TY - JOUR
T1 - Numerical analysis of different fracturing mechanisms between supercritical CO2 and water-based fracturing fluids
AU - Liu, Bailong
AU - Suzuki, Anna
AU - Ito, Takatoshi
N1 - Funding Information:
This work was supported by ACT-X, Japan Science and Technology Agency (JST) Grant Number JPMJAX190H, which is gratefully acknowledged. Some results reported herein were obtained under a project commissioned by the New Energy and Industrial Technology Development Organization (NEDO).
Funding Information:
This work was supported by ACT-X, Japan Science and Technology Agency (JST) Grant Number JPMJAX190H , which is gratefully acknowledged. Some results reported herein were obtained under a project commissioned by the New Energy and Industrial Technology Development Organization (NEDO).
PY - 2020/8
Y1 - 2020/8
N2 - Hydraulic fracturing using water-based fluid consumes a large amount of freshwater resources and pollutes a reservoir by substantially decreasing its matrix permeability. To address the problems caused by water-based fracturing fluids, the possibility of using SC-CO2 as a fracturing fluid was studied for its special properties (such as low viscosity, high density, and miscibility with hydrocarbons). Previous experimental studies have indicated that SC-CO2 is superior to water-based fracturing fluid in inducing complex fractures at the laboratory scale, while the mechanism of complex fractures induced by SC-CO2 remains unclear. This study develops a new numerical model to simulate the different performances of SC-CO2 fracturing and water-based fluid fracturing to determine the mechanisms of complex fractures. The numerical model couples an unsteady flow model based on the pore-scale network method and a solid model using the finite element method with cohesive zone elements. The unsteady flow model reproduces a two-phase flow considering viscous and capillary forces at the pore scale. Our simulation results show that both viscous and capillary forces contribute to the different fracturing performances between SC-CO2 and water-based fluid. The capillary force should be considered in the flow model when simulating fracturing in low matrix permeability rock.
AB - Hydraulic fracturing using water-based fluid consumes a large amount of freshwater resources and pollutes a reservoir by substantially decreasing its matrix permeability. To address the problems caused by water-based fracturing fluids, the possibility of using SC-CO2 as a fracturing fluid was studied for its special properties (such as low viscosity, high density, and miscibility with hydrocarbons). Previous experimental studies have indicated that SC-CO2 is superior to water-based fracturing fluid in inducing complex fractures at the laboratory scale, while the mechanism of complex fractures induced by SC-CO2 remains unclear. This study develops a new numerical model to simulate the different performances of SC-CO2 fracturing and water-based fluid fracturing to determine the mechanisms of complex fractures. The numerical model couples an unsteady flow model based on the pore-scale network method and a solid model using the finite element method with cohesive zone elements. The unsteady flow model reproduces a two-phase flow considering viscous and capillary forces at the pore scale. Our simulation results show that both viscous and capillary forces contribute to the different fracturing performances between SC-CO2 and water-based fluid. The capillary force should be considered in the flow model when simulating fracturing in low matrix permeability rock.
KW - Complex fracture
KW - Rough fracture surface
KW - SC-CO fracturing
KW - Shale rock
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U2 - 10.1016/j.ijrmms.2020.104385
DO - 10.1016/j.ijrmms.2020.104385
M3 - Article
AN - SCOPUS:85085252498
VL - 132
JO - International Journal of Rock Mechanics and Mining Sciences
JF - International Journal of Rock Mechanics and Mining Sciences
SN - 1365-1609
M1 - 104385
ER -