Continuous Circulation Systems (CCS) have been around since the JIP between Shell, BP, Statoil, BG, Total and Eni in October 2000. Initial reports of these systems demonstrated that while cumbersome, the use of CCS is of benefit to drilling ERD wells. Continuous circulation keeps cuttings moving out of the wellbore, reducing or eliminating the time required to circulate clean any high-angle section before making a drill pipe connection or before tripping out of the hole.
Continuous Circulation over each connection enhances the management of Equivalent Circulating Density(ECD) to control the bottom hole pressure on the well by never switching off the pumps, therefore the wellbore never experiences an Equivalent Static Density(ESD). Through this mechanism, the application of CCS has also been proven to manage bottom hole pressure constantly, which in conjunction with good drilling practices for torque and drag management, are key factors in drilling any Extended Reach Drilling(ERD), Complex or High Pressure/High Temperature (HPHT) well.