大庆油田套损井大规模压裂工艺及配套工具

大庆油田累计套损井近万口，为了动用这些压裂程度低、剩余油相对富集的潜力井，开展了多级大规模压裂工艺研究。通过有限元软件分析胶筒肩部角度、长度与应力之间的关系，并通过油浸实验验证了胶筒在大形变下的耐温承压性能；应用自编软件优化调整关键部件尺寸，设计了工艺配套工具。最终确定了小直径封隔器胶筒肩部角度50°，长度550 mm；小直径喷砂器能够针对套管内径大于?104 mm的套损井进行施工，工艺覆盖率提升至70%；新型锚定工具可确保工具通过套损点并使管柱稳定；双功能防喷封隔器能够实现目的层封隔及油管防喷。现场试验结果表明，该工艺及配套工具能够用于套损井压裂，单趟管柱可压裂5层，砂量289 m3，初步实现了套损井大规模压裂施工。

Large-scale fracturing technology suitable for casing damaged wells in Daqing Oilfield and its supporting tools

There are cumulatively about 10 thousand casing damaged wells in Daqing Oilfield. In order to activate the potential wells whose fracturing degree is low and remaining oil is relatively enriched, large-scale multi-stage fracturing technology was researched in this paper. Firstly, the relationships of shoulder angle and length of rubber cylinder vs. stress were analyzed by using the finite element analysis software, and the temperature and pressure resistance of rubber cylinder in the case of great deformation was verified by conducting oil immersion experiments. Then, the size of key components was adjusted and optimized by using the independently developed software, and the supporting tools were designed. It is eventually determined that the shoulder angle of rubber cylinder in the pony packer is 50° and its length is 550 mm. In addition, small-diameter sand blower is applicable to the casing damaged wells whose casing ID is larger than 104 mm and its technological coverage rate is increased to 70%; the novel anchor tool can ensure tools to run through the casing damage points while keeping the string stable; and bi-functional blowout preventing packer can realize the isolation of target layer and the blowout prevention of tubing. Field test results show that this technology and its supporting tools can be used for fracturing of casing damaged wells. In one trip of string, 5 layers can be fractured with proppant of 289 m3. Thus, the large-scale fracturing of casing damaged wells is preliminarily realized.