关键词: 页岩, 流固耦合, 水力压裂, 石英填充, 数值模拟, 破坏模式

Abstract: To explore the fracture growth in the single-hole shale by the hydraulic fracturing under the fluid-structure interaction, the RFPA2D-Flow shale fracture analysis software was used to establish seven numerical models under different hydraulic pressure increments, and hydraulic fracturing tests were also performed. The results show that the initial crack starts from the borehole circumference of the single-hole shale during the loading process along the weakest part of the shale matrix and quartz junction, and the crack expands along the edge of the quartz grain. Its final failure modes can be divided into oblique Y type and oblique X type; Due to the coupled of confining pressure and water pressure, the damage degradation occurs twice in the failure process, and when the water pressure increment is 0.45MPa/step, the shale damage failure stress is the largest, and the damage failure value is 60.97MPa; When the internal stress balance is broken, the microfractures generated by shale will be compacted, and when the hydraulic fracturing increment is 0.45MPa/step, the fracture rate reaches the maximum.

Key words: Shale, Fluid-Structure Interaction, Hydraulic Fracturing, Quartz Filled, Numerical Investigations, Failure Modes