考虑应力干扰的水平井分簇射孔破裂压力新模型及应用研究

New Model of Perforation Breakdown Pressure about Multiple Perforation Clusters of Horizontal Well with Induced Stress Considered and Its’ Application

众多研究者往往先在原地应力系统的基础上,将原三向主应力转化到斜井或水平井筒坐标系中,再转化到射孔眼对应的坐标系中,转换关系繁琐。笔者在研究上述模型的基础上,建立了一种直接从原应力场转化到射孔孔眼的应力计算模型,并在此基础上建立了水平井分簇射孔孔眼破裂压力计算模型,同时考虑应力诱导对原应力场的影响,建立了考虑诱导应力的射孔孔眼破裂压力模型。经过模拟计算发现:(1)不考虑应力干扰时,最先破裂的是位于或者位置接近井筒前端与后端的孔眼;裂缝初始破裂方向为水平状态。(2)考虑应力干扰时,第二波开启的射孔孔眼不是同一簇上的其他射孔孔眼,而是不同簇上的射孔孔眼;优先开启的仍然是前端与后端的射孔孔眼。

On the foundation of in-situ stress systemic,many investigators often firstly translate three-dimensional stress to inclined or horizontal well coordinate system,then reconvert it to perforation corresponding coordinate system,the transition relation of which is tedious.On the foundation of the model mentioned above,this article establishes a sort of new simple and clear model translating directly from original stress field to perf hole stress field.At the same time,considering induced stress,perforation breakdown pressure model is built.Through simulation calculation,the following results can be found:(1)without regard to the induced stress,the first opening perforation is located in the front-end and back-end of the wellbore,or near front-end and back-end.In the initial opening,the fracture direction is horizontal.(2)If the induced stress is considered,the opening perf holes by the second wave are not the other perf holes in the same cluster,but the perf holes in different clusters.It is still the front end and back end perf holes which open first.The fracture direction is also horizontal.