Simulation of supercritical CO2 fracturing based on the cohesive phase-field method
YANG Zhaozhong1, LIU Jianping1, YI Liangping2, YI Duo1, WU Zhonghu3, PU Junhong4, ZHU Sitao5
(1. Petroleum Engineering School, Southwest Petroleum University, Sichuan Chengdu 610500, China; 2. School of Mechatronic Engineering, Southwest Petroleum University, Sichuan Chengdu 610500, China; 3. College of Civil Engineering, Guizhou
University, Guiyang, Guizhou 550025, China; 4. Development Division of PetroChina Southwest Oil and Gasfield Company,
Chengdu, Sichuan 610066, China; 5. School of Civil and Resource Engineering, Beijing University of Science and
Technology, Beijing 100083, China)
Abstract：Considering the heat transfer between the fracturing fluid and the rock, a thermo-hydro-mechanical coupled cohesive phase-field model is proposed to address the dynamic fracture propagation problem in supercritical CO? fracturing. The failure mode of the rock is assumed to be dynamic quasi-brittle fracture, facilitated by the introduction of an inertial term and the traction-separation law. CO? property parameters under varying temperature and pressure conditions are obtained using REFPROP software and integrated with the governing equations for fluid flow and heat transfer through interpolation functions. A two-dimensional numerical model for supercritical CO? fracturing was established to investigate the fracture propagation behavior under different injection rates, viscosities, reservoir horizontal stress differentials, and initial temperatures. The results indicate that: (1) There exists an optimal displacement for supercritical CO? fracturing, maximizing both fracture length and stimulated area; (2) Provided that the wellhead pressure does not exceed the limit, increasing the viscosity of the supercritical CO? fracturing fluid can reduce leak-off and enhance the stimulated reservoir area; (3) The magnitude of the horizontal stress differential has minimal impact on temperature and pressure changes within the formation, yet it significantly influences fracture morphology; (4) The initial temperature of the reservoir primarily affects rock fracture through thermal stress; higher initial temperatures lead to more complex fracture morphologies. By examining the branching patterns of fractures and their fluid pressure responses, the fracturing effects of supercritical CO? under various engineering and geological parameters are elucidated, providing valuable guidance for the design of field supercritical CO? fracturing operations.
杨兆中1，刘建平1，易良平2，易 多1，邬忠虎3，蒲军宏4，朱斯陶5. 基于内聚力相场法的超临界CO2压裂模拟[J]. 岩石力学与工程学报, 2025, 44(12): 3184-3197.
YANG Zhaozhong1, LIU Jianping1, YI Liangping2, YI Duo1, WU Zhonghu3, PU Junhong4, ZHU Sitao5. Simulation of supercritical CO2 fracturing based on the cohesive phase-field method. , 2025, 44(12): 3184-3197.
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2025, Vol. 44 
