Some Key Problems Encountered for Demulsifier Research

Main reasons, of which viscous crude emulsion and chemical flooding emulsion are difficult to demulsify, is that their compositions and structures have tremendous differences to water flooding emulsion. To resolve main difficulties encountered in demulsifier research today, such as demulsification of viscous crude oil emulsion, demulsification of chemical flooding emulsion, some research value routes, such as increasing aromaticity, molecular weight and branch degree of demulsifier molecule, and leading double-function groups meeting W/O type and O/W type emulsion and groups with alkyl carbon number matching equivalent alkyl carbon number of the crude oil into demulsifier molecule, were suggested according to demulsification mechanisms and their emulsion characteristics, and action mechanisms of the above-mentioned research routes were elaborated at the same time.

Effect of Live Crude on Alkaline/Surfactant Polymer Formulations: Implications for Final Formulation Design

Summary Phase-behavior experiments have identified several surfactant systems that develop high solubilization ratios and low interfacial tension (IFT) with a specific dead paraffinic crude oil at specific salinities. The purpose of this work is to test these surfactant systems with reconstituted live crude. Emulsion-screening tests were performed in sight cells where an equilibrium amount of solution gas is dissolved in the crude at reservoir pressure (1,100 psi). The results indicate that the surfactant is relatively more soluble in the oil phase under these conditions. Thus, a formulated chemical slug for field conditions should contain either less salinity or a more hydrophilic surfactant system than that used in formulations with dead crude. Phase-behavior measurements estimate this offset to be approximately 0.25% less NaCl for the particular live crude in this study. The relevance of this offset is shown by comparing the results of dead-crude corefloods with a live-crude coreflood. A control experiment pressurizing oil with nitrogen at the same condition, 1,100 psi, did not show enhanced relative surfactant solubility in the oil phase.

An inquiry into the influence of the constituents of a bacterial emulsion on the opsonic index

In preparing an emulsion of bacteria for opsonic estimations it is necessary to break up the masses so far as possible into their constituent bacterial elements and then to separate these from any clumps by centrifugalisation. The rate at which the suspended particles of an emulsion settle depends not only on the centrifugal force applied, but also on the fineness of the particles, and therefore on the efficiency of the method of breaking up the masses. If this is not efficient the suspended matter will fall in the form of coarse particles, leaving a relatively clear supernatant fluid containing very little in suspension. In the case of a tubercle emulsion we find that the best results are given by triturating a small quantity of dried bacilli with a pestle and mortar of which the grinding surfaces have the same curvature; using these, five minutes’ grinding is ample. The mass of dried bacilli is first ground up in the dry state and then made into a paste with a little 1-per-cent. saline (the strength used in all our experiments). The crude emulsion is then made by taking up the paste with 1 to 1½ c. c. of saline. When this emulsion is thoroughly centrifugalised it separates out into a deposit and an opaque supernatant fluid which is practically free from bacilli but which contains a considerable amount of bacterial detritus. If this supernatant fluid be pipetted off and the deposit again mixed with fresh saline and thoroughly centrifugalised, the second supernatant fluid will contain much less detritus and will be correspondingly clearer. By repeating this process several times it is possible to get a supernatant fluid which is almost clear and free from detritus. The deposit will then consist wholly of washed bacteria.