Petroleum Engineering School, Southwest Petroleum University , Sichuan, ChinaFulltext PDF
The Riserless Mud Recovery (RMR) system is an advanced drilling technology used in a deepwater formation with a narrow safety density window. In using the RMR system for drilling operations, it is also necessary to make a connection and round trip to ensure that the drilling operations reach the reservoir depth. This paper used the problem of bottom hole pressure change during the U-tube effect in the RMR system as the research background. We then built a mathematical model to determine the relationship between the bottom hole pressure and the annulus fluid return velocity during the period. The changes were simulated numerically, and the corresponding method of bottom hole pressure control was finally proposed. The research results show that the greater the displacement of the drilling pump on the platform before shutting down, the greater the return velocity of the fluid in the annulus, but the duration of the U-tube effect is not affected. During the U-tube effect, the greater the displacement of the drilling pump before shutting down, the greater the bottom hole pressure of the RMR system, but it will eventually stabilize at the same value. During the U-tube effect, the bottom hole pressure can be kept constant by adjusting the inlet pressure of the subsea pump of the RMR system.
Deepwater Drilling, RMR System, Bottom Hole Pressure, U-tube Effect, Return velocity
Xin Li, Jie Zhang, Chenghua Zhou, Zhen Zhang, Cuinan Li, Mingzhe Wang, et al. Variation and Control of Bottom Hole Pressure for the Deepwater Riserless Mud Recovery System during U-tube Effect Period. Oce Che Pet Eng Jour . 2021; 1(1): 1-12.