Scale effect in modeling of mechanical processes in the vicinity of a borhole on a true Triaxial Loading setup

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Abstract

One of the main problems when conducting laboratory tests of rock specimens aimed at determining their mechanical and strength properties is to transfer the test results of relatively small specimens to sufficiently large areas of a rock massif, often with a complex structure. This is due to the fact that generalized numerical indicators characterizing the degree of influence of structural heterogeneities of various sizes on the deformation and destruction of rocks and massifs are not yet available. In addition to heterogeneity, other factors also affect the processes under study, such as the stress state of the massif, the presence of geological disturbances, macrofractures, etc. These issues are studied in this paper based on a comparison of the results of experiments performed on the Triaxial Independent Loading Test System of the Institute of Problems in Vechanics of the Russian Academy of Sciences using the “hollow cylinder” scheme on specimens with a central hole of 10 and 20 mm in diameter and physical modeling of deformation processes in the vicinity of wells with a decrease in pressure at their bottomhole for reservoir rocks of the Prirazlomnoye oil field.

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About the authors

V. I. Karev

Ishlinsky Institute for Problems in Mechanics RAS

Email: perfolinkgeo@yandex.ru
Russian Federation, Moscow

Yu. F. Kovalenko

Ishlinsky Institute for Problems in Mechanics RAS

Author for correspondence.
Email: perfolinkgeo@yandex.ru
Russian Federation, Moscow

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Supplementary files

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2. Fig. 1. Schematic representation of the loading unit of the ISTNN installation for testing using the “hollow cylinder” scheme: 1 – sample

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3. Fig. 2. Loading program for a sample with a 10 mm hole: S – sample compression stress, MPa; t – time, s

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4. Fig. 3. Deformation curves of a sample with a 10 mm hole: S – sample compression stress, MPa; Ei – deformations along three axes of the sample

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5. Fig. 4. Sample with a hole after testing

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6. Fig. 5. Loading program for a sample with a 20 mm hole: S – sample compression stress, MPa; t – time, s

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7. Fig. 6. Deformation curves of a sample with a 20 mm hole: S – sample compression stress, MPa; Ei – deformations along three axes of the sample

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8. Fig. 7. Sample loading program P 10-4: Si – stresses applied to the sample faces, MPa; t – time, s

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9. Fig. 8. Deformation curves of sample P 10-4 during the experiment: S2 – loading parameter, MPa; Ei – deformations along three axes of the sample

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