Numerical Simulation of Temperature Field and Temperature Stress of Hydrothermal Spallation

doi:10.11885/j.issn.1674-5086.2019.03.15.01

Abstract

Abstract: Hydrothermal spallation drilling technology uses a high-temperature medium such as supercritical water for rapid heating of the rock locally to break the rock. The rock matrix has a very low thermal conductivity. Consequently, temperature stresses are formed on the rock surface. When the temperature stresses exceed the rock's strength, micro-cracks are formed inside the rock, and the crack will continue to expand and eventually cause thermal cracking on the rock surface, which causes the rock surface to fall off from the body, leading to breaking of the rock. Based on the thermo-solid coupling theory, a thermal cracking drilling model was established, and the distribution laws of temperature field and temperature stresses of the rock at the well bottom were obtained using the Crank-Nicolson differential method. The results show that, during the thermal cracking drilling process, the temperature of the heated part of the rock increases rapidly, and temperature gradients are generated in the radial and axial directions. The volume expansion of the heated part is subjected to compressive stress in the radial direction, and shear stress in the axial direction under buckling.

Key words: well drilling, hydrothermal spallation, thermal cracking, temperature field, temperature stress

CLC Number:

TE248

WANG Guohua, TAN jun, XIONG Jiyou, HAN Jinqiang, KUANG Shengping. Numerical Simulation of Temperature Field and Temperature Stress of Hydrothermal Spallation[J]. 西南石油大学学报(自然科学版), 2019, 41(3): 143-150.

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