Mechanical and structural behavior of a swelling elastomer under compressive loading

Swelling elastomers are a new breed of advanced polymers, and over the last two decades they have found increasing use in drilling of difficult oil and gas wells, remediation of damaged wells, and rejuvenation of abandoned wells. It is important to know whether an elastomer type or a certain seal design will function properly and reliably under a given set of oil or gas well conditions. This paper reports the results of an experimental and numerical study conducted to analyze how compressive and bulk behavior of an actual oilfield elastomer changes due to swelling. Tests were carried out on ASTM-standard compression and bulk samples (discs) before swelling and after different swelling periods. Elastic and bulk modulii were experimentally determined under different swelling conditions. Shear modulus and Poisson’s ratio were estimated using derived isotropic relations. Cross-link chain density and number average molecular weight were obtained using predictive equations of polymer physics. Mechanical testing was also modeled and simulated using the nonlinear finite element package ABAQUS, material model being Ogden hyperelastic model with second strain energy potential.