Özet:

The variational Lagrange principle and the Kantorovich method are applied in calculating the downhole packer sealing process with the influence of low rubber compressibility. The dependence between the sealing ratio and the stress ratio on the geometric parameters of the sealing element of the downhole packer is determined. It is found that the sealing effect of end faces leads to a significant difference in the stress-strain state of the packer seal assembly from uniaxial compression. Rubber is an elastic material in the entire load range. However, with increasing strain there is increasing deviation from the linear relationship between stress and strain, despite the fact that rubber remains an elastic material, and the relationship between stress and strain becomes nonlinear.The incompressibility should be considered as the property of rubber to maintain a constant volume under any strain. Volume decrease under higher strain is associated with the change in the physical state of rubber due to crystallization. The compressibility effect may become noticeable only in special structures, in downhole packers, so in this case the problem is divided into two: 1) the solution of the problem in the case of an incompressible material; 2) the solution of the problem, corresponding only to the three-dimensional compression, when the  strain  Еij=const, if loads are large enough and the rubber compressibility has to be taken into account. It is shown that strain in many designs of downhole packers should be written based on precisely this dependence, because the lateral strain in the seals appears constrained so that a large volume of rubber is under uniform compression. In this case, the assumption of absolute incompressibility of rubber can lead to a significant overestimation of the seal rigidity. Author Biographies Vasif Talibov Mamedov, Azerbaijan State University of Oil and Industry 20 Azadlig ave., Baku, Azerbaijan, AZ1010 Doctor of Technical Sciences, Professor, Head of Department Department "Oil and gas equipment"

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