Pump technique

Secondary recovery, infill drilling, various pumping techniques, and workover actions may still leave oil, sometimes the majority of the oil, in the reservoir. There are further applications of technology to extract the oil that can be utilized if the economics justifies them. These more elaborate procedures are called enhanced oil recovery. They fall into three general categories thermal recoveiy, chemical processes, and miscible methods. All involve injections of some substance into the reservoir. Thermal recovery methods inject steam or hot water m order to improve the mobility of the oil. They work best for heavy nils. In one version the production crew maintains steam or hot water injection continuously in order to displace the oil toward the production wells. In another version, called steam soak or huff and puff, the crew injects steam for a time into a production well and then lets it soak while the heat from the steam transfers to the resei voir. After a period of a week or more, the crew reopens the well and produces the heated oil. This sequence can be repeated as long as it is effective. 

In the mercury pump technique, the volume of a 25-g sample of shale is obtained by pressuring a chamber to 24 psig with and without the shale sample. In the mtid balance technique, shale cuttings are added in the mud balance cup until they weigh the equivalent of a cup of water. The volume of shale can be expressed as... 

VEDs are one of the most effective treatment modalities for ED. They have a success rate of greater than 90% in obtaining an erection sufficient for coitus and are considered a first-line non-invasive therapy.13 Rigidity may be improved by using a double pump technique in which the vacuum is applied for a couple of minutes, removed, then reapplied for another few minutes. Higher efficacy rates can also be achieved by combining VEDs with other therapies. 

Electroosmotic soil processing is an in situ separation/removal technique for extracting heavy metals and organic contaminants from soils.17 55 89 The fluid between the soil particles moves because a constant, low DC current is applied through electrodes inserted into the soil mass. The electroosmosis (EO) remedial method provides an advantage over conventional pumping techniques for in situ treatment of contaminated fine-grained soils and is more efficient in saturated conditions. 

Metallic electrodes may dissolve as a result of electrolysis and may introduce corrosion products into the solid mass. However, if the electrodes are made of carbon or graphite, no residue will be introduced in the treated soil mass as a result of the process. The energy expenditure for Pb removal has been estimated to in the range 30 to 60 kWh/m1 2 3 4 of soil. The EO method also provides an advantage over conventional pumping techniques for in situ treatment of contaminated finegrained soils. 

Optical pumping techniques are also very common. The source of the pumping light may be a continuous arclamp, a pulsed flashlamp, another laser, or even focused sunlight. 

The process can be applied to the cleanup of source areas such as dense pools of non-aqueous-phase liquid (NAPL) below the water table surface, light NAPL pools floating on the water table surface, and NAPL contamination remaining after conventional pumping techniques. Subsurface conditions after application of the thermal process are generally amenable to biodegradation of residual contaminants. 

A tube (length 1.5 m and volume 4 ml) was inserted in front of the injector and placed in a thermostat in order to ensure good temperature control of the mobile phase. 25 ml of an aqueous perchlorate solution was present as a separate layer in the solvent reservoir in order to keep the mobile phase saturated. The column coating was achieved by the pumping technique. Columns were first tested in the adsorption mode with n-hexane + 1-butanol (199 + 1)... 

Both methods can give identical information on Ai excited in process (8.1). The schemes for measuring directional correlations between two particles resulting from a collision process by coincidence techniques are discussed in some detail in chapter 2. Similarly details of optical pumping techniques can also be found in chapter 2. 

In a polarization pump, the average polarization force over all dipoles induces a body force on the dielectric liquid. Thus, the power required to achieve pumping is very low, leading to higher pumping efficiencies. Other benefits of the EHD pumping technique include low cost, very low power consumption, and minimal maintenance. 

Electroosmotic flow is the most popular of the electrokinetic pumping techniques. One of the main reasons for its popularity with microfluidic... 

An oxygen-free solution (N2 or freeze and pump technique) of 333 mg (1.0 mmol) of 4.18a in 190 mL of dry benzene was irradiated with a Hanovia 450 W mercury vapor lamp equipped with a Pyrex filter (A, > 290 nm). Nitrogen was passed through the solution during the irradiation period of 30 min. The solvent was rota-evaporated and the residue purified on a column (20 x 2.5 cm silica gel, petroleum ether (40 - 70 °C)/toluene 1 1). A twofold recrystallization from ethanol afforded 225 mg (72%) of the cyclophane as colorless crystals, mp 296 C. 

It may be seen from the scheme that although //ww-substituted olefins lead essentially to tran.v-substituted cyclopentanes, stereochemistry is not maintained in the case of n s-olefins. Thus, dialkylmaleates form a cisjtrans mixture of products. This is a result of palladium(0)-me-diated isomerization prior to codimerization. By employing the above-mentioned pumping technique, the yield of the same addition is nearly quantitative after 2 h at 130°C with 90% predominance of the m-isomer41. As with the TMM-Pd procedure, cyclodimerization with 2-cycloalkenones can only be achieved with 2-cyclopentenone in satisfactory yields wiLh the unsubstituted methylenecyclopropane. 

This pumping technique uses no moving parts, however, and does not require sophisticated fabrication techniques. It is relahvely easy to implement and operate in microchannels and other miniaturized systems [287]. The disadvantage of EOF is its dependency on huid physiochemical properties (ionic strength, pH, organic content, etc.) to develop the surface charge, so its effechveness will change for each huid used in the pump [290]. 

A study of free radical macrocyclisation has been published, very respectable yields were obtained using tin hydride to form the radical and enones as radical acceptors. Interestingly neither high dilution nor syringe pump techniques were found to be necessary. 

J. Fejes and S. Melnik, Pumping Techniques in Flow Injection Analysis [in Slovak]. Chem. Listy, 80 (1986) 586. 

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