Study On The Sealing Structure And Mechanical Behavior Of The Mandrel Casing Hanger

The casing hanger is an important connection device connecting the casings and the wellhead equipment.The stability of the casing hanger is vital to the safety of the wellhead.However,the rubber sealing structure of the existing casing hanger is easily to get corroded and invalid in the strongly corrosive environment,causing huge economic losses and safety hazards to the oil field.Therefore,it is of great practical significance to study and design a full-metal sealing structure of mandrel casing hanger to improve the integrity of the well-bore to prevent the occurrence of wellhead safety accidents so that to reduce the cost in the later production.Based on the existing slip type and mandrel casing hanger and referring the metal sealing mechanism and sealing structure,a mandrel casing hanger full metal sealing system is designed and simulated in this paper.The main research contents and achievements are as follows:(1)This paper summarizes the development status of casing hangers at home and abroad,analyzes the working principle and structure of existing slip and mandrel casing hangers in detail to figure out the causes of the seal failure.(2)Based on the metal sealing mechanism and the sealing structure,the design concept of the full metal seal of the mandrel casing hanger is proposed to solve the existing problems of the existing slip and mandrel casing hangers.The sealing system adopts an all-metal device to avoid the sealing failure caused by the aging corrosion of the rubber parts,and completes the conceptual design of the mandrel casing hanger sealing system.(3)According to the concept,the composition of the mandrel casing hanger is designed.The mandrel casing hanger is mainly composed by a four-way body,a mandrel and an upper tapered metal sealing component and a wedge-shaped metal seal component.The 3D solid model modeling of all parts of the mandrel casing hanger full metal seal structure is made by the SolidWorks software.(4)The mechanical model of the mandrel casing hanger full metal sealing system was established based on the finite element theory and ANSYS software.Strength analysis to the full metal sealing structure of the mandrel casing hanger and the different tops were carried out under actual working conditions.The sealing performance of the linear,sinusoidal,elliptical and parabolic cones of the all-metal sealing structure under the action of the wire thrust is obtained,and the result shows that sealing performance of the linear cone and the elliptical cone is more stable.(5)The sealing performance of sealing cones with different inner and outer cone angles and different cone spacing is studied based on the all-metal linear and elliptical sealing cone structure,and structural improvement suggestions are proposed.