Well Integrity Safety Factor for Tubular Connections in Petroleum, Geothermal, and Carbon Capture Wells

Abstract

Connection sealability is critical for well integrity and carbon control. With current operating practices, there is no way to know that a connection is about to fail and leak before failure actually occurs. API leak equation is uniaxial. Premium connection ratings are biaxial. To measure, monitor, and maintain connection sealability during drilling and production operations, a triaxial Integrity Safety Factor (ISF) for connections is introduced in this paper. Three leak constants evaluated from simple physical tests determine the connection ISFs. Example connection in the paper is 7-inch 35-ppf N80 LTC. Results from FEA leak predictions for 23 load cases, comprising both internal and external leak, show unexpected leak behavior relative to pipe failure.