On the fluid mechanics of slotted liners in horizontal wells

Slotted liners are flow control devices widely used in both injection and production wells for thermal oil sands recovery operations such as Steam-Assisted Gravity Drainage. In these devices, slots are cut into the well at regular intervals around and along the well. The dimensions tend to be from fractions to several millimeters in gap and a few to about twenty centimeters long along the pipe. The key benefits offered by slotted liners are that they are among the most economical solutions for sand control and well bore stability as well as manufacturing. Slotted liners have several design parameters including the slot density, pattern, slot opening size and shape that must be chosen to provide optimum inflow and outflow performance in the reservoir. Due to the complexity in deriving these parameters analytically or experimentally, we have examined the impact of design parameters on steam injection by using a realizable k-ε turbulence computational fluid dynamic model of a 5 m slotted liner section coupled to a reservoir flow domain outside of the well governed by a modified Darcy's law that accounts for inertial effects. The results reveal that slot open area affects the flow distribution in the reservoir. The role of drive forces changes through the flow with viscous and pressure forces dominant in the slot and upstream area and inertial forces just downstream of the slot and pressure and viscous forces in the reservoir.