Key drilling technology for marine deepwater relief wells

There is great risk in deepwater drilling and there is no international standard for reference regarding the design of relief well drilling, and not many relief wells are drilled for deepwater wells. In order to ensure safe and efficient development of deepwater oil/gas fields and in conjunction with the requirement of deepwater drilling in the South China Sea, a number of key technologies have been arranged and analyzed such as selection of relief well location, method of wellbore trajectory design, detection and location technology, connection technique, dynamic well killing technique, etc. The selection of relief well location should take into consideration the submarine geological conditions, ocean currents, wind directions, thermal radiation, commercial insurance, etc. The trajectory of relief well should be designed according to the location of connecting point, the requirement of detection and location tools and difficulty in following the trajectory. The preferred connecting method is to directly penetrate the borehole of trouble well. The formulation of dynamic killing program should be the most efficient and safest killing plan according to the capacity of the drilling ship. The research result is of certain reference value to establishing the design system for deepwater relief wells.