CA1248342A - Silicate-containing oil recovery compositions - Google Patents
Silicate-containing oil recovery compositionsInfo
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- CA1248342A CA1248342A CA000472261A CA472261A CA1248342A CA 1248342 A CA1248342 A CA 1248342A CA 000472261 A CA000472261 A CA 000472261A CA 472261 A CA472261 A CA 472261A CA 1248342 A CA1248342 A CA 1248342A
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- sulfonate
- alkali metal
- alkyl
- steam
- hydrotrope
- Prior art date
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Abstract
ABSTRACT OF THE INVENTION
There is provided herein a process and composition for the enhanced recovery of oil from subterranean formations comprising injecting in combination with steam a composition comprising (a) an anionic surfactant (b) a hydrotrope, and (c) an alkali metal silicate.
In a further embodiment, the anionic surfactant and alkali metal silicate alone may be used in 8 steam recovery process as an effective oil recovery method.
There is provided herein a process and composition for the enhanced recovery of oil from subterranean formations comprising injecting in combination with steam a composition comprising (a) an anionic surfactant (b) a hydrotrope, and (c) an alkali metal silicate.
In a further embodiment, the anionic surfactant and alkali metal silicate alone may be used in 8 steam recovery process as an effective oil recovery method.
Description
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BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention relates to novel silicate-containing oil recovery surfactant compositions and methods of using the same ln steam recovery systems to anhance the secondary and tertlary recovery of oil from subterranean formations. More particularly, these compositions comprise certain anionic surfactants, ln combination ~ith hydrotropes and alkali metal silicates, a~d methods comprising ln~ecting these compositions with steam into oil-bearing formations to greatly increase heavy oil racovery as compared with the use of surfactant-silicate compositions alone.
This invention also relates to the method of recovering oil with steam wherein a combinatlon of ~aid surfactants and sald silicates, ~ithout the hydrotrope, are employed to enhance the oil recovery.
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DESCRIPTION OF THE PRIOR ART
The use of secondary and tertiary oil recovery techniques, with or without the addition of various reagents such as surfactants9 water thickeners and the like to recover crude oil left behind in formations after the "primary" oil has been withdrawn is well establlshed in the are. These displacement methods have been improved by the addition of surfactant compositions in both secondary and tertiary processes, for example where a formation has already been waterflooded at least once.
Representative of th~se prior art compositions and methods are those taught in U.S. Patents 3,348,611 to Reisburg; 3,885,626 to Gale et al;
3,901,317 to Plummer et al; 3,994,342 to Healy et al; and 4~2953980 to Motz, all of which teach aqueous flooding technlques with at least one surfactant, and in some cases, with viscosity modifiers, co~surfactants or the like. Finally, in an unrelated field, U.S. Patent 3,501,409 teaches a liquid washing detergent composition comprising said detergent in combination with a hydrotrope.
It is also known from U.S. Patents 2,920,041; 3,805,B93; 3,871,452;
3,871,453; 3,920,074; and 4,141,416 to employe alkali metal silicates as additives in secondary and tertiary oil recovery methods which use aqueous flooding techniques. Further, it is known more recently to combine these and other silicates with surfactants in the form of micellar solutions of high or low molecular weight surfactants such as .
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alkyl aryl sulfonates, or mixtures thereof, as shown in U.~. Paeents 4,011,908 and 4,037,659. However, in the case of these latter two patents, it will be noted that the mechanism whereby micellar solutions operate in aqueous sys~ems is significantly different from those of steam recovery systems of the present invention, as described below.
In addition to the aforedescribed aqueous flooding techniques, the art has also employed steam for secondary and tertiary oil recovery, utilizing the effect of heat to obtain heavy oil from the formations in which it is found. See, for example, U.S. Patents 3,357,487 and 3,994,345. However, the mechanism and effects of surfactants and modifiers under these high temperatures and diverse formation conditions remain unclear, and thus make l~ impossible to predict from a knowledge of the effects of aqueous surfactant systems which surfactants, if any, can advantageously be employed in these steam recovery conditions. Thls is even more true in the choice of any modifiers which might enhance the effectiveness of the surfactant.
It is, therefore, an object of this invention to provide a novel silicate-containing surfactant composition useful for enhancing seeam recovery processes for secondary or tertiary recovery of heavy oil from subterranean formations.
LD/B40 ~ 4 It is a further object of this invention to provide an i~proved ~team recovery process for enhanced oil recovery, utilizing the novel compositions provided herein.
Further objects and advantages of the compositions and methods of the presen~ invention will becDme apparent in the course of the following detailed description thereof.
SUMMARY OF THE INVENTION
In ~ccordance with the present inven~ion, there is provided herein a novel ~ilicate-containing surfactant composition useful ln ~team recovery processes for the cnhanced recovery of typical heavy crude oil, said composition comprising (1) an anionlc surfactant; (2) an alkali metal silicate and (3) a h~vdrotrope, wherein the anionic surfactant is preferably selected from the group consisting of long-chain alkyl aryl sulfonates, petroleum sulfonates, and olefin sulfonates, including derivatives of said olefin sulfonates such as ether sulfonates, ethoxylated sulfonates and propoxylated sulfonates.
The hydrotrope, as described in further detail hereinbelow, is a sulfonated compound, but differing from the surfactants defined above in having considerably lower molecular weight, being extreme~
ly water soluble, having very short side chainsl and performfing poorly as a surfactant.
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In a further embodiment of this invention there i8 al80 provided a method of recoverin~ oil in steam recovery proces~es wherein there is employed a composition comprising (l) an anionic surfactant and (2) an alkali metal silicate without the added presence of a hydrotrope.
As will be evident from the examples and following description, the novel compositions of this invention comprising said anionic surfactants, silicates and a hydrotrope, when employed in a steam recovery process, or the method employing ~ust the surfactant and silicates in said steam process, exhibit unexpected benefits over what would be expected from the combined effects of steam alone, or steam and a surfactant.
As discussed further below, since a hydrotrope by definition is a compound which increases the solubility of a surfactant in water, the enhanced effect disclosed herein i6 particularly surprising because it would normally be supposed that the hydrotrope would thus increase the solubility of the surfactant in the aqueous portion of the steam, and decrease its solubility in the oil phase, ~hus rendering it less effective in oil recovery.
Moreover, apart from the mechanism of the hydrotrope, steam recovery systems themselves differ from water recovery systems in many ways.
Thus, for example, steam is present in a gas phase, which itself provides different oil recovery mechanisms than does water. ~1BO~ slnce it is in a gas phase, the steam has conslderably faster flow rates, allowing LD/B40 ~ 6 : ~ :
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physical effects such as aspiration to occur. Further, conaensation of the steam allows for much greater and more efficient heat transfer to the formation and the oil, so that the whole system can be heated hotter and faster than with water. Since the steam is hotter and less viscous than water, it can reach parts of the reservoir which are inaccesslble to wa~er. Also steam can effect distillation of lighter fractions of crude oil, producing unpredictable effects. Finally, steam can move heavy oils, which have different compositions from light oils moved by water, also with different effects. Thus, it will be seen that as between steam and water recovery systems, significant differences exist, the results of which are unpredictable from one system to the other.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
_ Amongst the anionic surfactants useful in the composition and methods of this invention, one preferred embodiment comprises a long chain alkyl aryl sulfonate, where the alkyl aryl sulfonate is most preferably either a benzene or toluene sulfonate, because ~f their high heat stability in the steam environment in which they are to be used, and their resistance to chemical degradation by the caustic silicate solution. Conversely, alkyl xylene sulfonates exhibit much less heat stability and are thus not as effective within the scope of this invention.
By the term "long chaln alkyl" is meant that the alkyl moiety of the alkyl aromatic sulfonate (which may be branched or straigh~-chain) should LDtB40 7 ' ~
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desirably have from 12 to 30 carbon atomg, and most preferably an average of about 16 to 20 carbon atoms. The term "average" is thus meant to signify that the alkyl moiety may be derived from mixtures of hydrocarbons having a weighted average of from 16 to 20 carbon atoms, even though shorter or longer chain lengths may be present in the mixture. Alternatively, pure olefins used as the source of the alkyl group having exactly the desired number of carbon atoms within this range may also be employed. Thus, in one embodiment of the invention, the alkyl moietY may be derived from a mixed C14_20 Qoe olefin which the molecular weight distribution is such that the resultant alkylate side chain has an average of 16 carbon atoms, even though lesser amounts of somewhat shor~er or longer chain lengths may be present in the alkylated product.
One preferred alkylate, having an average number of carbon atoms of about 16.2 in the side chain, may be derived from a wax-cracked C14 18 ~-olefin, and has the following weight distribution:
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Carbon Atoms in Side Chain Wei~ht Distribution (%) -Alternatively, the slkylate may be prepared from a C14 18 mixture derived from the polymerizatlon of ethylene in a known manner, wherein the average alkyl group is 16.09 and wherein the mixture is fur~her characterized by alkyl groups having even-numbered carbon atoms only. A
typical weight distribution of such a mixture is as follows:
Carbon Atoms in Side Chain Weight Distribution (%) ~ C18 : 25 :: :
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Alternatively, the alkylate may have a side chain derived from the oligomerization of propylene by known processes, as for example using phosphoric acid as the catalyst, or the like, wherein the side-chain may be either a single carbon number species which is a multiple o~ C3, i.e.
C12~ C15, C18, or C21, or a blend of the~e branched oligomers, such that the average molecular weight of the side chain is in the C15 18 range.
In place of alkyl aryl sulfonates there may be employed as the anionic surfactant in the compositions of this invention petroleum 6ulfonates. The petroleum sulfonates encompass a broad range of compounds which are well know in the art, and which are generally obtained by the sulfonation of naturally occurring petroleum streams derived from crude oil. Typical of this broad ran2e are those petroleum sulfonates described ln U.S. Patents 3,302,713; 3,508,612; 3,648,772; and 3,gOl,317.
Thus, the term "natural petroleum sulfona~es" is a commercial designation of petroleum sulfonates which are obtained by a treatmen~ of petroleum fractions, particularly solvent-treated aromatiG fractions, with, for example, solfuric acid, fumlng sulfuric acid, or sulfur trioxide. Upon sulfonation two type~ of general products are thereby formed which are known in the art a8 mahogany acid sulfonates and green acid suifonates, respectively, based on their color and solubility in oil or water.
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A third type of anionic surfactant which may be used in the compositions dis~losed herein are, as mentioned above, o~ -olefin sulfonates which are generally commercially available materials, as for example those obtained from olefins made by the "SHOP" process available from Shell Oil Co. Typically these olefins may have the following structures: R-C~=CH-R1, R-CH=CH2, or R.-C = CH2, Rl wherein R and R1 may be hydrogen, or alkyl groups having from 8-28 carbon atoms, and may be the same or different. Preferred amongst these are those alkyl groups having a total of from 10 to 16 carbon atoms. While the methods for preparing these olefins are generally well known, the olefin sulfonates may best be described as the sulfonation products of wax-cracked hydrocarbons having from about 12 to 30 carbon atoms, or alternatively of ethylene oligomers, e.g., those obtained by Ziegler-type polymerizations, and having from about 12 to 30 carbon atoms. Also contemplated within the scope of the i~vention are known derivatives of said olefin sulfonates such as ether sulfonates, ethoxylated sulfonates;
or propoxylated sulfonates. In general, these compounds may be prepared by well-known procedures.
The preparation of the anionic surfactants, i.e., the alkylation and sulfonation of the aromatic moiety, or the prepartion of the olefin or petroleum sulfonates, which are conventional techniques well known in the art, need not be described further herein. It is preferred, though not .. .. ~.. ... , :
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essential, that for purposes of this invention the sulfonates are in the form of their alkali metal salts.
A hydrotrope may be used as an additional component of the novel composition claimed herein, in combination with the anionic surfactants and alkali metal silicates, i.e. those compounds characterized in the art by their ability to increase the solubility of surfactants in aqueous systems. See, for example, the description in "Synthetic Detergents", Davidsohn et al, 6th Ed., Wiley and Sons, pages 79, 80. Included amongst these compounds are both aryl and non-aryl compounds. The aryl compounds are generally aryl sulfonates or short chain alkyl aryl sulfonates in the form of their alkali metal salts, in which there may be present from 1 to 3 alkyl groups containing from 1 to about 3 carbon atoms, and in which the aryl component may be benzene, toluene, xylene, cumene, or naphthalene. Included amongst these compounds are both aryl and non-~ryl compounds. Included amongst these aryl hydrotropes are such preferred compounds as sodium xylene sulfonate, sodium toluene sulfonate, sodium benzene sulfonate, and the like. The non-aryl hydrotropes which may llkewise be satisfactorily employed include such compounds as sodium isethionate, butane sulfonate, hexane sulfonate, and the like, i.e.
sulfonates whose alkyl moiety contains from about 1 to ~ carbon atoms.
The mechanism by which these hydrotropes operate to enhance steam-driven surfactant systems in an essentially non-aqueous liquid oit environment is not known. Also, as stated above, since hydrotropes ~2~33~
increase the solubility of ~urfactant~ in water, it should render them less effective in oil recovery for the reasons stated. How~ver, as will be shown in the examples below, when a hydrotrope is added to the surfactant-silicate system claimed herein, a further increase in oil recovery results compared ~o systems without the hydrotrope, in some cases as much as 31 percent.
The other component of the enhanced oil recovery composition is, as afore-described, an alkali metal silicate. These silicates are available in a wide range of compositions which are generally referred to and defined by ~he ratio of the alkali metal oxide to silica, i.e., by the weight ratio of SiO2/M20, where M is an alkali metal. This ratio is not a fixed quantity and may vary greatly depending upon the quantities of metal oxide and silica employed. Thus, a wide range of silicate compositions may be formed and used in the prac~ice of thls invention.
However, it is generally preferred ~o use those silcates which have a relatively high proportion of silica.
Accordingly, it is desirable to employ those silicates having a weight ratio of SiO2/M20 of about 0.5 to 4.0, preferably about l.S to 3.3, wherein M is an alkali metal, such as sodium, potassium, or lithium.
Examples of these silica~es lnclude alkali meeal orthosilicates, alkali metal metasilicates, alkali metasilicate pentahydrates, and alkali metal sequisilicates. Particularly useful in the practice of the invention are silicates such as sodlum and potassium orthosilicate, sodium and ~ ' ' - ~`. '~
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potassium metasllicate, sodium and potassium metasillcate pentahydrate, and sodium and potassium sequisilicate.
The alkaline alkali metal silicates used in the practice of this invention are available in solid form, and the respective alkaline alkali metal silicate solutions can be prepared by dissolving an appropriate quality of the alkaline alkali metal silicate in water. However, in many cases it is more convenient and less costly to prepare the alkaline alkali metal silicate by adding caustic to an aqueous solution of a low alkalinity alkali metal silicate having a SiO2/M2O weight ratio of more than 1. Alternatively, these silicates may be obtained commercially in pre-prepared ratios of SiO2/M2O of, for example, 1.6; 2.4; 3.2 and the like, such as those made available by ~Q Corp. under the trademark ACOR
(E-Series).
The weight ratio of the anionic surfactant to hydrotrope in the composition of this invention is desirably from about 1:0.05 to 0.5:2, and preferably about l:O.l to l:l, although this amount may be varied considerably, depending upon the properties of the oil field being treated, as well as the nature of the selected hydrotrope, and the nature of the resulting composition therefrom. The weight ratio of surfactant to alkali metal silicate, with or without the hydrotrope, fihould desirabIy be from about 1:0.05 to 0.5:2, preferably about I:O.I to I:l, but again this ratio may be varied depending upon the properties of the reservoir, the characteristics of the crude oil, and the properties of LDlB40 14 , ,,~, , 3~;~
the resulting surfactant formulation. For convenience, to this mixture of components may then desirably be added a solven~ in order to prepare an easily-handled solution to add to the steam to be inje~ted into the underground formation. This solvent is desirably water, although lighter-weight hydrocarbon solvents such as kerosene, toluene, naphtha, petroleum ether, lube oil base stocks or like inrt hydrocarbon streams may be used instead. Thus, for example, one preparation representing a preferred composition ready to be added to steam comprises 35% by weight of hexadecyltoluene sulfonate; 6% sodium silicate; optionally 17% sodium xylene sulfonate; and the balance water. However, these percentages may be varied somewhat, depending upon the nature o~ the oil, the subterranean formation, eec.
In addition to the three major components of the composition there may optionally be included minor amounts of materials such as known stabilizers, bacteriostats, anti-oxidants. These materials, alone or in combination, may be added in amoun~s of up to 10-15% by weight of the total composition.
As described above, the surfactant system of this invention is desirably injected into the subterranean formations admixed in steam;
wherein the steam recovery process is carried out either as a cyclic process or a steam drive process, and the heavy crude oil recovered in a generally well-known manner. Thus, in a typical cyclic steam process oil is produced from the same well from which the steam was previously added, -33~L~
while in a typical steam drive process the oil production well is remote from the steam injection well.
The amount of the surfactant-silicate or surfactant-silicate-hydro~rope composition of this invention to be admixed with the steam may vary widely according to the characteristics of the formation, but desirably is in the range of from about 0~02 to 10.0%, by weight9 based on the surfactant, of an aqueous solution of the composition, and preferably about a 0.5-5% concen~ration. This concentration, in turn, is achieved by metering it into the steam at those levels from a more concentrated aqueous solution, as described above, which is prepared beforehand.
In practice, the process of this invention may be applied equally to steam drive processes among multiple wells or to a cyclic process involv-ing an individual well.
The composition and method of this invention will no~ be illustrated by reference to the following examples, which are presented by way of illustration only and not by way of limitation on the scope of the invention.
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RXAMPLES
In the following examples, some of which are comparative, while others are illustrative of the invention, the same basic method to evaluate the usefulness of the compositlon was used wherein a tube having a diameter of 2" and a length of 18" was packed with oil-saturated 140-mesh Ottowa sand. The water-wet sand was coated with Midway Sunset crude oil to between 60-65~ residual oil saturation. The top 15~ of the tube was filled with clean sand to simulate a zone of high permeability frequently found in steamed reservoirs. The tube was insulated to reduce heat losses, and then elther a 40-50~ qua~ity steam alone or a 40-50%
quality steam in combination with various surfactant, hydrotrope, and silicate systems was passed through the sand pack diluted to concentrations of 1 weight percent surfactaDt based on the water equlvalent of the steam, and at appropriate rates until no more oil wa~
evident exitlng from the apparatus. The amount of oil recovered was measured in one or both of two ways: (1) total liquid oil obtained from the pack; or (2) the oil remaining on the said at the end of the experiment was determined, and the amount recovèred calculated as the difference from the value determined to be on the sand at the start of the experiment. The percent of oil recovered, for each system, based on the amount of oil originally in the pack, is summarized in Table I below.
In each of these examp1es 9.3cc (100% surfactant-active basis) of an alkyl toluene sulfonate whose alkyl moiety contained an average of 16 :lZ~3~'~
carbon atoms was admixed with the appropriate amounts of a sodium silicate having SiO2/Na20 weight ratios of 1.6, 2.4, and 3.2 respectively as indicated in the table sufficient to provide the weight ratios of surfactant to silicate also shown in the table. This mixture was diluted to provide a final concentration in the steam (based on the water equivalent) of 1% based on the surfactant. These silicates were obtained from PQ Corp. under the trademark ACOR (E-Series).
In Examples 10-16 the hydrotrope sodium xylene sulfonate was added to the above systems in amounts sufficient to provide a weight ratio of surfactant to hydrotrope of about 35:20, and the same procedure followed.
In addition, a series of runs was made with steam alone for purposes of comparison. The average percent recovery from these runs is reported in Example 17.
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EXAMPLE SURFACTANT ) HYDROTROPE ) SILICATE ) WRIGHT RATIO WEIGHT RATIO RECOVERY ) (SiO2/Na20) tSURF./SIL.) (SURF./HYDRO.) (%OOIP) 1 C16 ATS ~~~ 1.6d) 1:0.2 --- 60.8
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention relates to novel silicate-containing oil recovery surfactant compositions and methods of using the same ln steam recovery systems to anhance the secondary and tertlary recovery of oil from subterranean formations. More particularly, these compositions comprise certain anionic surfactants, ln combination ~ith hydrotropes and alkali metal silicates, a~d methods comprising ln~ecting these compositions with steam into oil-bearing formations to greatly increase heavy oil racovery as compared with the use of surfactant-silicate compositions alone.
This invention also relates to the method of recovering oil with steam wherein a combinatlon of ~aid surfactants and sald silicates, ~ithout the hydrotrope, are employed to enhance the oil recovery.
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DESCRIPTION OF THE PRIOR ART
The use of secondary and tertiary oil recovery techniques, with or without the addition of various reagents such as surfactants9 water thickeners and the like to recover crude oil left behind in formations after the "primary" oil has been withdrawn is well establlshed in the are. These displacement methods have been improved by the addition of surfactant compositions in both secondary and tertiary processes, for example where a formation has already been waterflooded at least once.
Representative of th~se prior art compositions and methods are those taught in U.S. Patents 3,348,611 to Reisburg; 3,885,626 to Gale et al;
3,901,317 to Plummer et al; 3,994,342 to Healy et al; and 4~2953980 to Motz, all of which teach aqueous flooding technlques with at least one surfactant, and in some cases, with viscosity modifiers, co~surfactants or the like. Finally, in an unrelated field, U.S. Patent 3,501,409 teaches a liquid washing detergent composition comprising said detergent in combination with a hydrotrope.
It is also known from U.S. Patents 2,920,041; 3,805,B93; 3,871,452;
3,871,453; 3,920,074; and 4,141,416 to employe alkali metal silicates as additives in secondary and tertiary oil recovery methods which use aqueous flooding techniques. Further, it is known more recently to combine these and other silicates with surfactants in the form of micellar solutions of high or low molecular weight surfactants such as .
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.
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alkyl aryl sulfonates, or mixtures thereof, as shown in U.~. Paeents 4,011,908 and 4,037,659. However, in the case of these latter two patents, it will be noted that the mechanism whereby micellar solutions operate in aqueous sys~ems is significantly different from those of steam recovery systems of the present invention, as described below.
In addition to the aforedescribed aqueous flooding techniques, the art has also employed steam for secondary and tertiary oil recovery, utilizing the effect of heat to obtain heavy oil from the formations in which it is found. See, for example, U.S. Patents 3,357,487 and 3,994,345. However, the mechanism and effects of surfactants and modifiers under these high temperatures and diverse formation conditions remain unclear, and thus make l~ impossible to predict from a knowledge of the effects of aqueous surfactant systems which surfactants, if any, can advantageously be employed in these steam recovery conditions. Thls is even more true in the choice of any modifiers which might enhance the effectiveness of the surfactant.
It is, therefore, an object of this invention to provide a novel silicate-containing surfactant composition useful for enhancing seeam recovery processes for secondary or tertiary recovery of heavy oil from subterranean formations.
LD/B40 ~ 4 It is a further object of this invention to provide an i~proved ~team recovery process for enhanced oil recovery, utilizing the novel compositions provided herein.
Further objects and advantages of the compositions and methods of the presen~ invention will becDme apparent in the course of the following detailed description thereof.
SUMMARY OF THE INVENTION
In ~ccordance with the present inven~ion, there is provided herein a novel ~ilicate-containing surfactant composition useful ln ~team recovery processes for the cnhanced recovery of typical heavy crude oil, said composition comprising (1) an anionlc surfactant; (2) an alkali metal silicate and (3) a h~vdrotrope, wherein the anionic surfactant is preferably selected from the group consisting of long-chain alkyl aryl sulfonates, petroleum sulfonates, and olefin sulfonates, including derivatives of said olefin sulfonates such as ether sulfonates, ethoxylated sulfonates and propoxylated sulfonates.
The hydrotrope, as described in further detail hereinbelow, is a sulfonated compound, but differing from the surfactants defined above in having considerably lower molecular weight, being extreme~
ly water soluble, having very short side chainsl and performfing poorly as a surfactant.
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In a further embodiment of this invention there i8 al80 provided a method of recoverin~ oil in steam recovery proces~es wherein there is employed a composition comprising (l) an anionic surfactant and (2) an alkali metal silicate without the added presence of a hydrotrope.
As will be evident from the examples and following description, the novel compositions of this invention comprising said anionic surfactants, silicates and a hydrotrope, when employed in a steam recovery process, or the method employing ~ust the surfactant and silicates in said steam process, exhibit unexpected benefits over what would be expected from the combined effects of steam alone, or steam and a surfactant.
As discussed further below, since a hydrotrope by definition is a compound which increases the solubility of a surfactant in water, the enhanced effect disclosed herein i6 particularly surprising because it would normally be supposed that the hydrotrope would thus increase the solubility of the surfactant in the aqueous portion of the steam, and decrease its solubility in the oil phase, ~hus rendering it less effective in oil recovery.
Moreover, apart from the mechanism of the hydrotrope, steam recovery systems themselves differ from water recovery systems in many ways.
Thus, for example, steam is present in a gas phase, which itself provides different oil recovery mechanisms than does water. ~1BO~ slnce it is in a gas phase, the steam has conslderably faster flow rates, allowing LD/B40 ~ 6 : ~ :
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physical effects such as aspiration to occur. Further, conaensation of the steam allows for much greater and more efficient heat transfer to the formation and the oil, so that the whole system can be heated hotter and faster than with water. Since the steam is hotter and less viscous than water, it can reach parts of the reservoir which are inaccesslble to wa~er. Also steam can effect distillation of lighter fractions of crude oil, producing unpredictable effects. Finally, steam can move heavy oils, which have different compositions from light oils moved by water, also with different effects. Thus, it will be seen that as between steam and water recovery systems, significant differences exist, the results of which are unpredictable from one system to the other.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
_ Amongst the anionic surfactants useful in the composition and methods of this invention, one preferred embodiment comprises a long chain alkyl aryl sulfonate, where the alkyl aryl sulfonate is most preferably either a benzene or toluene sulfonate, because ~f their high heat stability in the steam environment in which they are to be used, and their resistance to chemical degradation by the caustic silicate solution. Conversely, alkyl xylene sulfonates exhibit much less heat stability and are thus not as effective within the scope of this invention.
By the term "long chaln alkyl" is meant that the alkyl moiety of the alkyl aromatic sulfonate (which may be branched or straigh~-chain) should LDtB40 7 ' ~
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desirably have from 12 to 30 carbon atomg, and most preferably an average of about 16 to 20 carbon atoms. The term "average" is thus meant to signify that the alkyl moiety may be derived from mixtures of hydrocarbons having a weighted average of from 16 to 20 carbon atoms, even though shorter or longer chain lengths may be present in the mixture. Alternatively, pure olefins used as the source of the alkyl group having exactly the desired number of carbon atoms within this range may also be employed. Thus, in one embodiment of the invention, the alkyl moietY may be derived from a mixed C14_20 Qoe olefin which the molecular weight distribution is such that the resultant alkylate side chain has an average of 16 carbon atoms, even though lesser amounts of somewhat shor~er or longer chain lengths may be present in the alkylated product.
One preferred alkylate, having an average number of carbon atoms of about 16.2 in the side chain, may be derived from a wax-cracked C14 18 ~-olefin, and has the following weight distribution:
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.
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Carbon Atoms in Side Chain Wei~ht Distribution (%) -Alternatively, the slkylate may be prepared from a C14 18 mixture derived from the polymerizatlon of ethylene in a known manner, wherein the average alkyl group is 16.09 and wherein the mixture is fur~her characterized by alkyl groups having even-numbered carbon atoms only. A
typical weight distribution of such a mixture is as follows:
Carbon Atoms in Side Chain Weight Distribution (%) ~ C18 : 25 :: :
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Alternatively, the alkylate may have a side chain derived from the oligomerization of propylene by known processes, as for example using phosphoric acid as the catalyst, or the like, wherein the side-chain may be either a single carbon number species which is a multiple o~ C3, i.e.
C12~ C15, C18, or C21, or a blend of the~e branched oligomers, such that the average molecular weight of the side chain is in the C15 18 range.
In place of alkyl aryl sulfonates there may be employed as the anionic surfactant in the compositions of this invention petroleum 6ulfonates. The petroleum sulfonates encompass a broad range of compounds which are well know in the art, and which are generally obtained by the sulfonation of naturally occurring petroleum streams derived from crude oil. Typical of this broad ran2e are those petroleum sulfonates described ln U.S. Patents 3,302,713; 3,508,612; 3,648,772; and 3,gOl,317.
Thus, the term "natural petroleum sulfona~es" is a commercial designation of petroleum sulfonates which are obtained by a treatmen~ of petroleum fractions, particularly solvent-treated aromatiG fractions, with, for example, solfuric acid, fumlng sulfuric acid, or sulfur trioxide. Upon sulfonation two type~ of general products are thereby formed which are known in the art a8 mahogany acid sulfonates and green acid suifonates, respectively, based on their color and solubility in oil or water.
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A third type of anionic surfactant which may be used in the compositions dis~losed herein are, as mentioned above, o~ -olefin sulfonates which are generally commercially available materials, as for example those obtained from olefins made by the "SHOP" process available from Shell Oil Co. Typically these olefins may have the following structures: R-C~=CH-R1, R-CH=CH2, or R.-C = CH2, Rl wherein R and R1 may be hydrogen, or alkyl groups having from 8-28 carbon atoms, and may be the same or different. Preferred amongst these are those alkyl groups having a total of from 10 to 16 carbon atoms. While the methods for preparing these olefins are generally well known, the olefin sulfonates may best be described as the sulfonation products of wax-cracked hydrocarbons having from about 12 to 30 carbon atoms, or alternatively of ethylene oligomers, e.g., those obtained by Ziegler-type polymerizations, and having from about 12 to 30 carbon atoms. Also contemplated within the scope of the i~vention are known derivatives of said olefin sulfonates such as ether sulfonates, ethoxylated sulfonates;
or propoxylated sulfonates. In general, these compounds may be prepared by well-known procedures.
The preparation of the anionic surfactants, i.e., the alkylation and sulfonation of the aromatic moiety, or the prepartion of the olefin or petroleum sulfonates, which are conventional techniques well known in the art, need not be described further herein. It is preferred, though not .. .. ~.. ... , :
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essential, that for purposes of this invention the sulfonates are in the form of their alkali metal salts.
A hydrotrope may be used as an additional component of the novel composition claimed herein, in combination with the anionic surfactants and alkali metal silicates, i.e. those compounds characterized in the art by their ability to increase the solubility of surfactants in aqueous systems. See, for example, the description in "Synthetic Detergents", Davidsohn et al, 6th Ed., Wiley and Sons, pages 79, 80. Included amongst these compounds are both aryl and non-aryl compounds. The aryl compounds are generally aryl sulfonates or short chain alkyl aryl sulfonates in the form of their alkali metal salts, in which there may be present from 1 to 3 alkyl groups containing from 1 to about 3 carbon atoms, and in which the aryl component may be benzene, toluene, xylene, cumene, or naphthalene. Included amongst these compounds are both aryl and non-~ryl compounds. Included amongst these aryl hydrotropes are such preferred compounds as sodium xylene sulfonate, sodium toluene sulfonate, sodium benzene sulfonate, and the like. The non-aryl hydrotropes which may llkewise be satisfactorily employed include such compounds as sodium isethionate, butane sulfonate, hexane sulfonate, and the like, i.e.
sulfonates whose alkyl moiety contains from about 1 to ~ carbon atoms.
The mechanism by which these hydrotropes operate to enhance steam-driven surfactant systems in an essentially non-aqueous liquid oit environment is not known. Also, as stated above, since hydrotropes ~2~33~
increase the solubility of ~urfactant~ in water, it should render them less effective in oil recovery for the reasons stated. How~ver, as will be shown in the examples below, when a hydrotrope is added to the surfactant-silicate system claimed herein, a further increase in oil recovery results compared ~o systems without the hydrotrope, in some cases as much as 31 percent.
The other component of the enhanced oil recovery composition is, as afore-described, an alkali metal silicate. These silicates are available in a wide range of compositions which are generally referred to and defined by ~he ratio of the alkali metal oxide to silica, i.e., by the weight ratio of SiO2/M20, where M is an alkali metal. This ratio is not a fixed quantity and may vary greatly depending upon the quantities of metal oxide and silica employed. Thus, a wide range of silicate compositions may be formed and used in the prac~ice of thls invention.
However, it is generally preferred ~o use those silcates which have a relatively high proportion of silica.
Accordingly, it is desirable to employ those silicates having a weight ratio of SiO2/M20 of about 0.5 to 4.0, preferably about l.S to 3.3, wherein M is an alkali metal, such as sodium, potassium, or lithium.
Examples of these silica~es lnclude alkali meeal orthosilicates, alkali metal metasilicates, alkali metasilicate pentahydrates, and alkali metal sequisilicates. Particularly useful in the practice of the invention are silicates such as sodlum and potassium orthosilicate, sodium and ~ ' ' - ~`. '~
3~
potassium metasllicate, sodium and potassium metasillcate pentahydrate, and sodium and potassium sequisilicate.
The alkaline alkali metal silicates used in the practice of this invention are available in solid form, and the respective alkaline alkali metal silicate solutions can be prepared by dissolving an appropriate quality of the alkaline alkali metal silicate in water. However, in many cases it is more convenient and less costly to prepare the alkaline alkali metal silicate by adding caustic to an aqueous solution of a low alkalinity alkali metal silicate having a SiO2/M2O weight ratio of more than 1. Alternatively, these silicates may be obtained commercially in pre-prepared ratios of SiO2/M2O of, for example, 1.6; 2.4; 3.2 and the like, such as those made available by ~Q Corp. under the trademark ACOR
(E-Series).
The weight ratio of the anionic surfactant to hydrotrope in the composition of this invention is desirably from about 1:0.05 to 0.5:2, and preferably about l:O.l to l:l, although this amount may be varied considerably, depending upon the properties of the oil field being treated, as well as the nature of the selected hydrotrope, and the nature of the resulting composition therefrom. The weight ratio of surfactant to alkali metal silicate, with or without the hydrotrope, fihould desirabIy be from about 1:0.05 to 0.5:2, preferably about I:O.I to I:l, but again this ratio may be varied depending upon the properties of the reservoir, the characteristics of the crude oil, and the properties of LDlB40 14 , ,,~, , 3~;~
the resulting surfactant formulation. For convenience, to this mixture of components may then desirably be added a solven~ in order to prepare an easily-handled solution to add to the steam to be inje~ted into the underground formation. This solvent is desirably water, although lighter-weight hydrocarbon solvents such as kerosene, toluene, naphtha, petroleum ether, lube oil base stocks or like inrt hydrocarbon streams may be used instead. Thus, for example, one preparation representing a preferred composition ready to be added to steam comprises 35% by weight of hexadecyltoluene sulfonate; 6% sodium silicate; optionally 17% sodium xylene sulfonate; and the balance water. However, these percentages may be varied somewhat, depending upon the nature o~ the oil, the subterranean formation, eec.
In addition to the three major components of the composition there may optionally be included minor amounts of materials such as known stabilizers, bacteriostats, anti-oxidants. These materials, alone or in combination, may be added in amoun~s of up to 10-15% by weight of the total composition.
As described above, the surfactant system of this invention is desirably injected into the subterranean formations admixed in steam;
wherein the steam recovery process is carried out either as a cyclic process or a steam drive process, and the heavy crude oil recovered in a generally well-known manner. Thus, in a typical cyclic steam process oil is produced from the same well from which the steam was previously added, -33~L~
while in a typical steam drive process the oil production well is remote from the steam injection well.
The amount of the surfactant-silicate or surfactant-silicate-hydro~rope composition of this invention to be admixed with the steam may vary widely according to the characteristics of the formation, but desirably is in the range of from about 0~02 to 10.0%, by weight9 based on the surfactant, of an aqueous solution of the composition, and preferably about a 0.5-5% concen~ration. This concentration, in turn, is achieved by metering it into the steam at those levels from a more concentrated aqueous solution, as described above, which is prepared beforehand.
In practice, the process of this invention may be applied equally to steam drive processes among multiple wells or to a cyclic process involv-ing an individual well.
The composition and method of this invention will no~ be illustrated by reference to the following examples, which are presented by way of illustration only and not by way of limitation on the scope of the invention.
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RXAMPLES
In the following examples, some of which are comparative, while others are illustrative of the invention, the same basic method to evaluate the usefulness of the compositlon was used wherein a tube having a diameter of 2" and a length of 18" was packed with oil-saturated 140-mesh Ottowa sand. The water-wet sand was coated with Midway Sunset crude oil to between 60-65~ residual oil saturation. The top 15~ of the tube was filled with clean sand to simulate a zone of high permeability frequently found in steamed reservoirs. The tube was insulated to reduce heat losses, and then elther a 40-50~ qua~ity steam alone or a 40-50%
quality steam in combination with various surfactant, hydrotrope, and silicate systems was passed through the sand pack diluted to concentrations of 1 weight percent surfactaDt based on the water equlvalent of the steam, and at appropriate rates until no more oil wa~
evident exitlng from the apparatus. The amount of oil recovered was measured in one or both of two ways: (1) total liquid oil obtained from the pack; or (2) the oil remaining on the said at the end of the experiment was determined, and the amount recovèred calculated as the difference from the value determined to be on the sand at the start of the experiment. The percent of oil recovered, for each system, based on the amount of oil originally in the pack, is summarized in Table I below.
In each of these examp1es 9.3cc (100% surfactant-active basis) of an alkyl toluene sulfonate whose alkyl moiety contained an average of 16 :lZ~3~'~
carbon atoms was admixed with the appropriate amounts of a sodium silicate having SiO2/Na20 weight ratios of 1.6, 2.4, and 3.2 respectively as indicated in the table sufficient to provide the weight ratios of surfactant to silicate also shown in the table. This mixture was diluted to provide a final concentration in the steam (based on the water equivalent) of 1% based on the surfactant. These silicates were obtained from PQ Corp. under the trademark ACOR (E-Series).
In Examples 10-16 the hydrotrope sodium xylene sulfonate was added to the above systems in amounts sufficient to provide a weight ratio of surfactant to hydrotrope of about 35:20, and the same procedure followed.
In addition, a series of runs was made with steam alone for purposes of comparison. The average percent recovery from these runs is reported in Example 17.
.
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EXAMPLE SURFACTANT ) HYDROTROPE ) SILICATE ) WRIGHT RATIO WEIGHT RATIO RECOVERY ) (SiO2/Na20) tSURF./SIL.) (SURF./HYDRO.) (%OOIP) 1 C16 ATS ~~~ 1.6d) 1:0.2 --- 60.8
2 C16 ATS ~~~ l.6dd) 1:0.5 --- 74.5
3 C16 ATS --- 1.6 ) 1:1 --~ 79.6
4 C16 ATS --- 2.4e) 1:0.2 ___ 72.5 C16 ATS --- 2.4e) 1:0.5 ~~- 74.8 6 C16 ATS ~~~ 2.4e 1:1 --- 73.5 7 C ATS --- 3.2f) 1:0.2 --- 69.0 16 f~
8 C16 ATS --- 3.2 ' 1:0.5 --- 75.0 9 C16 ATS ~~~ 3.2f) 1:1 --- 79.4 C16 ATS SXS 1.6d) 1:0.2 35/20 69.9 11 C16 ATS SXS 1.6d) 1:0.5 35/20 87.9 12 C16 ATS SXS 1.6d) 1:1 35/20- 84.2 13 C16 SXS 2.4e) 1:0.2 35/20 83.4 14 16 SXS 2.4e) 1:0.5 35/20 84.4 16 SXS 2.4e) 1:1 35/20 87.0 16 16 SXS 3.2f) 1:0.2, etc. 35/20 g) 17h _ ___ ___ __ --- 44.5 a) surfactant = C16 ATS = a C16 (ave.) alkyl toluene sulfonate b) hydrotrope - SXS = sodium xylene sulfonate c) silicate = ACOR E-Series sodium siIicate d) SiO2/NazO weight ratio of 1.6, obtained from P0 Corp. under the trademark ACOR E-16 e) SiO2/Na20 weight ratio of 2.4, obtained from PQ Corp. under the trademark ACOR E-24 f) SiO2/Na2O weight ratlo of 3.2,~obtained from PQ Corp. under the trademark ACOR E-32 g) phase separation (3 runs combined) - could not resolubilize h) steam alone - average recovery from 8 runs i) OOIP = original oil in place -:
: :
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33~
In comparison to the average 44.5% OOIP normally experienced when only steam is employed in these experiments, the additional benefit of using the disclosed composltions is at minimum an additional 16~ of the OOIP, or one-third more then obtained with only steam, and can range to as much as an additional 43.4~ of the OOIP, or almost 100% increase over steam alone in recoverable oil.
In accordance with the procedures of Example ll, but substituting a Cl6 (ave.) alkyl benzene sulfonate for the alkyl toluene sulfonate, and sodium cumene sulfonate for the sodium xylene sulfona~e, comparable amounts of oil are recovered.
In accordance with the procedures of Example 16, but substituting an ~c-olefin sulfonate having an average of 15 carbon atoms for the alkyl toluene sulfonate, and sodium benzene sulfonate for sodium xylene sulfonate, comparable amounts of oil are recovered.
In accordance with the procedures of Example 14, but substituting a petroleum sulfonate having an average of 20 carbon atoms for the alkyl toluene sulfonate, and butane sulfonate for sodium xylene sulfonate, comparable amounts of oil are recovered.
8 C16 ATS --- 3.2 ' 1:0.5 --- 75.0 9 C16 ATS ~~~ 3.2f) 1:1 --- 79.4 C16 ATS SXS 1.6d) 1:0.2 35/20 69.9 11 C16 ATS SXS 1.6d) 1:0.5 35/20 87.9 12 C16 ATS SXS 1.6d) 1:1 35/20- 84.2 13 C16 SXS 2.4e) 1:0.2 35/20 83.4 14 16 SXS 2.4e) 1:0.5 35/20 84.4 16 SXS 2.4e) 1:1 35/20 87.0 16 16 SXS 3.2f) 1:0.2, etc. 35/20 g) 17h _ ___ ___ __ --- 44.5 a) surfactant = C16 ATS = a C16 (ave.) alkyl toluene sulfonate b) hydrotrope - SXS = sodium xylene sulfonate c) silicate = ACOR E-Series sodium siIicate d) SiO2/NazO weight ratio of 1.6, obtained from P0 Corp. under the trademark ACOR E-16 e) SiO2/Na20 weight ratio of 2.4, obtained from PQ Corp. under the trademark ACOR E-24 f) SiO2/Na2O weight ratlo of 3.2,~obtained from PQ Corp. under the trademark ACOR E-32 g) phase separation (3 runs combined) - could not resolubilize h) steam alone - average recovery from 8 runs i) OOIP = original oil in place -:
: :
- : :
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33~
In comparison to the average 44.5% OOIP normally experienced when only steam is employed in these experiments, the additional benefit of using the disclosed composltions is at minimum an additional 16~ of the OOIP, or one-third more then obtained with only steam, and can range to as much as an additional 43.4~ of the OOIP, or almost 100% increase over steam alone in recoverable oil.
In accordance with the procedures of Example ll, but substituting a Cl6 (ave.) alkyl benzene sulfonate for the alkyl toluene sulfonate, and sodium cumene sulfonate for the sodium xylene sulfona~e, comparable amounts of oil are recovered.
In accordance with the procedures of Example 16, but substituting an ~c-olefin sulfonate having an average of 15 carbon atoms for the alkyl toluene sulfonate, and sodium benzene sulfonate for sodium xylene sulfonate, comparable amounts of oil are recovered.
In accordance with the procedures of Example 14, but substituting a petroleum sulfonate having an average of 20 carbon atoms for the alkyl toluene sulfonate, and butane sulfonate for sodium xylene sulfonate, comparable amounts of oil are recovered.
Claims (47)
1. An improved method for the enhanced recovery of oil from subterranean formations whereby steam is injected into said formations, the improvement comprising incorporating in the steam an effective amount of a mixture comprising:
a. an anionic surfactant hydrocarbon containing a sulfur moiety, b. an alkali metal silicate, and c. a sulfonated hydrocarbon hydrotrope.
a. an anionic surfactant hydrocarbon containing a sulfur moiety, b. an alkali metal silicate, and c. a sulfonated hydrocarbon hydrotrope.
2. The process of claim 1 wherein the anionic surfactant is an alkyl aryl sulfonate having 12 to 30 carbon atoms in the alkyl group, a petroleum sulfonate, or a C8-30 .alpha.-olefin sulfonate.
3. The process of claim 2 wherein the alkyl aryl sulfonates is an alkyl benzene sulfonate or alkyl toluene sulfonate, and the alkyl group has from about 16 to 20 carbon atoms.
4. The process of claim 3 wherein the alkyl aryl sulfonate is an alkyl toluene sulfonate, wherein the alkyl group has an average of about 16 carbon atoms.
5. The process of claim 3 wherein the alkyl aryl sulfonate is an alkyl benzene sulfonate, wherein the alkyl group has an average of about 16 carbon atoms.
6. The process according to claim 1 wherein the anionic surfactant is a C8-30 .alpha.-olefin sulfonate or petroleum sulfonate.
7. The process according to claim 1 wherein the hydrotrope is an aryl sulfonate or alkyl aryl sulfonate, having from 1 to 3 alkyl groups, wherein the alkyl moiety has from 1 to 3 carbon atoms.
8. The process according to claim 7 wherein the hydrotrope is an alkali metal xylene sulfonate, an alkali metal toluene sulfonate, or an alkali metal cumene sulfonate.
9. The process according to claim 7 wherein the hydrotrope is an alkali metal isethlonate, an alkali metal butane sulfonate or an alkli metal hexane sulfonate.
10. The process according to claim 1 wherein the molar ratio of anionic surfactant to hydrotrope is from about 1:0.05 to 0.5:2.
11. The process according to claim 1 wherein the concentration of the surfactant-silicate-hydrotrope mixture in the steam is from about 0.02 to 10.0% by weight, based on the surfactant.
12. The process according to claim 1 wherein the alkali metal silicate has a weight ratio of S102/M20 of from about 0.5 to 4.0, wherein M is an alkali metal atom.
13. The process according to claim 12 wherein said ratio is from about 1.5 to 3.3.
14. The process according to claim I wherein the weight ratio of anionic surfactant to alkali metal silicate is in the range of from about 1:0.05 to 0.5:2.
15. An improved method for the enhanced recovery of oil from subterranean formations whereby steam is injected into said formation, the improvement comprising incorporating in the steam an effective amount of mixture comprising:
a. A C16-20 alkyl toluene sulfonate or C16-20 alkyl benzene sulfonate;
b. an alkali metal silicate having an SiO2/M20 weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal;
and c. a hydrotrope selected from the group consisting of an alkali metal xylene sulfonate, an alkali metal toluene sulfonate, alkali metal benzene sulfonate, and an alkali metal cumene sulfonate, wherein the weight ratio of alkyl toluene sulfonate or alkyl benzene sulfonate to alkali metal silicate is from about 1:0.05 to 0.5:2; and the weight ratio of alkyl toluene sulfonate or alkyl benzene sulfonate to hydrotrope is from about 1:0.05 to 0.5:2.
a. A C16-20 alkyl toluene sulfonate or C16-20 alkyl benzene sulfonate;
b. an alkali metal silicate having an SiO2/M20 weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal;
and c. a hydrotrope selected from the group consisting of an alkali metal xylene sulfonate, an alkali metal toluene sulfonate, alkali metal benzene sulfonate, and an alkali metal cumene sulfonate, wherein the weight ratio of alkyl toluene sulfonate or alkyl benzene sulfonate to alkali metal silicate is from about 1:0.05 to 0.5:2; and the weight ratio of alkyl toluene sulfonate or alkyl benzene sulfonate to hydrotrope is from about 1:0.05 to 0.5:2.
16. The process according to claim 15 wherein the alkyl moiety of the toluene or benzene sulfonate has an average of about 16 carbon atoms.
: 24
: 24
17. The process according to claim 15 wherein the concentration of the alkyl toluene sulfonate - alkali metal silicate - hydrotrope mixture in the steam is from about 0.02 to 10.0% by weight, based on the surfactants.
18. An improved method for the enhanced recovery of oil from subterranean formations whereby steam is injected into said foundation, the improvement comprising incorporating in the steam an effective amount of mixture comprising.
a. A C8-30 .alpha.-olefin sulfonate, or a petroleum sulfonate;
b. an alkali metal silicate having an SiO2/M20 weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal;
and c. a hydrotrope selected from the group consisting of an alkali metal xylene sulfonate, an alkali metal toluene sulfonate, alkali metal benzene sulfonate, and an alkali metal cumene sulfonate, wherein the weight ratio of petroleum sulfonate or .alpha.-olefin sulfonate to alkali metal silicate is from about 1:0.05 to 0.5:2; and the weight ratio of petroleum sulfonate or .alpha.-olefin sulfonate to hydrotrope is from about 1:0.05 to 0.5:2.
a. A C8-30 .alpha.-olefin sulfonate, or a petroleum sulfonate;
b. an alkali metal silicate having an SiO2/M20 weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal;
and c. a hydrotrope selected from the group consisting of an alkali metal xylene sulfonate, an alkali metal toluene sulfonate, alkali metal benzene sulfonate, and an alkali metal cumene sulfonate, wherein the weight ratio of petroleum sulfonate or .alpha.-olefin sulfonate to alkali metal silicate is from about 1:0.05 to 0.5:2; and the weight ratio of petroleum sulfonate or .alpha.-olefin sulfonate to hydrotrope is from about 1:0.05 to 0.5:2.
19. The process according to claim 18 wherein the concentration of the sulfonate - alkali metal silicate - hydrotrope mixture in the steam is from about 0.02 to 10.0% by weight, based on the surfactant.
20. A surfaceant composition useful in the enhanced steam recovery of oil from subterranean formations comprising:
a. an anionic surfactant selected from the group consisting of C12-30 alkyl aryl sulfonates, petroleum sulfonates, and C8-30 .alpha.-olefin sulfonates;
b. an alkali metal silicate; and b. a hydrotrope.
a. an anionic surfactant selected from the group consisting of C12-30 alkyl aryl sulfonates, petroleum sulfonates, and C8-30 .alpha.-olefin sulfonates;
b. an alkali metal silicate; and b. a hydrotrope.
21. The composition of claim 20 wherein the Cl2-30 alkyl aryl sulfonate is a toluene sulfonate or a benzene sulfonate, and the alkyl group has an average of about 16 carbon atoms.
22. The composition of claim 20 wherein the hydrotrope is an alkyl aryl sulfonate selected from the group consisting of an alkali metal salt of a benzene sulfonate, xylene sulfonate, a toluene sulfonate, and a cumene sulfonate.
23. The composition of claim 20 wherein the hydrotrope is an alkali metal isethionate, an alkali metal butane sulfonate or an alkali metal hexane sulfonate.
24. The composition of claim 20 wherein the weight ratio of surfac-tant to hydrotrope is in the range of about 1:0.05 to 0.5:2.
25. The composition according to claim 20 wherein the alkali metal silicate has a weight ratio of SiO2/M20 of from about 0.5 to 4.0, wherein M is an alkali metal atom.
26. The composition according to claim 25 wherein said weight ratio is from about 1.5 to 3.3.
27. The composition according to claim 20 wherein the weight ratio of anionic surfactant to alkali metal silicate is in the range of from about l:0.05 to 0,5:2.
28. A composition for the enhanced recovery of oil from subterranean formations comprising:
a A C16-20 alkyl toluene sulfonate or C16-20 alkyl benzene sulfonate;
b. an alkali metal silicate having an SiO2/M20 weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal;
and c. a hydrotrope selected from the group consisting of an alkali metal xylene sulfonate, an alkali metal toluene sulfonate, alkali metal benzene sulfonate, and an alkali metal cumene sulfonate, wherein the weight ratio of alkyl toluene sulfonate or alkyl benzene sulfonate to alkali metal silicate is from about 1:0.05 to 0.5:2; and the weight ratio of alkyl toluene sulfonate or alkyl benzene sulfonate to hydrotrope is from about 1:0.05 to 0.5:2.
a A C16-20 alkyl toluene sulfonate or C16-20 alkyl benzene sulfonate;
b. an alkali metal silicate having an SiO2/M20 weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal;
and c. a hydrotrope selected from the group consisting of an alkali metal xylene sulfonate, an alkali metal toluene sulfonate, alkali metal benzene sulfonate, and an alkali metal cumene sulfonate, wherein the weight ratio of alkyl toluene sulfonate or alkyl benzene sulfonate to alkali metal silicate is from about 1:0.05 to 0.5:2; and the weight ratio of alkyl toluene sulfonate or alkyl benzene sulfonate to hydrotrope is from about 1:0.05 to 0.5:2.
29. The composition according to claim 28 wherein the alkyl moiety of the toluene or benzene sulfonate has an average of about 16 carbon atoms.
30. The composition according to claim 28 wherein the concentration of the sulfonate - alkali metal silicate - hydrotrope mixture in the steam is from about 0.02 to 10.0% by weight, based on the surfactant.
31. A composition for the enhanced recovery of oil from subterranean fonmaeions comprising a. an .alpha.-olefin sulfonate or petroleum sulfonate, wherein the olefin has an average of from about 14-20 carbon atoms;
b. an alkali metal silicate having an SiO2/M20 weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal;
and c. a hydrotrope selected from the group consisting of an alkali metal xylene sulfonate, an alkali metal toluene sulfonate, alkali metal benzene sulfonate, and an alkali metal cumene sulfonate, wherein the weight ratio of .alpha.-olefin sulfonate or petroleum sulfonate to alkali metal silicate is from about 1:0.05 to 0.5:2; and the weight ratio of .alpha.-olefin sulfonate or petroleum sulfonate to hydrotrope is from about 1:0.05 to 0.5:2.
b. an alkali metal silicate having an SiO2/M20 weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal;
and c. a hydrotrope selected from the group consisting of an alkali metal xylene sulfonate, an alkali metal toluene sulfonate, alkali metal benzene sulfonate, and an alkali metal cumene sulfonate, wherein the weight ratio of .alpha.-olefin sulfonate or petroleum sulfonate to alkali metal silicate is from about 1:0.05 to 0.5:2; and the weight ratio of .alpha.-olefin sulfonate or petroleum sulfonate to hydrotrope is from about 1:0.05 to 0.5:2.
32. The composition according to claim 31 wherein the concentration of the sulfonate - alkali metal silicate - hydrotrope mixture in the steam is from about 0.02 to 10.0% by weight, based on the surfactant.
33. An improved method for the enhanced recovery of oil from subterranean formations whereby steam is injected into said formations, the improvement comprising incorporating in the steam an effective amount of a mixture comprising:
a. an anionic surfactant hydrocarbon continuing a sulfur-moiety, and b. an alkali metal silicate.
a. an anionic surfactant hydrocarbon continuing a sulfur-moiety, and b. an alkali metal silicate.
34. The process of claim 33 wherein the anionic surfaceant is an alkyl aryl sulfonate having 12 to 30 carbon atoms in the alkyl group, a petroleum sulfonate, or a C8-30 .alpha.-olefin sulfonate.
35. The process of claim 34 wherein the alkyl aryl sulfonates is an alkyl benzene sulfonate or alkyl toluene sulfonate, and the alkyl group has from about 16 to 20 carbon atoms.
36. The process of claim 35 wherein the alkyl aryl sulfonate is an alkyl toluene sulfonste, wherein the alkyl group has an average of about 16 carbon atoms.
37. The process of claim 35 wherein the alkyl aryl sulfonate is an alkyl benzene sulfonate, wherein the alkyl group has an average of about 16 carbon atoms.
38. The process according to claim 33 wherein the anionic surfactant is a C8-30 .alpha.-olefin sulfonate or petroleum sulfonate.
39. The process according to claim 33 wherein the concentration of the surfactant-silicate mixture in the steam is from about 0.02 to 10.0%
by weight, based on the surfactant.
by weight, based on the surfactant.
40. The process according to claim 33 wherein the alkali metal silicate has a weight ratio of SiO2/M20 of from about 0.5 to 4.0, wherein N is an alkali metal atom.
41. The process according to claim 40 wherein said ratio is from about 1.5 to 3.3.
42. The process according to claim 33 wherein the weight ratio of anionic surfactant to alksli metal silicate is in the range of from about 1:0.05 to 0.5:2.
43. An improved method for the enhanced recovery of oil from subterranean formations whereby steam is injected into said formation, the improvement comprising incorporating in the steam an effective amount of mixture comprising.
a. A C16-20 alkyl toluene sulfonate or C16-20 alkyl benzene sulfonate; and b. an alkali metal silicate having an SiO2/M20 weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal, wherein the weight ratio of alkyl toluene sulfonate or alkyl benzene sulfonate to alkali metal silicate is from about 1:0,05 to 0.5:2.
a. A C16-20 alkyl toluene sulfonate or C16-20 alkyl benzene sulfonate; and b. an alkali metal silicate having an SiO2/M20 weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal, wherein the weight ratio of alkyl toluene sulfonate or alkyl benzene sulfonate to alkali metal silicate is from about 1:0,05 to 0.5:2.
44. The process according to claim 43 wherein the alkyl moiety of the toluene or benzene sulfonate has an average of about 16 carbon atoms.
45. The process according to claim 43 wherein the concentration of the alkyl toluene sulfonate - alkali metal silicate mixture in the steam is from about 0.02 to 10.0% by weight, based on the surfactants.
46. An improved method for the enhanced recovery of oil from subterranean formations whereby steam is injected into said foundation, the improvement comprising incorporating in the steam an effective amount of mixture comprising.
a. A C8-30 ?-olefin sulfonate, or a petroleum ?-olefin sulfonate; and b. an alkali metal silicate having an SiO2/M2O weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal, wherein the weight ratio of petroleum sulfonate or ?-olefin sulfonate to alkali metal silicate is from about 1:0.05 to 0.5:2.
a. A C8-30 ?-olefin sulfonate, or a petroleum ?-olefin sulfonate; and b. an alkali metal silicate having an SiO2/M2O weight ratio of from about 0.5 to 4.0, wherein M is an alkali metal, wherein the weight ratio of petroleum sulfonate or ?-olefin sulfonate to alkali metal silicate is from about 1:0.05 to 0.5:2.
47. The process according to claim 46 wherein the concentration of the sulfonate - alkali metal silicate mixture in the steam is from about 0.02 to 10.0% by weight, based on the surfactant.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US68173584A | 1984-12-14 | 1984-12-14 | |
| US681,735 | 1984-12-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1248342A true CA1248342A (en) | 1989-01-10 |
Family
ID=24736556
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000472261A Expired CA1248342A (en) | 1984-12-14 | 1985-01-17 | Silicate-containing oil recovery compositions |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN1011151B (en) |
| CA (1) | CA1248342A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1081288C (en) * | 1999-03-25 | 2002-03-20 | 金军 | Steam chemical incoming-outcoming method for extracting superthick oil |
| CN102162351A (en) * | 2011-03-15 | 2011-08-24 | 彭仁田 | Application of hydrogen peroxide to thickened oil dilution |
-
1985
- 1985-01-17 CA CA000472261A patent/CA1248342A/en not_active Expired
- 1985-04-01 CN CN 85101161 patent/CN1011151B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN85101161A (en) | 1986-09-03 |
| CN1011151B (en) | 1991-01-09 |
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