Injection-induced seismicity: strategies for reducing risk using high stress path reservoirs and temperature-induced stress preconditioning

Abstract

SUMMARY It is suggested that fluid injection in normal faulting stress regimes can stabilize a reservoir if the stress path is high enough. This stabilization is not seen when the reservoir is significantly cooled as a result of injection. Further, a new strategy is suggested for stimulating reservoirs in shear with a reduced chance of inducing a large magnitude seismic event. The version of this methodology presented here is applicable for reverse faulting stress regimes and involves an initial stress preconditioning stage where the reservoir is cooled and the pressure increase is limited. This process reduces the horizontal total stress and thereby also the differential stress. Next, the reservoir is stimulated with a rapid increase in pore pressure, resulting in shear failure at a lower differential stress than was initially present in the reservoir. Due to the connection seen between the Gutenberg–Richter b-value and differential stress, it is suggested that reservoirs stimulated in this fashion will exhibit higher b-values and thereby also have a reduced chance of hosting a large magnitude event. It is suggested that adaptations of this methodology are applicable to both normal and strike-slip faulting stress regimes.

Hydraulic Transport Through Calcite Bearing Faults With Customized Roughness: Effects of Normal and Shear Loading

“…Further work is nevertheless needed to estimate at which stress levels this prediction stops being accurate and to predict the change at high normal stress. Indeed, by preconditioning the reservoir (reducing the effective stress on it; Fryer et al, 2018Fryer et al, , 2020, the predictions of transmissivity should become more accurate. We can speculate that the use of more complex models that include shear stress and wear processes can strongly improve the prediction of transmissivity with shear displacement (Aghababaei et al, 2016;Frérot et al, 2019;Milanese et al, 2019;Molinari et al, 2018;Shvarts & Yastrebov, 2018a, 2018bShvarts, 2019;Yastrebov et al, 2017).…”

“…We can conclude that changing the state of stress will improve fluid production in a larger scale than generating significant offsets in the fault (which can be technologically difficult). This can be done for example through stress preconditioning (Fryer et al, 2018(Fryer et al, , 2020.…”

Brittle Faulting of Ductile Rock Induced by Pore Fluid Pressure Build‐Up

“…On the one hand, high temperature favors plastic mechanisms and ductile deformations. On the other hand, as long term injection may lower the in situ reservoir temperature, it may induce thermal cracking (e.g., Fredrich & Wong, 1986), or stress field variations (e.g., Fryer et al., 2020). A combination of the pore fluid pressure and temperature variations of deep crustal rocks must be studied for safe injections.…”

Moving towards deep underground mineral resources: Drivers, challenges and potential solutions

“…Moreover, preconditioning of an orebody using the sublevel caving method (Fig. 3) has proved to be a reliable technique not only to improve production rates (because of a reduction of issues by using gravity flow) (Brown, 2007;Catalan et al, 2012;Castro et al, 2014;Brzovic et al, 2014), but also to reduce seismic intensity (Toper et al, 2000;Cordova et al, 2021;Fryer et al, 2019).…”