Zhu, D.; Li, W.; Niu, D.; Xiao, H.; Song, X. Propagation Law of Hydraulic Fracture across the Coal–Rock Interface under the Co-Effect of Natural Fractures and Tectonic Stress. Processes2023, 11, 1951.
Zhu, D.; Li, W.; Niu, D.; Xiao, H.; Song, X. Propagation Law of Hydraulic Fracture across the Coal–Rock Interface under the Co-Effect of Natural Fractures and Tectonic Stress. Processes 2023, 11, 1951.
Zhu, D.; Li, W.; Niu, D.; Xiao, H.; Song, X. Propagation Law of Hydraulic Fracture across the Coal–Rock Interface under the Co-Effect of Natural Fractures and Tectonic Stress. Processes2023, 11, 1951.
Zhu, D.; Li, W.; Niu, D.; Xiao, H.; Song, X. Propagation Law of Hydraulic Fracture across the Coal–Rock Interface under the Co-Effect of Natural Fractures and Tectonic Stress. Processes 2023, 11, 1951.
Abstract
Indirect fracturing from roof rock to coal using a horizontal well is a new and promising technology for coalbed methane surface exploitation in soft and low-permeability coal seams. In order to study the propagation law of hydraulic fracture across the coal-rock interface, a pore pressure cohesive element is used to establish a numerical model for indirect fracturing. Combined with practical engineering in 3# coal seam in Xinjing mine in China, the propagation behavior of hydraulic fracture across the coal-rock interface was researched, and the range of horizontal well position for indirect fracturing was determined. The results show that: (1) the pore pressure cohesive element can be used to simulate accurately the interaction between hydraulic fracture and natural fracture, and the propagation of hydraulic fracture across the coal-rock interface. (2) As the vertical distance between the horizontal well and coal-rock interface decreases, the breakdown pressure of perforation decreases; while the injection pressure increases when the hydraulic fracture crosses the coal-rock interface. (3) For the indirect fracturing engineering in 3# coal seam in Xinjing mine, the vertical distance between the horizontal well and coal-rock interface should not be larger than 2.0m to make the hydraulic fracture propagate into the coal seams.
Keywords
Pore pressure cohesive element; Indirect fracturing; Natural fracture; Tectonic stress; Horizontal well position
Subject
Engineering, Energy and Fuel Technology
Copyright:
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