When oil is present

Mud temperatures of 150° can present critical suction problems. Under low pressure or vacuum existing in the cylinder on the suction stroke, the mud can boil, hence decreasing the suction effectiveness. Furthermore, hot mud accelerates the deterioration of rubber parts, particularly when oil is present. Large mud tanks with cooling surfaces usually solve the problem. 

The presence of oil is obviously a factor that influences surfactant loss. Several factors in addition to those listed previously may contribute to surfactant loss when oil is present ... 

If we assume that in these chemical floods in water-wet cores the surfactant sees as much rock surface when oil is present at or below waterflood residual as it sees when there is no oil present at all, we can take PV gp = 0.04 from the flow experiment run under the same conditions in the absence of oil. The oil cut in the clean oil bank in this flood was 0.34, and = 0.82 by... 

Retention of xanthan biopoiymer depends on the effective permeability of the porous rock. Retention data from Huh i piotted in F. 5.24 show the same trend as Fig. 5.22. Polymer retention increases as the effective permeabiiity decreases. Tlie uncertainty range indicated in Fig. 5.24 shows Ae effect of different values of inaccessible PV (IPV) on polymer retention determined by material-balance calculations (inaccessible PV is discussed in Sec. 5.4.2). In experiments conducted in 10- and 33-md porous media, the injected concentration was not reached when the experiment ended. Some uncertainty exists in these values, possibly because of the effects of sandface plugging. Retention of biopolymers is generally less than polyacrylamides at comparable concentrations. Also, retention of biopolymer may be lower when oil is present in the porous media. Kolodziej reported retention of xanthan biopolymer in Berea sandstone to be 75 Ibm/acre-ft-PV for 100% brine corefloods and 38 Ibm/acre-ft-PV in corefloods at ROS. 

Pure ammonium nitrate decomposes in a complex manner in a series of progressive reactions having different thermochemical effects (Table 17). Oxygen is Hberated from combination with combustibles only at temperatures above 300°C. When a combustible material such as fuel oil is present in stoichiometric proportions (ca 5.6%) the energy evolved increases almost threefold... 

Additive packages have been developed which do an exceUent job of preventing IVD. The key to effective operation is to keep the valve wet so that the additive can prevent deposit buildup. Most packages include a combination of detergent/dispersant and a carrier oil or heavy solvent. If no carrier oil is present, then the fuel may evaporate off the valve too rapidly for the package to be effective. When the valves do not rotate, the portion of the valve which has the highest deposit level is the back side which is not constantly wet. 

Neutral aqueous salt solutions react slowly with tin when oxygen is present but oxidizing salt solutions, such as potassium peroxysulfate, ferric chloride and sulfate, and aluminum and stannic chlorides dissolve tin. Nonaqueous organic solvents, lubricating oils, and gasoline have Httle effect. 

Froth-over When water is present or enters a tank containing hot viscous oil, the sudden conversion of water to steam causes a portion of the tank contents to overflow. 

The oil companies supplying the rubber industry claim that there is no effect on ageing properties when sulphur is present in an oil (up to 6% is possible). They claim that the refining removes the active mercaptans and sulphides and the remainder of the sulphur is complexed into polycyclic compounds and there is no evidence that this type of sulphur has any effect on cure. This claim may be true in some circumstances. However, it is known from practical experience that with certain polymers and compounds the claim is incorrect, especially when the high sulphur oils are used as test media. Oils supplied to the same oil specification from oil fields in different parts of the world, and meeting all the requirements of the specification may, because of widely different sulphur levels, have serious effects on high temperature ageing. 

Collector sterylamine acetate works well on smithsonite, but not as well on calamine. When smithsonite is present in the ore, better results are achieved using a tallow amine emulsion with elevated additions of fuel oil emulsion. 

Viscosity is relatively higher in good solvents and lower in poor solvents. Polyisobutylene is used as an additive for motor oils. The oil is a poor solvent for the polymer at room temperature but becomes a good solvent at the operating temperatures of the gasoline combustion engine. Thus although the viscosity of an untreated 10-40 motor oil decreases as the temperature increases, the decrease is counteracted when polyisobutylene is present. Only traces (1-2%) of polyisobutylene are required to achieve the desired viscosity. 

For this water concentration, the micellar region for the bile salt mixture is large for all oleyl compounds except oleic acid. Oleic acid is distinguished from the other compounds in that it does not form a lyotropic liquid crystalline phase spontaneously in water and, similarly, is present as oil droplets in bile salt solution when its micellar solubility is exceeded. Figure 1 shows also that the micellar area of an equimolar mixture of monoolein and sodium oleate is considerably greater than that of an equimolar mixture of monoolein and oleic acid, indicating that fatty acid ionization also enhances micellar solubility when monoolein is present. The equimolar mixture of sodium oleate and oleic acid has a micellar area similar in size to that of monoolein, as does the equimolar combination of all three compounds. 

The ZDDP oil solution produced a long-chain polyphosphate tribofilm whereas the corresponding disulfide (no zinc present) yielded a simple phosphate antiwear film (Kasrai et al., 1994). The effect of zinc in the antiwear agent is very significant. The chemical nature of sulfur and phosphorus, in the films of isopropyl DDP (without zinc), is quite different from those with zinc. When zinc is present, phosphate in the film tends to polymerize more, and zinc acts as an antioxidant for sulfur in protecting the sliding surfaces. 

The hydrogen lost during their formation apparently goes into chain termination, i.e., the formation of isobutane most probably and possibly some propane when propylene is present In alkylation feed. HF alkylation has found no benefit from having acid-soluble oils present in the catalyst. When they are present in amounts greater than about one weight percent, they have a detrimental effect on alkylate quality and yield. 

Comparing the fractional flow curves. Figures 8 and 10 show that oil and CO2 production are delayed since the entire core cross section is swept and additional brine is displaced. Note the second hump in the brine production curve after 0.7 HCPV when foam is present. Without foam, brine production stops and oil production drops rapidly when CO2 breaks through. 

To evaluate the in-vivo gelation mechanism of the polymer, mice were injected with three different volumes of polymer. The polymer remained at the injection site and maintained its shape for 24h post injection as happens when oil is injected in the subcutaneous space. Based on data presented in this work we can classify poly(sebacic-co-ricinoleic acid) as in-situ organogel forming. 

A relationship between peroxide value and anisidine number that is used to measure the rancidity level of fats and oils. It is defined as (2 X PV) + AN. It reflects total oxidation to date. Considered an impurity. High levels of moisture in an oil can lead to deterioration in storage. Soap can be formed when moisture is present in the crude oil and reacts with the free fatty acids and a catalyst (alkali ion), or it can result from incomplete removal of soap from washed refined oil. 

Here, j = 1 for the aqueous phase, 2 for the oleic phase, and 3 for the microemulsion phase. The a parameters are determined by matching laboratory microemulsion viscosities at several compositions. In the absence of surfactant and polymer, aqueous and oleic phase viscosities reduce to pure water and oil viscosities ( a and 1 0), respectively. When polymer is present, is replaced by polymer viscosity ( Jp). Figure 7.28 shows an example of microemulsion viscosity expressed in the preceding equation, where a = (2, 3, 0, 0.9, 0.7), a = 1 cP, and j o = 5 cP. 

When oil is added to the surfactant and polymer solution, the system follows the typical pattern of a system without polymer—that is, from type I to type 111 to type II as salinity increases. The three-phase region simply shifts a small distance to the left on the salinity scale, compared with the three-phase region without polymer. When polymer is present, it remains almost exclusively in the most aqueous phase whether the phase is lower-phase microemulsion or excess brine. Consequently, polymers affect relative mobility of the phases generated during a chemical flood, but they do not appear to affect phase equilibria significantly (Nelson, 1982). Some of the aqueous phases in the critical region of the shift (which is also just above oil-free CEC salinity) were found to be gel-like in nature. 

Groundwater — Water present below the soil surface and occupying voids in the porous subsoil, specifically the porous layer that is completely saturated with water. The upper surface of the groundwater is referred to as the water table. Contamination of groundwater is a major concern when oil is spilled on land as groundwater supplies springs and wells and passes into surface water in many areas. 

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