STUDY ON SEALING PERFORMANCE OF AIRTIGHT BUCKLE UNDER COMPLEX LOADS

The existing studies on sealing performance of airtight buckle of production strings in oil and gas extraction mainly focus on complex loads without bending moment. In this paper, a numerical model of an airtight buckle under the complicated load with bending moment is constructed. The precision of the model is verified by comparing with theoretical value for thick-walled cylinders. The impact of simple and complex loads on the contact stress of the sealing surfaces is discussed. It should be noted that the contact stress exhibits a combined effect of multiple factors, and the internal pressure plays a dominant role. However, the influence of bending moments on the contact stress of the sealing surface can “reverse” under specific load combinations. The reason for this phenomenon is that the sensitivity of the tension side and compression side to internal pressure is different under bending moment. The obtained results can guide the design and usage for airtight buckle of the production string.