Identifying faults and fractures in unconventional reservoirs through microseismic monitoring

Wessels, Scott; Peña, Alejandro De La; Kratz, Michael; Williams-Stroud, Sherilyn; Jbeili, T.

doi:10.3997/1365-2397.29.7.51919

Cited by 40 publications

(7 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Within our enhanced earthquake catalog, there were 94 ≥ M L 2.0 and 10 ≥ M L 3.0 HF-induced earthquakes (supporting information, Table S3), and we calculated the Gutenberg-Richter b value to be 0.9 (Figure S8) (Caputo, 1976;Bender, 1983;Kijko & Smit, 2012;Wiemer & Wyss, 2000). Low b values (<1) and relatively large magnitudes are consistent with seismicity associated with fluid injection (Lei et al, 2008), whereas higher b values (~2) are typical of microseismicity (M < 1) directly related to the operational process of fracturing the reservoir (e.g., Wessels et al, 2011), suggesting the events we detected resulted from slip on preexisting faults instead of new fractures. We did not undertake earthquake relocation due to the sparse station coverage at the time of this analysis, but a 2019 seismic deployment across the EF (http://www.…”

Section: Correlations Between Hf and Seismicitymentioning

confidence: 98%

Hydraulic Fracture Injection Strategy Influences the Probability of Earthquakes in the Eagle Ford Shale Play of South Texas

Fasola

Brudzinski

Skoumal

et al. 2019

Geophysical Research Letters

View full text Add to dashboard Cite

Seismicity in the Eagle Ford play grew to 33 times the background rate in 2018. We identified how hydraulic fracturing (HF) contributed to seismicity since 2014 by comparing times and locations of HF with a catalog of seismicity extended with template matching. We found 94 ML ≥ 2.0 earthquakes spatiotemporally correlated to 211 HF well laterals. Injected volume and number of laterals on a pad influence the probability of seismicity, but effective injection rate has the strongest effect. Simultaneous stimulation of multiple laterals tripled the probability of seismicity relative to a single, isolated lateral. The 1 May 2018 MW 4.0 earthquake may have been the largest HF‐induced earthquake in the United States. It occurred ~10 km from a MW 4.8 earthquake in 2011 and was thought to be induced by fluid extraction. Thus, faults in this area are capable of producing felt and potentially damaging earthquakes due to operational activities.

show abstract

Section: Correlations Between Hf and Seismicitymentioning

confidence: 98%

Hydraulic Fracture Injection Strategy Influences the Probability of Earthquakes in the Eagle Ford Shale Play of South Texas

Fasola

Brudzinski

Skoumal

et al. 2019

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…6). We calculate M c using the maximum-curvature method of Wiemer and Wyss (2000). Given the reduction in noise during the period of quiescence (Fig.…”

Section: Characteristics Of Observed Seismicitymentioning

confidence: 99%

Unprecedented quiescence in resource development area allows detection of long-lived latent seismicity

Salvage

Eaton

2021

Solid Earth

View full text Add to dashboard Cite

Abstract. Recent seismicity in Alberta and north-east British Columbia has been attributed to ongoing oil and gas development in the area, due to its temporal and spatial correlation. Prior to such development, the area was seismically quiescent. Here, we show evidence that latent seismicity may occur in areas where previous operations have occurred, even during a shutdown in operations. The global COVID-19 pandemic furnished the unique opportunity to study seismicity during a long period of anthropogenic quiescence. Within the Kiskatinaw area of British Columbia, 389 events were detected from April to August 2020, which encompasses a period with very little hydraulic fracturing operations. This reduction in operations was the result of a government-imposed lockdown severely restricting the movement of people as well as a downturn in the economic market causing industry stock prices to collapse. Except for a reduction in the seismicity rate and a lack of temporal clustering that is often characteristic of hydraulic fracturing induced sequences, the general characteristics of the observed seismicity were similar to the preceding time period of active operations. During the period of relative quiescence, event magnitudes were observed between ML −0.7 and ML 1.2, which is consistent with previous event magnitudes in the area. Hypocentres occurred in a corridor orientated NW–SE, just as seismicity had done in previous years, and were located at depths associated with the target Montney formation or shallower (<2.5 km). A maximum of 21 % of the detected events during lockdown may be attributable to natural seismicity, with a further 8 % potentially attributed to dynamic triggering of seismicity from teleseismic events and 6 % related to ongoing saltwater disposal and a single operational well pad. However, this leaves ∼65 % of the seismicity detected during lockdown being unattributable to primary activation mechanisms. This seismicity is unlikely to be the result of direct pore pressure increases (as very little direct injection of fluids was occurring at the time) and we see no patterns of temporal or spatial migration in the seismicity as would be expected from direct pore pressure increases. Instead, we suggest that this latent seismicity may be generated by aseismic slip as fluids (resulting from previous hydraulic fracturing injection) become trapped within permeable formations at depth, keeping pore pressures in the area elevated and consequently allowing the generation of seismicity. Alternatively, this seismicity may be the result of fault and fracture weakening in response to previous fluid injection. This is the first time that this latent seismicity has been observed in this area of British Columbia and, as such, this may now represent the new normal background seismicity rate within the Kiskatinaw area.

show abstract

“…Although previously characterized by a complex fracture network (e.g., Michelet & Toksöz, 2007), recent analysis of the Soultz-sous-Forêts reservoir indicates that the fracture complexity deduced from the cloud of hypocenter locations might primarily be an artifact of ill-constrained data and that the reservoir might be dominated by a single fault (Baisch et al, 2010). Fault-like structures outlined by fluid injection induced earthquakes were also identified in the context of waste-water disposal (e.g., Schoenball et al, 2018) and hydraulic fracturing (e.g., Wessels et al, 2011). To what extend the proposed methodology can be applied to these data examples is subject of future research.…”

Section: Further Applicationsmentioning

confidence: 99%

Inferring In Situ Hydraulic Pressure From Induced Seismicity Observations: An Application to the Cooper Basin (Australia) Geothermal Reservoir

Baisch

2020

JGR Solid Earth

View full text Add to dashboard Cite

An approach is proposed for estimating in situ reservoir pressure changes based on induced earthquakes with overlapping slip patches. The approach is independent of absolute (tectonic) stresses and can also be applied in a scenario where the (unknown) tectonic stresses are strongly heterogeneous. Based on Coulomb friction, the approach makes use of the fact that stress‐strength conditions are in equilibrium at the time of seismic activation. Coseismic stress changes inferred from seismogram recordings provide the stress‐state relative to the failure stress immediately after seismic activation. If the same fracture patch is seismically activated again, relative changes of fluid pressure, that is, the fluid pressure change at which stress‐strength conditions reach equilibrium again, can be inferred from the stress‐deficit when accounting for stress re‐load from neighboring patches. The performance of the technique is demonstrated using a data set of 20,736 earthquakes induced during a hydraulic injection experiment in a geothermal reservoir in the Cooper Basin, Australia. The spatial hypocenter distribution indicates that the seismicity mainly occurred on a single‐layer structure with slip direction controlled by the regional stress field as evidenced by fault mechanisms. Due to the high earthquake density, interearthquake stress interaction is pronounced. The spatial stress impact associated with each earthquake is simulated using a slider‐block type propagation pattern based on Okada's analytical solutions. Using the scalar seismic moment determined from S‐wave spectra, the spatio‐temporal evolution of hydraulic pressure changes is inferred on a reservoir scale. Results indicate that hydraulic flow is most pronounced into NW‐SE direction.

show abstract

Identifying faults and fractures in unconventional reservoirs through microseismic monitoring

Cited by 40 publications

References 6 publications

Hydraulic Fracture Injection Strategy Influences the Probability of Earthquakes in the Eagle Ford Shale Play of South Texas

Hydraulic Fracture Injection Strategy Influences the Probability of Earthquakes in the Eagle Ford Shale Play of South Texas

Unprecedented quiescence in resource development area allows detection of long-lived latent seismicity

Inferring In Situ Hydraulic Pressure From Induced Seismicity Observations: An Application to the Cooper Basin (Australia) Geothermal Reservoir

Contact Info

Product

Resources

About