Hydraulic fracturing to determine the regional in situ stress field, Piceance Basin, Colorado

Bredehoeft, John; Wolff, Reinhard; Keys, W. Scott; Shuter, Eugene

doi:10.1130/0016-7606(1976)87<250:hftdtr>2.0.co;2

Cited by 239 publications

(81 citation statements)

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“…Thus, our apparently large (relative to uEW and up) value of uNS = -3.1 MPa is consistent with the borehole-pillar configuration, and the fact that fractures in the rock have an approximate vertical N-S orientation which would least effect stress in the N-S direction. Note that the measured UNS = -3.1 MPa is in (perhaps fortuitously) close agreement with the value of -3.9 MPa obtained by Bredehoeft et al (1976) for the N20E horizontal component of principal stress. The results of this study are also in qualitative agreement with those of Coates & Ignatieff (1966), who found the maximum principal pillar stress to be horizontal in a number of cases.…”

Section: F I E L D R E S U L T Ssupporting

confidence: 68%

Holographic in situ stress measurements

1987

International Journal of Rock Mechanics and Mining Sciences &am

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Summary.A new instrument for measuring the in siru level of stress in boreholes has been developed. The instrument operates on the principle of locally relieving the stresses acting on a rock mass by drilling a small hole into the borehole surface and recording the resultant displacement field by holographic interferometry. Because the recording technique is optical, the entire displacement field due to stress relief is obtained. A description of the stressmeter, theory of the interferometric technique, data reduction methodology, and results of laboratory stress relief calibration tests are presented. In addition, we present results from a field deployment of the instrument in an underground shale mine in Garfield County, Colorado using a test borehole within a support pillar. Sufficient data were obtained to constrain five of six stress components at a shallow level of the test borehole, thereby demonstrating the viability of the holographic technique. The holographic stressrelief data yield an approximate EW maximum horizontal stress direction. By comparison with previous hydrofracture measurements of Bredehoeft et al., our results indicate substantial stress-relief near the pillar face, thus masking any relicts of the far-field tectonic stress.

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Section: F I E L D R E S U L T Ssupporting

confidence: 68%

Holographic in situ stress measurements

1987

International Journal of Rock Mechanics and Mining Sciences &am

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“…If failure occurs along pre-existing fractures, the surrounding rock can be assumed to have no inherent tensile strength (Bredehoeft et al, 1976). Based on the Mohr-Coulomb criteria for failure, this introduction of tensional stress should produce me chanical failure along an azimuth that corresponds to the direc tion of maximum horizontal principal stress.…”

Section: Consequences Of An Elliptical Boreholementioning

confidence: 99%

Analysis and Interpretation of the Borehole Televiewer Log: Information on the State of Stress and the Lithostratigraphy at Hole 504B

Morin¹,

Anderson²,

Barton³

1989

Proceedings of the Ocean Drilling Program

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Hole 504B in the eastern equatorial Pacific has been the focus of several scientific expeditions during the past few years, where a series of re-entry, drilling, and coring operations has yielded important data regarding the structure of the upper kilometer of the oceanic lithosphere. As part of the extensive downhole experiments program planned for ODP Leg 111 at this site, a borehole televiewer (BHTV) log was obtained across a 355-m vertical section of crustal base ment, extending upward from 1531 to 1176 m below the seafloor. The BHTV record was analyzed in terms of both acoustic amplitude and traveltime in order to accurately identify zones of structural failure in the surrounding basement rock. A subsequent examination of breakout frequency vs. azimuth helped identify the orientation of in-situ horizontal principal stresses according to the well-substantiated hypothesis that breakouts occur coincident with the direction of minimum principal stress (S h ) where compressive forces are at their greatest. This S h orientation is found to be NI22.5°E, a direction that agrees closely with the results of a previous BHTV study of breakouts in the upper section of this same borehole and also with stress orientation estimates inferred from regional intraplate earthquakes. The distri bution of breakout frequency vs. azimuth shows the data to be bimodal and orthogonal to a degree that is statistically significant. The S h direction is inferred from the primary mode. The orthogonal pattern indicates that a considerable number of wellbore enlargements were detected coincident with the direction of maximum principal stress (S H ). These are interpreted as extensional fractures produced by localized tensional stresses parallel with the S H orientation. Consid eration of various hydraulic fracturing schemes and attendant analyses indicates that these fractures are likely to be in duced when the ratio of effective horizontal principal stresses {S H /S h ) is very large in a cylindrical wellbore or is some what smaller in a hole exhibiting a slight degree of ellipticity. This hypothesis is supported by the solutions to source mechanism studies associated with local earthquakes that indicate a strike-slip sense of faulting and a relative order of stress magnitude where S H » S h . The bimodal, orthogonal distribution of wellbore enlargements also results in a slight correction to the method used for estimating the principal stress orientation, one based upon the population modes rather than the mean.Inspection of three-dimensional images generated from the BHTV record in the lower portion of the borehole re veals the surprising appearance of pillow lavas at a depth previously assumed to be composed of sheeted dikes. When the ophiolite analogy is applied to contemporary oceanic crust, the transitional unit between the upper pillow lavas and minor flows and the variably metamorphosed diabase dikes below seems to be a complex, gradual, and gradational interlayering of lithologies that extends over a thicker vertical inter...

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“…If, on the other hand, the fracture is mechanically softer than the surrounding rock matrix, the stress tends to be smeared out along the fracture, reducing the stress concentration at the borehole wall. In such case, the minimum tangential stress can no longer be calculated from the solution in Equation (2), and therefore an error is introduced in the estimate of maximum horizontal stress when using Equation (1).…”

Section: Possible Uncertainties Due To the Induced Fracturementioning

confidence: 99%

“…The minimum horizontal stress, σ h is determined from the shut-in pressure; the maximum horizontal stress, σ H , may be evaluated using Bredehoeft's [1] (1) where P r is the reopening pressure and P 0 is the pore pressure in the fracture. This equation is derived from the Kirsch solution for a circular hole subjected to an internal pressure in an isotropic, homogeneous and, linear elastic medium.…”

Section: Introductionmentioning

confidence: 99%

Uncertainty in the maximum principal stress estimated from hydraulic fracturing measurements due to the presence of the induced fracture

Rutqvist

Tsang

Stephansson

2000

International Journal of Rock Mechanics and Mining Sciences

108

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The classical theory for hydraulic fracturing stress measurements assumes an ideal case with a linear elastic, homogenous, and isotropic medium; and a fracture that reopens distinctly when the minimum tangential borehole stress is exceeded. The induced fracture disturbs this ideal picture in several aspects, which are important for the evaluation of the maximum horizontal principal stress using the fracture reopening pressure. This disturbance can be attributed to the fracture normal stiffness and the initial hydraulic fracture permeability. In this paper, the hydraulic fracturing reopening test is studied by coupled hydromechanical modeling that takes into account an induced fracture that is incompletely closed. The result shows that with realistic equipment compliance, the apparent fracture reopening evaluated from the well-pressure is close to the magnitude of the minimum horizontal principal stress with little or no correlation to the maximum horizontal principal stress. This observation suggests that determination of maximum principal stress by hydraulic fracturing using the reopening pressure is very uncertain.

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Hydraulic fracturing to determine the regional in situ stress field, Piceance Basin, Colorado

Cited by 239 publications

References 0 publications

Holographic in situ stress measurements

Holographic in situ stress measurements

Analysis and Interpretation of the Borehole Televiewer Log: Information on the State of Stress and the Lithostratigraphy at Hole 504B

Uncertainty in the maximum principal stress estimated from hydraulic fracturing measurements due to the presence of the induced fracture

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