Holding hydrostatic

Failure to hold hydrostatic test pressure for 30 seconds or sufficiently longer to allow for complete expansion. 180.205(g)(5) 3,800. 

A knowledge of hold-up is particularly important for vertical flow since the hydrostatic pressure gradient, which is frequently the major component of the total pressure gradient, is directly proportional to liquid hold-up. However, in slug flow, the situation is complicated by the fact that any liquid which is in the form of an annular film surrounding the gas slug does not contribute to the hydrostatic pressure 14. ... 

The pressure drop due to acceleration is important in two-phase flow because the gas is normally flowing much faster than the liquid, and therefore as it expands the liquid phase will accelerate with consequent transfer of energy. For flow in a vertical direction, an additional term — AZ y must be added to the right hand side of equation 5.5 to account for the hydrostatic pressure attributable to the liquid in the pipe, and this may be calculated approximately provided that the liquid hold-up is known. 

Differential pressure sticking occurs when the drill pipe becomes imbedded in the mud wall cake opposite a permeable zone. The difference between the hydrostatic pressure in the drill pipe and the formation pressure holds the pipe in place, resulting in a sticking pipe. Differential sticking may be prevented, and a stuck drill bit may be freed, using an oil-mud or an oil- or water-based surfactant composition. 

The interfacial area in the contactor, which is directly related to the solids hold-up, strongly influences the mass transfer rate. To maximise the overall mass-transfer rate per unit volume of equipment, a high solids hold-up is necessary. On the other hand, the solids hold-up also influences the pressure drop over the contactor. The pressure drop has a hydrostatic and a dynamic component, both of which rise with increased solids hold-up. Since the adsorbent consists of extremely small particles, fluid friction between liquid and solids may lead to a relatively high dynamic pressure drop. The hydrostatic pressure drop is attributable to the density difference between the suspension in the contact zone and in the liquid. 

Single crystals of a-Pu have been grown by holding polycrystalline Pu metal at 675 K under a hydrostatic pressure of 5.5 GPa for several days (70). 

The gas holdups can be obtained by measuring Zp and Zp, or by measuring the corresponding hydrostatic heads. Evidently, the following relationship holds. 

Under nonflowing, hydrostatic, conditions, the normal stresses are equal to the negative of the pressure. This relationship must hold regardless of the coordinate system used to represent the stress state ... 

Equations (10.23) and (10.24) hold for the /3-phase as well and could be inserted into Eqn. (10.22). The additivity of pt with respect to the elastic and electric potential is based on 1) the assumption of linear elastic theory (which is an approximation) and 2) the low energy density of the electric field (resulting from the low value of the absolute permittivity e0 = 8.8x10 12 C/Vm). In equilibrium, V/i, = 0 and A V, = df-pf = 0. Therefore, in an ionic system with uniform hydrostatic pressure, the explicit equilibrium condition reads Aa/fi=A)... 

The additive constant term fij in Equation 2.4 is the chemical potential of species j for a specific reference state. From the preceding definitions of the various quantities involved, this reference state is attained when the following conditions hold The activity of species j is 1 (RT In cij = 0) the hydrostatic pressure equals atmospheric pressure (VjP = 0) the species is uncharged or the electrical potential is zero (ZjFE = 0) we are at the zero level for the gravitational term (rrijgh = 0) and the temperature equals the temperature of the system under consideration. Under these conditions, fij equals fij (Eq. 2.4). 

Hydrodynamic conditions affect the sealing capacity of a rock or fault, and consequently influence the holding capacity for hydrocarbons of hydrostatic structural, stratigraphic and combination traps. In addition, hydrodynamic conditions may create additional regions of minimum potential energy for separate phase hydrocarbons, i.e. purely hydrodsmamic trapping positions. 

Hydrodynamic influence on holding capacity of conventional hydrostatic traps... 

The hydrodynamic holding capacity of conventional hydrostatic traps is not only determined by the direct hydrodynamic influence on the sealing characteristics of the barrier rocks, or barrier rocks and faults, but also combined influence of the geometry of the trap and the hydrodynamic condition in the carrier-reservoir rock. This can be illustrated by looking at the hydrodynamic influence on the position of a hydrocarbon accumulation in a conventional hydrostatic trap. 

In addition, when the closing dip of a hydrostatic trap in the downstream direction is less than the angle of tilt of the hydrocarbon equipotential surface, the closed structure will not hold hydrocarbons under the prevailing hydrodynamic conditions. 

Tectonic forces may affect the hydrocarbon accumulation and entrapment indirectly by changing the hydrodynamic condition of the basin (Chapter 4) and thus the sealing capacity of rocks and the holding capacity of hydrostatic traps. 

Trapping condition Hydrostatic Recharge area (near-surface) unfavourable Recharge area (deep) increased holding capacity top seal Discharge area favourable charge decreased holding capacity top seal... 

Hydraulic compartment I covers the south-eastern area and holds an overpressure relative to hydrostatic of approximately 70 bar as observed in wells 10-1 and 10-2 (Figs. 4 and 7) ... 

As free flow occurs because of density gradients, we will assume a variable density whilst all other material properties shall be taken as constant. Gravity will act as the body force k.j = g,j. In areas where the density is constant, for example far away from a heated wall, hydrostatic equilibrium is reached. Here it holds that... 

The gas hold-up in the liquid can be determined via the measurement of the gassed liquid height Hg or the hydrostatic pressure. The following applies... 

AATCC Test Method 35 -2000 " is designed to simulate a rain event. A special apparatus is used to hold the 20 x 20 cm fabric sample in a vertical position backed by a weighed piece of blotter paper. The fabric face is sprayed with water under constant hydrostatic pressure for 5 min and the blotter paper reweighed. The increase in weight of the backing paper is a measure of the resistance of the fabric to penetration by the simulated rain. 

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