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. …
How can capillary pressure be reduced?
Surfactants can reduce capillary pressure in the matrix by reducing surface tension and/or by changing the wettability of the rock surface when they adsorb on a surface.
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 hysteresis in oil and gas?
Hysteresis. As is the case for capillary pressure, the relative permeabilities depend on the direction of saturation change, as shown schematically in Fig. 3. For this gas/oil system, hysteresis is much greater for the gas relative permeability. Actual observations of hysteresis for water/oil systems are shown in Figs.
Is capillary pressure high or low?
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 do you mean by capillary pressure?
Capillary pressure, Pc, is defined as the difference in pressure across the interface between two immiscible fluids, say oil and water, in the reservoir. It can be defined as: (5.33) This pressure difference is generated by the curvature at an interface of wetting and nonwetting fluids.
What determines capillary pressure?
Capillary pressure is usually determined by centrifuge experiments that provide a relationship between Pc and water saturation Sw. Capillary pressure is also important in describing fluid flow from fractured reservoirs because capillary pressure controls the flow of fluids between the fracture and the rock matrix.
What is the pressure in the capillaries?
Normal capillary pressure, measured at the apex of the capillary loop with the capillary at heart level, ranges from 10.5 to 22.5 mmHg (Figure 4). It is lower in premenopausal women than in postmenopausal women or in men and does not correlate with brachial artery blood pressure.
What is the importance of determining capillary pressure saturation and wettability?
The determination of representative capillary pressure ( ) data and wettability index of a reservoir rock is needed for the prediction of the fluids distribution in the reservoir: the initial water saturation and the volume of reserves.
What is mobility ratio?
The mobility ratio is a single term that describes the rate and efficiency of oil displacement by other immiscible fluids. Diminishing values of M(less than one) are generally considered as favorable values, and increasing values (greater than one) are considered as unfavorable values.
How does venous pressure affect capillary pressure?
Venous constriction increases PC, whereas venous dilation decreases PC. If this ratio increases, as occurs with arteriolar vasodilation, then arterial pressure has a greater influence on capillary pressure, which rises. Conversely, arteriolar constriction decreases this ratio and decreases capillary pressure.
How is the hysteretic dynamics model derived?
The hysteretic dynamics model is derived from the material, electrical, and mechanical fields. The complete modeling of the hysteretic dynamics consists of the static Preisach hysteresis, the creep effect, and electrical and vibration dynamics.
Does hysteresis affect the pumping speed of New coaters?
This example demonstrates a clear trend to enhance the pumping speed of new coaters. The hysteresis effect related to a bent peak of resonance is best evidenced when the nonlinear oscillator is excited by a sinusoidal signal, of which the frequency is progressively varied through the resonance peak.
What is the hysteresis effect?
The hysteresis effect arises in consequence of two competitive processes: (1) the sputtering of the target surface and (2) the covering of its surface by reaction products.
What is the difference between static hysteresis and creep effect?
The static hysteresis effect is typically coupled with the creep effect. The static hysteresis is rate independent. It is a strong nonlinearity and has global memories. Compared with the rate-independent static hysteresis effect, the creep effect has slow dynamics.
