多分支缝水力压裂暂堵起裂点位置研究

针对多分支缝压裂成缝起裂点不明确的问题,基于多孔介质流固耦合理论模型,通过ComsolMultiphysics软件进行有限元模拟分支缝压裂过程,分析不同应力差条件下缝内起裂点和井筒起裂点的集中应力变化规律,随着缝内净压力的增加,存在一个差别点,区分起裂点起裂的优先顺序。通过控制缝内净压力变化,调整起裂优先顺序,控制分支缝延伸条数,保证了多分支缝水力压裂缝网的复杂性。对海拉尔油田现场实例计算分析,调整缝内净压力,施工结果与模拟结果相同,可以指导现场施工,提高多分支缝水力压裂的成功率。

The Initial Cracking Point of Multi Branch Hydraulic Fracture Temporary Plugging

The seam crack point of multiple branch seam fracturing is not clear. Based on the theory of porous media of fluid solid coupling mode, Comsol software was used to simulate branch seam fracturing process using finite element simulation. The changing law of stress concentration of seam crack point and shaft crack point was analysized under the condition of different stress difference it was found that with the increase of net pressure on the seam, there was a difference which distinguished between crack priorities. By controlling the net pressure change within joint, the crack priorities was adjusted, the number of multi branch fracture was controlled, and the multi branch seam hydraulic pressure of the complexity of the fracture network was ensured. Calculation analysis of hailaer oil field on the spot was used to adjust the net pressure inside seam. The result of construction was same with simulation, and can be used to guide the construction to improve the success rate of multi branch seam hydraulic fracturing.