Stress determination from hydraulic test data and focal mechanisms of induced seismicity

Cornet, F. H.; Julien, Ph.

doi:10.1016/0148-9062(89)91973-6

Cited by 39 publications

(14 citation statements)

References 12 publications

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“…[YES?, YES? ] Fenton Hill Hot Dry Rock Site, New Mexico (hydraulic stimulation / geothermal): Bane and Fehler (1986), Cornet and Julien (1989), Fehler (1989), Fehler and Phillips (1991), Fehler et al (1987), Ferrazini et al (1990), House (1987), House et al (1992), Pearson (1981), Talebi and Cornet (1987) The Geysers, California (pressure maintenance / geothermal): Allis (1982), Eberhart-Phillips and Oppenheimer (1984), O'Connell andJohnson (1988), Oppenheimer (1986), Stark (1990) Maximum Magnitude --The largest earthquakes in the field have been approximately magnitude 4.0, although it is not dear if the largest earthquakes are associated with injection. 4a,b) The high background rate of seismic activity in the field suggests that in situ stresses are close to failure.…”

Section: Appendixmentioning

confidence: 99%

Did (Or Will) Fluid Injection Cause Earthquakes? - Criteria for a Rational Assessment

Davis

Frohlich

1993

Seismological Research Letters

148

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Occasionally, the injection of fluids into deep wells causes or triggers earthquake activity. We propose two lists of yes-or-no questions to assess 1) whether an ongoing injection project has induced an earthquake that has already occurred; or 2) whether a proposed injection project is likely to induce a nearby earthquake. The answers to these questions form a descriptive profile of the injection project that facilitates comparison with other projects. To illustrate the application of these questions, we describe the answers in detail for the first set of questions at two sites: 1) the Rocky Mountain Arsenal near Denver, Colorado, where three significant earthquakes occurred in 1967; and 2) an injection site near Painesville, Ohio, near the epicenter of an earthquake that occurred 31 January, 1986. We also present a table of answers to these questions for several additional sites, and review other factors that may affect the potential for induced, seismic activity. The profiles of injection sites presented herein provide a convenient tool for deciding whether an injection site more closely resembles other sites where injection does, or does not induce earthquakes.

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Section: Appendixmentioning

confidence: 99%

Did (Or Will) Fluid Injection Cause Earthquakes? - Criteria for a Rational Assessment

Davis

Frohlich

1993

Seismological Research Letters

148

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“…[3] Monitoring and locating acoustic emissions and microseismic clouds accompanying stimulation experiments is a novel technique to characterize the newly formed fracture system and other physical properties of the formation [Cornet and Julien, 1989;Cornet and Yin, 1995;Rutledge and Phillips, 2003;Shapiro et al, 1997]. The hypocenter can nowadays be located within ±20 m if borehole sensor arrays are used [e.g., Eisenblätter, 1988;House, 1987;Dahm et al, 1999;Manthei et al, 2003;Moriya et al, 2006;Rutledge et al, 2004;Oye et al, 2004;Evans et al, 2005;Eisner et al, 2006;Fischer et al, 2008], so that details of the seismicity patterns have been recognized.…”

Section: Introductionmentioning

confidence: 99%

Bidirectional and unidirectional fracture growth during hydrofracturing: Role of driving stress gradients

Dahm¹,

Hainzl²,

Fischer³

2010

J. Geophys. Res.

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[1] An unexpected observation from induced seismicity during stimulation experiments was the identification of asymmetric bidirectional and unidirectional growth of the seismic front and back front, indicating asymmetric growth of the hydrofracture itself. We develop and analyze a new analytical hydrofracture model that considers for the first time the effect of stress and pore pressure gradients on growth. It is based on plane strain linear elastic fracture mechanics and further considers 1-D laminar flow, the opening shape of the fracture, and a Griffith fracture criterion. The model explains asymmetric bidirectional growth during the injection and bidirectional and unidirectional growth during the postinjection phase. Analytical relations are derived for both cases to estimate the front and back front of the seismicity as a function of injection pressure, volume rate, stress gradients, viscosity, and elastic modules of the rock. Interestingly, the postinjection phase can be described by self-similar solutions, which depend only on the stress gradient and the injection pressure and which predict a parameter-independent length increase of the fracture after the injection stops. We use the theoretical opening shape of the fracture to calculate time-and space-dependent Coulomb stress changes in the rock in order to predict the patterns of induced seismicity in the neighborhood of the fracture. The model explains in detail the patterns of earthquakes induced during hydrofracturing stimulation experiments in a low-permeable gas field sandstone in west Texas, and we estimate a lateral stress or pore pressure gradient of more than 0.8 MPa km −1 . If the downhole net pressure during the experiments was 1 MPa, the gradient is constrained at about 10 MPa km −1 .Citation: Dahm, T., S. Hainzl, and T. Fischer (2010), Bidirectional and unidirectional fracture growth during hydrofracturing: Role of driving stress gradients,

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“…The most promising approach to the problem of determining the location of connected flow paths within the rock mass is to monitor the microseismicity that invariably accompanies the injections. The focal mechanisms of the individual events where they have been obtained are usually found to be predominantly double couple, reflecting localized, planar shear failure (Cash et al 1983; Cornet & Julian 1989; Jost et al 1998; Tezuka & Niitsuma 2000). At deep sites, it is usually necessary to install a network of seismic sensors in deep boreholes to secure adequate sensitivity to small magnitude events.…”

Section: Introductionmentioning

confidence: 99%

Microseismicity and permeability enhancement of hydrogeologic structures during massive fluid injections into granite at 3 km depth at the Soultz HDR site

Evans

Moriya

Niitsuma

et al. 2004

Geophysical Journal International

133

158

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S U M M A R YA high-rate injection of 20 000 m 3 of water into granite between 2.8 and 3.4 km depth at the Soultz hot dry rock (HDR) test site in France in 1993 September led to a 200-fold increase in borehole transmissivity and produced a subvertical cloud of microseismicity of dimensions 0.5 km wide, 1.2 km long, 1.5 km high and oriented 25 • NW. The resulting data set is unusually complete and well suited to studying permeability creation/enhancement processes in crystalline rock and the utility of microseismic data for revealing them. Although the microseismic cloud defined using joint hypocentre determination (JHD) locations was diffuse and showed little structure, application of the collapsing method showed it to be composed largely of discrete tubes and planes that propagated coherently. One prominent structure that extended 350 m downwards from the vicinity of a flow inlet early in the injection and that appears to contain a major flow path was subjected to detailed investigation to establish its hydrogeologic nature and the mechanisms underpinning its inferred permeability enhancement. High-resolution microseismic mapping techniques (i.e. multiplets and clustering) showed it to be a subvertical, NNW-SSE striking, fracture zone of width 10-20 m. The strike and scale of the structure identifies it as a member of a family of hydrothermally altered, cataclastic shear structures that constitute the primary permeable paths for fluid migration within the rock mass, both under ambient and forced fluid flow conditions. The microseismicity occurred on subvertical, smallscale fractures within the cataclastic shear zone whose azimuths scatter within 22 • of parallel to the parent structure. Although the structure is likely to have been naturally permeable to some degree, its permeability appears to have been significantly enhanced as a consequence of the injection. The most likely mechanism of permeability enhancement, which is in accord with the strong preference for the microseismicity to grow downwards, involves strike-slip shearing, which produced the opening of vertical tubes at along-strike jogs in the fault (the so-called Hill mesh). Seismic moment release averaged over the structure suggests shear displacements of at least 0.3 mm occurred, which are sufficient to generate aperture changes that are hydraulically significant. The preponderance of discrete structures within the microseismic cloud after collapsing suggests that significant flow and permeability enhancement (i.e. stimulation) within the rock mass is largely confined to the interiors of shear zones that appear to have a spacing of approximately 100 m.

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Stress determination from hydraulic test data and focal mechanisms of induced seismicity

Cited by 39 publications

References 12 publications

Did (Or Will) Fluid Injection Cause Earthquakes? - Criteria for a Rational Assessment

Did (Or Will) Fluid Injection Cause Earthquakes? - Criteria for a Rational Assessment

Bidirectional and unidirectional fracture growth during hydrofracturing: Role of driving stress gradients

Microseismicity and permeability enhancement of hydrogeologic structures during massive fluid injections into granite at 3 km depth at the Soultz HDR site

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