The Study Of Sealing Property Based On Pipeline Internal Plug In Deepwater

As an important channel of oil and gas transportation,submarine pipeline is the key components of the offshore oil and gas resources exploitation system.However,in the complex undersea environment,submarine pipeline suffered from the various forms of loss and damage inevitably.If it wasn't in time to repair and deal with the damage,the leakage of oil and gas would be caused,which not only can't product normally and result in economic losses,but also led to environmental pollution and ecological destruction.Aimed at plugging the leaking submarine pipeline rapidly,the pipeline internal plugging device in deepwater can realize timely repair of damaged submarine pipeline and rapid resumption of production.It plays a positive role in the emergency repair of submarine pipeline.This paper focuses on studying the sealing structure of pipeline internal plugging device working at a depth of 1500 m on the basis of the relevant submarine pipeline emergency repaired technology,and explain the working principle of the sealing structure.It establishes strain-energy function of rubber using the hyperelastic ultralinear constitutive theory,then gets the model parameters by uniaxial tensile test.According to different boundary condition during the two stages for free deformation and contact deformation,it analyzes the force to obtain the relationship between the pressure and axial force and ensure the deformation and stress distribution during the process of rubber sealing.It also analyzes the contact conditions through the elastic theory and has a micro stress analysis to the sealing surface,it studies the contact state in normal,tangential and adhesion three ways by the establishment of micro convex body.Also it builds its two-dimensional model using the fractal theory,and simulates the contact stress and friction stress of contact surface to get the distribution regularities of contact stress and friction stress on the contact surface,further analyzes the the effects of contact stress on the sealing.Besides,considering the actual situation,it puts forward the inverse method to measure the pipeline strain,then backsteps the contact stress by elastic finite element theory.It gets the relationship between the pipeline wall thickness and the measured contact stress.Finally,it researches the effects of different End-Angels on contact stress and contact area for the single rubber tube,analyzes the influence of sealing structure with the bulge-prevention ring on sealing stress.It also studies the contact stress and friction stress of double rubber tube and the role of each rubber tube.