Hydrostatic column

The fluid pressure in the rock at the bottom of a well is commonly defined as pore pressure (also called formation pressure, or reservoir pressure). Depending on the maturity of the sedimentary basin, the pore pressure will reflect geologic column overburden that may include a portion of the rock particle weight (i.e., immature basins), or a simple hydrostatic column of fluid (i.e., mature basins). The pore pressure and therefore its gradient can be obtained from well log data as wells are drilled. These pore pressure data are fundamental for the solution of engineering problems in drilling, well completions, production, and reservoir engineering. 

Figure 7.3 Sketch illustrating the two kinds of CCC columns. (Top) Hydrodynamic columns contain a long coiled tube rotating in a planetary way that creates a succession of mixing and decantation zones always having the two liquid phases in contact. (Bottom) In hydrostatic columns, the stationary phase is contained in channels interconnected by ducts in which there is only mobile phase.

C Cilm]Cl-K2HPO -water aqueous two-phase systems With the ATPS, the IL-rich phase is the lighter upper phase (Table 7.3). It implies that the denser mobile phase should be flown in fhe head-fo-fail direction in a hydrodynamic CCC column or in the descending direction in a hydrostatic column. Table 7.4 (bottom) shows that the IL phase retention by our hydrodynamic CCC column was extremely limited (less than 40% at 900 rpm and 1 mL/min). It has always been observed that ATPS with PEG and phosphate salts are difficult to retain in hydrodynamic CCC colunms [10,14]. Hydrostatic columns are more efficient in retaining the IL-rich aqueous phase. Fifty percent of the hydrostatic colunm volume was the IL-rich aqueous phase when the descending phosphate-phase flow rafe was <1 mL/ min and the rotor rotation was at least 500 rpm (Table 7.4). 

In this particular system, gas pressure is supplied by a hydrostatic column. This is simply a filler tube with a reservoir on top at a height of five to eight feet, depending on how much pressure you want in the system. Because the reservoir is at eye level or above, it must be very well secured. You absolutely do not want nasty KOH raining down on you during your experiments. Hose clamps should be used to secure the tubing to the reservoir so that hoses cannot slip off and squirt KOH all over the place. 

The gas pressure for the electrolyzer system is provided by a hydrostatic column. This can be simply a vertical tube, the height of which provides pressure to the system as described in this formula ... 

The hydrostatic column is a simple way to regulate the pressure up to a certain point. The Romans used this principle to apply pressure to the water supplied through pipes from their aqueducts This method is suitable and cost effective for stationary systems that require only a small amount of pressure to operate. It is also somewhat safer than pressurized systems when a caustic electrolyte is used. 

Level the electrolyzer for operation. Attach the hydrostatic column/electrolyte feed tube to the feed port at the bottom of the electrolyzer. The length of the feed tube/column will depend on how much pressure you want. Any length from 3.5 to 8 will suffice. You can add a set of gas... 

Set up the hydrostatic column along a wall or other support structure, and attach the tubes with pipe hangers. Attach the top of the column tube to a reservoir. 

An oil well is 10,000 ft deep. The pressure of the oil at the bottom is equal to the pressure of a column of seawater 10,000 ft deep. (This is typical of oil fields at the time of discovery, most have about the pressure of a hydrostatic column of seawater of equal depth there are exceptions.) The density of the oil is 551bm/ft What is the gauge pressure of the oil at the top of the well (at the surface) ... 

All experiments were performed using a CPC hydrostatic column with 10 mM CS concentration in the upper organic layer of a ternary solvent system composed of a mixture of MIBK - acetone - ammonium acetate buffer 0.1 M pH 8.0. Baseline separations of DNB-( )-Leu and DNZ-( )-NPG, among others, were achieved. After the optimization of conditions (Fig. 7), the best separations obtained were scaled up in order to determine loading capacity for the analyte. This resulted to be in the order of the equimolar amount than the CS involved in the separation. 

In the event of a sudden loss of mud In an Interval containing overpressures the mud column in the annulus will drop, thereby reducing the hydrostatic head acting on the formation to the point where formation pressure exceeds mud pressure. Formation fluids (oil, gas or water) can now enter the borehole and travel upwards. In the process the gas will expand considerably but will maintain its initial pressure. The last line of defence leff is the blowout preventer. However, although the BOP will prevent fluid or gas escape to the surface, closing in the well may lead to two potentially disastrous situations ... 

As in the case of capillary rise, Sugden [27] has made use of Bashforth s and Adams tables to calculate correction factors for this method. Because the figure is again one of revolution, the equation h = a lb + z is exact, where b is the value of / i = R2 at the origin and z is the distance of OC. The equation simply states that AP, expressed as height of a column of liquid, equals the sum of the hydrostatic head and the pressure... 

The oscillating jet method is not suitable for the study of liquid-air interfaces whose ages are in the range of tenths of a second, and an alternative method is based on the dependence of the shape of a falling column of liquid on its surface tension. Since the hydrostatic head, and hence the linear velocity, increases with h, the distance away from the nozzle, the cross-sectional area of the column must correspondingly decrease as a material balance requirement. The effect of surface tension is to oppose this shrinkage in cross section. The method is discussed in Refs. 110 and 111. A related method makes use of a falling sheet of liquid [112]. 

Density. The density of the drilling fluid is adjusted using powdered high density soHds or dissolved salts to provide a hydrostatic pressure against exposed formations in excess of the pressure of the formation fluids. In addition, the hydrostatic pressure of the mud column prevents coUapse of weak formations into the borehole. Fluid densities may range from that of air to >2500 kg/m (20.8 Ib/gal). Most drilling fluids have densities >1000 kg/m (8.33 lb/gal), the density of water. The hydrostatic pressure imposed by a column of drilling fluid is expressed as follows ... 

Water resistance test methods include AATCC 127 (hydrostatic pressure test), AATCC 42 (impact penetration test), and AATCC 35 (rain test). In the hydrostatic pressure test, a sample is subjected to a column of increasing water pressure until leakage occurs. The impact penetration test requires water to be sprayed on the taut surface of a fabric sample from a height of two feet. The fabric is backed by a blotter of predeterrnined weight, which is reweighed after water penetration. The rain test is similar in principle to the impact penetration test. 

Fair s method may also be modified to design forced-recirculation reboilers with horizontal tubes. In this case the hydrostatic-head-pressure effect through the tubes is zero but must be considered in the two-phase return Tines to the column. 

Coarse solids are discharged by siphons extending to the bottom of the hindered-settling zone. Siphon control is obtained by a novel hydrostatically actuated valve which makes or breaks the siphon to flow only when the teeter zone is in correct condition. Discharge by an intermediate fraction from the upper column is by means of additional siphons. Hydraulic-water consumption is considerably lower than required for multipocket sizers. 

From the calibration point of view, manometers can be divided into two groups. The first, fluid manometers, are fundamental instruments, where the indication of the measured quantity is based on a simple physical factor the hydrostatic pressure of a fluid column. In principle, such instruments do not require calibration. In practice they do, due to contamination of the manometer itself or the manometer fluid and different modifications from the basic principle, like the tilting of the manometer tube, which cause errors in the measurement result. The stability of high-quality fluid manometers is very good, and they tend to maintain their metrological properties for a long period. 

High Pressure. Limestones. Blowout prevention. Maintain adequate mud density. Maintain hole full of mud to prevent reduced hydrostatic head resulting from short column of mud. 

Definition of Concepts. The hydrostatic pressure in a borehole is the pressure exerted by a column of fluid that height is the true vertical depth. This is... 

The formation pressure is said normal when it corresponds to the hydrostatic pressure of a column of water of length Zp, the water having the densities stated in Table 4-134. 

The most common low-specific-gravity solids used to reduce cement slurry specific weight are bentonite, diatomaceous earth, solid hydrocarbons, expanded perlite and pozzolan. It may not be possible to reduce the cement slurry specific weight enough with the above low-specific-weight materials when very weak formations are exposed. In such cases nitrogen is used to aerate the mud column above the cement slurry to assist in further decreasing the hydrostatic pressure. 

When the well is circulated through the choke line, a rapid loss in hydrostatic pressure is seen when the kick fluid begins to enter the choke line. Hydrostatic pressure is lost because low density gas is displacing the drilling mud from the small volume of choke line. Small kick volumes can result in long columns of gas in the choke line. Surface choke response must be rapid enough to prevent new kick fluid from entering the well due to the reduction in bottomhole... 

Thermosyphon reboilers are the most economical type for most applications, but are not suitable for high viscosity fluids or high vacuum operation. They would not normally be specified for pressures below 0.3 bar. A disadvantage of this type is that the column base must be elevated to provide the hydrostatic head required for the thermosyphon effect. This will increase the cost of the column supporting-structure. Horizontal reboilers require less headroom than vertical, but have more complex pipework. Horizontal exchangers are more easily maintained than vertical, as tube bundle can be more easily withdrawn. 

For vessels under internal pressure, the design pressure is normally taken as the pressure at which the relief device is set. This will normally be 5 to 10 per cent above the normal working pressure, to avoid spurious operation during minor process upsets. When deciding the design pressure, the hydrostatic pressure in the base of the column should be added to the operating pressure, if significant. 

Injection pump. An injection pump is used to force the waste into the injection zone, although in very porous formations, such as cavernous limestone, the hydrostatic pressure of the waste column in the well is sufficient. The type of pump is determined primarily by the well-head pressures required, the volume of liquid to be injected, and the corrosiveness of the waste. Single-stage centrifugal pumps are used in systems that require well-head pressures up to about 10.5 kg/cm2 (150 psi), and multiplex piston pumps are used to achieve higher injection pressures. 

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