An examination of in situ rock stress estimation using the Kaiser effect

Lehtonen, Aleksis; Cosgrove, John; Hudson, John; Johansson, Erik

doi:10.1016/j.enggeo.2011.09.012

Cited by 68 publications

(24 citation statements)

References 10 publications

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“…In order to improve the effectiveness of test results, it is essential to set test conditions as close as possible to field conditions to obtain experimental results approved by field engineers. And many scholars have adopted field parameters as experimental conditions in the hydraulic fracture experiments with triaxial pressure vessels . So the test focuses on the conditions in the design process, such as experimental material, test time, test load, geometric size, kinematic condition, and so on.…”

Section: Methodsmentioning

confidence: 99%

Large‐scale experiments of the borehole instability on shale formation influenced by drill pipe rotation

Sun

Meng

Dai

et al. 2019

Energy Science & Engineering

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Wellbore instability happens mostly in the shale formation. Early researches have studied thoroughly on the physicochemical and mechanical mechanism that causes instability. However, only a few works have considered the influence of field drilling operations, such as drill pipe rotation. In this paper, a true triaxial cell is used to simulate the downhole field situations, and a drill pipe rotation device is innovatively designed and implemented into the true triaxial cell. Using this facility, the influence of drill pipe rotation on shale instability has been performed. Different rotation speed, weight on bit, drilling fluid pressure, and microcracks on borehole have been considered. The enlargement of the wellbore is quantitatively plotted and compared.Results show that the drill pipe rotation contributes to a more enlargement of the wellbore, and a higher rotation speed causes a more severe collapse. The drill string weight on bit also contributes to the enlargement of the wellbore, with a larger weight on bit induces a larger diameter of the collapsed wellbore. Compared with the rotation speed and weight on bit, the influence of drilling fluid density is relatively less significant. However, the influence of microcracks caused by hitting of drilling tools is profound. For a cracked shale formation, the wellbore diameter can be enlarged for more than 40%. Then, the variation of borehole collapse with time and depth under drill pipe rotation influence is analyzed. In all of these four factors, the significant sequence is microcracks > weight on bit > rotation speed > drilling fluid pressure.In all the collapse phenomena, the collapse is more severe in the minimum horizontal stress direction. This is explained by the analysis of the stress distribution in the whole circumferential angle (360°) of the wellbore. Overall, this work fills the gap of the influence of drilling operations on wellbore instability. K E Y W O R D Sborehole enlargement, drill pipe rotation, true triaxial cell, wellbore instability 2896 | SUN et al.

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Section: Methodsmentioning

confidence: 99%

Large‐scale experiments of the borehole instability on shale formation influenced by drill pipe rotation

Sun

Meng

Dai

et al. 2019

Energy Science & Engineering

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“…The practical application of this method is now used to study the memory effects in the rocks [25][26][27] and in the decision of methodological problems in the study of the parameters of acoustic emission in minerals and rocks which are different in composition and structure [28,29].…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

Serpentinites of the Ural: Mineralogical Features, Petrophysical Properties and Subduction Processes

Posukhova¹,

Panasian²,

Sas³

2013

OJG

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The article presents the results of study of composition, structure and properties of three genetic types of serpentinites from Ural: developed by chromite-bearing ultrabasic rocks, by metamorphic zones of carbonate rocks and within the zone of weathering of ultrabasic rocks. The samples were selected from deposits, located along the Main Ural Faultthe Paleozoic subduction zone (named GUR). Peculiarities of microstructure, chemical composition and properties of serpentinites formed in different geological conditions were investigated and their comparative study was held. Three groups of serpentinites with oriented and non-oriented structure, which formed by different protholites, were devided: mantle, lithosphere and crust.

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“…13 metal, wood and sandstone under tension (Kaiser 1950). Since then, many researchers have investigated the potential of this phenomenon as an inexpensive method for in situ stress determination (e.g., Villaescusa et al 2002;Lehtonen et al 2012). In a typical KE test, the cumulative AE count versus axial stress is plotted (schematically shown in Fig.…”

Section: Memorymentioning

confidence: 99%

Influence of stress path on stress memory and stress fracturing in brittle rocks

2019

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A two-dimensional numerical model based on the Distinct Element Method, previously calibrated to the laboratory properties of undamaged and damaged Lac du Bonnet (LdB) granite, was used to investigate the influence of stress path on the development of stress memory and stress fracturing in brittle rocks. Various cycles of loading and unloading, similar to those imposed during Kaiser Effect tests, were first applied to undamaged numerical specimens of LdB granite. The results of Kaiser Effect test simulations were found to be consistent with those of published laboratory and numerical investigations. Further simulations were conducted to investigate the influence of stress path resulting from the excavation of a tunnel on the depth of stress fracturing around the excavation boundary. For this purpose, the stress paths at points on and near the tunnel wall, obtained from a continuum finite element model, were applied to the calibrated numerical specimen. It was found that the amount of damage in the numerical specimens decreases rapidly with increasing distance from the excavation wall. The findings of this research shed some light on the influence of stress path and grain-scale heterogeneity on stress memory in brittle rocks and stress fracturing around underground openings.

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An examination of in situ rock stress estimation using the Kaiser effect

Cited by 68 publications

References 10 publications

Large‐scale experiments of the borehole instability on shale formation influenced by drill pipe rotation

Large‐scale experiments of the borehole instability on shale formation influenced by drill pipe rotation

Serpentinites of the Ural: Mineralogical Features, Petrophysical Properties and Subduction Processes

Influence of stress path on stress memory and stress fracturing in brittle rocks

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