The spatial footprint of injection wells in a global compilation of induced earthquake sequences

Science ◽  
2018 ◽  
Vol 361 (6405) ◽  
pp. 899-904 ◽  
Author(s):  
Thomas H. W. Goebel ◽  
Emily E. Brodsky
Keyword(s):  
Earthquake Activity ◽  
Spatial Effects ◽  
Spatial Decay ◽  
Root Space ◽  
Injection Wells ◽  
Time Migration ◽  
Pressure Diffusion ◽  
Zone Of Influence ◽  
Earthquake Sequences ◽  
Two Populations

Fluid injection can cause extensive earthquake activity, sometimes at unexpectedly large distances. Appropriately mitigating associated seismic hazards requires a better understanding of the zone of influence of injection. We analyze spatial seismicity decay in a global dataset of 18 induced cases with clear association between isolated wells and earthquakes. We distinguish two populations. The first is characterized by near-well seismicity density plateaus and abrupt decay, dominated by square-root space-time migration and pressure diffusion. Injection at these sites occurs within the crystalline basement. The second population exhibits larger spatial footprints and magnitudes, as well as a power law–like, steady spatial decay over more than 10 kilometers, potentially caused by poroelastic effects. Far-reaching spatial effects during injection may increase event magnitudes and seismic hazard beyond expectations based on purely pressure-driven seismicity.

Revisiting the Classical Experiment in Earthquake Control at the Rangely Oil Field, Colorado, 1970, Using a Coupled Flow and Geomechanical Model

2021 ◽  
Author(s):  
Josimar A. Silva ◽  
Hannah Byrne ◽  
Andreas Plesch ◽  
John H. Shaw ◽  
Ruben Juanes
Keyword(s):  
Pore Pressure ◽  
Oil Field ◽  
Coupled Flow ◽  
Injection Wells ◽  
Rock Types ◽  
Pressure Diffusion ◽  
Main Fault ◽  
Injection Interval ◽  
Using Data ◽  
Pressure Changes

ABSTRACT The injection experiment conducted at the Rangely oil field, Colorado, was a pioneering study that showed qualitatively the correlation between reservoir pressure increases and earthquake occurrence. Here, we revisit this field experiment using a mechanistic approach to investigate why and how the earthquakes occurred. Using data collected from decades of field operations, we build a geological model for the Rangely oil field, perform reservoir simulation to history match pore-pressure variations during the experiment, and perform geomechanical simulations to obtain stresses at the main fault, where the earthquakes were sourced. As a viable model, we hypothesize that pressure diffusion occurred through a system of highly permeable fractures, adjacent to the main fault in the field, connecting the injection wells to the area outside of the injection interval where intense seismic activity occurred. We also find that the main fault in the field is characterized by a friction coefficient μ  ≈  0.7—a value that is in good agreement with the classical laboratory estimates conducted by Byerlee for a variety of rock types. Finally, our modeling results suggest that earthquakes outside of the injection interval were released tectonic stresses and thus should be classified as triggered, whereas earthquakes inside the injection interval were driven mostly by anthropogenic pore-pressure changes and thus should be classified as induced.

Earthquake sequences and b values in the southeast United States

1974 ◽  
Vol 64 (1) ◽  
pp. 267-273
Author(s):  
Leland Timothy Long
Keyword(s):  
United States ◽  
South Carolina ◽  
B Value ◽  
Earthquake Activity ◽  
Southeast United States ◽  
B Values ◽  
History Of ◽  
Earthquake Sequences ◽  
Foreshock Activity ◽  
Epicentral Region

abstract Aftershock and foreshock activity within 12 hr of the July 13, 1971 earthquake near Seneca, South Carolina, indicates a b value of 0.9 at ML = 3.0. Approximately 40 events recorded in a 5-day aftershock survey near Seneca indicate a b value of 1.7 at ML = 0.5. A sequence of over 40 events occurring west of McCormick, South Carolina, indicates a b value of 1.3 at ML = 2.4. The McCormick sequence was active for 4 months. Unlike the Seneca region, the McCormick region has a history of earthquake activity. Examinations of other published southeastern b values suggest that southeastern United States earthquakes originate from conditions of ambient stress which vary with epicentral region or magnitude.

Natural Seismicity in and around the Rome Trough, Eastern Kentucky, from a Temporary Seismic Network

2020 ◽  
Vol 91 (3) ◽  
pp. 1831-1845 ◽  
Author(s):  
N. Seth Carpenter ◽  
Andrew S. Holcomb ◽  
Edward W. Woolery ◽  
Zhenming Wang ◽  
John B. Hickman ◽  
...  
Keyword(s):  
New York ◽  
Oil And Gas ◽  
Seismic Network ◽  
Earthquake Activity ◽  
Seismic Zone ◽  
Injection Wells ◽  
Eastern Kentucky ◽  
The North ◽  
Horizontal Compressive Stress ◽  
Natural Seismicity

Abstract The Rome trough is a northeast-trending graben system extending from eastern Kentucky northeastward across West Virginia and Pennsylvania into southern New York. The oil and gas potential of a formation deep in the trough, the Rogersville shale, which is ∼1  km above Precambrian basement, is being tested in eastern Kentucky. Because induced seismicity can occur from fracking formations in close proximity to basement, a temporary seismic network was deployed along the trend of the Rome trough from June 2015 through May 2019 to characterize natural seismicity. Using empirical noise models and theoretical Brune sources, minimum detectable magnitudes, Mmin, were estimated in the study area. The temporary stations reduced Mmin by an estimated 0.3–0.8 magnitude units in the vicinity of wastewater-injection wells and deep oil and gas wells testing the Rogersville shale. The first 3 yr of seismicity detected and located in the study area has been compiled. Consistent with the long-term seismicity patterns in the Advanced National Seismic System Comprehensive Catalog, very few earthquakes occurred in the crust beneath the Rome trough—only three events were recorded—where the temporary network was most sensitive. None of these events appear to have been associated with Rogersville shale oil and gas test wells. Outside of the trough boundary faults, earthquakes are diffusely distributed in zones extending into southern Ohio to the north, and into the eastern Tennessee seismic zone to the south. The orientations of P axes from the seven first-motion focal mechanisms determined in this study are nearly parallel with both the trend of the Rome trough and with the orientation of maximum horizontal compressive stress in the region. This apparent alignment between the regional stress field and the strikes of faults in the trough at seismogenic depths may explain the relative lack of earthquake activity in the trough compared with the surrounding crust to the north and south.

The Role of Spatial Demand on Outlet Location and Pricing

2009 ◽  
Vol 46 (2) ◽  
pp. 260-278 ◽  
Author(s):  
Jason A. Duan ◽  
Carl F. Mela
Keyword(s):  
Capacity Constraints ◽  
Spatial Effects ◽  
Spatial Decay ◽  
Spatial Covariance ◽  
Latent Demand ◽  
Capacity Constrained ◽  
Demand Patterns ◽  
Spatial Demand ◽  
Equilibrium Effect

In this article, the authors consider the problem of outlet pricing and location in the context of unobserved spatial demand. The analysis constitutes a scenario in which capacity-constrained firms set prices conditional on their location, demand, and costs. This enables firms to develop maps of latent demand patterns across the market in which they compete. The analysis further suggests locations for additional outlets and the resultant equilibrium effect on profits and prices. Using Bayesian spatial statistics, the authors apply their model to seven years of data on apartment location and prices in Roanoke, Va. They find that spatial covariation in demand is material in outlet choice; the 95% spatial decay in demand extends 3.6 miles in a region that measures slightly more than 9.5 miles. They also find that capacity constraints can cost complexes upward of $100 per apartment. As they predict, price elasticities and costs are biased downward when spatial covariance in demand is ignored. Costs are biased upward when capacity constraints are ignored. Using the analysis to suggest locations for entry, the authors find that properly accounting for spatial effects and capacity constraints leads to an entry recommendation that improves profitability by 66% over a model that ignores these effects.

Earthquakes caused by underground nuclear explosions on Pahute Mesa, Nevada Test Site

1972 ◽  
Vol 62 (5) ◽  
pp. 1319-1341
Author(s):  
R. M. Hamilton ◽  
B. E. Smith ◽  
F. G. Fischer ◽  
P. J. Papanek
Keyword(s):  
Test Site ◽  
Geological Structure ◽  
Earthquake Activity ◽  
Nevada Test Site ◽  
Fault Plane Solutions ◽  
Fault Movement ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Earthquake Sequences ◽  
Frequency Magnitude

Abstract The underground nuclear explosions BENHAM, PURSE, JORUM, and HANDLEY, detonated on Pahute Mesa, initiated earthquake sequences lasting approximately 70, 10, 20, and 60 days, respectively. Earthquakes of magnitude 2.0 or larger in these sequences numbered 2012, 24, 159, and 231, respectively; earthquake magnitudes were all less than 5. The explosion PIPKIN, also detonated on Pahute Mesa, had no apparent effect on seismicity. Ninety-four per cent of the earthquakes with well-determined focal depths occurred at depths shallower than 5 km, and 95 per cent of the located earthquakes were within 14 km of ground zero of the preceding explosion. There is no evidence for explosion-stimulated earthquake activity extending outside the area of Pahute Mesa. The spatial distribution of earthquakes seems to be largely controlled by geological structure; however, the epicenter distribution can be correlated with observed fault movement only for aftershocks of HANDLEY. Fault-plane solutions indicate predominant dip-slip movement in the northern part of the Pahute Mesa area for aftershocks of BENHAM, JORUM, and HANDLEY. In the southern part, dextral strike-slip movement was found for aftershocks of BENHAM and HANDLEY. The frequency-magnitude relations are similar for earthquakes following BENHAM, PURSE, JORUM, and HANDLEY.

The effect of correlated permeability on spatiotemporal distribution of microseismic events in a conceptual model of fluid-induced seismicity

2020 ◽  
Author(s):  
Omid Khajehdehi ◽  
Kamran Karimi ◽  
Jörn Davidsen
Keyword(s):  
Seismic Hazard ◽  
Conceptual Model ◽  
Seismic Activity ◽  
Induced Seismicity ◽  
Enhanced Geothermal Systems ◽  
Large Set ◽  
Spatial Effects ◽  
Geothermal Systems ◽  
Spatial Decay ◽  
Microseismic Events

<p>Seismic hazard due to fluid invasion in hydraulic fracturing, wastewater disposal, and enhanced geothermal systems has become a concern for industry and nearby residents. One of the challenges associated with this seismic hazard is the estimation of the spatial effects of these industry operations. Based on a large set of real-world fluid-induced seismicity catalogs, it was recently found that the spatial decay of seismic activity with distance from injection wells exhibits two typical behaviors: short-range decay and long-range decay. The distinction between the two groups can be captured by the exponent in the seismicity density but the underlying origin remains unknown. Here, we introduce a novel conceptual model that not only can capture the observed frequency magnitude distribution of fluid-induced seismic events but also explains different spatial decay exponents observed. In particular, previous models of fluid-induced seismicity have assumed that the permeability and porosity field is either uniform or random and spatially uncorrelated. However, power-law scaling in the spatial frequency power spectrum of well-logs, S(k)∝1/k^β, has been observed for many different physical properties of rocks such as sonic velocity, porosity, and log(permeability). Our model takes advantage of this by introducing a spatially correlated field for porosity and permeability. Our analysis shows that increasing β can decrease the spatial decay exponent, leading to more seismic activity at larger distances from the injection site. In particular, our model explains the two different types of behavior in the spatial distribution of fluid-induced microseismic events as a consequence of different correlations in permeability.</p>

Comparison of Principal Component Solutions in Two Populations

Methodology ◽  
2016 ◽  
Vol 12 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Gregor Sočan
Keyword(s):  
Simulation Study ◽  
Principal Components ◽  
Common Factor ◽  
Principal Component ◽  
Component Model ◽  
Bootstrap Procedure ◽  
Factor Loadings ◽  
Component Loadings ◽  
Principal Component Model ◽  
Two Populations

Abstract. When principal component solutions are compared across two groups, a question arises whether the extracted components have the same interpretation in both populations. The problem can be approached by testing null hypotheses stating that the congruence coefficients between pairs of vectors of component loadings are equal to 1. Chan, Leung, Chan, Ho, and Yung (1999) proposed a bootstrap procedure for testing the hypothesis of perfect congruence between vectors of common factor loadings. We demonstrate that the procedure by Chan et al. is both theoretically and empirically inadequate for the application on principal components. We propose a modification of their procedure, which constructs the resampling space according to the characteristics of the principal component model. The results of a simulation study show satisfactory empirical properties of the modified procedure.

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