Effect of capillary pressure

Chapter 11 consists of following Sect. 11.2 deals with the pattern of capillary flow in a heated micro-channel with phase change at the meniscus. The perturbed equations and conditions on the interface are presented in Sect. 11.3. Section 11.4 contains the results of the investigation on the stability of capillary flow at a very small Peclet number. The effect of capillary pressure and heat flux oscillations on the stability of the flow is considered in Sect. 11.5. Section 11.6 deals with the study of capillary flow at a moderate Peclet number. 

Effect of Capillary Pressure and Heat Flux Oscillations... 

Productive wells in vapour-dominated systems discharge steam only. Characteristically, wells in liquid-dominated systems discharge a mixture of water and steam. The steam forms essentially by depressurization boiling of the reservoir water. It is, however, not uncommon that some wells drilled into liquid-dominated systems discharge dry steam or possess a higher steam to water ratio than can be accounted for by depressurization boiling. The reason for this is partial or complete immobilization of the water in the aquifer due to the effects of capillary pressure and relative permeability. 

Ambient Preparations. Economic and safely considerations have provided a strong motivation for the development of techniques that can produce aerogel-like materials at ambient conditions, i.e., without supercritical drying. The strategy is to minimize the deleterious effect of capillary pressure which is given by ... 

Larger values of the accumulation ratio can be reached in dry foams [24,25,47,73,74,76-78]. Kruglyakov and Kuznetsova [47,71] have studied the effect of capillary pressure, foam expansion ratio and dispersity on / mjn. The foam was prepared from NaDoBS and NP20 solutions. The accumulation ratio //m,n increased directly proportional to the expansion ratio (at a = const) and inversely proportional to the parameter a (at n = const) (Fig. 10.4). The maximum degree of accumulation in a NaDoBS solution (0.3 g dm 3 + 0.4 mol dm 3 NaCl) which could be achieved was = 1050 at Ap = 102 kPa. Further increase in... 

Khatib, Z. I., Hirasaki, G. J., and Falls, A. H., "Effects of Capillary Pressure on Coalescence and Phase Mobilities in Foams Flowing Through Porous Media", paper SPE 15442 presented at the 1986 SPE Fall Meeting, New Orleans, October 5-8, 1986. 

The next question regards the means by which values of any of these quantities to be used in reservoir-engineering calculations may be obtained. There is a continuing history of theoretical attempts to calculate the mobility of foam starting from known quantities and familiar principles of two-phase flow in porous rocks. One of these principally considers the effect of capillary pressure and concludes that this quantity is a principal determinant of the stability and therefore of the population of lamellae. Presuming equilibrium conditions in which the radii of curvature of the Plateau boundaries determines the excess of absolute pressures in the gas over that in the liquid, Khatib et al. (16) computed a limiting value of the capillary pressure. Above this value, the lamellae become too thin for the surfactant to stabilize. Increasing the gas fractional flow decreases the water saturation and raises the capillary pressure. 

On Figure 4, we present simulations of triaxial compression tests performed with different water saturation degrees. Even if constant elastic parameters have been used, there is a qualitatively good agreement between simulations and data. Mechanical strength of material increases when saturation degree decreases due to effect of capillary pressure. 

YOKOYAMA, and LAKE, L. W., The Effects of Capillary Pressure on Immiscible Displacements in Stratified Permeable Media, SPE 10109, presented at 56th Annual Fall Conference of SPE, San Antonio, Texas,... 

In this section, we will study the immiscible, constant density flow through a homogeneous lineal core where the effects of capillary pressure are insignificant. In particular, we will derive exact, analytical, closed form solutions for the forward modeling problem for a single core. These solutions include those for saturation, pressure and shock front velocity, for arbitrary relative permeability and fractional flow functions. We will determine what formations properties can be inferred, assuming the existence of a propagating front, when the front velocity is known. The Darcy velocities are... 

Douglas, J., Blair, P.M., and Wagner, R.J., Calculation of Linear Waterflood Behavior Including the Effects of Capillary Pressure, Petroleum Transactions, AIME, Vol. 213, 1958, pp. 96-102. 

Payers, F.J., and Sheldon, J.W., The Effect of Capillary Pressure and Gravity on Two-Phase Fluid Flow in a Porous Medium, Petroleum Transactions, AIME, Vol. 216, 1959, pp. 147-155. 

Temperature and Heat Flux Driven Flow A fourth mode of transport that has been shown to drive water flux in the membrane is heat flux driven flow. As a general rule, water will move through the membrane toward a colder location. This occurs in a freezing process due to capillary forces [20, 21], and nonfreezing processes [22,23]. The nonfrozen mode of transport is poorly understood but is likely a result of the combined effects of capillary pressure change with temperature and thermo-osmosis in membranes. 

This is why we consider here the spreading of the miCTodroplet, whose apex is located in the range of action of the surface forces. In the following text, we neglect the effect of capillary pressure. The hydrodynamic pressure in the liquid is described by Equation 3.16. 

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