Simulation And Structural Improvement Of Expanded Tail Hook

Liner completion technology can reduce the weight of casings and the amount of cement, thereby reducing completion costs. Currently it is used in most deep oil wells. Expandable liner hanger is the core hardware which is used in liner completion, providing reliable suspension force for the tail pipe string and sealing the annulus area between tail pipe and casing, when the construction is completed.Based on the literature research of expandable liner hanger, this paper researched the factors which influent the course of expansion through the theoretical analysis and finite element simulation. analyzed the law about how constraint condition, taper angle, friction coefficient, expansion speed, hanger thickness and expansion rate influence the expansion force and shrinkage rate. These series of conclusions is of great significance for the design of expandable liner hanger, and with practical guiding significance to determine the casing setting depth and the type selection of hydraulic equipment.Completed the finite element simulation of the expansion of the PZXG178×127liner hanger by CNPC drilling research institute; the stress distribution law and expansion force changing with time is obtained in the process of casing setting, studied the contact pressure distribution on the surface of upper casing after the completion; calculated the largest suspension force of this model of expandable liner hanger. At the same time, a new type of structure was designed according to the features of expandable liner hanger, which is composed of discontinuous metal ring. Compared with the conventional structure, the maximum expansion force decreases by13.6%, the largest suspension force provided after setting increased by21.0%. New rubber structure combined five separate rubber into a cohesive whole, and with0.5mm thick built-in metal frame. After the setting, contact pressure of tube surface increased by63%, and avoided the repeated contact pressure attenuation on both ends of the rubber ring, sealing performance is increased obviously.The research results of this paper provide theory basis for structure design of expandable liner hanger, Found out a method to improve the sealing performance and the suspension ability through the structure research of expandable liner hanger, therefore it is helpful to reduce the technical difficulties of liner completion.