Compositions – Leather or fur treating
Patent
1980-07-13
1983-09-13
Guynn, Herbert B.
Compositions
Leather or fur treating
166275, 252312, 252356, 252546, 260404, E21B 4322
Patent
active
044041098
DESCRIPTION:
BRIEF SUMMARY
The invention concerns emulsions and particularly aqueous micro-emulsions of organic substances, and also the preparation thereof; it relates more particularly to new surface-active agents for use in such preparation.
Micro-emulsions, that is to say thermodynamically stable liquid dispersions having two phases, in which the dispersed liquid droplets generally measure less than 0.2 micron and more often about 0.01 to 0.1 micron, have various applications at the present time, one of the most important being the "assisted" tertiary recovery of crude oil. In this latter case, a micro-emulsion of water with hydrocarbon is injected into the well in order to remove the crude oil contained in the structure of the oil-bearing layer, by dissolving this oil in the micro-emulsion. The latter is prepared by mixing water with a hydrocarbon in the presence of a surface-active agent and an appropriate additive, usually an alcohol.
The invention is of particular interest in connection with the preparation of micro-emulsions of hydrocarbons with water of high salinity which is stable at high temperatures and which is absorbed to only a slight extent by rock.
It is known to use in processes for the tertiary recovery of hydrocarbons, additives which enable the interfacial surface tension between water and oil to be reduced. A number of compositions have already been proposed for this purpose. In known practice, the surface-active agents most commonly used for this purpose are sulphonates, in particular sulphonated cuts of crude oil, alkyl-aryl sulphonates of alkali metals or alkaline earth metals or ammonium salts; there substances are economic to use and are freely available. However, they have the disadvantage of losing their effectiveness when the salt-content in the water exceeds 30 g/liter (expressed as the equivalent of NaCl); since higher salt-contents are common in oil-bearing layers, this difficulty therefore limits the usefulness of petroleum sulphonates.
This has raised the problem of finding a composition containing a surface-active substance which will make it possible to obtain micro-emulsions of water containing monovalent and divalent ions at levels greater than 30 g/liter and hydrocarbons, and which will be chemically stable in use up to 100.degree. C. and for four or five years, and which will have a low level of absorption by rocks and will be economic.
The present invention leads to an improvement in the technique in question; it makes possible the preparation of micro-emulsions which are stable in the conditions of salinity of the medium to be treated, even in the case of aqueous solutions having a concentration of salts which may reach 280 g or more of NaCl per liter, the content of CaCl.sub.2 possibly exceeding 50 g/liter. The surface-active substances according to the invention enable the interfacial tension between water and crude oil to be substantially reduced. On the other hand, the invention makes it possible to obtain micro-emulsions in which the losses of surface-active agent by absorption on to the rocks are less than in previous practice. The consumption of surface-active substances, which are readily obtainable industrially, is thus reduced by the application of the invention. This constitutes a marked advantage as compared with the known art.
The process according to the invention, which consists in mixing one or more hydrocarbons with water, with a surface-active agent, with a co-agent and possibly with other additives in a manner known per se, is characterized in that the surface-active agent is constituted by one or more .alpha.-amino-acid salts of the type: ##STR2## wherein each of the groups R and R' is a straight-chain or branched aliphatic group or an alkyl-aryl group, R being C.sub.6 to C.sub.120, preferably C.sub.12 to C.sub.60 and particularly C.sub.16 to C.sub.32, R' being C.sub.1 to C.sub.18 and M designating an alkali metal cation, an alkaline earth metal cation, ammonium, an amine group or hydrogen.
The radical R is preferably a relatively heavy alkyl radical, that is to say it
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patent: 3766266 (1973-10-01), Wakamatsu et al.
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Chambu Claude
Coste Jean-Francois
Grangette Henri
Tellier Jacques
Guynn Herbert B.
Societe Nationale Elf Aquitaine (Production)
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