scholarly journals Lateral migration patterns toward or away from injection wells for earthquake clusters in Oklahoma

2020 ◽  
Author(s):  
José Ángel López-Comino ◽  
Martin Galis ◽  
P. Martin Mai ◽  
Xiaowei Chen ◽  
Daniel Stich
Keyword(s):  
Injection Rate ◽  
Lateral Migration ◽  
Injection Wells ◽  
Migration Patterns ◽  
Wastewater Disposal ◽  
Migration Direction ◽  
Cumulative Volume ◽  
Stress Changes ◽  
Earthquake Clusters ◽  
Seismic Clusters

<p>Exploring the connections between injection wells and seismic migration patterns is key to understanding processes controlling growth of fluid-injection induced seismicity. Numerous seismic clusters in Oklahoma have been associated with wastewater disposal operations, providing a unique opportunity to investigate migration directions of each cluster with respect to the injection-well locations. We introduce new directivity migration parameters to identify and quantify lateral migration toward or away from the injection wells. We take into account cumulative volume and injection rate from multiple injection wells. Our results suggest a weak relationship between migration direction and the cluster-well distances. Migration away from injection wells is found for distances shorter than 5-13 km, while an opposite migration towards the wells is observed for larger distances, suggesting an increasing influence of poroelastic stress changes. This finding is more stable when considering cumulative injected volume instead of injection rate. We do not observe any relationship between migration direction and injected volume or equivalent magnitudes.</p>

scholarly journals Lateral migration patterns toward or away from injection wells for earthquake clusters in Oklahoma

2019 ◽  
Author(s):  
José-Ángel López-Comino ◽  
martin galis ◽  
P. Martin Mai ◽  
Xiaowei Chen ◽  
Daniel Stich
Keyword(s):  
Lateral Migration ◽  
Injection Wells ◽  
Migration Patterns ◽  
Earthquake Clusters

Did Wastewater Disposal Drive the Longest Seismic Swarm Triggered by Fluid Manipulations? Lacq, France, 1969–2016

2021 ◽  
Author(s):  
Jean-Robert Grasso ◽  
Daniel Amorese ◽  
Abror Karimov
Keyword(s):  
Injection Rate ◽  
Injection Well ◽  
Gas Reservoir ◽  
Gas Field ◽  
Wastewater Disposal ◽  
Seismic Swarm ◽  
Stress Changes ◽  
Changepoint Analysis ◽  
Poroelastic Model ◽  
Fluid Manipulation

ABSTRACT The activation of tectonics and anthropogenic swarms in time and space and size remains challenging for seismologists. One remarkably long swarm is the Lacq swarm. It has been ongoing since 1969 and is located in a compound oil–gas field with a complex fluid manipulation history. Based on the overlap between the volumes where poroelastic model predicts stresses buildup and those where earthquakes occur, gas reservoir depletion was proposed to control the Lacq seismic swarm. The 2016 Mw 3.9, the largest event on the site, is located within a few kilometers downward the deep injection well. It questions the possible interactions between the 1955–2016 wastewater injections and the Lacq seismicity. Revisiting 60 yr of fluid manipulation history and seismicity indicates that the impacts of the wastewater injections on the Lacq seismicity were previously underevaluated. The main lines of evidence toward a wastewater injection cause are (1) cumulative injected volume enough in 1969 to trigger Mw 3 events, onset of Lacq seismicity; (2) 1976 injection below the gas reservoir occurs only a few years before the sharp increase in seismicity. It matches the onset of deep seismicity (below the gas reservoir, at the injection depth); (3) the (2007–2010) 2–3 folds increase in injection rate precedes 2013, 2016 top largest events; and (4) 75% of the 2013–2016 events cluster within 4–8 km depths, that is, close to and downward the 4.5 km deep injection well. As quantified by changepoint analysis, our results suggest that timely overlaps between injection operations and seismicity patterns are as decisive as extraction operations to control the Lacq seismicity. The seismicity onset is contemporary to cumulative stress changes (induced by depletion and injection operations) in the 0.1–1 MPa range. The interrelation between injection and extraction is the most probable cause of the Lacq seismicity onset and is sustenance over time. The injected volume–largest magnitude pair for Lacq field is in the same range (90% confidence level) than wastewater volume–magnitude pairs reported worldwide, in a wide variety of tectonic settings.

Detection and characterization of fluid-driven earthquake clusters

2020 ◽  
Author(s):  
Sebastian Hainzl ◽  
Tomas Fischer
Keyword(s):  
Fluid Flow ◽  
Synthetic Data ◽  
Aftershock Sequence ◽  
Migration Patterns ◽  
Long Valley Caldera ◽  
Epidemic Type Aftershock Sequence ◽  
Aftershock Sequences ◽  
Stress Changes ◽  
Earthquake Sequences ◽  
Earthquake Clusters

<p>Natural earthquake clusters are often related to a mainshock, which triggers the sequence by its induced stress changes. These clusters are called mainshock-aftershock sequences and statistically well explained by earthquake-earthquake interactions according to the Epidemic Type Aftershock Sequence (ETAS) model. Additionally, aseismic processes such as slow slip, dike propagation or fluid flow might also play a role in the initiation and driving of the earthquake sequence. Earthquake swarms, which lacks a dominant earthquake, are often believed to indicate such transient aseismic forcing signals. However, swarm-type clusters can also occur by chance in ETAS-simulations and thus not necessarily related to aseismic drivers. Thus, more sophisticated quantification of the space-time-magnitude characteristics of earthquake sequences are required for discrimination. Migration patterns are one of those properties which can be indicative for aseismic triggering. We suggest simple measures to identify and quantify migration patterns and test those for synthetic data, data from fluid injection experiments, and natural swarm activity related to fluid flow in NW Bohemia and Long Valley caldera. We analyze their potential to discriminate from ETAS-type clusters and compare it with those of time-magnitude characteristics of the activity such as seismic moment ratios and skewness. Our results are finally used to discriminate earthquake clusters in California and elsewhere.</p>

Coupling poroelastic stress change and rate-state fault slip models to simulate fluid injection induced seismic and aseismic slip

2020 ◽  
Author(s):  
Yajing Liu ◽  
Alessandro Verdecchia ◽  
Kai Deng ◽  
Rebecca Harrington
Keyword(s):  
Hydraulic Fracturing ◽  
Pore Pressure ◽  
Fault Slip ◽  
Stress Change ◽  
Fluid Injection ◽  
Coulomb Stress ◽  
Aseismic Slip ◽  
Injection Wells ◽  
Wastewater Disposal ◽  
Stress Changes

<p>Fluid injection in unconventional hydrocarbon resource exploration can introduce poroelastic stress and pore pressure changes, which in some cases may lead to aseismic slip on pre-existing fractures or faults. All three processes have been proposed as candidates for inducing earthquakes up to 10s of kilometers from injection wells. In this study, we examine their relative roles in triggering fault slip under both wastewater disposal and hydraulic fracturing scenarios. We first present modeling results of poroelastic stress changes on a previously unmapped fault near Cushing, Oklahoma, due to injection at multiple wastewater disposal wells within ~ 10 km of distance, where over 100 small to moderate earthquakes were reported between 2015/09 to 2016/11 including a Mw5.0 event at the end of the sequence. Despite the much larger amplitude of pore pressure change, we find that earthquake hypocenters are well correlated with positive shear stress change, which dominates the regimes of positive Coulomb stress change encouraging failure. Depending on the relative location of the disposal well to the recipient fault and its sense of motion, fluid injection can introduce either positive or negative Coulomb stress changes, therefore promoting or inhibiting seismicity. Our results suggest that interaction between multiple injection wells needs to be considered in induced seismicity hazard assessment, particularly for areas of dense well distributions. Next, we plan to apply the model to simulate poroelastic stress changes due to multi-stage hydraulic fracturing wells near Dawson Creek, British Columbia, where a dense local broadband seismic array has been in operation since 2016. We will investigate the relative amplitudes, time scales, and spatial ranges of pore pressure versus solid matrix stress changes in influencing local seismicity.</p><p>Finally, we have developed a rate-state friction framework for calculating slip on a pre-existing fault under stress perturbations for both the disposal and hydraulic fracturing cases. Preliminary fault slip simulation results suggest that fault response (aseismic versus seismic) highly depends on 1) the relative timing in the intrinsic earthquake cycle (under tectonic loading) when the stress perturbation is introduced, 2) the amplitude of the perturbation relative to the background fault stress state, and 3) the duration of the perturbation relative to the “memory” timescale governed by the rate-state properties of the fault. Our modeling results suggest the design of injection parameters could be critical for preventing the onset of seismic slip.</p>

Data analytics to investigate the cohort of injection wells with earthquakes in Oklahoma

2021 ◽  
pp. 875529302198972
Author(s):  
Amin Amirlatifi ◽  
Bijay KC ◽  
Meisam Adibifard ◽  
Farshid Vahedifard ◽  
Ehsan Ghazanfari
Keyword(s):  
Induced Seismicity ◽  
Data Analytics ◽  
Energy Production ◽  
Hybrid Genetic Algorithm ◽  
Injection Wells ◽  
Cumulative Volume ◽  
Level Of Activity ◽  
Underground Injection ◽  
Injection Control ◽  
Volume Range

The number of recorded earthquakes in Oklahoma has substantially increased during the last few decades, a trend that coincides with the increases in the injected volume in underground injection control (UIC) wells. Several studies have suggested the existence of spatial and temporal links between earthquakes and injection wells. However, creating a spatial connection between the earthquakes and UIC wells requires making a prior assumption about the radius of induced seismicity. In this study, we use intrinsic features of the UIC wells to find the cohort of wells with associated earthquakes, based on the level of activity and proximity of the wells to the events. For this purpose, a hybrid genetic algorithm–K-means (GA-K-means) algorithm was applied over UIC wells, and the geographical representation of the clustered wells was co-visualized with earthquake data to determine wells with induced seismic activities. The analysis was performed every year since 2002, and the most critical attributes to distinguish the behavior of wells were identified. The analysis showed a distinct change in cluster identifiers before the year 2010, which is believed to be the beginning of increased seismic activities, compared to later dates. Our approach was able to group the earthquake-associated wells from the rest of the data, and centroid analysis of these wells helped us identify the critical pressure and cumulative volume range that result in induced seismicity. These findings can be used as guidelines for designing safer injection sites for sustainable energy production in Oklahoma.

Earthquake clusters expected from bare statistics: How bursts and swarms emerge from exogenous and epidemic aftershock processes.

2021 ◽  
Author(s):  
Jordi Baro
Keyword(s):  
Heat Flow ◽  
Solid Earth ◽  
Point Process ◽  
Branching Process ◽  
Aftershock Sequence ◽  
Statistical Properties ◽  
Etas Model ◽  
Stress Changes ◽  
Earthquake Clusters ◽  
Statistical Laws

<p>Earthquake catalogs exhibit strong spatio-temporal correlations. As such, earthquakes are often classified into clusters of correlated activity. Clusters themselves are traditionally classified in two different kinds: (i) bursts, with a clear hierarchical structure between a single strong mainshock, preceded by a few foreshocks and followed by a power-law decaying aftershock sequence, and (ii) swarms, exhibiting a non-trivial activity rate that cannot be reduced to such a simple hierarchy between events. </p><p>The Epidemic Aftershock Sequence (ETAS) model is a linear Hawkes point process able to reproduce earthquake clusters from empirical statistical laws [Ogata, 1998]. Although not always explicit, the ETAS model is often interpreted as the outcome of a background activity driven by external forces and a Galton-Watson branching process with one-to-one causal links between events [Saichev et al., 2005]. Declustering techniques based on field observations [Baiesi & Paczuski, 2004] can be used to infer the most likely causal links between events in a cluster. Following this method, Zaliapin and Ben‐Zion (2013) determined the statistical properties of earthquake clusters characterizing bursts and swarms, finding a relationship between the predominant cluster-class and the heat flow in seismic regions.</p><p>Here, I show how the statistical properties of clusters are related to the fundamental statistics of the underlying seismogenic process, modeled in two point-process paradigms [Baró, 2020].</p><p>The classification of clusters into bursts and swarms appears naturally in the standard ETAS model with homogeneous rates and are determined by the average branching ratio (nb) and the ratio between exponents α and b characterizing the production of aftershocks and the distribution of magnitudes, respectively. The scale-free ETAS model, equivalent to the BASS model [Turcotte, et al., 2007], and usual in cold active tectonic regions, is imposed by α=b and reproduces bursts. In contrast, by imposing α<0.5b, we recover the properties of swarms, characteristic of regions with high heat flow. </p><p>Alternatively, the same declustering methodology applied to a non-homogeneous Poisson process with a non-factorizable intensity, i.e. in absence of causal links, recovers swarms with α=0, i.e. a Poisson Galton-Watson process, with similar statistical properties to the ETAS model in the regime α<0.5b.</p><p>Therefore, while bursts are likely to represent actual causal links between events, swarms can either denote causal links with low α/b ratio or variations of the background rate caused by exogenous processes introducing local and transient stress changes. Furthermore, the redundancy in the statistical laws can be used to test the hypotheses posed by the ETAS model as a memory‐less branching process. </p><p>References:</p><ul><li> <p>Baiesi, M., & Paczuski, M. (2004). <em>Physical Review E</em>, 69, 66,106. doi:10.1103/PhysRevE.69.066106.</p> </li> <li> <p>Baró, J. (2020).  <em>Journal of Geophysical Research: Solid Earth,</em> 125, e2019JB018530. doi:10.1029/2019JB018530.</p> </li> <li> <p>Ogata, Y. (1998) <em>Annals of the Institute of Statistical Mathematics,</em> 50(2), 379–402. doi:10.1023/A:1003403601725.</p> </li> <li> <p>Saichev, A., Helmstetter, A. & Sornette, D. (2005) <em>Pure appl. geophys.</em> 162, 1113–1134. doi:10.1007/s00024-004-2663-6.</p> </li> <li> <p>Turcotte, D. L., Holliday, J. R., and Rundle, J. B. (2007), <em>Geophys. Res. Lett.</em>, 34, L12303, doi:10.1029/2007GL029696.</p> </li> <li> <p>Zaliapin, I., and Ben‐Zion, Y. (2013), <em>J. Geophys. Res. Solid Earth</em>, 118, 2865– 2877, doi:10.1002/jgrb.50178.</p> </li> </ul>

scholarly journals Capillary processes increase salt precipitation during CO2 injection in saline formations

2018 ◽  
Vol 852 ◽  
pp. 398-421
Author(s):  
Helena L. Kelly ◽  
Simon A. Mathias
Keyword(s):  
High Salinity ◽  
Volume Fraction ◽  
Injection Rate ◽  
Injection Well ◽  
Co2 Injection ◽  
Salt Precipitation ◽  
Injection Wells ◽  
Tenfold Increase ◽  
Entry Pressure ◽  
Injection Rates

An important attraction of saline formations for CO2 storage is that their high salinity renders their associated brine unlikely to be identified as a potential water resource in the future. However, high salinity can lead to dissolved salt precipitating around injection wells, resulting in loss of injectivity and well deterioration. Earlier numerical simulations have revealed that salt precipitation becomes more problematic at lower injection rates. This article presents a new similarity solution, which is used to study the relationship between capillary pressure and salt precipitation around CO2 injection wells in saline formations. Mathematical analysis reveals that the process is strongly controlled by a dimensionless capillary number, which represents the ratio of the CO2 injection rate to the product of the CO2 mobility and air-entry pressure of the porous medium. Low injection rates lead to low capillary numbers, which in turn are found to lead to large volume fractions of precipitated salt around the injection well. For one example studied, reducing the CO2 injection rate by 94 % led to a tenfold increase in the volume fraction of precipitated salt around the injection well.

An Active Method for Characterization of Flow Units Between Injection/Production Wells by Injection-Rate Design

2011 ◽  
Vol 14 (04) ◽  
pp. 433-445 ◽  
Author(s):  
Kun-Han Lee ◽  
Antonio Ortega ◽  
Amir Mohammad Nejad ◽  
Iraj Ershaghi
Keyword(s):  
Reservoir Characterization ◽  
Injection Rate ◽  
High Permeability ◽  
Injection Wells ◽  
Flow Units ◽  
Weight Factors ◽  
Production Wells ◽  
Preferential Flows ◽  
Injection Rates

Summary This paper presents a novel data-mining method to characterize the flow units between injection and production wells in a waterflood, using carefully implemented variations in injection rates. The method allows the computation of weight factors representing the influence of any of the injectors surrounding a given producer. The weight factors are used to characterize the effective contribution of injection wells to the total gross production in surrounding production wells. A wavelet approach is used to design the perturbation in the injection rates and to analyze the observed variations in the gross production rates. Tracking the contribution of injectors to various producers can help in balancing voidage replacement in waterflood optimization. A second application is reservoir characterization, in which information provided by the proposed procedure can help in mapping high-permeability flow units such as channels and fractures as well as flow barriers between wells. The method was calibrated and tested successfully for simulated line-drive and five-spot patterns with various assumed flow units and flow-heterogeneity conditions. The paper also includes a case study for a tight-formation waterflood in which the weight factors are intended to delineate the pattern of natural high-permeability channels causing preferential flows.

scholarly journals Modeling Transient Flow in CO2 Injection Wells by Considering the Phase Change

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2164
Author(s):  
Nian-Hui Wan ◽  
Li-Song Wang ◽  
Lin-Tong Hou ◽  
Qi-Lin Wu ◽  
Jing-Yu Xu
Keyword(s):  
Transient Flow ◽  
Maximum Error ◽  
Injection Rate ◽  
Co2 Injection ◽  
Injection Wells ◽  
Transient Model ◽  
Pressure Profiles ◽  
Wellbore Temperature ◽  
Temperature And Pressure

A transient model to simulate the temperature and pressure in CO2 injection wells is proposed and solved using the finite difference method. The model couples the variability of CO2 properties and conservation laws. The maximum error between the simulated and measured results is 5.04%. The case study shows that the phase state is primarily controlled by the wellbore temperature. Increasing the injection temperature or decreasing the injection rate contributes to obtaining the supercritical state. The variability of density can be ignored when the injection rate is low, but for a high injection rate, ignoring this may cause considerable errors in pressure profiles.

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