限流压裂曲线分析及压开层位的判定计算

Analysis of limited entry fracture curve and judgement of opened or screen out zones.

水力压裂曲线隐藏了大量的压裂信息，但是对多层压裂曲线目前尚没有论及（ 尤其是对限流和投球压裂曲线） 。利用孔眼摩阻公式分析了限流压裂曲线的瞬时仃泵时的压降落差、以及限流压裂中压力上升的幅度，并建立了相应的关系式。限流压裂的瞬时停泵压降落差表现为压开层位的畅通孔眼的摩阻值，而限流压裂过程中，压裂曲线压力突然上升，说明有层位在压裂过程中砂堵，其砂堵造成的压力上升幅度表现为其它压开层的孔眼摩阻的增值。用建立的关系式计算的畅通孔眼数与压裂层位的孔眼数进行匹配，可以判定限流压开及其砂堵的层位，并可以在现场进行实时分析。此方法经济、简单、可靠并具有自我验证性。在新疆鄯善等油田得到了应用，其计算结果与压后井温、压后产液剖面测试结果及层间布孔匹配吻合得很好。

Fracturing curves imply much information about formation, but multi zone fracturing curve is rarely discussed at present. With the perforation friction pressure equation, this paper analyses two important parts of the limited entry fracture pressure curve one of which is the instantaneous shut in pressure drop, and the other is the sudden step like pressure rise resulted in by the screen out for the limited entry, and new equations have been built up with which we can judge which zones are fractured up or not, and which zones are screened out for the limited entry. This method has been proved by information of ten wells, its results very much fit to that of well temperature testing, production section measurement and perforation distribution on the section. This method is economical, prompt, simple and reliable.