Simulation study of emerging well control methods for influxes caused by bottomhole pressure fluctuations during managed pressure drilling

Managed Pressure Drilling (MPD) is an emerging drilling technology that utilizes mud weight, surface backpressure and annular frictional pressure loss (AFP) to precisely control the wellbore pressure. The goal of this project is to identify the most appropriate initial response and kick circulation method for the kicks that result from complications specific to MPD. These complications that can cause a reduction in bottomhole pressure were classified as surface equipment failures and unintended equivalent circulating density (ECD) reductions. Rotating control device (RCD) and pump failures are the examples of surface equipment failures. Pump efficiency loss and BHA position change represent the unintended ECD reductions. Shut-in (SI), MPD pump shut down, increasing surface backpressure, increasing pump rate, starting a new pump with surface backpressure and increasing pump rate with surface backpressure responses were simulated on a transient drilling simulator for kicks taken due to the pump efficiency loss, and the simulation results were evaluated. Shut-in and starting a new pump with a surface backpressure were simulated for a pump failure, which led to a loss of total AFP, and the simulation results were evaluated. A shut-in response was simulated for surface pressure loss (RCD failure), and its results were evaluated. Shut-in, MPD pump shut down, increasing surface backpressure pressure, increasing pump rate and increasing pump rate with surface backpressure responses were simulated, and the simulation results were evaluated for the kick taken due to BHA position change. Kick circulation was also simulated after the influx was stopped by the initial responses. The kicks were circulated using driller’s method at normal, half, and increased circulating rates depending on the initial response. The results of circulating simulations were also evaluated. SI was concluded to be applicable for all kicks caused by bottomhole pressure fluctuations. However, increasing casing pressure is the most effective response if it is practical given the surface equipment and its condition. Normal rate circulation following these responses is generally better than using an increased or slow pump rate for these kinds of kicks. It reduces the surface backpressure and non productive time (NPT) required versus slower pump rates.