Gravity segregation

Fluid samples will be taken using downhole sample bombs or the MDT tool in selected development wells to confirm the PVT properties assumed in the development plan, and to check for areal and vertical variations in the reservoir. In long hydrocarbon columns (say 1000 ft) it is common to observe vertical variation of fluid properties due to gravity segregation. 

In high permeability reservoirs, wells may produce dry oil for a limited time following a shut-in period, during which gravity forces have segregated oil and water near the wellbore. In fields with more production potential than production capacity, wells can be alternately produced and shut in (intermittentproduction) to reduce the field water cut. This may still be an attractive option at reduced rates very late in field life, if redundant facilities can be decommissioned to reduce operating costs. 

The performance of steamflooding often suffers from channeling and gravity segregation. Alkaline additives may be used with steam for certain types... 

The metal is most often recovered from its principal ore, zircon. The ore is mined, crushed and preliminary segregation is by gravity, electrostatic, and magnetic separation. Separated ore mixed with carbon is charged into an arc furnace and heated to about 3,500°C. This forms zirconium carbide and silicon monoxide, and the monoxide is driven off as vapor. Zirconium carbide is then placed in a chlorinator and heated with chlorine gas at high temperatures. The carbide is converted to zirconium tetrachloride, ZrCfl. Also, small amounts of hafnium that is always associated with zirconium converts to its tetrachloride, HfCfl. 

Segregation can take place whenever forces are applied to the powder, for example by way of gravity, vibration, or air flow. These forces act differently on particles with different physical characteristics, such as particle size, shape, and density. Most commonly, particles separate as a result of particle size differences. The result of segregation is that particles with different characteristics end up in different zones within the processing equipment (e.g., bin). 

Historically, slags have been an important by-product of the smelting of ores to produce metals. They serve the primary purpose of dissolving all of the extraneous rock into one homogeneous liquid from which the heavier metal reduced to its elemental state can separate by simple gravity segregation. They can also serve to absorb certain metal oxides while allowing another to be reduced to the elemental state. In some... 

In equations 5-8, the variables and symbols are defined as follows p0 is reference mass density, v is dimensional velocity field vector, p is dimensional pressure field vector, x is Newtonian viscosity of the melt, g is acceleration due to gravity, T is dimensional temperature, tT is the reference temperature, c is dimensional concentration, c0 is far-field level of concentration, e, is a unit vector in the direction of the z axis, Fb is a dimensional applied body force field, V is the gradient operator, v(x, t) is the velocity vector field, p(x, t) is the pressure field, jl is the fluid viscosity, am is the thermal diffiisivity of the melt, and D is the solute diffiisivity in the melt. The vector Fb is a body force imposed on the melt in addition to gravity. The body force caused by an imposed magnetic field B(x, t) is the Lorentz force, Fb = ac(v X v X B). The effect of this field on convection and segregation is discussed in a later section. 

Prepared coal any coal, regardless of its top size, that has been cleaned manually or mechanically includes coal that has been processed over a picking table or air tables through a breaker, jig, or other device which segregates according to size or density (specific gravity) (ASTM D-4749). 

Gravity segregation partial separation of fluids in a reservoir caused by the gravity force acting on differences in density. 

In the case of low-dose formulations, it is important that the feed system convey material without allowing the material to segregate. All of the feed system arrangements shown in Fig. 6.1 rely on gravity feed for the powder to reach the force feeding screws. Feed systems i, ii, and iii can be outfitted with an agitator in the intermediate hopper which will aid in powder flow and delumping. 

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