斜井套管射孔破裂压力及起裂位置研究

Study on fracture initiation pressure and fracture starting point in deviated wellbore with perforations

针对以往斜井压裂破裂压力计算中存在的问题,根据套管射孔斜井中钻井井眼与射孔孔眼相交处的应力状态,研究了射孔孔边切应力的计算方法,并分析了存在微环面时的两孔相交处的应力场、破裂压力及起裂方位的计算方法以及环空胶结严密时两孔相交处破裂压力的计算方法。利用空间几何知识,推导出了裂缝起裂平面与理想平面夹角及用于判断裂缝的转向程度的计算公式,并给出了计算实例。

There are some lacks in the former models for calculating fracture initiation pressure and fracture starting point in deviated wellbore with perforations. On the basis of the stress field in the intersection between drilling hole and perforations, the calculating models for transverse stress, fracture initiation pressure and fracture starting point at the intersection of two perforated holes existing Micro-Annulus plane were analyzed. In order to estimate the turning degree of fractures, the models for calculating angle between fracture initiation plane and the perfect hydraulic fracture plane are presented. A calculation example is given.