基于FDEM-flow的多孔水力压裂模拟

Simulation of Multi-hole Hydraulic Fracturing Using FDEM-flow Method

为指导水力压裂施工,用FDEM-flow方法对多孔水力压裂问题进行了研究。研究结果显示:当H2孔的水压较小时,由H1孔出发的裂缝几乎不朝H2孔偏转;当H2孔的水压较大时,H1孔出发朝下扩展的裂缝,向H2孔偏转明显;当H1,H3孔同步增大水压时,H1出发向下扩展的裂缝朝H3孔偏转,H3孔出发向上扩展的裂缝朝H1孔偏转,最终在H1孔和H3孔间形成2条相向扩展的裂缝。上述研究结果表明:水力压裂裂缝的走向会受到相邻孔的干涉,可以通过相邻孔应力干扰控制压裂裂缝的走向;同时相邻孔的干涉,可以降低注水孔的起裂水压力,这也从侧面说明了同步压裂技术的合理性。

In order to instruct construction of hydraulic fracturing,with the proposed FDEM-flow method,we studied multi-hole hydraulic fracturing. When the pressure of hole H2 is small,crack starting from hole H1 hardly deflects toward hole H2; when water pressure of H2 is large,crack starting from H1 propagates to H2 obviously;while when pressures of H1 and H3 increase synchronously,crack extended downward from hole H1 deflects towards hole H3,and crack starting from hole H3 develops towards hole H1,and finally,two opposing propagation cracks form between H1 and H3. Results show that,direction of hydraulic fracturing cracks will be interfered by adjacent holes,hence the direction can be controlled through adjusting the pressure of adjacent holes; while the initiation water pressure that crack begins to occur can be reduced through the adjacent interference,which validated the rationality of synchronous hydraulic fracturing technology.