摘要
确定裂缝是否转向及其主要影响因素是目前榆树林油田重复压裂问题之一。通过Fracpro PT软件拟合分析了现场压裂数据,施工过程净压力7.8-17.0 MPa,目前最大最小主应力差为9.6-20.6 MPa,平均14.4MPa;采用重复压裂应力分析软件计算了油水井在不同生产压差和裂缝缝长与缝宽条件下生产时不同位置处的最大最小应力差的演变,5 mm缝宽比1.6 mm缝宽最大最小应力差小1.0 MPa;120 m缝长比60 m缝长最大与最小应力差小0.5 MPa;22 MPa比17 MPa的油水井生产压差的最大最小应力差小2.0 MPa。初始最大最小主应力差16MPa对该油田部分井重复压裂实现裂缝转向具有较大难度,不易形成新缝;目前最大最小应力差小、初次压裂形成宽和长的裂缝、压后油水井生产压差较大及重复压裂过程中净压力较高的井层有利于重复压裂时发生裂缝的重定向而产生新裂缝。
Recently,there is an important question about re-fracturing of Yushulin oilfield that determining whether the cracks steering and the main factors. By the software of Fracpro PT analyzing the site fracturing data,the net pressure during construction is about 7. 8 ~ 17.0 MPa. Currently,the maximum and minimum principal stress difference is about 9. 6 MPa- 20. 6 MPa,and an average of 14. 4 MPa.By the re-fracturing stress analysis software,we calculate the evolution of the maximum and minimum stress of difference at different positions,when production under the different conditions of pressure,fracture length and fracture width. The maximum and minimum stress of difference of 5mm slot width,smaller 16 mm slot width than 1. 0 MPa; The maximum and minimum stress of difference of 120 m slot length,smaller 60 m slot length than 0. 5 MPa; The maximum and minimum stress of difference of production pressure of 22 MPa,smaller 17 MPa than 2. 0 MPa. Because the initial maximum and minimum principal stress difference is 16 MPa,the part of the oil wells re-fracturing steering have greater difficulty and difficult to form a new fracture. At present,there are some conducive conditions of the reorientation of re-fracturing and generating new cracks. For example,the maximum and minimum stress of difference is smaller; the width and length of initial fracture is bigger; the production pressure is more and the net pressure is higher during the process of re-fracturing.
出处
《油气井测试》
2015年第1期13-16,75,共4页
Well Testing
基金
国家科技重大专项项目"复杂油气田地质与提高采收率技术"下属专题"低渗透油田弹性驱替界限与开发后期井网优化调整技术研究"(2011ZX05009-004)内容
关键词
裂缝转向
重复压裂
主应力差
净压力
榆树林油田
cracks steering,multiple fracturing,principal stress difference,net pressure,Yushulin oilfield
