低渗透油田薄夹层压裂界限试验研究

Experimental research on the fracturing limit of thin interbed in low permeability oilfield.

随着老油田进入中高含水开发期,由于非均质影响,纵向上潜力层与高含水层交错存在。由于夹层较薄,压裂易导致水窜,隔层遮挡作用的判断及缝高的控制显得更为重要,这也是压裂选井选层及优化设计的难点和关键。在定性研究薄夹层遮挡作用的基础上,对隔层的界限进行了试验研究,提出了一套新的压裂隔层选择方法,给出了配套的技术。现场试验27口井,打破了以往按厚度分层,夹层厚度小于4 m不能分层压裂的界限,从而拓宽了压裂选井选层的范围,尤其对高含水阶段油层改造具有重要意义。

For oilfields which have already came into high water cut stage,potential layers and high water cut layers coexist vertically because of serious heterogeneity.It is easy for water breakthrough while fracturing because the interbed is generally thin.Therefore,the estimation of barrier function for interbeds and fracture height controlling are very important for hydraulic fracturing,which are also the difficulty and critical points of fracturing optimization design and well selecting.Based on the qualitative research on the barrier function of thin interbed,experiments were conducted on the interbed limits,and a new method of fracturing interbed selecting has been put forward.At the same time,the corresponding technics is provided,and 27 wells have been tested on-site.The conventional viewpoint that fracturing couldn't be conducted if the interbed is less 4 m is broken.This technology enlarges the range of selecting wells and layers for fracturing and has very important significance for improving the reservoir stimulation efficiency in high water cut stage.