Oilfield emulsions

Lei, Z.-X., Chen, Y.-M., Chen, Y.-W., Yan, J., Jin, X.-R, 2006. Preliminary results of the pilot test of deep profile control using inverse polymer emulsion. Oilfield Chemistry 23 (1), 81-84. 

Oilfield Uses. Calcium chloride has two uses in the oilfield as a primary ingredient in completion fluids and as the brine phase in an invert emulsion oil mud. An excellent review of oil well drilling fluids is available (36) (see also Petroleum, drilling fluids). 

M. J. Bronaley, S. H. Gaffney, and G. E. Jackson. Oilfield emulsion control, techniques and chemicals used to separate oil and water. In Proceedings Volume, volume 3. Inst Corrosion UK (Corrosion 91) Conf (Manchester, England, 10/22-10/24), 1991. 

Oilfield drilling fluids, organic titanium compounds in, 25 133 Oilfield emulsions, colloid, 7 274t Oilfield hydraulic fracturing fluids, organic titanium compounds in, 25 133 Oil fields, lithium in, 15 124 Oil-field waters, lithium-bearing, 15 128 Oil filters, phenolic resins in, 18 790 Oil-furnace blacks, 4 762 manufacture, 4 780—785 Oil gas, 6 787... 

Example. It may happen that an emulsion that is desirable in one part of the oil production process may be undesirable at the next stage. For example, in the oilfields, an in situ emulsion that is purposely created in a reservoir as part of an oil recovery process may change to a different, undesirable type of emulsion (water dispersed in oil) when produced at the wellhead. This emulsion may have to be broken and reformulated as a new emulsion suitable for transportation by pipeline to a refinery. Here, the new emulsion will have to be broken and water from the emulsion removed, which otherwise would cause processing problems in the refining process. 

Treating Oilfield Emulsions, 3rd ed. American Petroleum Institute Austin, TX, 1974. 

K. L. Sublette, Method and Apparatus for Separating Oilfield Emulsions, US Patent 4,581,120, 1986. 

Chang, M.-S.M., Wasan, D.T, 1980. Emulsion characteristics associated with an alkaline water flooding process. Paper SPE 9001 presented at the SPE Oilfield and Geothermal Chemistry Symposium, Stanford, 28—30 May. 

Clearbreak. [Chemron] Polymeric amine emulsion breaker for oilfield implies. 

Coskuner, G. Oilfield Emulsions Report No. 1988-18 Petroleum Recovery Institute Calgary, Canada, 1988. 

The free water knockout (FWKO) is a separation vessel used extensively in the oil industry to treat oilfield-produced emulsions. The FWKO separates the large volumes of free water associated with the produced fluid. Produced solids can collect in the FWKO. The use of water jets and drains is also an effective method for eliminating produced solids in the FWKO operation. 

Polyester IdOd, N-95. (Chemron] Emulsion tnedeer for oilfield qiplics. 

Ronningsen, H.P. (1995) Correlations for predicting viscosity of W/O-emulsions based on north sea crude oils, in Proceedings of SPE International Symposium on Oilfield Chemistry, Society of Petroleum Engineers, Richardson, TX, SPE paper 28968. 

Work on the characterization of oilfield emulsions coupled with chemical characterization of commercially available demulsifier formulations has shown that physical processes (temperature, pumping and dispersed water size distribution) can be at least as important as the chemical effects associated with demulsifiers themselves in determining demulsifier effectiveness [90, 91]. In fact, there are so many variables involved in industrial demulsification that, to a large degree, demulsifier selection and performance evaluation are stUl conducted using simple test procedures developed for use in the plant or field. These tests, usually bottle or centrifuge tests, can be good indicators of performance trends, and are usually carried out for selected suites of commercial demulsifier formulations. 

In surface emulsion treaters (e.g. oil-water separators), the occurrence of foams is generally undesirable and any such foams will have to be broken, either downhole or at the surface [12, 15). Oilfield-produced water may also foam, which can also cause problems in handling and in gas separation. This is usually dealt with by adding antifoaming or defoaming chemicals such as silicones, polyglycol esters or polymers such as polyfethylene oxide)—polyfpropylene oxide) block copolymers. 

In the oilfield, water-in-crude oil emulsions are gen er-ally called regular, while 0/W emulsions are called inverse or reverse (47). It is noteworthy that more than 95% of the crude oil emulsions formed in the field are of the W/0 type. Nevertheless, multiple or complex emulsions (O/W/0 or W/OAV) can also be encoun tered. 

In regular oilfield emulsions, the dispersed aqueous phase is usually called sediment and water (S W) and the continuous phase is crude oil. The dispersed S W phase is essentially saline water, but different types of solids such as sand, mud, scale, eorrosion resi dues, or precipitates are often present and ean partiei pate in flie meeh-anisms of stabilization of emulsions. Petroleum emulsions vary from one field to another beeause etude oils differ by their geological age, ehe mieal composition, and associated impurities, and furthermore, the water exhibits physical and chemical properties that are also specific to each reservoir. Neverflieless, all fields have in common the fact that a great number of emulsifying agents are present in the fluids produced (48) ... 

As in the case of chocolate mousses, W/0 oilfield emulsions are often difficult to characterize because of their opacity, their high water concentration, the pre sence of various solids in both phases, and the organic nature of the continuous phase. It is of prime impor-tanhce to be able to assess the droplet size distribution in oilfield emulsions, because of the strong dependence between the rate of separation and the size of the dro plets. A knowledge of the drop size distribution is clearly an important factor in the design of separation equipment (46). Furthermore, the phase continuity of the mixture is also a parameter which must be... 

Figure 9 Thermogram of cooling of an oilfield emulsion after homogenization by gentle shaking.

Figure 10 Influence of agitation on the thermogram of coofing of an oilfield emulsion —gentle shaking —17,500 rpm —24,000 rpm.

Generally, oilfield emulsions are most often W/O with the surface-active emulsifiers residing in the crude-oil continuous phase. According to the Bancroft rule (109) the phase for which the emulsifiers are most soluble is the continuous phase. The emulsifiers possess some degree of polarity which attracts them to the water phase. Solid emulsifiers would be very fine particles in a state of incipient flocculation (110). The emulsifiers may be one or more of the following solids whieh are partially hydrophobic with contact angle (9>90°), polar asphaltenes and resins with some partial insolubility indueed by solvents which dilute the crude oils, or metalloporphyrins integrated within the asphaltenes (24, 25). 

Uses Preservative, antibacterial for cosmetics, toiletries, topical pharmaceuticals biocide, in-can preservative for latex paints, adhesives, slurries, inks, resin emulsion systems, oilfield water systems, drilling muds, water treatment defoaming antimicrobial preservative in textiles Features Does not increase VOC content Regulatory USA not restricted Europe provisional list 3000 ppm max. Manuf./Distrib. Aldrich Fluka... 

Pena, A.A. and Hirasaki, G.J., Enhanced characterization of oilfield emulsions via NMR diffusion and transverse relaxation experiments, Adv. Colloid Interface Sci., 105, 103, 2003. 

A high interfacial viscosity can contribute to emulsion stability by reducing the rate of droplet coalescence [118-121], This is therefore a property that one may wish to enhance in the formulation of a desirable emulsion. For example, oilfield water-in-oil (W/0) emulsions may be stabilized by the presence of a protective film around the water droplets. 

In oilfields, after the primary and secondary cycles of oil recovery, chemicals may be injected to drive out additional oil in an enhanced oil recovery process, which may involve creating in situ emulsions in the reservoir. Figure 7 shows a reservoir schematic with such a chemical flood. 

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