Abstract: Extended-reach well drilling has numerous problems in the artificial island of the Jidong Oilfield,They include,high levels of friction torque,poor sand transport,frequent wellbore collapse in the basalt section of Guantao formation and the mudstone section of Shahejie formation,circulation lost through fractures and faults,back pressure in directional drilling of deep section,and difficulty in safely completing RIH casing safely.To determine solutions for the problems,a study of drilling/completion technologies of extended-reach wells in the artificial island of Jidong Oilfield was carried out.Landmark software was used to analyze wellbore trajectory,drilling parameters,wellbore cleaning,friction drag,torque,drilling tools,and casing RIH safety data.Drilling fluid flowrate,drilling fluid rheology,and the relationship between the installation position of cuttings bed breaker and the cuttings bed were investigated.In addition,the solutions to back pressure in directional drilling,lost circulation and wellbore collapse by integrated application of KCl film-blocking drilling fluid together with new lubrication,anti-collapse,plugging agents,as well as the installation position and method of friction/torque reducing coupling were studied.Through those studies and investigations,problems have been solved,and new technologies have been developed for equipment matching,software prediction and optimization,lubrication and anti-collapse sealing drilling fluid,wellbore cleaning,friction and torsion reduction,cuttings bed damage,and casing RIH safety.The drilling and completion performance in 15 extended-reach wells in the artificial island of Jidong Oilfield showed that the drilling/completion period is significantly reduced,and the downhole problems and complex conditions are effectively controlled.The maximum well depth is up to 6 387.00 m and the horizontal displacement reaches 4 940.99 m.The results demonstrated that the application of drilling and completion technologies of extended-reach wells in the artificial island of Jidong Oilfield have been supporting safe and efficient development of the oil reservoir accessed through the artificial.These technologies would have good prospects for application in other situations in the near future.