deep aquifers. Although the rate of seismicity has declined with injection rates, some earthquake sequences remained active in 2018 and new clusters have developed. Most of this seismicity occurred away from regionally mapped faults, challenging efforts to constrain the continuing hazards of injection‐induced seismicity in the basin. Here, we present detailed new models of potentially seismogenic faults and the stress field, which we use to build a probabilistic assessment of fault‐slip potential. Our new fault map, based on reflection seismic data, tens of thousands of well logs, and outcrop characterization, includes 251 basement‐rooted normal faults that strike dominantly north‐northeast, several of which extend under populated areas. The updated stress map indicates a relatively consistent north‐northeast–south‐southwest azimuth of the maximum horizontal principal stress over seismically active parts of the basin, with a transition from strike‐slip faulting in the north to normal faulting in the southeast. Based on these new data, our probabilistic analysis shows that a majority of the total trace length of the mapped faults have slip potential that is equal to or higher than that of the faults that have already hosted injection‐induced earthquake sequences. We conclude that most faults in the system are highly sensitive to reactivation, and we postulate that many faults are still unidentified. Ongoing injection operations in the region should be conducted with these understandings in mind.

Attribute illumination of basement faults, examples from Cuu Long Basin basement, Vietnam and the Midcontinent, USA

2014 ◽  
Vol 2 (1) ◽  
pp. SA119-SA126 ◽  
Author(s):  
Ha T. Mai ◽  
Olubunmi O. Elebiju ◽  
Kurt J. Marfurt
Keyword(s):  
Sedimentary Basins ◽  
Fort Worth ◽  
North Texas ◽  
Fort Worth Basin ◽  
Diagenetic Alteration ◽  
Basement Faults ◽  
The Usa ◽  
Lead Zinc ◽  
Granite Basement ◽  
Osage County

Geometric attributes such as coherence and curvature have been very successful in delineating faults in sedimentary basins. Albeit not a common exploration objective, fractured and faulted basement forms important reservoirs in Southern California, Mexico, India, Yemen, and Vietnam. Basement faulting controls hydrothermally altered dolomite in the Appalachian Basin of the USA, and is suspected to play a role in diagenetic alteration of carbonates in the Fort Worth Basin of north Texas where copper has been found in some wells, as well as in Osage County, Oklahoma, not far from the classic Mississippi type lead-zinc deposits. Because of the absence of stratified, coherent reflectors, illumination of basement faults is more problematic than illumination of faults within the sedimentary column. To address these limitations, we make simple modifications to well-established vector attributes including structural dip, azimuth, and amplitude gradients, in combination with variance, and most positive and most negative principal curvature to provide greater interpreter interaction. Using these methods, we can better illuminate fracture “sweet spots” and estimate their intensity and orientation. We apply these methods to better characterize faults in the granite basement of the Cuu Long Basin, Vietnam, and the granite and rhyolite-metarhyolite basement of Osage County, Oklahoma, USA. Cuu Long forms an important unconventional reservoir. In Osage County, we suspect basement control of shallower fractures in the Mississippi chat deposits.

Multi-phase hydromechanical modeling of induced seismicity: general insights and the case study of the deep geothermal project in St. Gallen, Switzerland

2020 ◽  
Author(s):  
Dominik Zbinden ◽  
Antonio Pio Rinaldi ◽  
Tobias Diehl ◽  
Stefan Wiemer
Keyword(s):  
Fluid Flow ◽  
Induced Seismicity ◽  
Gas Flow ◽  
Fluid Injection ◽  
Induced Earthquakes ◽  
Stress Changes ◽  
Reservoir Conditions ◽  
Multi Phase ◽  
Phase Fluid

&lt;p&gt;Industrial projects that involve fluid injection into the deep underground (e.g., geothermal energy, wastewater disposal) can induce seismicity, which may jeopardize the acceptance of such geo-energy projects and, in the case of larger induced earthquakes, damage infrastructure and pose a threat to the population. Such earthquakes can occur because fluid injection yields pressure and stress changes in the subsurface, which can reactivate pre-existing faults. Many studies have so far focused on injection into undisturbed reservoir conditions (i.e., hydrostatic pressure and single-phase flow), while only very few studies consider disturbed &lt;em&gt;in-situ&lt;/em&gt; conditions including multi-phase fluid flow (i.e., gas and water). Gas flow has been suggested as a trigger mechanism of aftershocks in natural seismic sequences and can play an important role at volcanic sites. In addition, the deep geothermal project in St. Gallen, Switzerland, is a unique case study where an induced seismic sequence occurred almost simultaneously with a gas kick, suggesting that the gas may have affected the induced seismicity.&lt;/p&gt;&lt;p&gt;Here, we focus on the hydro-mechanical modeling of fluid injection into disturbed reservoir conditions considering multi-phase fluid flow. We couple the fluid flow simulator TOUGH2 with different geomechanical codes to study the effect of gas on induced seismicity in general and in the case of St. Gallen. The results show that overpressurized gas can affect the size and timing of induced earthquakes and that it may have contributed to enhance the induced seismicity in St. Gallen. Our findings can lead to a more detailed understanding of the influence of a gas phase on the induced seismicity.&lt;/p&gt;

A SUMMARY OF FORT WORTH BASIN INDUCED EARTHQUAKE SEQUENCES 2008-PRESENT

2020 ◽  
Author(s):  
Heather R. DeShon ◽  
◽  
Louis A. Quinones ◽  
SeongJu Jeong ◽  
M. Beatrice Magnani
Keyword(s):  
Fort Worth ◽  
Fort Worth Basin ◽  
Induced Earthquake ◽  
Earthquake Sequences

MODELING INJECTION INDUCED STRESS CHANGES IN THE FORT WORTH BASIN, TEXAS

2020 ◽  
Author(s):  
Louis A. Quinones ◽  
◽  
Heather R. DeShon ◽  
Peter H. Hennings ◽  
Elizabeth Horne ◽  
...  
Keyword(s):  
Fort Worth ◽  
Fort Worth Basin ◽  
Induced Stress ◽  
Stress Changes

More Than 40 yr of Potentially Induced Seismicity Close to the San Andreas Fault in San Ardo, Central California

2020 ◽  
Vol 92 (1) ◽  
pp. 187-198
Author(s):  
Thomas H. W. Goebel ◽  
Manoochehr Shirzaei
Keyword(s):  
Induced Seismicity ◽  
Surface Deformation ◽  
Active Faults ◽  
Stress Transfer ◽  
Correlation Coefficients ◽  
Spatial Proximity ◽  
Fluid Injection ◽  
Induced Earthquakes ◽  
Temporal Correlations ◽  
Stress Changes

Abstract Evidence for fluid-injection-induced seismicity is rare in California hydrocarbon basins, despite widespread injection close to seismically active faults. We investigate a potential case of injection-induced earthquakes associated with San Ardo oilfield operations that began in the early 1950s. The largest potentially induced events occurred in 1955 (ML 5.2) and 1985 (Mw 4.5) within ∼6  km from the oilfield. We analyze Synthetic Aperture Radar interferometric images acquired by Sentinel-1A/B satellites between 2016 and 2020 and find surface deformation of up to 1.5  cm/yr, indicating pressure-imbalance in parts of the oilfield. Fluid injection in San Ardo is concentrated within highly permeable rocks directly above the granitic basement at a depth of ∼800  m. Seismicity predominantly occurs along basement faults at 6–13 km depths. Seismicity and wastewater disposal wells are spatially correlated to the north of the oilfield. Temporal correlations are observed over more than 40 yr with correlation coefficients of up to 0.71 for seismicity within a 24 km distance from the oilfield. Such large distances have not previously been observed in California but are similar to the large spatial footprint of injection in Oklahoma. The San Ardo seismicity shows anomalous clustering with earthquakes consistently occurring at close spatial proximity but long interevent times. Similar clustering has previously been reported in California geothermal fields and may be indicative of seismicity driven by long-term, spatially persistent external forcing. The complexity of seismic behavior at San Ardo suggests that multiple processes, such as elastic stress transfer and aseismic slip transients, contribute to the potentially induced earthquakes. The present observations show that fluid-injection operations occur close to seismically active faults in California. Yet, seismicity is predominantly observed on smaller unmapped faults with little observational evidence that large faults are sensitive to induced stress changes.

New insights into the mechanisms of seismicity in the Azle area, North Texas

Geophysics ◽  
2019 ◽  
Vol 85 (1) ◽  
pp. EN1-EN15
Author(s):  
Rongqiang Chen ◽  
Xu Xue ◽  
Jaeyoung Park ◽  
Akhil Datta-Gupta ◽  
Michael J. King
Keyword(s):  
Fluid Flow ◽  
Stress Distribution ◽  
Pore Pressure ◽  
Induced Seismicity ◽  
Crystalline Basement ◽  
Water Volume ◽  
Optimization Approach ◽  
North Texas ◽  
Stress Changes ◽  
Area North

We have performed a site-specific study of the mechanics of induced seismicity in the Azle area, North Texas, using a coupled 3D fluid flow and poroelastic simulation model, extending from the overburden into the crystalline basement. The distinguishing feature of our study is that we account for the combined impact of water disposal injection and gas and water production on the pore pressure and stress distribution in this area. The model is calibrated using observed injection wellhead pressures and the location, timing, and magnitude of seismic events. We used a stochastic multiobjective optimization approach to obtain estimated ranges of fluid flow and poroelastic parameters, calibrated to the pressure, rate, and seismic event data. Mechanisms for induced seismicity were examined using these calibrated models. The calibrated models indicate no fluid movement or pressure increase in the crystalline basement, although there is plastic strain accumulation for the weaker elements along the fault in the basement. The accumulation of strain change appears to be caused by the unbalanced loading on different sides of the fault due to the differential in fluid injection and production. Previous studies ignored the produced gas volume, which is almost an order of magnitude larger than the produced water volume under reservoir conditions and which significantly impacts the pore pressure in the sedimentary formations and the stress distribution in the basement. A quantitative analysis indicates that the poroelastic stress changes dominate in the basement with no noticeable change in pore pressure. Even though the low-permeability faults in the basement are not in pressure communication with the Ellenburger formation, the poroelastic stresses transmitted to the basement can trigger seismicity without elevated pore pressure.

Induced seismicity in the Dallas-Fort Worth Basin: Enhanced seismic catalogue and evaluation of fault slip potential

2020 ◽  
Author(s):  
Bing Q. Li ◽  
Jean-Philippe Avouac ◽  
Zachary E. Ross ◽  
Jing Du ◽  
Estelle Rebel
Keyword(s):  
Induced Seismicity ◽  
Fault Slip ◽  
Fort Worth ◽  
Fort Worth Basin ◽  
Seismic Catalogue

3D volumetric multispectral estimates of reflector curvature and rotation

Geophysics ◽  
2006 ◽  
Vol 71 (5) ◽  
pp. P41-P51 ◽  
Author(s):  
Saleh Al-Dossary ◽  
Kurt J. Marfurt
Keyword(s):  
Seismic Data ◽  
Gulf Coast ◽  
Data Sets ◽  
Fort Worth ◽  
North Texas ◽  
Fort Worth Basin ◽  
Spectral Estimates ◽  
Curvature Estimates ◽  
Data Volume ◽  
Conventional Mapping

One of the most accepted geologic models is the relation between reflector curvature and the presence of open and closed fractures. Such fractures, as well as other small discontinuities, are relatively small and below the imaging range of conventional seismic data. Depending on the tectonic regime, structural geologists link open fractures to either Gaussian curvature or to curvature in the dip or strike directions. Reflector curvature is fractal in nature, with different tectonic and lithologic effects being illuminated at the [Formula: see text] and [Formula: see text] scales. Until now, such curvature estimates have been limited to the analysis of picked horizons. We have developed what we feel to be the first volumetric spectral estimates of reflector curvature. We find that the most positive and negative curvatures are the most valuable in the conventional mapping of lineations — including faults, folds, and flexures. Curvature is mathematically independent of, and interpretatively complementary to, the well-established coherence geometric attribute. We find the long spectral wavelength curvature estimates to be of particular value in extracting subtle, broad features in the seismic data such as folds, flexures, collapse features, fault drags, and under- and overmigrated fault terminations. We illustrate the value of these spectral curvature estimates and compare them to other attributes through application to two land data sets — a salt dome from the onshore Louisiana Gulf Coast and a fractured/karsted data volume from Fort Worth basin of North Texas.

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