Mechanical Simulation Of Coiled Tubing Injector Head

With the development of the coiled tubing operation technology, a growing number of coiled tubing in the rig is applied to oilfield development. Since the coiled tubing appeared, it has many situations for example the drum too fast and out of control, hydraulic system disordering, providing not enough clamping force, injection head system of fault, the chain being damaged. Becouse of these situations, it has bad effects on construction work. Injection head, which is the core of the coiled tubing unit components, its performance is becoming more and more attention by people.On the the damage and failure at the scene of using the injection head system, this paper carries out a study of the coiled tubing injector head system for the following several aspects:The paper first expounds the working principles of coiled tubing injector head and the basic functions, analyzing the environmental load;Analyz the contact between the clamping piece and coiled tubing mechanics and obtain the contact stress with the change of the friction coefficient curve. By comparing the selected the optimal coefficient of friction,the paper makes the clamping blocks and coiled tubing have small stress concentration and can have very good clamping effect,which provides the optimization of clamping block theory basis.The paper studies the clamping mechanism of the coiled tubing unit injector and improves the the clamping cylinder radial pressure assumption of the predecessors.Put forwards my own theory: Based on the mechanics of elasticity plane problem of complex variable function method. Coiled tubing was deduced in detail in the clamping block clamping force under the action of stress formula. The correctness of the method is verified by using Ansys software.With the help of ANSYS and the method of orthogonal test, clamping blocks and key components of the injection head structure is analyzed and optimized and obtain the clamping piece of parameter sensitivity analysis. From the related parameters such as cross section parameters of clamping block, inner diameter size and the tooth interface card design facing the clamping piece of the parameter analysis and optimization, to minimize coiled tubing stress concentration, prolong service life, and to improve work efficiency of the service life of the injection head and site provides a good theoretical basis and reference data.