Well-head emulsions

A petroleum industry term used to denote an oil-in-water emulsion (most well-head emulsions are W/O). Reverse emulsion has the opposite meaning of the term invert emulsion . See also Invert Emulsion. 

Emulsion drilUng fluids emulsion fracturing, stimulation, acidizing fluids enhanced oil recovery (EOR) in situ emulsions produced (well-head) emulsions bituminous oil sand process and froth emulsions heavy oil pipeUne emulsions fuel oil and tanker emulsions... 

Liquid/Liquid Systems Emulsion drilling fluids Enhanced oil recovery in situ emulsions Oil sand flotation process slurry Oil sand flotation process froths Well-head emulsions Heavy oil pipeline emulsions Fuel oil emulsions Asphalt emulsion Oil spill emulsions Tanker bilge emulsions... 

Any kind of dispersion that was useful in the reservoir may be, or may become, an undesirable dispersion when produced at a well-head. This could include used drilling fluid that has returned to the surface, conventional oil production that occurs in the form of a W/O emulsion, or foam from an enhanced oil-recovery process. These can present some immediate handling, process control, and storage problems. In addition, pipeline and refinery specifications place severe limitations on the water, solids, and salt contents of oil they will accept in order to avoid corrosion, catalyst poisoning, and process-upset problems. For pipeline transportation, an oil must usually contain less than 0.5% basic sediment and water (BS W). 

Emulsions may be encountered throughout all stages of the process industries. For example, in the petroleum industry both desirable and imdesirable emulsions permeate the entire production cycle, including emulsion drilling fluid, injected or in situ emulsions used in enhanced oil recovery processes, well-head production emulsions, pipeline transportation emulsions, and reflnery process emulsions (13). Such emulsions may contain not just oil and water, but also solid particles and even gas, as occur in the large Canadian oil sands mining and processing operations (13-15). 

Extremely viscous so-called heavy oils are often produced from wells in Canada, Venezuela, and China. These oils often have reported viscosities in the range of (3-30) x 10 mPa s [38 0] and are often produced at the well head as a gas-in-oil emulsion with a gas volume fractions of from 0.05 to 0.40 [41], which has the appearance of chocolate mousse [38]. The foams formed from such gas-in-oil emulsions upon standing can be extremely stable, persisting for several hours in open vessels [38]. 

The composition of crude oil that arrives at a refinery is not identical to reservoir fluids. Gas and water is separated at the well head and emulsions are broken. Consequently, oils lose some light hydrocarbons (from multiple fields and reservoirs, which individually may be of varying composition and quality. For these reasons, testing of subsurface fluids from individual reservoirs is necessary to determine field economics and design reservoir management practices. 

Using copolymerization theory and well known phase equilibrium laws a mathematical model is reported for predicting conversions in an emulsion polymerization reactor. The model is demonstrated to accurately predict conversions from the head space vapor compositions during copolymerization reactions for two commercial products. However, it appears that for products with compositions lower than the azeotropic compositions the model becomes semi-empirical. 

In order to use supersolubilisation for DNAPL extraction, the reduction of interfacial tension must be well controlled. The critical level of interfacial tension is dependent on size and heterogeneity of the pore space. For example, a value of 4 mN m 1 was found for soil from a contaminated site [47]. Since supersolubilising systems exhibit lower interfacial tension, they cannot be directly applied for contaminant extraction. Therefore, a salinity gradient was used for column experiments in preparation for a field test [47,63]. When the salinity was increased in two steps from 0 to 0.6 wt.% and 1 wt.% CaC, a mixture of a sul-phated alkyl propoxylate (Isalchem 145-4P0-S04) and a twin-head aromatic sulphonate (Dowfax 8390) exhibited the usual micellar solubilisation, supersolubilisation and formation of bicontinuous micro emulsions with perchloroethylene. Applying this three-step gradient to soil columns contaminated with PCE yielded high extraction values and no mobilisation of DNAPL [47]. 

Well over 300 publications concerning emulsion polymerization have appeared during the period convered by this Report. In the space available, it is possible to draw attention to only the more important of these. Note will first be taken of important reviews which have appeared. An attempt will then be made to group the other publications under appropriate headings. 

The concentration of the very aroma active (F,Z)-2,6-nonadienol (cf. 10.3.6) in the head space is below the detection limit. However, this odorant can be detected by headspace GC-olfactometry (cf. 5.2.2.2). The results in Table 5.36 show that this alcohol as well as (Z)-3-hexenol no longer contribute to the aroma in the 20% fat emulsion. In the emulsion with 1% of fat, (F,Z)-2,6-nonadienol, allyl isothiocyanate and allyl thiocyanate predominate and produce the green, mustard-like aroma (Table 5.36). 

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