Analytical model of elastomer seal performance in oil wells

Elastomer seals are growing in popularity in various applications in the oil and gas sector, and in many other fields. In this paper, the deformation of an elastomer seal confined between a metal tube and a rigid casing is analytically investigated. The elastomer is strained radially against the casing by means of a controlled tubular expansion process. The elastomer is also naturally strained axially by means of annuls reservoir fluid. The total strain causes the elastomer to develop internal pressure which leads to the sealing effect. The developed analytical results show the effect of elastomer geometry and its material properties on sealing performance in terms of maximum sealing pressure. In addition, sealing performance of the elastomer is studied under different strain conditions. The main contribution of this work is in finding a closed-form solution for the sealing pressure distribution along the axial direction of the elastomer as a function of compression ratio, seal geometry, and material properties. This analytical model can be used by field engineers for selection and evaluation of elastomer materials for a given set of field conditions, and by developers for improvement of elastomer seal design.