Christian Berg har til forsvar for graden philosophiae doctor (ph.d.) ved Universitetet i Sørøst-Norge, Fakultet for teknologi, naturvitenskap og maritime fag, innlevert avhandling med tittelen «Modeling for Automatic Control and Estimation of Influx and Loss During Drilling Operations».
Prøveforelesningen «State of the art of hole cleaning and torque-drag modelling for digital twin simulations and optimisation of drilling operations» starter klokken 09:30 og disputas klokken 12:00 i auditorium A-271 ved campus Porsgrunn fredag 20. mars.
Arrangementet er lukket for publikum av smittevernhensyn i forbindelse med koronautbruddet.
With the rapid increase in global energy consumption, any realistic near-future scenarios will include a mixture of energy sources, including fossil fuel. Oil and gas wells with challenging pressure windows are more commonly drilled, and in recent years the drop in oil prices has led to an industry focus on reduction of non-productive time. Managed Pressure Drilling, considered an unconventional drilling method tackles many current industry challenges and has been forecasted to grow in the next years, fueled by an increase in the level of automation.
This doctoral thesis focuses on the topic of modelling, at different detail levels, the hydraulics of the oil and gas drilling process. Drilling for oil and gas is a complex process, involving pumping of fluid through kilometers of fluid conduit, leading to wave propagation phenomena that becomes apparent at timescales relevant for automatic control. If gas enters the well during drilling, models have to describe a gas/liquid multiphase system that is mathematically challenging.
Modelling of these phenomena is crucial for control design, planning and training for Managed Pressure Drilling. The modeling work in this thesis has been performed in parallel with the development of a Managed Pressure Drilling control system at Kelda Drilling Controls. This system is now in operation, and has numerous successful wells drilled.