Simulation Experiment On Wellpath Control Mechanism Of Static Push-the-Bit Rotary Steerable System

Rotary steerable drilling technology is currently the most advanced directional drilling technology,and its core is the downhole rotary steerble drilling system.The biggest advantage of the rotary steerble system is the real-time wellpathcontrol under rotating state.Now,a static push-the-bit rotary steerable drilling system is about to be developed in China.In order to improve the development and application level,it is necessary to study the regulation mechanism,and to optimize the regulation mode for the static push-the-bit rotary steerable tool to reduce the adjustment error of the tool-face.In order to achieve the goal above,based on the similarity theory and the existing conditions of the laboratory,a static push-the-bit rotary steerable drilling simulation device with theoretical and practical feasibility was developed,and the modification and upgrade scheme of the existing experimental device was given.Secondly,the simulation experiment scheme of the regulation mechanism of the rotary steerable drilling system was designed and the simulation experiment was carried out.By changing the drilling parameters(including the weight-on-bit,the rotation speed),the pushing force of the three ribs,and the direction of the reference tool-face,the tool-face direction and the build-up ability with the drilling parameters are discussed.Finally,the differences between the direction of the resultant force,the direction of the eccentric displacement and the direction of the actual lateral force of the drill bit were compared and analyzed in two cases.The control method suitable for static push-the-bit rotary steerable system is preferred.Several countermeasures have been developed to improve the ability to create skew.The results showed that in the case of horizontal wellbore,the influence of the movement state of the drill string on the regulation effect is considered,and the larger fundamental force scheme can effectively increase the build-up ability;the regulation mechanism of the eccentric displacement is more suitable.The static push-the-bit-steerable,and the direction of the eccentric displacement is very stable,and it is not easily affected by the drilling parameters.The research results can support the wellbpath control mode of the preferred rotary steerable system and reduce the tool-face control error.