Nonlinear finite element analysis on the sealing performance of rubber packer for hydraulic fracturing

Abstract

As the core component of a fracturing tool, a rubber packer plays a vital role during the well stimulation process. Its sealing performance significantly affects the fracturing effects. This study adopted a 3D multi-body contact nonlinear finite element analysis with the Mooney–Rivlin constitutive model to investigate the sealing performance of the hydrogenated nitrile butadiene rubber. The effects of key parameters such as the total thickness, sub-thickness, height, and rubber hardness on the sealing performance were systemically investigated. Numerical results indicated that maximum contact stress appeared around the rubber packer's upper part because of the combined effect of friction and axial compression. Besides, the numerical results were validated with theoretical and experimental results, in which the error between theoretical and numerical results was less than 7%, and that between the numerical results and experimental results was approximately 17.7%. Under the conditions considered, key parameters of rubber packer were optimized as a total thickness of 20 mm, a sub-thickness of 13 mm, a height of 70 mm, and a hardness of 70 International Rubber Hardness Degrees, in terms of the maximum contact stress and deformation displacement. The proposed numerical approaches could accurately predict rubber packer's deformation status, which consequently had technical guiding significance for the design of similar sealing components in various applications.