Fluids miscible

The capillary effect is apparent whenever two non-miscible fluids are in contact, and is a result of the interaction of attractive forces between molecules in the two liquids (surface tension effects), and between the fluids and the solid surface (wettability effects). 

Miscible fluid displacement is a process in which a fluid, which is miscible with oil at reservoir temperature and pressure conditions, is injected into a reservoir to displace oil. The miscible fluid (an oil-soluble gas or liquid) allows trapped oil to dissolve in it, and the oil is therefore mobilised. 

For any given process, one takes a qualitative look at the possible role of fluid shear stresses. Then one tries to consider pathways related to fluid shear stress that may affect the process. If there are none, then this extremely complex phenomenon can be dismissed and the process design can be based on such things as uniformity, circulation time, blend time, or velocity specifications. This is often the case in the blending of miscible fluids and the suspension of sohds. 

In the Lagrangian approach, individual parcels or blobs of (miscible) fluid added via some feed pipe or otherwise are tracked, while they may exhibit properties (density, viscosity, concentrations, color, temperature, but also vorti-city) that distinguish them from the ambient fluid. Their path through the turbulent-flow field in response to the local advection and further local forces if applicable) is calculated by means of Newton s law, usually under the assumption of one-way coupling that these parcels do not affect the flow field. On their way through the tank, these parcels or blobs may mix or exchange mass and/or temperature with the ambient fluid or may adapt shape or internal velocity distributions in response to events in the surrounding fluid. 

A turbine type agitator is commonly used for liquid-solid systems. Mixing rates depend on the forces required to suspend all solid particles. Minimum levels can be determined for (1) lifting the particles, and (2) for suspending them in an homogeneous manner [200]. Similar requirements apply to liquid-liquid systems. For cases where two poorly miscible fluids of about equal volume are used in the reaction, the mixer is placed at the interface. For a bench-scale experimental system of about 2 liters capacity, the minimum rotational speed to obtain well-dispersed system is 300 to 400 rpm [201], depending on the type of mixer. This rotational value decreases as the vessel volume increases. 

Figure 16.5 Partial segregation in the mixing of two miscible fluids in a reactor.

Agitators capable of level 2 will Blend miscible fluids to uniformity, if specific gravity differences are less than 0.1 and if the viscosity of the most viscous is less than 100 times the viscosity of the other Establish complete fluid batch control Produce a flat, but moving fluid-batch surface. 

Numerous methods have been explored to recover at least some of this vast resource. Injection of oil-miscible fluids, gases under high pressure, and steam —either separately or in combination — have all been tried with various degrees of success. This is where microemulsions enter the picture. Under optimum conditions an aqueous surfactant solution — which may also contain cosurfactants, electrolytes, polymers, and so on —injected into an oil reservoir has the potential to solubilize the oil, effectively dispersing it as a microemulsion. 

Miscible fluid displacement (miscible displacement) is an oil displacement process in which an alcohol, a refined hydrocarbon, a condensed petroleum gas, carbon dioxide, liquefied natural gas, or even exhaust gas is injected into an oil reservoir, at pressure levels such that the injected gas or fluid and reservoir oil are miscible the process may include the concurrent, alternating, or subsequent injection of water. 

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