Study On The Mechanical Properties Of Glass-Fibre Reinforced Composite Bridge Plug

The glass fiber has the characteristics of a high modulus, high strength, stability, and moderate thermal expansion coefficien. It is often regarded as a reinforcing agent in the composites, inorder to improve the mechanical properties of the composite materials. According to the different length of glass fiber, glass fiber reinforced plastic is divided into two broad categories, composite materials made with short fiber as reinforcing agent and composite materials made with long fiber as reinforcing agent. Under the action of outer load, high stress areass of hort fibre reinforced composites are present. Material will be destroyed locally. In the article, the slip body with five teeth is made with short fiber as reinforcing agent. Under the action of axial load of150MPa, materials appear large area destroy in the surrounding areas of the teeth, Therefore, bridge plug lost the ability of the bridge plug.The scheme of usage of glass fiber cloth reinforced composites is proposed in the paper for the above problems. Above all, the long glass fibers are woven into glass fiber clothes through the textile machinery. The glass fiber clothes are added into the molded slip body. Because the glass fibers have excellent mechanical properties in a certain direction, mechanical performance of slip can be significantly improved, and consequently, the ability of bridge plug becomes better.In this thesis, a contact destruction test about composite matrix and hard alloy teeth is carried out. In the course of the trial, the hard alloy tooth is pressurized with universal testing machine until the destruction of the material. Recording all process informationan data acquisition, the obtained force-displacement curve shows that, the composite material is overall damaged when400Mpa (31KN) surface force is loaded on hard alloy tooth. The yield strength of the composite material could be drawn225MPa, this is almost the same results with finite element analysis results.According to the above experimental data and the finite element method of the composite material.Different number of layers of glass fiber clothes are set around the composite slip teeth and on the bottom of it at equal spacing.The carrying capacity of slip is analysed by the finite element method, comparing with the Kava and the bridge plugs with short glass fiber, compared with Mechanical Properties of the slip and packer capacity of the bridge plugs without glass fiber,5laying methods for glass fiber clothes are presented, the number of layers (n) of glass fiber is respectively2,4,6,8,10, the interval between two neighbouring glass fiber cloth is0.5mm, Contact analysis of the slip body teeth and the casing is studied by the finite element method. Due to the complexity of contact analysis, the calculation results rely on selection of the coefficient of friction between the hard alloy teeth and casing and the mesh quality. The model is divided into several parts to improve the quality of the grid, reduce the adjacent grid stiffness difference. During selection process of the friction coefficient in the contact region, the coefficient of friction is usually taken between0.1-0.8. If friction coefficient value in the contact region is smaller, the teeth can not be embedded in the casing. The calculation results do not converge. When friction coefficient value is0.6, the calculation results do not converge. The teeth can be embedded into the casing, the calculation results can converge.The results show that, the glass fiber of slip bears the high stress and reduces the extent of the damage of the slip body, The bridge plug with short glass fiber could endure a internal differential pressureof45-50MPa, but the bridge plug laid with glass fiber clothes could endure a internal differential pressure of58.5-81MPa, which proves glass giber could enhance sealing pressure capability of the bridge plug. As a critical component for sealing, the rubber tube is analysed by finite element method, analysis result shows that the contact stress between the casing pipe and the rubber-sleeve is4MPa, the sealing effect is achieved. The results of this article provide a solid foundation for the usage of bridge plug laid with glass fiber in the oil and gas exploration and development.Finally the article is concluded, the novelty and the limitations of this study are summarized, and the future research prospect is presented.