Finite Element Simulation of Compression of Elastomeric Seals in Open Hole Liners

Abstract

Control of water flow in open hole wells is an urgent necessity to minimize water production and maximize oil output. Elastomers provide tight seals as they deform against formation during the expansion process of a solid expandable tubular. A better prediction of behavior of elastomers in compression will achieve an effective sealing mechanism. Due to the inherent nonlinearity of tubular expansion and elastomer compression against open hole formation, a closed form solution is extremely difficult to obtain. Finite element modeling provides a viable alternative, as an approximate simulation tool, to determine the seal pressure without significant compromise on the complexity of the problem. The finite element analysis software is employed to model the tubular expansion resulting in compression of elastomer seal to effectively isolate unwanted water producing zones. The formation is modeled as a rigid body or an elastic or elastic-plastic material. Two different boundary conditions, fixed-free and fixed-fixed, are employed depending on prevailing practices of oil operators in such applications. The effect of seal length and thickness, compression ratio and shear resistance at seal-formation interface are determined on the contact pressure between seal and formation.