Nondestructive Test Technologies And Applications Studies Of Coiled Tubing

Coiled tubing has been widely used in the implementation stimulation, drilling, completion, workover, well sand control, downhole tools fishing and other operations. The failure of coiled tubing is particularly outstanding because of its extensiveness of application and complexity of downhole operation conditions. Therefore, in order to reduce the appearance of accident when the operation is running, it is very important to inspect the coiled tubing before running in hole.According to the practical needs and principles of ultrasonic nondestructive testing, the nondestructive testing method which is suitable for coiled tubing is designed on the basis of analysis of coiled tubing testing methods and equipments of overseas. In this method, the inspected probes are fixed, the coiled tubing make a straightaway mode moving driven by the idler wheels. The probe unit is constituted by two probes groups, and there are four probes in a probe group. Longitudinal or transverse defects and dimensional changes are collected by these probes. Workpiece transferring mechanical system which make a straightaway transferring for coiled tubing is run by the motor. Charging and cropping system are controlled by the programmable logic controller.The parameters of detecting are confirmed according to the principle of immersion ultrasonic testing, and on the basis of these parameters the experimental evaluation model of NDT is made. The feasibility of the inspecting system has been proven through the experiment evaluation and the analysis of longitudinal or transverse defects on the exterior wall and corrosion defects on the internal wall.