What is a capillary pressure curve?

The relationship describing the capillary pressure required to obtain a given nonwetting phase saturation in a rock. … The capillary pressure curve is important for understanding saturation distribution in the reservoir and affects imbibition and multiphase fluid flow through the rock.

How is capillary pressure calculated?

Capillary pressure (P_c) is the difference in pressure measured across the interface in the capillary (P_c = P_nw – P_w). This pressure results from the contrast in pressure gradients caused by the different densities of the nonwetting (ρ_nw) and wetting (ρ_w) phases (right).

What does capillary pressure depend on?

The Young–Laplace equation (Amyx et al., 1960) states that the capillary pressure is proportional to the surface tension, σ, and inversely proportional to the effective radius, r, of the interface; it also depends on the wetting angle, θ, of the liquid on the surface of the capillary.

What is typical capillary pressure?

Capillaroscopy has been used to visualize capillaries in the skin in 2D, and has been reported to observe an average range of capillary pressure of 10.5 to 22.5 mmHg in humans, and an increase in pressure among people with type 1 diabetes and hypertension.

What are the uses of capillary pressure?

Capillary pressure concepts can be used to evaluate reservoir rock quality, expected reservoir fluid saturations and depths of fluid contacts, thickness of transition zone, seal capacity, and pay versus nonpay, and to approximate recovery efficiency.

What is capillary pressure hysteresis?

The process of generating the capillary pressure curve by displacing the wetting phase, i.e., water, with the non-wetting phase (such as with gas or oil), is called the drainage process. …

Is capillary pressure positive?

Capillary force equilibrium at an interface between two immiscible fluids. By definition, the capillary pressure is always a positive (or zero) quantity. The capillary pressure is often expressed as an equivalent water height, denoted h_c and called capillary‐pressure head.

Why does pressure drop in capillary tube?

capillary tube, several combinations of length and diameter are possible. Higher pressure drop in the capillary tube leads to lower saturation pressure in the evaporator and hence, lower refrigeration temperature. Additionally, increase in mass flow rate through the system increases cooling capacity.

Do capillaries have high or low pressure?

Capillaries. Found in the muscles and lungs. Very low blood pressure. Where gas exchange takes place – oxygen passes through the capillary wall and into the tissues, while carbon dioxide passes from the tissues into the blood.

How is capillary pressure curve used to determine the initial distribution of fluids in a reservoir?

If you know the rock quality, namely porosity and permeability of the rock at a certain depth in the reservoir, you can use the capillary pressure (determined from the difference in densities between water and hydrocarbon and the height above the Free Water Level) to determine the initial water saturation of the …

What is negative capillary pressure?

In conclusion, a negative capillary pressure means nothing else than that a larger water injection pressure than the oil-phase pressure has to be applied to remove oil from the sample (see Eq. 1).

What is the effect of capillary pressure on oil recovery?

One can see that the cumulative oil production increases with the decrease in capillary pressure. Note that the initial water saturation decreases with capillary pressure when the reservoir is initially at capillary/ gravity equilibrium.

What is capillary pressure in plants?

Plants use capillary action to bring water up the roots and stems to the rest of the plant. The molecules of the water (the liquid) are attracted to the molecules of the inside of the stem (the solid). This attraction is used to help force the water up from the ground and disperse it throughout the plant.

How are permeability and capillary pressure related?

Capillary pressure and relative permeability both depend on the same fluid-fluid and rock-fluid interaction energies. If the capillary pressure vanishes, the residual saturations approach zero and the relative permeability of a phase becomes equal to its saturation.

What is the hydrostatic pressure in capillaries?

The force of hydrostatic pressure means that as blood moves along the capillary, fluid moves out through its pores and into the interstitial space. This movement means that the pressure exerted by the blood will become lower, as the blood moves along the capillary, from the arterial to the venous end.

What is a drainage curve?

Drainage capillary curves reflect the process when non-wetting phase drives out the wetting phase (e.g secondary migration of hydrocarbon into a water-wet reservoir, water injection into oil-wet reservoir, gas injection into water-, or oil-wet reservoirs).

What process in plants is due to capillary action?

The process that occurs in plants that is due to capillary action is transpiration. Plants get water from the soil, and this water moves through the…

What is displacement pressure?

Displacement pressure (P_d) is the pressure necessary to force hydrocarbons into the pore space of a rock and form a continuous hydrocarbon filament.

What is meant by static pressure?

: the force per unit area that is exerted by a fluid upon a surface at rest relative to the fluid.

What is capillary suction?

Sorptivity, or capillary suction, is the transport of liquids in porous solids due to surface tension acting in capillaries. It is a function of the viscosity, density and surface tension of the liquid, and the pore structure (radius, tortuosity and continuity of capillaries) of the solid.

How does capillary tube reduce pressure?

The pressure reduction in a capillary tube occurs due to the following two factors: 1. The refrigerant has to overcome the frictional resistance offered by tube walls. This leads to some pressure drop, and 2. The liquid refrigerant flashes (evaporates) into mixture of liquid and vapour as its pressure reduces.

What is drawback of capillary tube as a throttling device?

The capillary tube is non-adjustable device that means one cannot control the flow of the refrigerant through it as one can do in the automatic throttling valve. Due to this the flow of the refrigerant through the capillary changes as the surrounding conditions changes.

What is the pressure at the outlet of a refrigerant compressor?

3. What is the pressure at the outlet of a refrigerant compressor? Explanation: The absolute pressure at which the refrigerant comes out of the compressor is called Discharge pressure.

Do capillaries carry blood at high pressure?

This allows them to carry blood that is at a high pressure. Capillaries are tiny, thin walled vessels that form a network to take blood through the organs and other body tissues.

Why is blood pressure so low in the capillaries and veins?

Mean blood pressure decreases as circulating blood moves away from the heart through arteries, capillaries, and veins due to viscous loss of energy. Mean blood pressure decreases during circulation, although most of this decrease occurs along the small arteries and arterioles.

What pressure pulls water into capillaries?

oncotic pressure The total oncotic pressure of an average capillary is about 28 mmHg with albumin contributing approximately 22 mmHg of this oncotic pressure. Because blood proteins cannot escape through capillary endothelium, oncotic pressure of capillary beds tends to draw water into the vessels.