The Effect of Pipe Rotation on Dynamic Well Control Casing Pressure Using the Dispersed Bubble Model

Managed Pressure Drilling is a new technology that has recently emerged in the industry. It has special well control capabilities supported by the rotating control device to simultaneously provide the required pressure control on a certain volume gas influx and maintain the pipe rotation for drilling or any other operation. This paper examines the effect of pipe rotation on casing pressure profiles while circulating out the kick using MPD equipment. The PERTT lab personnel conducted experiments during the 80s in a real scale well under controlled environment that mimicked downhole conditions with a gas influx entering the wellbore. The data experimental analysis was coupled with the effect of pipe rotation through the application of correlations. The correlations from literature show a change in the expected frictional pressure loss when comparing the rotating case to the non-rotating case. This change is then applied on the geometric configuration of the well to find the changein the surface casing pressure caused by rotation.This paper covers the developed dispersed bubble model in WBM. This model includes the effect of the bubble dispersing into smaller bubble size on surface casing pressure. The validity of the single bubble model was examined inthis paper. The results showed that the changes in surface pressure are considerable when the gas bubble is able to break down with a decrease of up to 30 %. These changes are only applicable to cases with similar mud properties and well design of the experiments. The practical outcome is to further the understanding of a gas bubble behavior in a wellbore experiencing an influx. Since new technologies allow for the rotation of the pipe during the kick circulation process, this paper helps in answering the question of whether or not the pipe rotation aids in overall expected surface pressure. Furthering the window of applicability of the MPD can possibly touch into its unexploited potential.