高温高压下扩张式封隔器胶筒非线性流动仿真计算  

Simulation calculation of nonlinear flow for expansion packer rubber under temperature and pressure environment well

作　　者：岳欠杯[1] 王岗 刘巨保[1] 孙国昊 王笑笑 刘跃秋 曹文 张强[1] YUE Qian-bei;WANG Gang;LIU Ju-bao;SUN Guo-hao;WANG Xiao-xiao;LIU Yue-qiu;CHAO Wen;ZHANG Qiang(College of Mechanical Science and Engineering,Northeast Petroleum University,Daqing 163318,China)

机构地区：[1]东北石油大学机械科学与工程学院,大庆163318

出　　处：《计算力学学报》2023年第3期411-423,共13页Chinese Journal of Computational Mechanics

基　　金：国家自然科学基金青年基金(51904075);国家自然科学基金面上项目(11972114);黑龙江省自然科学基金(LH2020A001)资助项目.

摘　　要：针对井下温度压力环境下扩张式封隔器的工作状态,本文建立了卡距内管柱及封隔器力学模型,采用网格重划分方法来描述胶筒在环空间隙中的非线性流动,并将重划分前后的网格信息进行映射,解决了封隔器有限元方程矩阵奇异问题.对不同压裂泵压、不同井温和不同环空间隙下封隔器胶筒的位移、剪切应力及接触压力进行仿真计算.压裂泵压为30MPa~80MPa时,胶筒未发生轴向窜动,橡胶基体的剪切应力及接触压力随着压裂泵压的增加而增大;井温为25℃~175℃时,胶筒基体剪切应力随井温的升高而增大,胶筒与套管间接触压力随井温升高而降低;胶筒与套管环空间隙为2.5mm~9.5mm,胶筒剪切应力随间隙增加而增大,胶筒与套管接触压力随间隙增加而降低.通过胶筒网格变形可知,胶筒橡胶在环空间隙中产生非线性流动是引起胶筒剪切应力数值增大、接触压力数值降低的根本原因.综上可得,在压裂作业中,随着压裂泵压的增大、井温的升高和环空间隙的增大,封隔器胶筒更容易发生剪切撕裂破坏,且封隔器的密封效果亦降低.Aiming at the working condition of the expandable packer in the temperature and pressure environment wells,the mechanical model of the pipe string and packers in card distance was established in this paper.Remeshing was used to describe the nonlinear flow of rubber in annular gap and the grid information before and after remeshing was mapped to solve the finite element equation of packer singular problem.Under different fracturing pump pressure,different temperatures and gaps,the displacement,shear stress and contact pressure of the packer rubber were simulated.Through calculation,it is found that the nonlinear flow of rubber is the main cause of shear tear failure,which leads to the decrease of sealing performance of packer.When the fracturing pump pressure was 30 MPa~80 MPa,the rubber did not move in axial direction.The shear stress and contact pressure of the rubber increased with the increase of the fracturing pump pressure.In the well temperature of 25 ℃~175 ℃,the shear stress of the rubber increased with the increase of well temperature.While,the contact pressure between the rubber and casing decreased with the increase of well temperature.In addition,the annulus gap of 2.5 mm~9.5 mm,the shear stress of the rubber increased with the increase of the gap,while the contact pressure decreased with the increase of the gap.Based on the deformation of the rubber mesh,it could be known that the non-linear flow of the rubber in the annulus gap was the basic reason for the increase of shear stress value and the decrease of the contact pressure.At last,we could conclude that with the increase of fracturing pump pressure,well temperature and annulus gap,it was easy to appear shear-tear failure on the packer rubber and the sealing effect of packer was also reduced.

关 键 词：高温 高压 胶筒 网格重划分 非线性流动 

分 类 号：TE931[石油与天然气工程—石油机械设备] O35[理学—流体力学]