Gas columns

As the gas is produced, the pressure in the reservoir drops, and the aquifer responds to this by expanding and moving into the gas column. As the gas water contact moves up, the risk of coning water into the well Increases, hence the need to initially place the perforations as high as possible in the reservoir. 

Adiabatic Head. The height in ft of gas supported at the compressor discharge as the gas discharges into a system at the desired pressure level is the adiabatic head. The compression of the gas column is adiabatic. The temperature and pressure of the compression column will be related by the adiabatic expression. 

Polytropic Head. The polytropic head more closely approaches the conditions of an actual compressor and is the actual height of a gas column that can be maintained at... 

Continuous reactor liquid mixed ideally, plug flow of gas (bubble gas column, tall reactors with multistirrer system)... 

Chlornitrofen and nitrofen conditions for GC/MS column, cross-linked methyl silicone capillary (12 m x 0.22-mm i.d., 0.33- am film thickness) column temperature, 60 °C (1 min), 18 °C min to 265 °C inlet, transfer line and ion source temperature, 260, 200 and 200 °C, respectively He gas column head pressure, 7.5 psi injection method, splitless mode solvent delay, 3 min electron ionization voltage, 70 eV scan rate, 0.62 s per scan cycle scanned mass range, m/z 100-400. The retention times for chlornitrofen and nitrofen were 11.8 and 11.3 min, respectively. The main ions of the mass spectrum of chlornitrofen were at m/z 317, 319 and 236. Nitrofen presented a fragmentation pattern with the main ions at m/z 283, 202 and 285. ... 

Reference Number Column Carrier Gas Column Temp., °C Detector... 

One of the most common problems associated with deterioration of columns is the presence of water and/or oxygen in the carrier gas. This is more common with nitrogen than with helium. Stationary phases such as polyesters, FFAP, SP-1000, and carbowax depolymer-ize rapidly with 100 ppm of water in the carrier gas columns may be satisfactory the first day and destroyed the next. If this is occurring, peaks for polar compounds will begin to tail and this will become progressively worse. It is not necessary to have a fancy device to remove the water, but it should have the capacity to remove large quantities of water. 

Measurements of sound velocity at ultrasonic frequencies are usually made by an acoustic interferometer. An example of this apparatus11 is shown in Fig. 2. An optically flat piezo-quartz crystal is set into oscillation by an appropriate electrical circuit, which is coupled to an accurate means of measuring electrical power consumption. A reflector, consisting of a bronze piston with an optically flat head parallel to the oscillating face of the quartz, is moved slowly towards or away from the quartz by a micrometer screw. The electrical power consumption shows successive fluctuations as the distance between quartz and reflector varies between positions of resonance and non-resonance of the gas column. Measurement of the distance between resonance positions gives a value for A/2, and if /... 

GC involves taking the concentrated residue and passing it through a gas column. 

It is generally very difficult to measure total gas column densities through a cloud, while it is relatively straightforward to measure die extinction (essentially optical depth) due to dust at some wavelength. The extinction is related to the total dust column density via a dust model, including a particle size distribution. These dust models are typically not unique, hence the additional constraint from the elemental abundances of dust constituents, in particular Si and Fe. Therefore, the conversion factor between the two is an important number, and significant efforts have been directed toward its measurement. 

Column. 2.5% OV-17 on 80-100 mesh Chromosorb G, treatment and dimensions as for System GA. Column Temperature, Carrier Gas, Reference Compounds. As for System GA. 

Reactor effluent was continuously fed to a 0.25 ml sampling loop located inside a Hewlett-Packard Model 2520 Gas Analyzer. Separation of the products was over two serial columns, 6 x 1/8" Poropak Q 80/100 mesh, followed by 10 x 1/8" molecular sieve 5A 60/80 mesh. Thermal conductivity detection was used with helium carrier gas. Columns were isothermal at 60 C. 

The sealing capacity of a rock under hydrostatic conditions is determined by the minimum hydrocarbon-water displacement pressure of the rock, which depends on the radius of the largest connected pore throats in the rock and the oil-water and gas-water interfacial tensions, and in addition on the densities of groundwater and hydrocarbons accumulating in the adjacent reservoir rock. The maximum height of an oil or gas column that can accumulate below a seal is given by Equation 4.17 (Section 4.1.3)... 

The fault has its minimum displacement (ca. 75 m) where it branches with Fault 3. In this area the SGR is just below 20% or higher, and by analogy with Fault 1, the potential for having a trapped HC-column at the extension of G Central is good. In addition, a gas column is more likely to be present rather than an oil column, increasing the possibilities for a static seal. 

It is reported that gas flow as a separate phase through a seal is given if the pressure of a non-wetting phase (gas) can displace the connate water out of the pore space, or in other words if the buoyancy forces created by the gas column exceed the capillary pressure within the seal. It is important to state that the most relevant factor controlling capillary pressure is the effective interconnected pore radius and that the pore radius does not depend on seal thickness (Zieglar, 1992 Antonellini and Aydin, 1994). 

If gas flow as a separate phase was controlled by capillary pressure, the gas column held under a seal would exclusively be a function of the petrophysical properties of the seal and not of its thickness, except under perfect conditions, e.g., as observed with shales, when a thick seal may result in a greater continuity and higher resistance against later fracturing (Hunsche and Schulze, 1993). This consequence clearly contradicts the boundary conditions put on the process to be found by the empirical observations. Therefore, it is unlikely that capillary pressure exerts a control on migration of gas through rocks even through rock salt. 

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