人工隔层技术在控缝高压裂井中的应用

Application of artificial barrier technology to fracture height control in fracturing wells

压裂施工中,如果隔层的遮挡能力较差,裂缝就会穿过隔层,含水层离产层较近的情况下还会引起含水急剧上升,影响压裂效果,甚至造成压裂失败。为了提高压裂作业的成功率,对缝高控制技术进行深入研究,实验分析了人工隔层上转向剂和下转向剂的上率浮、沉降率、上浮相对速率、沉降相对速率及隔层应力提高率,优选出了上转向剂KR2(上浮率为97%,上浮相对速率1.78,突破压力提高7.23 MPa)和下转向剂KR4(沉降率为98%,沉降相对速率1.83,突破压力提高6.29 MPa)。现场试验中,上转向剂的加入很好控制了裂缝在高度上的延伸,控缝高效果显著,人工裂缝高度降低2.7 m且未压穿水层,为以后控缝高压裂井的施工提供了很好的参考。

In the process of fracturing,fractures can run through barriers whose their barrier capacity is poorer.And if the aquifer is closer to the producing zone,water cut will rise sharply and fracturing effect will be impacted and even fail.To increase the success ratio of fracturing operation,the fracture height control technology was studied deeply in this paper.The floating diversion agent and settling diversion agent of artificial barrier were experimentally analyzed in terms of floating rate,settling rate,relative floating speed,relative settling speed and barrier stress improvement rate.And accordingly,floating diversion agent KR2(floating rate97%,relative floating speed1.78and breakthrough pressure increase7.23MPa)and settling diversion agent KR4(settling rate98%,relative settling speed1.83and breakthrough pressure increase6.29MPa)were adopted.In the field test,the adding of floating diversion agent implements the best control on fracture height extension,presenting remarkable fracture height control effect.It can be used as the reference for the construction of fracturing wells with fracture height control.