Structure Design And Mechanics Analysis On Key Components Of Super Short-radius Horizontal Well Flexible Drilling

Along with old oilfield of our country has entered into the middle and latterdevelopment. There is a serious decline in oil production. The urgent task is how totap the potential of residual oil and improve oil well production. Super-short radiushorizontal wells flexible drillpipe is widely used in oil field with the technology oftapping the potential of residual oil. It is important to have reasonable structuraldesign and mechanical analysis of the three link of the flexible drill pipe and thedrilling tool, because the three link is the key compent of them. Therefore, accordingto the technical characteristics of super-short radius horizontal wells, we obtain thelimit load by theoretical calculation method and have structural design of the threelink of the flexible drill pipe and the drilling tool by the design requirements of thekey compent of super-short radius horizontal wells flexible drillpipe. Wherein, theflexible drill pipe adopts a limit type of spherical hinge structure to satisfy its crookeddegree, and realizes the transfer of the torque and drilling pressure; The drilling tooluses internal and external nested structure to satisfy fast matching of the flexible drillstring and drill pipe, to achieve three different load classification transmission shaft,and to change the condition of drilling by the help of adjustment cap. Then, inconsidering that the structure and stress state of the three link of the flexible drillpipe and the drilling tool, we respectively established its three-dimensional finiteelement model. In the finite element modeling process, fully considering its contactconditions that we calculated its stress distribution under different working conditions,and completed its strength evaluation. According to various components of the stresscalculation results, the individual components were optimized. We provided thetheoretical basis of the reasonable structural design of the three link of the flexibledrill pipe and the drilling tool by the mechanical analysis and optimization of thematerials of the key components.