US2233381A - Flooding process for recovering oil from subterranean oil-bearing strata - Google Patents

Description

UNITED STATES- PATENT OFFICE FLOODING PROCESS. FOR RECOVERING 01L FROM SUBTERRANEAN OIL-BEARING STRATA Melvin De Groote, UniversityCity, and Bernhard Keiser, Webster Groves, Mo.,

assignors to Petrolite Corporation, Ltd., Wilmington, Del., a corporation of Delaware No Drawing. Application March 6, 1940.

Serial No. 322,534

10 Claims. (c1. 166-21) This invention rel-ates to the recovery of oil from subterranean oil sands and oil-bearing strata, and has for its main object to provide a practicable, inexpensive flooding prOCSSS for re- 5 covering oil that is held by adsorption, absorption, or in some equivalent manner, on subterranean oil-bearing strata, such as, for example, the oil sands or. oil-bearing strata of exhausted oil fields, or the oil sands or oil-bearing strata of .oil flelds that have been tested and abandoned because they did not contain a sufficient quantity of oil to make it feasible .to attempt to recover the oil by conventional oil-producing procedure.

Briefly described, our process consists in introducing water with which a treating agent or addition agent is mixed to form an aqueous treating solution, into a number of oil wells located in an exhausted or abandoned oilfield, and permitting said treating solution to travel through-the sub- 29 terranean oil sands or oil-bearing strata and rise to the surface of the ground through a predetermined opening. The treating solution or aqueous vehicle employed asthe flooding medium, operates to liberate the film or coating of oil on the 25 particles of the oleiferous structure, and then flush the oil off said particles and carry the oil upwardly to the surface of the ground.

Oil exists in oil sands or similar strata in two" different states, :1. e., as free oil, that is located 30 between the voids of the sands, and as fixed oil,"

which is held by adsorption (and perhaps to some degree-by absorption) on the particles of sand, and which is commonly referred to as the film of oil that adheres to the particles'of sand or to the 35 particles of the oleiferous structure. Such fixed oil may be said to be held by sorption."

Free oil can be recovered by conventional methods of oil producing, such as draining the oil in conjunction with liquid or gaseous pressure, and

40 creating an artificial fluid or gaseous pressure in the sand bed, so as to dislodge the oil from the sand bed and thereafter conduct the dislodged oil to the surface of'the ground by any suitable means ormethod. Fixed oil, i. e., the coating or 45 film of oil on the sand or organized strata, cannot be recovered by any of the conventional.

methods or means used to produce oil, because it is held as -a film surrounding the grain of sand duction by conventional methods, it is not always desirable to use old oil wells for either the purpose of introducing the aqueous vehicle into the subterranean oil sands or oil-bearing strata, or for I expulsion of the oil or the fluid with its oil content 5 in loose admixture or emulsion. In some in-- stances the entire operation is carried out by means of wells drilled specifically for the purpose of flooding the formation in accordance with a predetermined plan. Sometimes the operation is 10 conducted in part by means of some of the old existing wells, and in ,part by means of some new wells drilled in accordance with a predetermined arrangement. The above described procedure, which is commonly referred to as the flooding I5 process, has been employed successfully'in numerous fields, including certain fields in Pennsylvania, certain fields in northern Oklahoma, certain fields in southeastern Kansas, and elsewhere.

Attention is directed to the'bibliography pf water-flooding which appears in "Petroleum Prpduction, by Cloud, University of Oklahoma Press, 1937, page 435. See also U. S. Patent No. 1,826,371, dated October 6, 1931, to Spindler.

It is not necessary to-indicate all the advantages to be obtained by the addition of a suitable chemical compound or treating agent to water, so as to produce an aqueous treating solution that is intended to be used instead of ordinarywater, which may, in essence, represent a dilute brine containing usually appreciable amounts of soluble calcium and magnesium salts. Such a. treating solution, if properlyprepared, constitutes an aqueous vehicle which hasv at least an apparent preferential wetting efiect for the sand or strata, and thus loosens or removes the oil which might not be removed by water alone. Said aqueous vehicle also has the characteristic of tending to prevent the formation of emulsions as said aqueous vehicle and the liberated oil travel through the 40 sand or strata and through the various conduits used in the procedure. It probably has the effect of decreasing the apparent viscosity of water;or to state the matter in another way, the aqueous vehicle or treating solution probably permeates sands and various oil-containing strata which might not be permeated at all by water alone, or at least, under conditions of diminished pressure. There are numerous other advantages not'necessary to mentionfwhich resuit from the use of an aqueous vehicle or treatme solution of the kind above mentioned.

In actual practice, it is found that very few chemical compounds are actually of value as addition agents to the water employed in recovering although there are available thousands of wetting agents and perhaps hundreds of demulslfying agents, very few have the desired property of being suitably resistant to the soluble calcium and magnesium salts, which are either invariably present in the Water used for flooding the subterranean sands or strata, or liable to come in contact with said water and contaminate the same. Some wetting agents and demulsifying agents, although stable in the ordinary sense, are not stable for the purposes of flooding. Sometimes, six to eighteen months may pass before the flood water re-appears atthe surface, carrying the recovered oil. Accordingly, it is necessary that the addition agent must be stable forsuch a period of time; and furthermore, since the same flooding water is used over again, it is necessary that the addition agent must continue to be stable almost. indefinitely. Furthermore, there are chemical compounds which meet the test of stability; but they do not sufllciently lower'the surface tension of the aqueous vehicle within the limits 01 possible economic use. Then too, although some chemical compoundsmay lower thesurface tension, and may be feasible economically, they are not employed for the reason that they do not show other desirable properties, as, for instance,

apparent preferential wetting effect, etc. Some chemical compounds which appear stable under ordinary conditions, even'when allowed to stand for a long period of time, for instance, eighteen months, decompose readily under conditions of use, where they are subjected to pressures such as are required in the ordinary course of forcing the aqueous fluid through the sands or strata. Some addition agents are objectionable apparently for the reason that they build up deposits on the strata, which greatly decreases the speed offlooding, and perhaps in some ways, produce results which are inferior to those which are obtainable by the use of water alone, It has been suggested that this objectionable characteristic is related to excessive preferential wetting effect, but this is purely a matter of speculation, al-' though the assumption may be correct.

We have found that a very desirable agent for addition to the water used in flooding procedure (the said water usually consisting of a dilute brine), is a glycol or polyglycol ether of the type obtainable by causing an aromatic or hydroaromatic hydroxyl compound substituted in the nucleus by at least one hydrocarbon radical or the equivalent thereof, containing at least four carvbutylene oxide, or the like.

bon atoms, to'react with an alpha beta alkylene oxide, suchas ethylene oxide, propylene oxide,

broadly speaking, 'are well known compositions of matter, but it may be desirable to indicate their method of manufacture in some detail.

One may employ any ofthe procedures here-' inafter described, in order. to obtain glycol or polyglycol ethers from aromatic or hydroaro- Such compounds,

, 2,233,381 oil by flooding procedure. One reason is, that water insoluble prior to-the introduction of the ether chain.

Addition agents suitable for use in our process, may be obtained by treating or reacting substituted hydroxy alicyclic compounds of the kind described withalkylene oxides of the type which is characterized by the presence of a radical indicated by the following structure:

Such compounds may be prepared in such a manner that the alkylene oxide enters the substituted isocyclic hydroxyl compound only once, but

preferably the compounds are prepared in such a manner that the alkylene oxide enters several times, preferably at least four times.

In a general way, the products obtained, or at least part of them, may following constitution:

Li. 4.. l

R.o :H- c11 cH0- -H R 5H it: ,JX wherein R stands for the aromatic or hydroaromatic radical, which is substituted by at least one hydrocarbon or acyl radical containing at be exemplified by the least four carbon atoms, and the radical R may also be further substituted. As previously indicated, the carbon atom chain in either the hydrocarbon radical or the acyl radical, may be interrupted by an oxygen atom, or an oxygen atom may serve as aside chain carbon atom-nuclear carbon atom link. R1 and R2 stand for hydrogen or aliphatic radicals, which may be substituted by OH or Cl; and X stands for a whole number from 1-100, but usually and preferably, from 3 or 4 to 40. Compounds of the second general formula may possibly be formed when an alkylene oxide, such as glycidol is employed. It is understood thatall reference to alkylene oxide or its functional equivalent is intended to mean the type of alkylene oxide commonly referred to as in alpha beta alkylene oxide, i. e., where an oxygen atom represents a linkage between-two adjacent carbon atoms, although the oxygen linkage does not necessarily involve a terminal carbon atom; and any functional equivalents are intended to include this same characteristic structure in an equivalent manner. 7

'Aswill be subsequently pointed out, a wide variety of alkylene oxides may be employed, and also equivalents such as glycidol, epichlorhydrin,

various chlorhydrins, etc. Furthermore, it is quite possible that the structure of the. polymerized' alkylene oxide chain or its equivalent, at

least insome instances, is not as simple as indicated by the above formulas. This is based -on the well known properties of polyethylene oxide and related compounds, and particularly,

polymerization products derived from ethylene Reference is oxide. under various conditions. made to Chemistry of Synthetic Resins,-by Ellis, 1935, chapter 50, and to U. S. Patent No. 1,921,378,

dated August a, .1933, to Webel, and 5. Patent 1 No. 1,976,628, dated October 9, 1934, to Wittwer. For this reason the previous structural formulas are submitted primarily to show the point of introduction of the polymerized ether radical or its equivalent, rather than the actual structure itself, although such formulas may be applicable to a number of members of the broad genus.

Thus, it would appear best to characterize the products in the hereto appended claims in terms of the method of manufacture, rather than attempting to rely upon structural formulas, in view of what has been said.

An alkylene oxide may be added in the gaseous or liquid phase, to the melt of a substituted water-insoluble isocyclic hydroxyl compound, as defined above, at a temperature at which the alkylene oxide is absorbed by the hydroxyl compound, and which generally lies between 50? C.

and 250 C. It is also possible to cause the subduring which heating may be advantageous at the beginning of the reaction. In these reactions the length of the polyglycol ether chain is determined by the proportion of the alkylene oxide caused to react. In any event, the amount employed must be suiiieient to produce water solubility, but not of such proportion that surface activity is lost. This particular point will be discussed in detail subsequently. It is well known that various catalysts may be employed for the formation of the ethers and polyethers; and the particularly desirable catalysts include caustic alkalies, alkali alcoholates, tertiary non-hydroxylated organic bases, and the like; and furthermore, in some instances at least acid compounds,

- in place of the oxides themselves.

such as potassium bisulfate, may be employed. It is also known, of course, that the halohydrins corresponding to the alkylene oxides may be used The previously formed glycol ether chains may also be combined with polycyclic hydroxyl compounds substituted in the manner indicated, but in any one of various methods, for instance, the following procedure:

The substituted isocyclic hydroxyl compound in the form of its alkali compound (alcoholate or phenolate) is caused to react with a selected halohydrin, so that one obtains a monoglycol ether of the substituted isocyclic hydroxyl compound. Such derivative is then transformed into the halogen alkyl ether, for instance; by treatment with thionyl chloride; and the halogen alkyl ether of the substituted isocyclic hydroxyl compound is caused to react with polymerized alkylene oxide, for instance, a polyglycol derived from ethylene oxide in the presence of caustic alkali.

As suggested previously, as far as the substituted radical is concerned, carbon-oxygen-carbon linkages may replace carbon-carbon linkages. As examples of substituted isocyclic hydroxyl compounds, which may be used as startingmaterials for the addition agents employed in our process, are the following: Normal butylphenols,

isobutyl-orthoacresols, .di-isobutyl-phenols, isoiso-octylphenols, iso-octyl-orthochlorphenols, nhep tadecyl-para-hydroxyphenylketone of the formula C1'IH35CO.CsH4OH, orthoand para-benzylphenol, cyclohexyl orthocresols, para oxydiphenyl, para-oxy-phenyl-camphanes, the corre-- sponding condensation products of phenol or the cresols, with diterpenes, and the like.

Likewise, one may employ various partially or totally hydrogenated derivatives of the above. Generally speaking, if the isocyclic nucleus contains only one nucleus substituent radical (excluding the hydroxyl radical), and if such substituent radical contains a tertiary alkyl radical, then it is desirable that such alkyl radical contain at least 8 carbon atoms. In any event, however,-the hydroxyl compound, prior to etherization, must be water-insoluble.

Besides the compounds mentioned, there may be used various other isocyclic hydroxyl compounds substituted, as stated above, which are obtained in the form of technical mixtures. The substituted isocyclic hydroxyl compounds may be prepared in various ways. For instance, olefinic compounds containing at least four carbon atoms may be caused to react in known manner with aromatic hydroxyl compounds. In this case there may be used definite olefines, for instance, isobutylene, d-i-isobutylene, normal dodeoylene, cyclohexane, camphene or the like, or the olefinemixtures obtained, for instance, by dehydrating the mixtures of primary alcohols having about four to eight carbon atoms produced in the reduction of carbon monoxide by means of certain catalysts or by catalytic polymerization by one of the known methods of low-molecular olefines, such as ethylene, propylene, isobutylene or the like, or of olefines obtained from the primary alcohols having about four to eight carbon atoms produced in the reduction of carbon monoxide.

Substituted aromatic hydroxyl compounds, suitable for use in producing the addition agents contemplated by our invention, may also be obtained by the known condensation of aromatic hydroxyl compounds with alcohols containing at least four carbon atoms, for instance, tertiary butyl alcohol, alcohols having about four to eight carbon atoms (which; as above mentioned, are produced in the catalytic reduction of carbon monoxide), cyclohexanol, methylcyclohexanols or others, including derivatives of hydrogenated naphthols.

Alkyl substituted aromatic hydroxyl compounds may also be obtained from acyl-substituted aromatic hydroxyl compounds by reducing in known manner only the keto group.

The acylaromatic hydroxyl compounds, which may be used as starting materials, may be prepared by esterifying the appropriate carboxylic acids or their derivatives with the aromatic hydroxyl compounds and then treating these esters with aluminum chloride, whereby they undergo molecular rearrangement to the corresponding ketones.

The hydroaromatic hydroxyl compounds substituted in the nucleus by at least one hydrocarbon radicalQwhich may also be,used as starting materials, may easily be obtained according to known methods, for instance, by the catalytichydrogenation of the corresponding aromatic hydroxyl compounds in the presence of a hydrogenation catalyst.

As examples of alkylene oxides or equivalents which are brought into reaction with the substituted isocyclic hydroxyl-compounds, the following may be mentioned: ethylene oxide, 1:2-propylene oxide, 1:2- or 2:3-butylene oxide, butadiene dioxide, cyclohexene oxide, glycidol, epichlorhydrin, beta methyl glycidol, beta methyl epichlorhydrin, isobutylene oxide, or the like.

The glycol and polyglycol ethers of the type referred to are products of comparatively recent commercial development; in other words, having found application during the last decade. Many are produced in a form that is water-insoluble or only shows a slight tendency towards water solubility. In other words, the products so obtained are used as readily emulsifiable oils, and some will produce a more or less stable emulsion with water.

Solubilities depend upon the alkylene oxide used and the length of the chain formed in relationship to the orignial water-insoluble parent ma- I terial. It is to be noted, however, that the type employed for the present purpose is limited to the water-soluble surface-active type. Such types are readily available from the water-insoluble and partially water-soluble type by the introduction of a longer ether chain. Furthermore, it has been found possible to develop certain types of compounds which represent distinctly new species. For this reason, it would appear desirable to indicate the range of suitable material by reference to a number of examples.

Example 1 Iso-octylphenol is treated with approximately b-lO moles of ethylene oxide (or a slightly additional amount, if need be), so as to produce a water-soluble surface-active iso-octylphenyl polyglycol ether.

Example 2 Isododecylphenol or a closely allied homologue may be employed. Such materials. can be obtained in various manners, for instance, by condensing phenol with a mixture of the polymerization products with propylene or propylene-containing gases, which consist mostly of unsaturated hydrocarbons havingtwelve carbon atoms. Similarly, one may treat phenol with isododecylchloride in the presence of aluminum chloride or a catalyst of similar action. Such material, i. e., dodecylphenol, may be treated in the manner in dicated in Example 1, or may be treated in the following manner:

To approximately 260 parts of the alkylated phenol (isododecylphenol) there is added one part of sodium methylate. Thereupon ethylene oxide is introduced at 140460 0., until the increase in weight amounts to 570 parts. The isododecylchloride can be prepared in any manner, but is most suitably prepared by the monochlorination of the light oil traction, consisting essentially of hydrocarbons having 12 carbon atoms.

Example 3 A kerosene fraction distilling between substantially 160 C. and 245 C. and consisting of paraffinic hydrocarbons, the major proportion of which is selected from the group consisting of decane,

undecane, dodecanc, and tridecane, is subjected to a monochlorination process. The alkyl chlorides so obtained are employed in the same manner as isododecylchloride was employed in the previous example, but in any event, sufficient oxide is employed to yield a water-soluble surface active product.

Example 4 250 parts of an alkylated cresol mixture, which is. obtained by causing crude cresol (containing Gil ortho-, metaand paracresol) to react with the moncchlorination products of a middle oil fracstrength and condensed with 600 parts of ethylene oxide.

Example 5 7 Example 6 358 parts of a compound of the formula:

wherein R. stands for the acyl radical of oleic acid, are mixed with 3 parts of sodium ethylate and the mixture is heated in an iron pressure vessel with 300 parts of ethylene oxide to -100 C.; the temperature is maintained until the originally existing pressure has disappeared. Thereupon, this treatment is repeated, using each time 300 parts of ethylene oxide until in all 1100 parts of ethylene oxide are absorbed.

Example 7 A product of similar action is obtained, by causing, according to one of the methods described in the preceding examples, about 700 parts of ethylene oxide to'act upon 2'76 parts'of a compound of the formula CuH22CO.CcH4.0H (undecyl-para-hydroxy-phenyl-ketone) Example 8 150 parts of lsobutylphenol are mixed with 15 parts of a solution of 10 per cent strength of sodium methylate in methyl alcohol, the mixture is heated to C.- C., and the methyl alcohol is removed under reduced pressure while stirring; thereupon, 260 parts of ethylene oxide are introduced at C. C., with the absorption of the'oxide.

Example 9 600 parts of crude decylphenol (obtained by condensation of crude decyl chloride and phenol) are subjected with addition of 20 parts of caustic soda solution of 46 B. at 120140 C. for about 15 hours to reaction with ethylene oxide gas until 1320 parts of ethylene oxide are absorbed.

Example 10 Example 11 290 parts of an alkylphenol (which is regarded as consisting mainly of tetradecylphenol, and is obtainable by first introducing 3 parts of boron fluoride into 280 parts of molten phenol and then introducing at 25-30 C. 588 parts of an olefine having a boiling point of 212-21'7 C. and consisting mainly of the hydrocarbon C14H28 and subsequently stirring for about two hours at the same temperature) are mixed with 2.5 parts of caustic soda solution of 40 B. The whole is heated to 130 C. and 528 parts of ethylene oxide are then introduced.

Example 12 Into 288 parts of an alkylphenol, which is ob tained by adding 940 parts ofmolten phenol to polymerizing olefines with six or seven carbon atoms obtainable from the corresponding alcohols in the catalytic reduction of carbon monoxide.

' Example 13 439 parts of an alkylnaphthoi containing as substituent a radical of about 21 carbon atoms, obtainable by condensing with naphthol a trimeric isoheptylene obtained by dehydrating and polymerizing the alcohols produced in the catalytic reduction of carbon monoxide, are mixed with 1 part of powdered caustic potash and the mixture is heated under reduced pressure to a temperature of Bil- C., in order to eliminate the water formed. Then 1100 parts of ethylene oxide are, introduced at Mil- 0.

Example 14 206 parts of iso-octylphenol, prepared by condensing di-isobutylene with phenol in, thepresence of boron fluoride, are mixed with 0.7 part of powdered caustic soda and heated to 120-130 C. under reduced pressure until the product is anhydrous. 1:2-propylene oxide is then introduced at a temperature between 160180 C. un-

til 1810 parts have been absorbed.

Example 15 Example 16 V v 182 parts v of p-cyclohexylcyclohexanol are mixed with 1.8 parts 'of caustic soda solution of 40 B. The mixtureis heated to 140-160and 1:2-propy1ene oxide is then introduced until parts have been absorbed. A bright water-insoluble oil is obtained.

In order to render the product soluble in water, 356-parts of the oily polyether are converted into the alcoholate with the equivalent amount of sodium in xylene. The suspension of the alcoholate is then heated to boiling, while stirring, with 150 parts of sodium chloracetate. After removing the solvent there remains a solid product which contains the sodium salt of the cyclohexyltripropylene glycol hydroxy acetic acid. The oil can also be solubilized by treatment with an additional amount of ethylene oxide.

Example 17 222 parts of iso-octylresorcinol are caused to react, according to one of the above processes, with about 530 parts of ethylene oxide.

Example 18 262 parts of tri-isobutylphenol CLEO-- are treated with 420 parts of ethylene oxide according to one of the methods above described.

Example 19 parts of p-caproylphenol-(p-hydroxy-caprophenone) oimonmo oOon prepared by condensation of caproic acid chlo- I ride and phenol in the presence of AlCla, are

dissolved in an alcoholic caustic potash solution containing the equivalent amount of caustic potash, and the whole is caused to react with 225 parts of ethylene oxide in the manner pre-- number of aryl fatty acids used for various puretc. Reference isalso made to U. S. Patent No. 2

2,144,324, dated January 17, 1939, to Bowles and Kaplan. The procedure there employed may be used in connection with hydroxybenzyl chloride or the like.

Another procedure, andin some respects, the simplest procedure for the manufacture of hydroxy aryl fatty acids, is described in U. S. Patent No. 2,026,217, dated December 31, 1935, to De Groote and Keiser. In methods employing a Freidel-Crafts reaction, one is not limited to ordinary. fatty acids, but may employ acids such as butyric acid, pentanoic acid, heptoic acid, octanoic acid, decanoic acid, and the like. Some of these, acids, containing either straight or branched chains, are obtained by the oxidation of paraflin and are available in the open market. These acids are generally saturated, but the products derived by monochlorin'at ion can be reacted with phenolic bodies, or even with hydroxy hydroaromatic bodies by the Freidel-Crafts or similar reactions, to' give suitable products for subsequent treatment with alkylene oxides, particularly ethylene oxide, in the manner previously indicated.

Example 21 1 mole of resorcinol is etherized with 1 mole of octyl or octadecyl alcohol. The ether thus derived, i. e., the one obtained by means of octadecyl alcohol, is treated in the manner previously indicated with ethylene oxide to give a suitable water-soluble product.

Example 22 Butylated phenyl phenol is treated in the manner previously suggested with ethylene oxide to give a water-soluble product.

Example 23 Phenolic bodies of the kind described in U. S. Patent No. 2,086,216, dated July 6, 1937, to De Groote, are employed for treatment withan alkylene oxide such as ethylene oxide. Such materials include hexadecyl phenol, palmityl phenol, catyl phenol, capryl phenol, and other phenolic derivatives of waxes having, in some instances, as many as 32 carbon atoms in the alkyl side chain, or in the acyl radical attached to the aromatic nucleus. It is to be noted that treatment with ethylene oxide need not be limited to any single compound; but if, desired, a mixture of suitable hydroxy hydroaromatics or phenolic bodies may be treated. This applies not only to the present example, but to all the examples previously mentioned and the next succeeding example.

' Example 24 Two moles of amyl phenol are reacted with one mole of acetone to produce bis-amylphenylol (2,2) propane. The above product is treated with approximately 15-20 moles of ethylene oxide in the manner previously indicated to give a water-soluble surface-active material.

Example 25 Various substituted phenols above described,

particularly alkylated phenols, which are indi-.

equally suitable compounds.

It happens that there are known a iew alicyclic Q derivatives which are in essence analogs of substituted hydroaromatlc alcohols, but instead of being derivatives of cyclohexanol, are derivatives of cyclobutanol and hydro-cycloheptanol, as, for example, 2-octyl-cycloheptanol-1 and comparable alkylated cyclobutanols. Such materials are water-insoluble and can be solubilized with ethylene oxide or the like so as to result in surfaceactive material which may be employed in the present process. For the sake of simplicity, it is understood in the hereto attached claims that the expression hydroaromatic is employed in its conventional meaning, whereas, the expression cyclo-aliphatic is employed in a restricted sense and is intended to include the adjacent cyclic bodies of the kind just mentioned, to wit,

the derivatives of cyclobutanol and cyclohepta' n01 as well as the hydroaromatic type. In some instances, these compounds appear as minor constituents in naphthenyl alcohols derived by the reduction of esters, which, in turn, are derived from naphthenic acids which occur naturally in various crude oils.

Attention is directed to the fact that in certain instances an alkyl side chain may in essence be a modification in which there is an oxygen atom attached to a carbon atom as a derivative of a ketone; for example, as a reaction product de rived from phenol and mono-chloropropyl ketone; and one may also note obvious instances in which the hydrocarbon chain is interrupted at least once by an oxygen atom. The introdiic tion of a ketone residue, that is, a ketone radical derived hypothetically by the removal of a hydrogen atom, is in essence an acylalkyl radical, as is readily apparent from examination of its structure. More broadly, as when derived from an aromatic ketone, or an alicyclic or an aralkyl ketone, (where the hydrogen atom is removed from the alkyl portion) the radical may be considered as an acylhydrocarbon radical. Sometimes such radicals are referred to as ketonyl compared with acetonyl. However, an arcmatic or hydroaromatic hydroxy compound having a long alkyl chain, even though such alkyl chain is interrupted at least once by an oxygen atom, is still perfectly satisfactory, provided that (a) such phenolic body or al.0holic body is water-insoluble prior to treatment with alkylene oxide; and (b) it becomes water-soluble upon treatment with an alkylene oxide or the equiva lent. It should be noted that although the treatment with an alkylene oxide or its equivalent is necessary in all instances to produce water-solubility, yet excessive treatment should be avoided, in that the compound may become extremely hydrophile. Generally speaking, it is safe to treat the water-insoluble product with ethylene oxide so as to increase its weight not less than and not more than 250%, or possibly 300% in some cases. Such procedure is generally a satisfactory guide; and if some other alkylene oxide is employed, for instance, propylene oxide, then of course an increased amount of alkylene oxide must be employed, based on the increased molecular weight of propylene oxide and the like, and also based on the fact that its solubilizing effect per mole is somewhat less than that of ethylene oxide. If too great an amount of ethylene oxide is used, the resultant compound loses its surface activity. Generally speaking, 8-15 moles of the alkylene oxides or the equivalent per mole of isocyclic compounds, represent an upper limit.

Another convenient guide is that for each carbon atom present in the original water-insoluble material, one must add one-half molecular proportions of the alkylene oxide, if ethylene oxide is used, and possibly a greater amount if an alkylene oxide of higher molecular weight is employed. An oxide such as benzyl ethylene oxide may be employed where the original raw material is almost on the verge of being water-soluble per se. It also must be remembered that 'the solubility of the product obtained varies somewhat with the method of manufacture and the particular catalyst which is present. It has previously been stated that this is one of the reasons that the exact composition of the compounds cannot be indicated as satisfactorily as might be desired in all instances. If solubility is not obtained with any other alkylene oxide, then ethylene oxide should be employed, because it appears to be best suited, for the reason that it reacts most readily, and because it promotes water solubility to a greater degree than other alkylene oxides or the equivalent. Glycidol, of course, or a similar type of compound is just as satisfactory as ethylene oxide. In any event,

water solubility can always be obtained, and the range of surfaceeactivity is such that there is no difficulty in stopping short of the point where surface-activity would disappear, due to the presence of unusually excessive hydrophile properties. Oxygen atoms, if present in the parent material (in addition to the required hydroxyl radical or radicals) increases water solubility. If the product becomes water-soluble too easily (1. e., shows insumcient surface-activity) repeat the procedure, but use an alkylene oxide of higher molecular weight.

It may be well to emphasize what has been said previously in regard to surface-activity of the water-soluble compound. If a dilution of the water-soluble reaction product of 1 part in 3,000, or 1 part in 5,000, or 20,000, no longer shows any decrease in the surface tension of the resulting solution, as compared with the raw water from which it was prepared, then one has'obtained a water-soluble product from the parent waterinsoluble product; but surface-activity has been destroyed, due to the introduction of an extremely hydrophilic property. Needless to say, suchproduct should be removed and the changes made in the introduction of the alkylene oxide along the lines previously indicated so as to obtain a product that is water-soluble and also surfaceactive. In order that it be understood that such extremely hydrophilic compounds are not contemplated for use in the present process, it will be noted that the hereto appended claims are limited to the surface-active type.

Another point which must beborne in mind is that the products, in addition to being watersoluble and surface-active, must be resistant to soluble alkaline earth salts, such as soluble calcium and magnesium salts. It sometimes happens that the compound obtained by treatment with the alkylene oxide is water-soluble and surface-active, but not resistant to calcium and magnesium salts, i. e., the alkaline earth salts.

even with a sulfonic acid; and such derivatives may be employed. In such instances it is to be I equivalent is a non-functional constituent.

noted that the carboxyl group or sulfonic group .is not a functional group in the sense that it particularly adds or detracts from the solubility of the compound, but may'yield the product which has some other desirable property. Usual- 1y, however, the introduction of an acyl radical will tend to increase the water solubility, but is apt to decrease the resistance to soluble calcium and magnesium salts, unless the acyl radical can also be subjected to similar etherization. Similarly, the hydroxyl radical may be removed, if desired, by an etherization process. One reaction which may be employed is concerned with the use of a material such as methyl sulfate or the like.

Acyl groups, such as sulphonic groups, may beintroduced directly into the cyclic nucleus. Then again, the presence of a halogen atom or possibly a sulfonic group, would not be objectionable; but it is unnecessary and as a rule, means only possible increased complexity of reaction and perhaps an undue added cost. If one desired, one might start with a chlorinated phenol; but in this instance also the chlorine atom or its All such conventional variants are well known.

For practical purposes our preference is to use ethylene oxide, rather than any other alkylene oxide, because it is cheaper, has lower molecular weight, and appears to be more reactive. It is also our preference to use isocyclic hydroxy compounds free from atoms or radicals of the kind which have just been described. It is alsov our preference to obtain water-solubility, surfaceactivity, and resistance to calcium and magnesium salts, by means of the alkylene oxide only, preferably ethylene oxide or glycidol, and not to obtain these properties by the introduction of some radical, such as a carboxyl radical or sulfonic acid radical.

Our preferred water-insoluble raw material is a monocyclic phenol in which there is present at least one allwl constituent containing at least six carbon atoms and not more than 18 carbon atoms, such as octyl phenol or octadecyl phenol. "It is understood, in view of what has been said, that a large class of the materials contemplated may be referred to as glycol, or preferably, polyglycol ethers of water-insoluble substituted isocyclic hydroxyl compounds of the kind described, i. e., contain substituted isocyclic nuclei of the kind previously discussed, and which are characterized by also containing the group kylene oxides may react with'hydrogen atoms linked to oxygen as in an ordinary high molecular weight aliphatic alcohol; or such oxides may react with a hydrogen atom linked to an amido or amino nitrogen atom. If such other reactive hydrogen atoms are present, then in that event it is obvious that one may obtain a solubilizing.

effect, due in part, to the presence of such other reactive groups. For sake of simplicity, it is to be noted that compounds so obtained, i. e., by

virtue of the presence of such other radicals, are contemplated for the same 'purpose, i. e., the

flooding of subterranean oil sands or strata, in our co-penciing applications Serial Nos. 322,535

' and 322,536 and filed March 6, 1940.

More specifically then, our preferred flooding agent, treating agent or addition agent, is prepared by treating a monocyclic alkylated phenol having at least one alkyl group, and not more scribed. As a. specific example of this preferred type, we prefer to treat octyl phenol, preferably having a normal octyl group, although a branched octyl group or a mixture may be employed, with ethylene oxide until one has'obtained an increase in weight equivalent to approximately -l75'%.

With the normal octyl phenol, our preference is to use ethylene oxide until an increase in weight is approximately In any event, the finished product must be soluble in presence of soluble calcium and magnesium salts; and if it is not soluble, a new batch must be prepared employing an increased amount of ethylene oxide, as previously indicated. Compare with Example labove.

In practising or carrying out our process, the flooding of the subterranean sands or strata is effected in the conventional'manner, except that in our process the flooding water has added to same, a treating agent or chemical'compound of the kind previously described. The amount of said treating agent or compound added to the flooding water, is generally relatively small, varying from approximately 1-10,000, to approximately 1100,000, and in some instances even less. In some particular cases, where the Water employed has an extremely high salinity, and where the oil to be recovered is particularly valuable, one might use a concentration as high as 1-5,000; .but such concentration represents an unusual condition and one which would be ordinarily uneconomical. In fact, in the majority of cases a ratio of 140,000 to 1-80,000 represents a limit which gives both a valuable flooding vehicle and a cost that is economically feasible. As has been previously pointed out, the actual flooding procedure may involve the repeated uses ofthe same flooding }-.vehicle, and after the addition of the initial treating agent, it may be necessary to add small amounts of said treating agent from time to time to keep the effectiveness of the flooding vehicle at a predetermined standard of effectiveness.

It is understood that in the hereto appended claims, reference to an alkylene oxide broadly or a specific member as ethylene oxide, is intended to include obvious functional equivalents of the kind referred to, to wit, halohydrins, glycidol, epichlorhydrin, and the like. It is also understood that reference in the appended claims to substituted isocyclic compounds containing substituents of the kind described may, of course, contain other substituent atoms or radicals, or may contain more than one of the required type of the substituent radical.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A flooding process for recovering oil from subterranean sands and other oil-bearing strata, which consists in flooding the oleiferous structure with an aqueous treating solution, comprising a water-soluble, surface-active, alkaline earth-resistant polyglycol ether, which is derived by reacting an alkylene oxide with a member of the class consisting of water-insoluble substituted aromatic and hydroaromatic compounds containing at least one hydroxyl radical attached to a nuclear carbon atom, and a least one nuclear substituent selected from the class consisting of a hydrocarbon radical containing at least four carbon atoms; a ketonyl radical containing at least four carbon atoms; a sat fitufed hydrocarbon radical containing at least four carbon atoms and interrupted-at least once by an oxygen atom; an acyl radical containing at least four carbon atoms; and an oxy-alkyl radical forming an ether linkage with a nuclear carbon atom, the alkyl part of such oxy-alkyl radical containing at least four carbon atoms.

2. A flooding process for recovering oil from subterranean sands and other oil-bearing strata, which consists in flooding the oleiferous structure with an aqueous treating solution, comprising a water-soluble, surface-active, alkaline earth-resistant polyglycol ether. which is derived by reacting an alkylene oxide with a water-insoluble substituted phenol having at least one nuclear substituted alkyl radical containing at least four carbon atoms.

3. A flooding process for recovering oil from subterranean sands and other oil-bearing strata, which consists in flooding the oleiferous structure with an aqueous treating solution; comprising a sistant polyglycol ether, which is derived by reacting an alkylene oxide with a, water-insoluble monocyclic phenol having at least one nuclear substituted alkyl radical containing at least six carbon atoms.

4. A flooding process for recovering oil from subterranean sands and other oil-bearing strata, which consists in flooding the oleiferous structure with an aqueous treating solution, comprising a water-soluble, surface-active, alkaline earth-resistant polyglycol ether, which is derived by reacting an alkylene oxide with a water-insoluble monocyclic phenol having at least one nuclear substituted alkyl radical containing at least six carbon atoms and not more than -18 carbon atoms.

5. A flooding process for recovering oil from subterranean sands and other oil-bearing strata, which consists in flooding the oleiferous structure with an aqueous treating solution, comprising a water-soluble, surface-active, alkaline earth-resistant polyglycol ether, which is derived by reacting an alkylene oxide having at least two car-.

bon atoms and not less than four carbon atoms, with a water-insoluble monocyclic phenol having at least one nuclear substituted alkyl radical containing at least six carbon atoms and not more than 18 carbon atoms.

6. A flooding process for recovering oil from subterranean sands and other oil-bearing strata, which consists in flooding the oleiferous structure with an aqueous treating solution, comprising a water-soluble, surface-active, alkaline earth-resistant polyglycol ether, which is derived by, reacting ethylene oxide with a water-insoluble monocyclic phenol having at least one nuclear substituted alkyl radical containing at least six carbon atoms and not more than 18 carbon atoms.

7. A flooding process for recovering oil from subterranean sands and other oil-bearing" strata, which consists in flooding the oleiferous structure with an aqueous treating solution, comprising a water-soluble, surface-active, alkaline earth-resistant polyglycol ether, which is derivedby reacting ethylene oxide with a water-insoluble monocyclic phenol having at least one nuclear substituted alkyl radical containing at least six carbon atoms and not more than 18 carbon atoms; and said ether being further characterized by the factthat the increase inweight obtained by reaction of ethylene oxide with the'phenolic body is within the range of 80% to 150%, based on the original weight of the phenolic body.

8. A flooding process for recovering oil from subterranean sands and other oil-bearing strata, which consists in flooding the oleiferous structure with an aqueous treating solution, comprising a water-soluble, surface-active, alkaline earth-resistant poiyglycol ether, which is derived by reacting ethylene oxide with a water-insoluble monocyclic phenol having at least one nuclear substituted alkyl radical containing at least six carbon atoms and not more than 8 carbon atoms; and said ether being further characterized by the fact that the increase in weight obtained by reaction of ethylene oxide with the phenolic body is within the range of 80% to 150%, based on the original weight of the phenolic body.

9.. A flooding process for recovering oil .from subterranean sands and other oil-bearing strata, which consists in flooding the oleiferous structure with an aqueous treating solution, comprising a water-soluble, surface-active, alkaline earth-rewater-soluble, surface-active, alkaline earth-resistant polyglycol ether,'which is derived by reacting ethylene oxide with a water-insoluble monocyclic phenol having at least one nuclear substituted alkyl radical containing at least six carbon atoms and not more than eight carbon atoms; and said ethen being further characterized by the fact that the increase in weight obtained by reaction of ethylene oxide with the phenolic body is within the range of 80% to 150%, based on the original weight 'of the phenolic body; said increase being obtained by the introduction of at least three and not more than six moles of ethylene oxide for each mole of phenolic raw material. I

10. A flooding process for recovering oil from subterranean sands and other oil-bearing strata, which consists in flooding the oleiferous structure with an aqueous treating solution, comprising a water-soluble, surface-active, alkaline earth-resistant polyglycol ether, which is derived by reacting ethylene oxide with octyl phenol so as to introduce at least three moles of'ethylene oxide and not more than five moles of ethylene oxide for each mole of phenolic raw material employed. m

MELVIN DE GROOTE. IBERNHARD KEISER.