A New and Novel Managed Pressure Drilling System

Abstract Managed Pressure Drilling (MPD) is an adaptive drilling process used to precisely control the annular pressure profile throughout a well-bore. Drilling fluid is added to the annular by surface backpressure, which can be adjusted much faster in response to downhole conditions compared with conventional drilling method of changing the mud weight. Constant Bottom-Hole Pressure (CBHP) is a drilling methodology where the bottom hole pressure is kept at a constant value when the mud-pumps are on or off, i.e. when making a drill pipe connection. The constant bottom hole pressure method ensures well-bore stability is maintained during connection times. The most crucial part of a Managed Pressure Drilling equipment package is the Rotating Annular pressure Control Device (RCD). The rotating annular pressure control device creates a constant annular seal around drill pipe allowing for annular pressure management by manipulation of the annular pressure from surface using flow chokes and a backpressure pump. The rotating annular pressure control device, however, also represents significant operating costs due to the requirement of regular changes and maintenance. This paper describes a novel solution and alternative to a full managed pressure drilling equipment package that will trap mud returns in the drilling well-bore annulus to maintain a constant well bore pressure while making or breaking drill pipe connections as the mud pumps are shut down. As the technique is trapping pressure in the annulus opposed to using a closed loop pressurized mud returns system to precisely control the bottom hole pressure the overall system is a lot simpler, more robust and easier to maintain compared to a full managed pressure drilling system The new solution can provide an estimated 70% of the well-bore pressure control possible with a full managed pressure drilling equipment package but at at 20% of the cost when compared to a full managed pressure drilling system. The reduced cost and reliability of the new system make an attractive alternative to using a full managed pressure drilling system for Constant Bottom-Hole Pressure applications.