Circumferential Sealing Structure of a Subsea Oil and Gas Pipeline Repair Clamp

Abstract

A subsea oil and gas pipeline repair clamp and circumferential sealing structure are designed. Based on the principle of equal contact pressure on the contact surface and the thick-walled cylinder calculation, a formula for the contact pressure between the sealing ring and the outer wall of the pipeline is derived. An axisymmetric finite element model is constructed for circumferential sealing with an ABAQUS software suite. The model is used to calculate the contact pressure necessary for the sealing structure, which requires different sealing pressures, and to determine the respective bolt preload for a ∅219-mm clamp. The model also defines a maximum effective contact pressure and average effective contact pressure between the sealing ring and the outer wall of the pipeline. The prediction of the contact force caused by the deformation of a sealing ring due to the geometry restriction was experimentally verified. The finite element and experimental results confirm the validity of grounding in theory and derived formula. The calculations can provide the guidelines for the design of the seal structure of a clamp and the overall structure, as well as future engineering applications.