MPD: Simulation and Control Systems

Abstract

Managed Pressure Drilling (MPD) has solved many conventional drilling problems. It has given the access to the reservoirs where conventional drilling was facing difficulties. The tight pressure windows in depleted reservoirs, the kick scenarios, the loss circulation problems, the differentially stuck pipe problems and many other drilling relating problems has been solved by the means of Managed Pressure Drilling. Focus in this thesis has been to present the main idea behind the MPD concept and equipment involved. This has also been explained in the light of MPD vendors Halliburton and Weatherford. MPD Automation is another important aspect which is expected to become more popular with time. The use of automatic top side choke to maintain the bottom hole pressure constant has helped the oil industry very efficiently. This provides more accurate pressure control of the well throughout the drilling. Before, it was difficult to operate the choke manually in order to keep the pressure constant especially during connections. But with the introduction of automatic control systems the risk of making errors has reduced to minimum. In this thesis, a pipe connection is simulated with the help of automatic operating of choke while keeping the bottom hole pressure constant. The AUSMV transient scheme has been used for this purpose along with PI-regulator. The simulation has been done with two different approaches, first with the adjustment of choke opening and secondly with the adjustment of choke pressure. The results have shown the importance of the correct adjustment of the tuning parameters. It has been observed that choke opening regulation is sensitive to changes and can cause errors if proper tuning isn’t done for parameters. On the other side choke differential pressure regulation has shown a great reliability in getting the desired results.