Influence of temperature on the interaction of metal veins and hydraulic fractures in shale formations: Experiment and simulation

Abstract

In the field construction of shale oil (gas) hydraulic fracturing, the veins present in the shale may deflect the propagation path of hydraulic fractures. The metal chalcopyrite veins are widely contained in Jimusar Shale, but the effect of the metal veins on the fracture propagation at different temperatures is still unclear. Based on the extended finite element simulation and semicircular bending test method, the effect of temperature on the interaction law of the metal veins and hydraulic fractures is studied. The results show that the fracture propagation path in the rock sample is more tortuous with the increasing temperature; Compared with the 23 °C rock sample, the fracture toughness of rock samples without the vein and with the vein at 200 °C increase by 7.79% and 22.78%, respectively. The higher the temperature, the more difficult it is for the fracture to offset at the interface between the rock and the metal veins. But the temperature does not affect the distance of fractures offset. The results of this study can provide a reference for the design of hydraulic fractures of shale with the metal veins.