Evolution of Geomechanical and Electrohydrodynamic Fields in Deep Borehole Drilling in Rocks
L. A. NAZAROVA1,2, L. A. NAZAROV1,2, M. I. EPOV3,2, I. N. EL’TSOV3,2
1N.A. Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences, Krasnyi pr. 54, Novosibirsk, 630091 Russia
2Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia
3A.A. Trofimuk Institute of Petroleum Geology and Geophysics, pr. Akademika Koptyuga 3, Novosibirsk, 630090 Russia
Keywords: rock mass, multi-phase filtration, borehole, stress state, failure, flushed zone, permeability, reservoir, resistivity
Abstract
The authors have developed and numerically implemented 3D model of evolution of geomechanical and hydrodynamic fields during deep borehole drilling. The modeling exercises showed low-permeable zone of irreversible deformations that appear under definitely interrelated rock strength properties, drilling mud pressure and in situ horizontal stresses in borehole environment. These low-permeable irreversible-deformation zones give rise to angular anisotropy of distribution of water content and drilling mud resistivity in the flushed zone, which greatly affects readings of geophysical logging and must be considered in the logging data inversion.
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