Measuring In Situ Rock Stress by Borehole Slotting

Bock, Helmut

doi:10.1016/b978-0-08-042066-0.50023-9

Cited by 13 publications

(12 citation statements)

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“…This shape-compensation method does not require rock elastic properties to determine stresses. A review of borehole-slotting methods is given by Bock (1993). The method does not require any overcoring and is quick to use (Ljunggren et al 2003; ten measurements per day).…”

Section: Classification Of Measurement Techniquesmentioning

confidence: 98%

Stress Field of the Earth’s Crust

2010

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Section: Classification Of Measurement Techniquesmentioning

confidence: 98%

Stress Field of the Earth’s Crust

2010

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“…Here we compare our estimated stress tensor with previous tests conducted at the Mont Terri URL. The stress tensor has been estimated at different locations in the Mont Terri Laboratory through three different types of measurements: (1) slotter probe utilizing a strain relief testing method (Bock 1993); (2) undercore method using the CSIRO triaxial strain cells and (3) HF (Haimson & Fairhurst 1970). The results from all these measurements are discussed in several technical notes (Martin & Lanyon 2003;Corkum & Martin 2007;Doe & Vietor 2015).…”

Section: Comparison With Other Stress Tensor Estimations At Mont Terrimentioning

confidence: 99%

Estimating perturbed stress from 3-D borehole displacements induced by fluid injection in fractured or faulted shales

Guglielmi

Nussbaum²,

Rutqvist

et al. 2020

Geophysical Journal International

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S U M M A R YHydrofracturing stress measurements in fractured and anisotropic shales are notoriously difficult, because opening of existing geological features tends to prevent the creation of a pure hydraulic fracture perpendicular to the least compressive principal stress. Here we show how adding 3-D borehole-displacement measurements while conducting the hydraulic injection test helps to better constrain the principal stress orientations and magnitudes. We developed a 3-D fully coupled hydromechanical numerical model to analyse the displacement, fluid pressure and injection flow-rate data measured during an injection pressure-step-rate test conducted to activate a faulted borehole interval in the Mont Terri Opalinus Clay (Switzerland). We find that injected fluids can only penetrate the fault when it is at or above the Coulomb failure pressure. Borehole displacement orientations are sensitive to a ∼15 • variation in the stress-tensor orientation and a 1 MPa stress magnitude variation. Although some dispersion occurs while rupture is propagating along the fault plane ∼4 m away from the borehole, the maximum density of displacement orientations consistently informs about the stress orientation. Thus, an extended injection step-rate approach coupled with an accurate in situ measurement of the borehole wall displacements can be used to better constrain the local stress field perturbations in fractured shales and in heterogeneous rock in general.

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“…A detailed description of the borehole slotter, including the recoverable strain sensor, the test procedure and the theoretical background, was given by Bock (1993) and in a previous volume of this journal ( Becker and Werner, 1994). Two developments are important: (i) no adhesives are needed for a secure contact between sensor and rock surface, and (ii) the borehole slotter can be used in pre‐existing boreholes, allowing the separation of drilling from measuring activities.…”

Section: Introductionmentioning

confidence: 99%

In situ stress data from the Jura Mountains — new results and interpretation

Becker

1999

Terra Nova

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Recently completed in situ stress measurements using the borehole slotter at 33 new test sites within the Swiss and French Jura Mountains are presented. When combined with previously published stress data, these new measurements allow a detailed description of the contemporary state of stress in this fold‐and‐thrust belt and the adjacent foreland. The data now allow the recognition of five stress provinces, within which two general and different orientations of maximum horizontal stress SH can be distinguished: the Central and the Southwest Provinces, with a NNW–SSE to NNE–SSW orientation, and the East, Northwest and Southeast Provinces, orientated E–W to NW–SE. Each province has its own characteristic orientation. Measurements in three study areas are presented for comparison with already published acoustic anisotropy measurements, borehole breakout data, overcoring tests and triangulation measurements. The results show a generally good agreement with the new borehole slotter measurements. The tectonic implications of these stress data are discussed in terms of a large‐scale stress reorientation of the NW–SE orientated contemporary Central European stress field in the foreland of the western Alpine arc.

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Measuring In Situ Rock Stress by Borehole Slotting

Cited by 13 publications

References 0 publications

Stress Field of the Earth’s Crust

Stress Field of the Earth’s Crust

Estimating perturbed stress from 3-D borehole displacements induced by fluid injection in fractured or faulted shales

In situ stress data from the Jura Mountains — new results and interpretation

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