The Riserless Mud Recovery (RMR) System is a new and emerging technology for top hole/open hole drilling. The technology is planned to be used in Russia in 2006. The RMR Technology is applied for the open hole sections (no BOP installed), enabling return of fluid and cuttings in a closed system. A subsea mud pump is returning mud and cuttings to the drilling rig for treatment/recirculation instead of dispersal on the seabed. Since weighted mud is used the risk of shallow gas influx is reduced compared to conventional top hole/open hole drilling. However, since the return is routed to the platform, shallow gas is a cause of concern.

A new transient coupled reservoir-well two phase well control simulator for modelling drilling and well control scenarios with a dual pump drilling system has been developed.

The paper describes the RMR System and its potential related to shallow gas detection and control compared to conventional top hole drilling.

Shallow gas scenarios during top hole drilling with the RMR System have been simulated and the results evaluated. The focus has been to detect a kick before gas reaches the return line. The evaluations have confirmed that the RMR System is a safe system, which can detect a shallow gas influx prior to gas reaching the return line, and also handle the influx in a safe manner. Modelling further shows that pit gain, sub sea power and RPM of subsea pump are the main parameters for kick indication. These results verify the feasibility of the RMR System related to safety and well control. In addition this System will reduce discharges to sea during top hole drilling, as well as significantly reduce the frequencies of shallow gas incidents.

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