Research on Non-Linear Flow Characteristics for the Expandable Packer Rubber in High Temperature and High Pressure Wells

According to the working condition of the expandable packer in high temperature and high pressure wells, the dynamic model of the pipe string and packers was established in this paper. Remeshing was used to describe the nonlinear flow behavior for sealing rubbers in annular clearance and the force and displacement information from old grids to new grids was mapped. Then the difficult problem of high-order element distortion caused by the large nonlinear deformation of rubber was solved by remeshing. The numerical calculation of mechanical behavior for the expandable packer rubber was carried out in different fracturing pressures, temperatures and distances between packers. The results were as follows: The fracturing pressure was in the range of 30 MPa~80 MPa, the sealing rubber had no axial movement. The sealing effect of the lower sealing rubber was better than the upper sealing rubber. But the the maximal shear stress of the lower sealing rubber was greater than the upper sealling rubber and the value increased from 13.20 MPa in 30 MPa to 34.70 MPa in 80 MPa. So it was easy to appear tearing failure on the lower rubber sealing rubber. The well temperature was 25 ~145 , the shear stress and the contact pressure of sealing rubber increased with the increase of well temperature. That was, the sealing effect of the packers was reduced with the increase of well temperature, and the lower sealing rubber was reduced more obviously. The distance between two packers was 10 m~70 m, the shear stress and contact pressure also showed non-linear increase or decrease trend with the increase of distance between two packers. We could get that the reasonable distance between two packers was 30 m