| In the process of oil and gas field development,especially in the process of drilling and production of extended reach wells,the problem of high friction and high torque is very prominent as the casing structure becomes more and more complex.During the operation of drilling string and casing string,the influence of friction is more obvious,which leads to the decrease of strength of pipe string.During the construction of fracturing,it is difficult to enter the fracturing pipe string with open hole packer,and sand plugging is easy.When the axial vibration reduction tool is used,the drill assembly will produce a small regression and reduce the drilling efficiency.To solve the above problems,after a comprehensive analysis of the research results of friction reduction and torsion reduction in the field of drilling engineering at home and abroad,a direct and effective mechanical friction reduction and torsion reduction method is finally adopted,namely,the use of friction reducing and torsion reducing tools in downhole.Through the data search and investigation,we know that the kinds and quantity of the tools that can be used at present are limited,and there are some inadequacies in the process of use.Firstly,the structure design of friction reducing and torsion reducing tools is carried out.Four tools,such as drill pipe wear reduction joint,pipe string friction reduction and torque reduction device,sand drain packer and axial vibration crawler,are designed and built.An experimental device for reducing friction and torsion of oil and gas well string is designed and built.The performance test of 3D printing tool model is carried out.According to different working conditions such as rotary drilling and pipe string down,the performance of the tool is tested,and the adaptability of friction reducing and torsion reducing tools for different downhole conditions is simulated.The performance experiments of four kinds of tools are carried out.The experimental results showed that: in the same experimental conditions,analysis of the maximum torque fluctuation and the mean torque for experimental data,determine the reduction of ellipse radius of grinding drill pipe joint ideal ratio is 1.0625;determine the friction reduction twisting elliptical contour length radius ratio of 1.1 minimum torque reduction column the best effect was verified with torsion;dredging sand trough packer has obvious drag reduction effect of sand dredging,under laboratory conditions,sparse sand tank number 6 packer under process of friction on minimum;axial vibration of crawling experimental phenomena were observed,to prove the feasibility and effect of anti-reverse structure significant. |
