两层压裂井下管柱力学分析及其应用

Mechanical analysis of downhole strings for two-layer fracturing and its application

李子丰 戴江 于振东

LI Zifeng DAI Jiang YU Zhendong

燕山大学，河北秦皇岛　066004 大庆油田有限责任公司，黑龙??大庆　163412

Yanshan University, Qinhuangdao 066004, China Daqing Oilfield Company, Daqing 163412, China

不动管柱两层压裂技术是环保施工、提高劳动效率的新型工艺。为保证该工艺的科学有效实施，对井下管柱及各种压裂工具进行了屈曲分析、变形分析、轴向受力分析、应力与强度分析，确定管串的危险截面为井口和封隔器上截面，并编制了应用软件。通过输入油井的井眼轨迹、井身结构、油管柱组成、摩擦系数、油管内流体性能、温度、注入方式、井口油管内压力、锚定状态等各项参数，给出了井口与井下封隔器处的内外压、轴力、应力强度、安全系数及轴向变形情况。在实际井上进行了应用，有效地指导了压裂管柱设计及工具的选型，从而保证了压裂施工的顺利进行。

Two-layer fracturing with original production string is a novel technology to implement environmental protection operation and improve labor efficiency. This paper analyzes the force of downhole strings and various fracturing tools used by this technology, including buckling, deformation, axial force and stress and strength. Wellhead and top section of packer are believed to be the dangerous section of strings. Then application software is compiled. After inputting a series of parameters, we can get the internal pressure and external pressure, axial force and stress intensity, safety factor and the state of axial deformation at wellhead and downhole packer. Inputting parameters include well trajectory, casing program, tubing combination, friction coefficient, fluid property in tubing, temperature, injection mode, tubing pressure at wellhead and the anchoring state. This technology has been applied in actual wells to guide the design of fracturing strings and the selection of tools effectively, thus ensuring the success of the fracturing operation.