Derrick Design And Its Characteristic Analysis Of Vehicle-Mounted Pressure Balancing Workover Rig

Workover rig is necessary equipment of tripping operation of petroleum string and replacing downhole tools in various oil field operation, which plays a cita role in increasing national oil production and improving economic benefit. With the improvement of the requirements in high efficiency, low cost and environmental protection of petroleum industry, vehicle-mounted pressure balancing workover rig has an important engineering value. The vehicle-mounted snubbing workover rig in this paper has an important engineering practical value. However derrick is the key part of workover rig, inconect design may waste raw materials, even results to accident in use. Therefore, studying static and dynamic characteristic of the whole derrick to find the weak links and potential danger, provides theoretical base for workover rig operation on site, avoids accident happening, and rich, perfect and development the analysis theory of derrick structure of workover rig.On the base of collecting of the information of designing, analyzing and using materials about workover rig in the world, the designing standard of rig is discussed. Based on the latest API Spec 4F" Specification for Drilling and Well Servicing Structures" design principles, two designs of the truck-mounted workover rig derrick are presented and the finite element model of the derricks are established. Using the method of FEA, after the static analysis of derriek under various typical loads conditions, the static stress and displacement evolutional law are obtained. Finally choosing the second design of derrick through comparing the results. And the design feasibility of the workover rig derrick is verified through analysing the key bearing parts of the derrick.Modal analysis as one of the method of structural dynamic characteristics researching, gradually become the core of dynamic analysis and design regions. It determines natural frequency and mode shape are important parameters in the design of structural bearing dynamic loads, so it is the start of transient analysis and others. This paper complete the modal analysis of the derrick, and get the first ten steps natural frequency and mode shape, observing its calculated displacement, get the vibration characters of the derrick of truck-mounted snubbing workover rig.