Deepwater riserless mud recovery drilling technology

In order to solve the problems associated with complex deepwater environment, the riserless mud recovery (RMR) drill- ing system has been developed by the AGR Corp in Norway. As the ocean riser is eliminated in this technique, cuttings and mud are separated from the wellbore by the subsea suction module, and returned to the drilling platform through a small diameter hose from the seabed by the subsea pumps. The paper summarizes the research and application of RMR technology abroad, analyzes the principle of RMR technology, presents the basic equipments of the system, including subsea suction module, subsea pump module, mud return line and control system. Some suggestions about the technology are also proposed at last, and it can be a reference for the application and dissemination of the technology in China.