Mechanical properties and sealing performance evaluation of packers in high temperature underground gas storage

Abstract

The sealing performance of packers is crucial for ensuring efficient cyclic injection and production in underground gas storage (UGS) operations. Unlike conventional oil and gas production, UGS operations experience significant temperature and pressure fluctuations due to the larger gas volumes involved. These fluctuations can lead to premature seal failure and reduce the wellbore's service life. However, the challenges of sealing in unique UGS environments are often overlooked. This study addresses this gap by investigating the sealing efficacy of two distinct rubber material combinations under high temperature and pressure conditions. First, elastoplastic theory is applied to analyze the stress distribution in the packer’s rubber cylinder, establishing a comprehensive gas sealing evaluation index. Then, two analytical models are developed to simulate large deformation contact patterns. These simulations reveal how extreme conditions influence Mises stress, shear stress, contact stress, residual stress, and fatigue life. A comparative analysis of the two packers highlights differences in sealing performance. Additionally, to validate the finite element analysis (FEA), two high temperature gas sealing tests are conducted on the packers. This study underscores the effects of temperature and pressure on packer sealing, offering insights to optimize designs and improve UGS reliability and service life.