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Coupled well-reservoir models
We are interested in mathematical models for various coupled well-reservoir flow systems like
- Mathematical modeling of drilling operations on deep water
- Underbalanced drilling
- Gas-lift operations
Dual Gradient Drilling method for deepwater
Relevant publications
[1] S. Evje and K.H.Karlsen, A hyperbolic-elliptic model for coupled well-porous media flow, In Eleventh International Conference on Hyperbolic Problems: Theory, Numerics, Applications (Lyon 2006). Edt: S. Benzoni-Gavage and D. Serre, Jan 28, 2008.
[2] S. Evje and K.H.Karlsen, Hyperbolic-elliptic models for well-reservoir flow, Networks and Heterogenous Media, vol 4 (1), 639-773, 2006.
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Left: A schematic figure of a well with drillstring and annulus relevant for a dual gradient drilling (DGD) flow system. The free air/mud interface is seen in the riser (upper part of annulus). The location of the interface can be adjusted actively to control the pressure in the well by means of the mud pump mounted on the riser.
Middle: The movement of the mud/air interface.
Right: Pressure profiles in annulus (green curve) produced by a DGD flow system where the position of the mud-air interface is varied as shown in the middle figure. The main goal is to ensure that pressure lies above pore pressure (red curve) and below fracture pressure (blue curve). The different pressure curves at times T1, T2, and T3, correspond to different circulation rates and different levels of the air/mud interface.
Example with gas-kick
Top: Influx of gas in the open zone after approximately 600 s due to the fact that well pressure drops below pore pressure, see right figure.
Left: The movement of the mud/air interface, influx of gas at the open zone, and migration of the gas up annulus.
Right: Pressure profiles in annulus (green curve) produced as a function of position of mud/air interface, mud density, and circulation rate.
