The elevator being used in field application causes several problems such as low level of mechanization and high intensity of labor. Therefore, electromotion elevator is developed and tested in this paper, which works with mechanized workover equipments. On the base of traditional elevator, the safety pin for the rings is driven by a spring and its own gravity, while the door of the elevator, with self-locking function, is driven by a DC motor which is remotely controlled. Through the field test and application, the electromotion elevator shows desirable safety, reliability and continuous working ability, which satisfy the requirement of workover operation.

Abstract. The fixed clamp should be installed inside the BOP stack for sectional blockage and tubing pulling job. When there is combined string in downhole, it causes inconvenience in replacing slips of different specifications because of pressure in BOP stack. To solve the problems mentioned above, variable diameter slip was invented. Different arc's central angle model of slip was set by ANSYS, the oil tube was divided by sweep while the slip was divided randomly. The analysis shows the arc's central angle for clamping ø73 oil tube is 106°and the clamping force meets operation needs and the design requirements.