CA1077700A - Alkyl glyceryl ether sulfonate salts in oil recovery - Google Patents

Abstract

AGENT FOR OIL RECOVERY AND PROCESS OF RECOVERY

Abstract New compositions comprising salts of alkyl glyceryl sulfonates are found to be effective surfactants for use in the recovery of oil from subterranean geologic formations.
The materials can be employed in aqueous displacement brines, quite effectively in conjunction with other surfactant materials of known type, and they exhibit high stability against hydrolytic degradation frequently encountered with prior art materials in the presence of salt and alkaline earth metal ions as usually encountered in aqueous brines as used in the field.

Description

Case 4243/4243-A
Canada 777~) This invention relates to the use of new surfactant salts useful to enhance the recovery of oil from oil-bearing formations.

_scrip tiOIl of the Prior Art The prior art in the field of oil recovery by displacement involves the use of various surfactants, singly or in combination. Such art is typified, for example, by U. S. Patents 3,308,068; 3,508,612; 3,527 ? ~01; 3,714,062;
3,777,818; 3,782,472; 3,g27,497. The references cited in such patents are also, of course, of interest. Although numerous surfactant and auxiliary materials are known, it is also known that the effectiveness and longevity of various materials depend upon numerous factors such as temperature, and the fortuitous or planned presence or absence of salt and of metal ions contributed by the formation, or otherwise.
The compositions disclosed in U. S. Patent 3,827,~97 have limitations in regard to temperature since they are based on or include the salts of sulfated oxyalkylated alcohol.
Salts which contain the C-0-S linkage are known to be hydrolytically unstable at elevated temperatures. Sulfonates of 3,827,497 are ethyl sulfonates which are difficult to produce.
Summary of the Invention In accordance with the teachings of the present invention, improved surfactant salt compositions, aqueous compositions of such salts, and methods of using such in oil recovery are disclosed. Salts of sulfated oxyalkylated alcohol are avoided. By the use of the alkyl gl-yceryl ether sulfonate salts of the present application, based on 2-10 mol ethyoxylates of alcohols having from about 8 to about 20 carbon atoms per molec~le? typically as produced by reacting from about 1 to about 2 mols of epichlorohyd:rin per mol of alcohol and Streckerization with alkali metal sulfite, 77(3~
compositions are provided which are easily produced and which have inherently improved hydrolyti.c stability at elevated temperatures especially in comparison to sulfated ethoxylated alcohols. As a result, the present compositions are more resistant to hydrolysis during the prolonged time the oil recovery surfactant compositions are required to be in the ground in contact with brine and alkaline earth metal ions. This property is of particular value in situations where the oil-bearing formations are located comparatively deep within the earth's crust.
Although useful in other ways, the compositions of the present invention are especially useful in ternary com-bination with polyalkylene glycol alkyl ethers and a surfactant salt of an organic sulfonate such as those described in U. S.
Patent 3,827,497. On the other hand, the surfactant compositions are useful in aqueous solutions in general and have utility per se, especially for purposes of making aqueous solutions.
Compositions in accordance with the present inven-tion are alkyl glyceryl ether sulfonate salts. Such salts consist essentially of compositions represented by the formula RO(CH2CH2O)n(CH2CHOHCH2SO3M)m where R is alkyl having from about 8 to about 20 carbon atoms as determined by starting alcohol subjected to alkoxylation, n is from about 2 to about 10, as determined by the mole ratio of alkylene oxide reacted with the starting alcohol, m is from about 1 to about 2 as determined by the ratio of epichlorohydrin reacted with the alkoxylated alcohol and M is selected from the group consisting of alkali metal, amine and ammonium. Preferably ~ has from ~, æ
about 12 to about 16 carbon atoms. Pre~erably n is from ~ to about 6. Preferably M is sodium. Preferably the salt consists eSsentially of Cl2-l6H25-33o(cH2cH2o)3(cH2cHoHcH2so3Na)l 2.

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The foregoing salt compositions are in general used in aqueous media so that other preferred compositions are aqueous solutions of the foregoing alkyl glyceryl ether sulfonate salts.
The present invention also is directed to an improved process for recovering oil from a subterranean oil-bearing formation wherein the improvement consists in using the foregoing alkyl glyceryl ether sulfonate salts.
In another aspect, the present invention relates to a method of recovering oil from a subterranean oil-bearing ~77~
formation which comprises A - injecting into the formation a ~aline ~olution cOntA~ning a mixture O~ the following oomponents:
(a) from 0.5 to 15 perc~nt by weight ba~ed on ~aid eolution of a ~urfactant ~alt of an organic Rulfonate, tb) ~rom 0.25 to 10 percent by weight based on sald solution o a polyalkylene glycol alkyl ether~ and ~c) frnm 0.25 to 10 percent by weiyht ba~ed on said ~olution of alkyl gl~c~ryl ether ~alt of ~he formula RO(C112CEI~O)n(CH~CHOE~ÇH2SO3M)m whexein R i~ alkyl having rom about 8 to about 20 carbon atom~, n is from about 2 to abou~
10, m i~ fro~ abou~ 1 to about 2, and M is selected from th~
group consi~ting of alkali metal, am~ne and ammonlum and ~loodlng the foxmation with a salln~ ~olution to effect oil recovery therefrom. Preferably, Component a is ~n alk~li metal salt of a petroleum ~ulfonate~ Component b i~ die~hylene glycol hexyl lS ~ther and Component c i9 an alkali metAl salt. Pre~erabl~, the amount~ of Compon~nt~ a, b and c are, respectively, 2~10 p~rcent, 1-8 p~rcent and l-B percent by welght. Preferably, Componen~ a is an alkali metal salt of a petroleum ~ulfonate, Component b is a diethylene ~lycol hexyl ether and Compon~nt c 1~ an alkali me~al salt, the amount~ of Component6 a, b and c, respectively, belng 2-10 percent, 1-~ perc~nt and 1-8 ~)ercent by ~eicJht. Preferably, the ~aline s~lution in St2p B contain~ a pol~mer to lmprove the mobility th~reof, ~uch polymer ~referably being a poly~aacharide~
~5 Th~ compo~itions o~ the pre~ent proce~s can be used in combination with sul~onated oxyalkylated alcohol such as that descr~bed in ~. S. Patent 3,827,497 a~ an extender in situations where the utmo~t stability again~t hydroly3is i9 not xequired for th~ entir2 p~riod of wat~r floodin~ operation. Thus in some ln3t~nce~ it may be desired to include sulfated or sulona~d 777~
oxy~lkylat~d alc:ohol ~al ln t:he px~en~ c:ompositlon~ with th~ -exp~ct~tion t:hat as th~ ~ur~ctnnt ~alt cont:alning ~y~tem pro~re~s throu~h th~ ~or~nat~on, normally ~ecoming mor~ dilute du~ to the combina~ion with w~t~r or brlne pre~nt in the S formation it~3lf, that a progr~E;siv~ timew~f;e deterioratlon o~
the le~8 ~cabl~ nalt o~ ~ulfated or 6ulfonated oxy~lkyl~ted alcohol can pxoduce A pref~rred c>~r~rall proce~, e~p~cially in ~he pxe~nc~ of certaln alkD.l~ mQtal ion.s ~uch a~ calc:ium or magne~um ion~.
lû Brief Descx~ ption o~ ~
The f igur~3~ o~ the drawlny ~how 8ta]~ y Ch~lrclCter-l~tics ~or v~riou~ compo~ltions ~ambodying the features of the pre~en~ invention as well ~s ~or comp~rat:ive compo~ition~ to ~how th~ ~uperiorlty o~ th~ p~e~ent compo~ition~ over pr~or art.
Fig. 1 shown the stability charact~ristics of composltion~ u~ilixing the ~alt C12-16~25-33 (CH2C~o) 3 (Cl~ ~C~OHCli2S03k~a) 1 ;i!
at 75F.
Fig~ 2 shows tll~ stability prop~rties of th~ salt of Fig. 1 at the tempexatu~e o 15ûP.
Fi51o 3 show~ the unsatl~factory ~tability pr~p~rtieG
o~ ~h~s comyaratiY~ ~alt cl2-l6H;~s-33o~c~I2c~o~cH2so3~Ja) 1 ;~
at 75~F~, FigO 4 show~ th~ tisEactory ~tability `propertie~
~S of th~ compos~tion of FigO 3 at 150~Fc Pigs. 5~1~ show th~ ~tabi~lty prop~r~ie~ of thQ
~salt of Fig. 1 at 7S~F and 150~F with thx~e additional petroleum ~ulfonate~D
E~lgs. 11 ~nd 12 ~how th~ ~t~bility prop~rt~e~l of the @D
crud~ ~alt oE P'ig.-1 s~rith P~ro~tep 4S0 ~t~75CF a~d 150F~
re~pactl~ely.
In the formulae of compounds identified in Figs. 1 to 12, E represents CH2CH2~ and G represents ~CH2CHOHCH2-.

5 o ~C~777~
Descri ~ n of the Preferr _ Em odiments The preerred alkyl ~lyceryl ether sulfonate sur-factant salts oE the present invention are representad by the formula RO(C~12CH20)n(CH2C~IO~ICH2SO3M)m wherein R is alkyl having from about 8 to about 20 carbon atoms, n is from about 2 to about 10, m is from about 1 to about 2, and M is selected from the group consisting of alkali metal, amine and ammonium. It is noteworthy that this composition contains only C-C linkages, C-0-C linkages and C-S-0 linkages in the fundamental skeleton thereof. Notably absent from these compositions are the known unstable ester linkage ~-0-C and the C-0-S linkage of sulfated oxyalkylated alcohol. It is seen therefore that the compositions of the present invention are characteri2ed by the absence oE the usual linkages known to be hydrolytically unstable at elevated temperatures and by the presence in the molecule oE the glyceryl sulfonate group -CH2CHOHCH2SO3M. An outstanding advantage of such structures is that they are readily prepared by reaction or an oxyalkylated alcohol with epichlorohydrin followed by sulfo-nation with alkali metal sulfite.
In general, the salts of the ~resent invention are used in aqueous solutions so as to facilitate the introduction thereof into oil-bearing formations in the earth. Typical solutions contain from about 0.005 wt. percent to about a saturation amount of the preferred salt in water; however, these concentrations may vary depending upon the method chosen for making the solutions and introducing them into the Eormation.
Solutions may be introduced into the formation separately for ~ach individual solute or in combinations such as with sur~actant salts of organic sulfonates and of polyalkylene glycol alkyl ethers, such ternary systems in water frequently ;
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7770~
being e~pccially yref~rxed ~or inj~ction. Such ~y~t~m~ can ~: be u~ed wl~ mor~ or lc~ pure wat~x or with w~t.e~ whlch contalns alkali m~l halide such a~ ~odlum chlorid~ in solutions vl~., br~ne, ~ w~ll as with water cont~ining S ~lkaline earth m~tal ion~, ~ith~r with or without th~ alkali ~etal hali~e o~ the brine. A preferred procle~6 then ln accordanc~ with the pxe~nt lnv~ntlon ~nvolve6 th~ recovery of oil from a subterranQan oil-be~ring formation by lnjecting into the formation a sallne solution containing the alkyl glyceryl ether sulfonate salt of th~ pre~ent invention, a surfactant ~al~ o~ an organic ~ulfonate and a polyalkylen~
~lyc(~l alkyl ether and then 100ding the formation with a.n aqueou3 medium to ~fec~ o~l recover~ therefrom. Preerred ~loodlng ~queous med~um ~s ~x~qu~ntly a brine or s~line PS solution ~o minimize costs lnherent in obtainin~ non-~al~ne a~ueous solutlons in the flold.
The organic sul~onate components useful in connection with the pre~ent inve~tion are t~pically tho~e de~cribed ln U. S. Patent 3~827,497. Pr~ferabl~, sulfonates are used which are r~adily available comm~rcially such as "Bryton Chemical ~467n, "Witco Chemical TRS-10"~ Suitable sul~on~tes are u~5uall~
and pr~f~rably metal salts of alkaryl ~ulonates, preferably alkali metal ~alt6 and slkyl benzene sulfonate~ con~aininc3 12 to 30 carbo~ atom~. Sultable sulfonates al~o can be aliphatlc

2~ . eulfonat~s, alkyl~ted naphthale~ ~ulfonate~ and th~ like, the a~ntia~ re~uirement~ ~ein~ that they have ~ur~actant prop~r~i~s and avoid ~he unstabls ~ructur~s if utmost hydrolytic ~tability 18 de~lredO The cationic portion of ~uc~ ~ulfonate~ can he &mmonlum o~ amlne a~ w~ alkall metal but i~ usuall~ and preferably ~odium. Th~ molecular w~lght of thc organlc ~ul~onate * Trademark ~7- .

~7~70~
su~Eactarlt :L~ usually in the range of 30~-G00, ~ref~rably 350 525~ The~ material~ can b~3 pxepar~d by well };nown pro-cedures ~uch a~ those de~cribed ln U. S . Patent 3, 308, 0~8 . They can be prepared ~ynth~1:ically or aan be prepared from petrol~um S a:nd c:t)mmonly known as p~-~roleum sulfonates.
The polyalkylene ~lycol monoalkyl ~tll~rs are widely av~ilabl~ c:cmm~r~iall~r. The al}cylene yroup is usually ethyl~.~e but can b~ pxopylenQ or othff~r~ up to ~bout :Ei~re carbon atc~m~.
It can repeat it~;elf up to about 10 times li . ~ ~ the "poly" can 10 be up to about 1~) but u3ually r~peat~ it~el~ ~6 times, more usually twice3, e.g. diethylene. It ~hould also be understood that ~or any speci:l~ied polyalkyl~e, the nu~n~er ~? alkylene unit~ 3ither e~xactly as ~pecifi~d or varie~ but the avera~a i~ as spec~ fied. Thi~ ~ame principle applie~ also to th~3 15 alkyl group. Pre3fer~bly the glycol portion is diethylene glycol.
The alkyl group will normally aontain 2-12 carbon atom6, prefer-ably 4-10. In general th~ mo~ alkyl~ne unlts or th~ longer the alkyl~nt3 unit, the lonye:r the alkyl ~roup ~hould b~O Th~
pre:f~rred component is di~th~lene glycol llexyl ~3th~x. These 20 materials are availa~lc con~n~rcially or can be made by known procedures .
It i~ e~ldent from the foregcalng that the preferrecl c:omposition&l in accordance with the prQsent inv~ntion are tho~e chara¢terized by an alkyll glyceryl ether sulfonate structure 2~ ba~ged on a pr~rred alkoxylated alcohol ~tructure. 8ucl~ mate-ri~l~ typically are readily pr~parQd by th~3 reactton of alkoxy-late~ alcohol~ with ~3p~chlorohydr5Ln followed by a reaction with alkali ~netal sulfite. This in~roduc~s the glyceryl sul:~onat~
~tructure r~2~dlly and at good ~i~lds. Such proce~ pre~ 3rably .~0 utiliz~ ~thoxyl~ted alc ohs~ of th~ formula RO ~CR2CH;2O3 nH

~ 7 7 7 ~ ~

where n ~3 from ~bout 2 to abou~ 10 producad by reacting ~lcohol ROH w~th a~hyl~e oxlde. The ~lcohol ~o ren~d may b~
nn aliphatic alcohol having ~rom about B ~o about ~.0 carl~on atom~ per mol~cule with a rang~ of from about 12 to about 16 5 caxbon ~toms being e~pecially pr0ferred. Prefera~ly, the alcohol used 1~ predominantly a primary ~lkanol, pre~e~ably a ~ynthetic prlm~ry alcohol mixture contain.Lng up to about 50 percent o branched primary alcohol~. Other alcoholic materials c~n be used ~uch as alkyl ph~nol~ containing ~rom about 5 to about 20 carbon atoms per ~lkyl group and the liXe. ~lthou~h ethylene oxide i~ preferably reacted with the alcohol in the ratio o~ from about 2 to about 10 molecule~ ~f ethylen~ oxide per molecule of aloohol, othe.~ low~r ~lkylene oxides containing from 2 to about 6 carbon atoms are suitable; for ~xample, propylen~ oxide or butylene oxide. Typical alkoxylated alcohols u~eul in the pro~nt inv~ntion may include substit~nts such as hydrox~l or am~ne groups and the like on eithe~ ~ne alcohol molety or the oxyalkyl portion.
Alkyl glyceryl eth~r sulfonat~ prepared a~ d~scrlbed 1~ the following examples and comp~rative ~anlE~les were te~ted using the ~ollowlng procedure.
To a 4-ounce bottle wa~ added Z.5 gram.s o~ patroleum sul~onate ~Petronate L o~ Wltco Chemical Company) which 15 a petroleum sulfonate o~ 415 to 430 equivalent weigh~ range.
. Then 1 gram o~ hexanol ethoxylat~ av~raging two ethoxy group~ p~r molecul~ was addedO
Next~ 1~5 gr~ms 6active ba~ oandidate alkyl glyc~ryl ~ther ~ulonat~ composltion or comparatlv~ material was ~dd~d pre~erably a~ ~n aqu~o~ ~olutlon of 10~40 pexcent con~ntratlo~ or a~ ioo porccnt act~ve material.

09_ :

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1~777~
~ xt the appropriate amount of sodium chloride wa~
added preera~1y a~ a 10 parc~nt a~uevu~ solution to give tha de~re~ final concentratlon of salt (brine).
Similarly7 th~ appropriate amount of calcium ion wa~
adde~ pr~a~erably as a 1 pexeent ~olutlon o~ calci~n ion prep~red as cqlcium chlorlde.
The sampl~ was then adjustea to 100 ~ram~ to provide the Ae6ired concentration o~ the ~n~red.i~nts. The ~ample was then heated and ~tirr~d ~i~orou~ly in a ~ale~ ~y~m to prevent e~aporation of ~ny o the compon~nts and when di~per~ion or dissolut~on wa~ compl~te the ~amples w~re placed ~n an environment o~ the de3ired temp~rat~re:and ob~ex~ed after 24 hOUr8 or more. Obs~r~ations were made as t~ the ~t~bili~y or ln3~abll~ty o the ~ys~m. In~tab~lity in gener~l is a defini~a and ea~ily vi8ible phQ8e s~paratlon 30 that a curd of wa~er ln~vluble mate~ial ~eparate~ ~ither at the bottom or ~he top clepending on the brine conc~ntration~. Generally~ all ~lutions are opaque. Satisf~ctory condition3 ar~ stable di~p~r~ions. Rarely, clear sy~t~m~ are o~tained and indicated by "C". Tho~e which showed good re~ult3 were te~t~d further by dilution with th~ appropriat~ ~dium chloride and calc.ium ion ~olution~ at proportlon~ o 1~ 5 and l l0, and r~xa~i~ed at the indica~ed temperature~ for ~tability or in~tabillty. Sample~ we~e te~t~d with 1, 2, 3, 4 and 5 percent ~5 by w~i~ht of sodlum chlorid~ and ~it~ 200, 500, 1000 and 2000 pax~s per million o ~alcium lon. Data ar~ ~hown on the Flgur~s for the variou~ con~en~ of sodium chloride, calcium ion and ~or thQ various dllutions of 0, 1:1 with brine and calcium ion ~olution, ls2 wlth brin~ and cal~ium lon solution, etc.
~h~ f~llo~ing ~xample5 indicat~ pr~ferr~d ,embodiments and aspa~t~ of th~ pr~sent invention.
.

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~77700 EX~MPLE I

Cl2-l6H2s~33o(cH2cR2o13(cH2cHoHcil2so3N~l 2 The alkyl glyceryl ether sulfonate co~po~ition wa~
prQpared u3ing the following procedure. Separate three mol S ethoxylate~ ~avera~e) of dodecanol, tetr~decallol and hexadecanol were combined in approximately 65/25/10 weight ratlo~.
13~.1 grams of do~ecanol ~ 52.5 grams of tetrade~anol 21.4 grams of hexadecanol Th~ ~ix~ure was hea~ed to 90C, then 4 yrama of tin tetrachloride was addQd. Than 72.1 grams of eplchlorohydrin wa~
: added. The mol ratio o~ eplchlorohydrin to alkoxylated alaohol was ~.2:~. The mixture wa~ pl~cea in a separatory funnel and about S percQnt by w lum~ of ~eioni~ed water was added to de~troy ~he ca~aly~t ac~ivity.
~ 00 Grams (0.45 mol) D th~ adduct wa~ plac~d ln a 2~ er autoclave. 103 Gram~ o~ ~a~O3 ~Or817 mol) was a~ded.
20 Grams of a 50 wt. percen~ ~olution of ~aO~I wa~ adae~. 677 Grams of wat~r was added~ T~e~autoclave wa~ closad, h~a~ed to 200C, agi~at~d for 1 hour, th~n covle~l to room temperatureO
~ e re~ulting active ~lkyl ~lyceryl ethex ~ul~onate was recov~red and te~ted a~ ~escr~bed. Data obtain~d ar~
pre~en~ed in E'ig~, 1 and 2 for 75F and 150~F, respectively.
The recovery proc~dur~ ~m~oyed wa t~e following.
~5 . The cooled crude product ~rom the autoclave wa~ de-oiled by mixin~ with ~queous ethanol ~1~1 by volume o~ ethanol and water) in ~uch proportions to prori~ a ~10 w~. ~ercent of ~ulfonate in th~ mixture and then ~xtracting 4 times w~th 20 25 percent by volume o~ petrol~um ether. The ethanol WQ~
then remo~ed ~y boil1ng and isopropanol added to r~store th~

. . . ~ _ '777 1;)~

orlginal alcohol-water-crude sul~onate volume. The de-oila~
mixture was then hea ed to about 45C and enou~h ~odiu~ carbonate add~d to ~ro~ide a sy~t~m sup~r~atur~ted in ~odium carbonate.
The ~ystem was agitated and ~llow~d to ~ool to roo~ temperature.
5 q'he up~er ~i~opropanol) pha~e containin~ the active sul~onate wa~ ~parated and th~ aloohol remov~d by avapora~lon. The ~ul fona~e was th~n dri~d for ap~ro~imately 3 hour~ in a vacuum ov~n at 100C and l~s~ than 50 mm llg ab301ute pres6ure.
~XAMPLE II
(Comparative) 12 16~25-33O(cH2c~oHc~l~so3Na)l 2 This alkyl glyceryl 5ulfollate comp~rat~Y~ ~ample was prepar~d u~lng t~e procedure o~ Ex~mple I; however, alcohol was used th~t had not been pr~vlou~ly e~hoxylat~d. The comparative re3ults o~ ~ig~. 3 and 4 show the ~uperlority o~ the alkoxylated 5 composltion of the pre~ent ln~antion.
~YAMPLE~
C12-16H~5_3~O~CH2c~l2~3~cl~2~OElC~2503Na~)l 2 ~ he above al~yl glyceryl ether sulfonat~ as used in Example I wa~ tested wl~h dif~rent petrol~n sulfona~e wi~h 2~ di~fer~nt propor~ion~. In E~ample VI, the candldate ~lkyl glyceryl ~ulfonat~ was u~d dix~ctly from th~ r~ction with ~odium ~ulfite an~ NaO~I wlthou~ recov2ry.
~or each o~ th~ followlng ex~mpl~s, lnstead o~
2.S g~am~ o~ th~ petroleum ~ul~onate, ~.O grams wa~ u~ed. A~
~efore9 one gram of the hexanol eth~yl~te averaying two ethoxy group~ p~r mol~cule waB u8ed. Instead o 1.5 grams lactive ha8~3 o~ candi~at~ alkyl glyc~ryl ~th~r ~ul~onate, 1.0 gram~ wa~ used. Otherwise the procedur~ d~scrlb~d p~viously w~
~ollowed at 1, 3 and 5 percent by w~ight of ~sdi~ ohlorid~ and w~th 200, 500, 1000 And 2000 part~ pex million of calc~um ion, ~L~777~C~
the te~tlnq ~or th~ non~diluted 3ampl~ o ~x~mpl~ IV being extend~d to include 6, 8, 10 and 12 p~rcent b~ wei~llt; o~
~od~um ohlorid~ ~nd 5000 ~nd 10, 000 par~a per milli~n o~
calclum ion to shC)W how far ~ability extcn~led be~ond the ran~a~ of u~ual intere~t.
EX}UIPLE III
~) ~h~ petroleum sulfonato used was Petro~tep ~20 o~
Stepan Cll~mical Company wh~ ch i~ a 60 ps~rcent 2ctive materlal havlng 21 perc~nt frea oil, 1~ 0 5 percent water, 1. 5 perc~nt lnorganic ~alt~ and an approx~mate ~3quivalent w~ight of 420.
Dat~ are ~hown for 75F and 150F by Flg~. S and 6, re~pectively .
EX~lPL~; IV
Th~ petroleum sulfonate ufied was Petxo~tep~45n of 1~ StepaTI Chemic~l Company whlch 18 a 60 percent ~LCtiYe. material having 13 . S percent ~r~e oll, 24 . 5 percent water, 2 . O percent inor~Janlc ~a~ and an appr~Jxlma~ equ~Lralent wei~ht o~ 450.
I~ata are shown for 75F and l5ûF by Figs~ 7 and 8, re~pectively .
2 0 EXAM~L:E: V
The pe~croleum sul~onate u~Qd was ~etrostep 4~5 of St;epan Chemical Comp~ny which ls a 6û percent activ~ ma~erial ha~ g 13.1 percent fr~ oil, 23.5 p~rcent water, 3.6 p~rcen~ lnorgalllc ~alts ~nd an approximat~ equivalent weight of 465~ ~ata are ~how~ ~or 75~ ~d lSO~F by ~igs 9 ~nd 10 ~ re~p~ctlvelyO
qPLE: VI
l~xa~pl~ IV wa~ r~pea ed at 1~ 3~ æ~d 5 wt. p~rces~t Nl3Cl nd 200 ~ 500 ~ 1000 ax~d 200û par~ per m~ on of cs~lcium lo~ u~n~ th/3 crud~ ~lkyl glyceryl ~ither ~ulfonate a~ prepAr~cl ~1 .-- , ? ¦

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in Example I but ~ hout u~ing the recovPry pro~ ed~lre described in Example I. The amount o~ cxude was u~ed on a ba~ of the active content. Data ar~ ~hown ~or ~5~F and 150QF by ~iy~. 11 and 12 ~ r~spectively.
From the foreyoing, lt is evident that tlle eatures of the present invention may be employe~ in ~ariou~ w~ys. Al-though the C12_16 IYal'c compositlon i~ ~ preferred mixturl3, ~ndividu~l ~alts ~uch a8 tho~e wh~reln the alkyl yroup h~$
8, 10, 12, 14, 16, 18, 20, etc. carbon atoms may be us~3d.

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Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a process for recovering oil from a sub-terranean oil bearing formation the improvement of using a surfactant salt of the following composition RO(CH2CH2O)n(CH2CHOHCH2SO3M)m wherein R is alkyl group having from about 8 to about 20 carbon atons, n is from about 2 to about 10, m is from about 1 to about 2, and M is selected from the group consisting of alkali metal, amine and ammonium.

2. Method of recovering oil from a subterranean oil-bearing formation which comprises:
A. injecting into the formation a saline solution containing a mixture of the following components:
a. 0.5-15 percent by weight based on said solution of a surfactant salt of an organic sulfonate, b. 0.25-10 percent by weight based on said solution of a polyalkylene glycol alkyl ether and c. 0.25-10 percent by weight based on said solution of a salt of the formula RO(CH2CH2O)n(CH2CHOHCH2SO3M)m wherein R is alkyl group having from about 8 to about 20 carbon atoms, n is from about 2 to about 10, m is from about 1 to about 2, and M is selected from the group consisting of alkali metal, amine and ammonium, and B. flooding the formation with a saline solution to affect oil recovery therefrom.

3. Method according to claim 2 wherein Component (a) is an alkali metal salt of a petroleum sulfonate containing 12-30 carbon atoms and Component (b) is diethylene glycol hexyl ether and Component (c) is an alkali metal salt.

4. Method according to claim 3 wherein the amounts of Components (a), (b) and (e) respectively are 2-10 percent, 1-8 percent and 1-8 percent.

5. Method according to claim 2 wherein the amounts of Components (a), (b) and (e) respectively are 2-10 percent, 1-8 percent and 1-8 percent.

6. Method according to claim 2 wherein the saline solution in Step (B) contains a polymer to improve the mobility thereof.

7. Method according to claim 6 wherein said polymer is a polysaccharide.

8. A process in accordance with claim 1 wherein R
has from about 12 to about 16 carbon atoms.

9. A process in accordance with claim 1 wherein n is from 2 to about 6.

10. A process in accordance with claim 1 wherein M
is sodium.

11. A process in accordance with claim 1 wherein the salt is:

C12-16H25-33O(CH2CH2O)3(CH2CHOHCH2SO3Na)1.2