Objective:
To determine the location and orientation of mechanical mixers inside the LFHO tank to achieve maximum homogenization inside the LFHO Storage Tanks.
Design Approach:
The Lower Fars Heavy Oil (LFHO) development is targeted at a large heavy oil accumulation of approximately 7 to 15 billion barrels of oil-in-place located in a desert area some 1,200 square kilometer in northern Kuwait.
In the mathematical modeling, following assumptions are made for mixing operation inside the LFHO Tank, and a Computational Fluid Dynamics (CFD) simulation has been run.
•Mixing flow is three-dimensional and steady state.
•Lower Fars Heavy Oil (LFHO) in the tank and BS&W in the stirred tank are incompressible, isothermal and Newtonian fluids.
•Considering the volume concentration of BS&W inside the tank, model is single phase without accounting for multi-phase interactions.
Conclusion:
Based on analyses, it can be concluded that, with given impeller arrangement, homogeneity is maintained for the given design condition. The blending time has been considered conservatively as four (4) time the circulation time estimated from CFD simulations. However, once the flow attains steady-state operation, even in the maximum density case, the mixing time will be 40 minutes. The sump design guarantees that all oil droplets greater than 16 μm will not remain present inside the BS&W region after 24 hours of settling time, in the designed operating conditions. Therefore, with 16 μm oil droplet entrained in BS&W region, 30 PPM oil at oily water outlet will be guaranteed.
