An industry-supported research project has investigated well control methods for managed pressure drilling (MPD) using the constant bottom hole pressure (CBHP) method. This paper proposes a method for pre-selecting the best initial response to be taken when a kick occurs during CBHP MPD based on conclusions from the research. That research (Davoudi et al 2010) concluded that the three most widely applicable initial responses to kicks during MPD were increasing casing pressure until flow out equals flow in, shutting the well in, and using an adaptation of a MPD pump shut down schedule to detect and shut in a low rate kick. Increasing pump rate until flow out equals flow in was concluded to have limited, but potentially still important applications.
The proposed method uses a decision tree to pre-select the best response to be used if an influx of formation fluid is detected. This selection is based on the desired tolerance to kicks, equipment being used, well geometry and conclusiveness of the kick warning signs. The equations necessary to calculate decision parameters, example calculations for an application of the decision tree and comparison of simulation results to application of the decision tree are included. The decision tree indicates the response that maximizes kick tolerance within the well design, gives a basis for revising equipment or well design to maximize kick tolerance, and supports calculation of the expected kick tolerance advantage of the increasing casing pressure response versus a shut in response.