The Research On Anchor Plile Installment And Load-bearing Capacity Of Workover Rig

Workover rig is the necessary equipment to uprooted and insert Tubing string and replace downhole tools in various of fields of oilfield. Derrick is the key component, bearing the main load. Derrick and workover anchor pile are the weakest parts in safe operation. While evaluating the safety of workover rig derrick, most researchers only analysis the forcement of the main structure of the derrick, often overlook this part of the anchor piles, rarely taking consider into the relation between carrying capacity of the derrick structure and ground anchors. Ground anchor piles that fix workover derrick wire, whose installation location, installation size and ultimate capacity of pulling on workover rig has very important effects. Therefore, we must develop a set of scientific-basis standards for the installation of rig derrick piles, and provide a strong theoretical basis.for the safe operation of workover operating system. This paper introduces the theory of finite element nonlinear analysis firstly, and establish a model of derrick finite element analysis with ANSYS,make a linear static analysis of ideal workover derrick in which wire anchor pile is not considered to assess the stress and displacement distributions under the load and its own gravity conditions; secondly, by using ANSYS software, do buckling analysis, geometric nonlinearity and double nonlinear analysis to determine the calculation of workover derrick structure's ultimate bearing capacity which does not include the wire anchor pile; subsequently establish the finite element analysis model of the derrick-wire-anchor pile system, use ANSYS software to make linear and nonlinear analysises about the ideal workover derrick,including wire pile, assess the ultimate load capacity of the derrick structure in this case, the comparative analysis results show that wire anchor piles can significantly increase the limited carrying capacity; finally, with the using of parametric programming methods, take pile installation location as a variable parameter, obtain the relationship between the carrying capacity of workover derrick and the location of anchor pile, analyze the impact which the installation location of pile foundation have on the carrying capacity of workover derrick,the distribution discipline is also obtained.