Salinity requirement system

From the previous discussion, we can see that which salinity system is favored depends on the salinity requirement diagram, and the diagram depends on the surfactant system. In diagram I, the SG(-) system may be the most... 

At the concentrations of alkali above that required for minimum interfacial tension, the systems become overoptimum. The excess alkali plays the same role as excess salt. When synthetic surfactants are added, the salinity requirement of alkaline flooding system is increased. NEODOL 25-3S is such a synthetic surfactant used by Nelson et al. (1984). Figure 12.4, shown earlier, is a composite of three activity maps for 0, 0.1, and 0.2% of NEODOL 25-3S as a synthetic surfactant for 1.55% sodium metasilicate with Oil G at 30.2°C. We can see in the figure that without the synthetic surfactant, the active region of this system is below the sodium ion concentration supplied by the alkali. However, with 0.1 and 0.2% of NEODOL 25-3S (60% active) present, the active region is above the sodium ion concentration supplied by the alkali, so additional sodium ions must be added to reach optimum salinity. 

This is the type of information that is presented in a Salinity Requirement Diagram. Figure 6 is the Salinity Requirement Diagram for the system under discussion. The vertical bars show, as a function of overall surfactant concentration, the range of brine salinity over which the system is in a Type III phase environment (although not necessarily three phases). The position of the circle on the bar indicates midpoint salinity at that overall surfactant concentration. Optimal salinity for oil-displacement efficiency should be close to that level of salinity. The number within the circle is the volume fraction of surfactant in the invariant phase at midpoint salinity. Healy and Reed (12) found lower microemulsion /ex cess brine and microemulsion/excess oil interfacial tensions for systems in which the volume fraction of surfactant in... 

Absolute values of M /Na" effectiveness and the dependency of those values on surfactant concentration depend upon the particular surfactant or surfactant blend. For example, for Petrostep 450 alone in the same system as the 80/20, Petrostep 450/NEODOL 25-3S, blend we have been discussing, the M /Na" effectiveness ratio rises from 21 to 67 as the surfactant concentration is lowered from 5.0 to 2.0 percent. On the ocher hand, judging from how "flat its Salinity Requirement Diagram is, the M /Na+ effectiveness ratio for NEODOL 25-3S by itself does not change much with surfactant concentration. (The midpoint salinity of NEODOL 25-3S drops only 11 percent, from 185 percent to 165 percent SDSW, as its concentration in the subject system is decreased from 5.0 to 0.8 percent.)... 

Witco s petroleum sulfonate, Petronate TRS 12B, is similar to Petrostep 465, and Witco s Petronate TRS lOB falls between Petro-step 465 and Petrostep 450. The Salinity Requirement Diagram of Amoco s (polybutene) Sulfonate 151 lies even lower than the diagrams for Petrostep 465 and Petronate TRS 12B. Midpoint salinity for that sulfonate at 5.0 percent surfactant in the system is about five percent SDSW. 

Cationic surfactants may be used [94] and the effect of salinity and valence of electrolyte on charged systems has been investigated [95-98]. The phospholipid lecithin can also produce microemulsions when combined with an alcohol cosolvent [99]. Microemulsions formed with a double-tailed surfactant such as Aerosol OT (AOT) do not require a cosurfactant for stability (see, for instance. Refs. 100, 101). Morphological hysteresis has been observed in the inversion process and the formation of stable mixtures of microemulsion indicated [102]. 

In the most widely applied procedures, the test system is restricted in flexibility by the salinity and pH requirements of the test organisms, but probably the most serious limitation of these test systems... 

A large-diameter multihole urethral catheter should be inserted to facilitate saline lavage and evacuation of blood clots. Surgical removal of blood clots under anesthesia may be required if saline lavage is ineffective. Active bleeding from isolated areas may be cauterized with an electrode or laser. In severe cases that are unresponsive to local or systemic pharmacologic intervention,... 

Commonly administered LVPs include such products as Lactated Ringers Injection USP, Sodium Chloride Injection USP (0.9%), which replenish fluids and electrolytes, and Dextrose Injection USP (5%), which provides fluid plus nutrition (calories), or various combinations of dextrose and saline. In addition, numerous other nutrient and ionic solutions are available for clinical use, the most popular of which are solutions of essential amino acids or lipid emulsions. These solutions are modified to be hypertonic, isotonic, or hypotonic to aid in maintaining both fluid, nutritional, and electrolyte balance in a particular patient according to need. Indwelling needles or catheters are required in LVP administration. Care must be taken to avoid local or systemic infections or thrombophlebitis owing to faulty injection or administration technique. 

Calcium-sodium-chloride-type brines (which typically occur in deep-well-injection zones) require sophisticated electrolyte models to calculate their thermodynamic properties. Many parameters for characterizing the partial molal properties of the dissolved constituents in such brines have not been determined. (Molality is a measure of the relative number of solute and solvent particles in a solution and is expressed as the number of gram-molecular weights of solute in 1000 g of solvent.) Precise modeling is limited to relatively low salinities (where many parameters are unnecessary) or to chemically simple systems operating near 25°C. 

The introduction of samples via nebulizers requires that they are either pneumatically or peristaltically pumped into the nebulizer for aerosol formation. This restricts the range of viscosities that can be easily handled by the nebulizer. For example highly saline or oil samples may well have to be diluted by an order of magnitude or greater. This dilution can be carried out either in a batch mode or continuously. Batch systems are quite complex in design but the rate of analysis is high. It is often the case that where dilution is required, in addition, a fast rate of analysis is also desirable. Some batch systems have been introduced commercially, notably to monitor wear metals in the oil industry. 

The electrokinetic process will be limited by the solnbUity of the contaminant and the desorption from the clay matrix that is contaminated. Heterogeneities or anomalies in the soil wiU rednce removal efficiencies. Extreme pHs at the electrodes and the may inhibit the system s effectiveness. Electrokinetic remediation is most efficient when the pore water has low salinity. The process requires sufficient pore water to transmit the electrical charge. Contaminant and noncontaminant concentrations effect the efficiency of the process. 

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