CA1184865A - Process for breaking petroleum emulsions - Google Patents
Process for breaking petroleum emulsionsInfo
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- CA1184865A CA1184865A CA000404726A CA404726A CA1184865A CA 1184865 A CA1184865 A CA 1184865A CA 000404726 A CA000404726 A CA 000404726A CA 404726 A CA404726 A CA 404726A CA 1184865 A CA1184865 A CA 1184865A
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Abstract
PROCESS FOR BREAKING PETROLEUM EMULSIONS
Abstract of the Disclosure A process for breaking petroleum emulsions of the oil-in-water type obtained by tertiary recovery methods in which said emulsion is first subjected to at least one first nonionic demulsifier of the alkoxylated alkyl phenol aldehyde resin type and the water phase and oil phase formed are recovered. Subsequently the water phase obtained is further subjected to at least one second nonionic demulsifier of the ethoxylated alkyl phenol aldehyde resin type and the oil phase formed is recovered. The process of the invention provides for the removal of an increased amount of oil from tertiary oil recovery oil-in-water emulsions.
Abstract of the Disclosure A process for breaking petroleum emulsions of the oil-in-water type obtained by tertiary recovery methods in which said emulsion is first subjected to at least one first nonionic demulsifier of the alkoxylated alkyl phenol aldehyde resin type and the water phase and oil phase formed are recovered. Subsequently the water phase obtained is further subjected to at least one second nonionic demulsifier of the ethoxylated alkyl phenol aldehyde resin type and the oil phase formed is recovered. The process of the invention provides for the removal of an increased amount of oil from tertiary oil recovery oil-in-water emulsions.
Description
i5 PROCESS FOR BREAKING PETROLEUI!I EMULSIONS
Background of the Invention 1~ Field of the Invention The invention relates to processes for the enhanced reCQvery of oil in which the oil is obtained from a producing well in an oil-in-water emulsion or dispersion.
Background of the Invention 1~ Field of the Invention The invention relates to processes for the enhanced reCQvery of oil in which the oil is obtained from a producing well in an oil-in-water emulsion or dispersion.
2. Description of the Prior Art Processes for enhanced oil recovery can involve the injection of heat, chemicals, or gases into an oil reservoir in order to lower the ViSCQsity of the oil, strip it from the rock surface, and push it towards producing wells. Enhanced oil recovery processes are often called tertiary oil recovery processes because they often follow primary (pressurized) and secondary (water flooding) recovery methods at a well field It has been estimated that an average of 67% of the original-oil-in-place remains in the reservoir rocks subsequent to primary and secondary methods of oil recovery.
Where the oil is recovered by tertiary methods in combination with a large amount o water, as is the case generally with methods such as micellar-polymer flooding techniques, the separation of the produced oil and water mixture into two phases is generally accomplished by the addition of demulsifying agents~ These vary in effective-ness with various crude mineral oils and with the type of surfactant utilized to reduce oil-water interfacial tension in recovering the oil by tertiary methods. As demulsifying i5 agents, alkyl sulfates and alkyl aryl sulfonates as well as petroleum sulfonates in the form of amine salts already have been proposed. Also, the addition products of ethylene oxide with active hydrogen compounds such as alkyl phenols, fatty acids, fatty alcohols, and alkyl phenol aldehyde resins have also been proposed. Despite the large number of demulsifiers available on the market, it has not been possible to obtain efficient recovery of the petroleum oil contained in emulsion form in aqueous media from tertiary oil recovery processes. The alkyl phenol aldehyde resin alkoxylates as a class are more particularly described in U.S. 2,49g,370 for use in a process for breaking petroleum emulsions~
Summarv of the Invention . _ ~ .
It has been found that petroleum emulsions of the oil-in-water type obtained by tertiary petroleum oil recovery methods, particularly micellar-polymer flooding enhanced oil recovery techniques, can be effectively separated into oil and water phases by subjecting the oil-in-water emulsion obtained from a producing well to the action of at least one first nonionic demulsifier selected from the group consisting of the reaction product of ethylene oxidP and at least one other lower alkylene oxide with an alkyl phenol aldehyde resin and thereafter separating and recovering a water phase and an oil phase.
Thereafter, the water phase is subjected to at least one second nonionic demulsifier selected from the group consisting o the reaction product of ethylene oxide with an alkyl phenol aldehyde resin and thereafter the oil phase is recovered therefrom.
Detailed Description of the Invention The demulsifiers o the invention are suitable for demulsifying oil-in-water emulsions generally, but are particularly suitable for demulsifying those petroleum ~
sul~onate-derived oil-water-emulsions obtained by tertiary recovery methods, particularly micellar-polymer flooding methods of tertiary oil recovery. In the micellar-polymer flooding process, it is common to proceed in three stages, namely, preflush, micellar-flood (displacing fluid), and mobility control ~polymer) flood and brine or water as driving fluid.
The preflush is used to adjust the salini~y oE the reservoir brine and cause precipitation and removal of divalent ions from the brine which would otherwise cause increased adsorption of surfactant onto the rock.
Sacrificial agents such as sodium tripolyphosphate, sodium carbonate, nitrilotriacetic acid and pyridines are also sometimes introduced into the well to Eurther reduce surfactant adsorption and improve wetting of the reservoir rock surfaces.
The micellar-flood is the primary active chemical component utilized in micellar-polymer flooding processes~
Generally a petroleum sulfonate surfactant is utilized at a concentration of about 2 to about 17 percent active i5 ingredient in water in order to reduce oil~water interfacial tension from roughly 35 to less than 0.01 dynes per centi-meter. As interfacial tension is reduced in the well, micelles (micro-emulsions) of oil and water are Eormed.
This allows the oil to be carried along in the surfactant-water flood as a stable, single-phase, low-viscosity medium. In addition to aqueous mixtures of petroleum sulfonater the petroleum sulfonate can be utilized in the well in combination with soluble oil rather than water as a carrier.
The amount of petroleum sulfonate utilized in the well is determined by the rate of dilution by the oil in the brine of the well and adsorption on the well rock surfaces. The petroleum sulfonates are anionic and there-fore the negative:Ly charged hydrophilic end of the molecule will be attracted to the positively charged sites on the reservoir surfaceO The duration of flood and the quantity of surfactant employed is a function of the pore volume which is equal to the volume of all pores and fractures in a reservoir which can be contacted by fluids. Usually the petroleum sulfonate constitutes 0.1 to about 12% of the pore volume at a 5 to about 11% by weight active petroleum sulfonate concentration in water.
Flooding of the well is typically designed to be at an injection rate of one foot per day through the reservoir but the actual rate can be much less should injection problems occur. In the well, the formation of micelles ~micro-emulsions) by the contact of the petroleum sulfonate with the oil can in itself increase the viscosity of the mixture of petroleum sulfonate and water or oil carrier enough to positively influence sweep efficiency.
However, it is occasionally necessary to enhance the viscosity of the petroleum sulfonate and carrier mixture in order to avoid by-passing of residual oil.
The petroleum sulfonates generally used in the formation of microemulsions within the well in tertiary oil recovery processes are selected from compounds having the following general formulaD
R -o-(cnH2no)m~R2-so3x wherein Rl is a henzene, toluene or xylene monovalent radical having a linear or branched alkyl substituent containing from about 6 to about 24 carbon atoms; R2 is an alkyl, cycloalkyl~ alkene or aryl radical containing up to about 8 carbon atoms; R3 is a hydrogen atom, a hydroxyl radical, or an aliphatic radical containing from 1 to about 8 carbon atoms; n has a value of 2 or 3; m generally has a value of from 1 to about 20; and X is a cation selected from ammonium and alkali metal ions.
Petroleum sulfonates have classically been produced as by-products of white oil manufacture. They are characterized as the oil-soluble, monosulfated "mahogany"
sulfonates and, as the water-soluble, disulfonated "green acid sulfonates". Typical mahogany sulfonates have a broad equivalent-weight distribution. The equivalent weight for sulfonates is the molecular weight divided by the number of sulfonate groups present in the molecule. The water-soluble, low equivalent weight compounds in these products tend to solubilize the higher molecular weight, oil-soluble compounds. The available range of average equivalent weights (about 350 to 550) provides sufficient variety for blending to obtain the optimum surfactant system. Recently, replacements of the traditional mahogany sulfonates have become available. Thus, petroleum sulfonates can be produced as by-products of linear alkyl benzene manufacture by reacting a suitable olefin with benzene and then sulfonating. They can also be manufactured by treating a petroleum product with SO3.
Generally, the petroleum sulfonates are utilized in combination with co~surfactants and co-solvents. Co-surfactants can be oxyalkylated linear or branched chain alcohols, sulfated ethoxylated alcohols, ethoxylated alkyl phenols, naphthylene sulfonates, ligno-sulfonates~ or tall oil sulfonates. Useful co-solvents are alcohols having 3 to about 8 carbon atoms such as isopropyl, isobutyl, amyl, and hexyl alcohols. The co-solvents reduce the surface tension of small drops of oil so they become more mobile through the pores of the rock strata.
Sodium tripolyphosphate and other agents are oEten advantageously used in conjunction with the petroleum sulfonates as so-called "sacrificial agents" to tie up multivalent ions 50 as to lower the adsorption of petroleum sulfonate onto the rock and increase the tolerance of the petroleum sulfonate to oil reservoir brines. An additional advantage is the increase in reservoir pH which occurs upon adding these agents to the reservoir. This effect is important because generally alkaline conditions increase the tertiary oil recovery efficiency of surfactant solutions.
Alternatively, sodium carbonate has also been utilized to precipitate divalent ions within the well. In addition, ligno-sulfonates are alternatively useful sacrificial agents. These materials can be used to impart a negative charge to rock surfaces, les~ening the loss of the anionic petroleum sulfonates. Ligno-sulfonates also lower inter-facial tension as well as reduce surfactant adsorption thus increasing oil recovery.
Tertiary oil recovery methods often utilize a mobility control (polymer) flood. Instead of the usual brine or surface water, polymer thickened water can be used as the driving fluid to move the petroleum sulfonate water mixture toward the production well from the injection well in which it is added. Usually, the drive Eluid is injected following the injection of the micellar flood containing the petroleum sulfonate surfactant. In polymer flooding, the molecular weight of the polymer is generally tailored to the i5 conditions of the reservoir. A high molecular weight polymer will yield hiyh viscosities at low concentrations but may cause excessive plugging in low permeabili~y formations or may not be injectable readily enough for economic development. Typically, in a medium specific gravity crude reservior, about 1.5 times the pore volume of polymer solution is injected. Polymers that are effective water thickeners are acrylamide/acrylic a~id copolymers, acrylamide/acrylic acid~vinyl terpolymers, polysaccharides, polyethylene oxide, polycarboxymethyl cellulose, and hydroxyethyl cellulose.
In addition to the effect of all the above additives on the emulsion stability of the mixture of oil and water recovered from the producing well in tertiary oil recovery methods, the stability of the emulsion is also affected by the formation of surfactants by the various alkaline materials added in the injection well upon reaction with the acids normally present in the petroleum oil reservolr .
The alkoxylated alkyl phenol aldehyde demulsifiers and the ethoxylated alkyl phenol aldehyde demulsifiers employed in accordance with the process of the present invention are liquid substances which can be dispersed or dissolved in water and certain organic solvents. They can be added to the oil-in-water petroleum emulsion obtained from the producing well either directly or in the form of concentrated solutions or dispersions. Good results are also obtained when the demulsifiers useful in the process of the invention are dissolved in small amounts of organic solvents such as, for example, toluene or methanol or high aromatic naphtha and subsequently added directly to the petroleum emulsion or further diluted with wa~er prior to addition to the petroleum emulsion. Generally, the surfactant demulsifiers are added to the oil-in-water produced mixtures as about 10 to about 50 percent, prefer-ably abou~ 20 to about 40 percent, most preferably about 25 to abou~ 30 percen~, all by weight~ active aqueous solutions.
The alkoxylated phenol aldehyde resin demulsifiers useful in the process of the present invention are reaction products of ethylene oxide and at least one other lower three to four carbon atom alkylene oxide such as propylene oxide, butylene oxide and tetrahydrofuran with an alkyl phenol aldehyde resin. The useful alkyl phenol aldehyde resins are soluble in organic solvents and contain free hydroxyl groups. These are in turn reacted with ethylene oxide, or ethylene oxide and at least one other lower alkylene oxide as recited above to prepare the demulsifiers useful in the process of the invention.
Generally, alkyl phenols are required to prepare the alkyl phenol aldehyde resins. These are preferably monoalkyl phenols with straight chain or branched alkyl groups having about 4 to about 18, preferably about 6 to about 14, carbon atoms in the ortho or para position. These g_ monoalkyl phenols are converted into resins preferably by reaction with formaldehyde or substances which yield formaldehyde under the conditions of the acid or alkaline condensation reaction utilized. For instance, acetaldehyde and higher aldehydes such as propionaldehyde or butyr-aldehyde can also be used alone or in combination with other of said aldehydes or with formaldehyde in the preparation of these resins. The quantity of aldehyde utilized during condensation generally amounts to approximately 0.5 to about 2~0 moles, preferably about 0.9 to about 1.1 moles, per mole of phenol. The reaction takes place in a known manner in the presence of an acid or an alkaline catalyst with or without the addition oE inert solvents.
The alkyl phenol-formaldehyde resins are oxy-ethylated or oxyalkylated using oxyalkylation or oxyethyla-tion agents, the amount of which is employed depends partly upon the length of the alkyl groups contained in the starting alkyl phenol aldehyde resin. Generally, about 2 to about 20 moles, preferably about 4 to about 12 moles, and most preferably about 4 to about 10 moles, of ethylene oxide or a combination of ethylene oxide and one other lower alkylene oxide per single hydroxyl equivalent of the alkyl phenol aldehyde resin are used so as to obtain a demulsifier having a molecular weight of about 500 to about 25,000, preferably about 1000 to about 15,000, and most preferably about 1000 to about 5000. These contain about 10 percent to about 90 percent, preferably about 20 to about 80 percent, by weight of ethylene oxide residue or mixed alkylene oxide residues based upon the total weight of the demulsifier.
A preferred de~ulsifier is a block copolymer prepared by first oxypropylating the reaction product of an alkyl phenol aldehyde such as the reaction product of nonyl phenol and formaldehyde to add about 4 to about 12 moles of the residue of propylene oxide per hydroxyl equivalent of said reaction product and second oxyethylating said oxy-propylated reaction product to add about 4 to about 12 moles of ethylene oxide residue per hydroxyl equivalent.
Both block and heteric polymerizates of ethylene oxide and one other lower alkylene oxide as well as ethoxylates of said alkyl phenol aldehyde resin are useful demulsifiers. Methods for the preparation of these demulsi-fiers are generally described in U.S. 2,499,370 .
The following examples illustrate the various aspects of the process of the invention. Where not other-wise specified throughout this specification and claims, temperatures are given in degrees centigrade and parts, percentages, and proportions are by weight.
Example 1 Utilizing a crude petroleum-water ~oil-in-water) mixture obtained by tertiary oil recovery means at the Gary Energy Micellar Flood Project in the Belle Creek field, Belle Creek, Montana, the process of the invention was evaluated by bottle testing.
Normal production data is as follows for the well.
Volume of produced fluid 2000 barrels per day Volume of produced oil 240 barrels per day Volume of produced water 1760 barrels per day The bottle testing procedure was as follows:
utilizing a sample size of 800 cc and a demulsifier solution active concentration of 10 percent by weight, 2.4 cc of a first demulsifier under test was injected into the 800 cc sample of produced oil-in-water emulsion fluid. The sample was shaken 100 times and the oil was allowed to separate from an aqueous layer. The oil phase was pippetted off and the remaining produced water was treated by injecting 0.8 cc of a second 10 percent by weight demulsifier solution under test and shaken 100 times. The oil phase produced was removed and the amount of oil remaining in the water determined.
The demulsifiers utilized are described as follows:
Demulsifer A is a block copolymer of a nonylphenol formaldehyde reaction product (resin) containing 4O3 moles of propylene oxide per phenol (hydroxyl) equivalent of said nonylphenol formaldehyde reaction product and 5.7 moles of ethylene oxide per phenol equivalent of the nonylphenol formaldehyde resin. The block copolymer is first oxy-propylated and then oxyethylated in the preparation thereof.
Demulsifier B is an ethoxylated nonylphenol formaldehyde resin containing 7.8 moles of ethylene oxide residue per phenol equivalent of the nonylphenol formaldehyde resin. Both the nonylphenol formaldehyde resin and the alkoxylated or ethoxylated derivatives thereof are produced by known processes using an acid or a basic catalyst.
The use of a 10 percent by weight aqueous solutions of these demulsifiers in accordance with the test procedure described above resulted in 2000 parts per million of oil remaining in the aqueous phase subsequent to the addition and shaking of the sample with Demulsifier A
included therein and 40 parts per million of oil remaining in the aqueous phase subsequent to the addition of Demulsifier B and the shaking of the sample prior to evaluation.
Example 2 (Comparative axample forming no part of this invention) Example 1 was repeated utilizing the same demulsifiers ~ut reversing the order in which they are used, namaly, Demulsifier B was utilized first in the amount oE
2.4 cc and Demulsifier A was utilizad second in the amount of 0.8 cc of the 10 percent by weight aqueous solutions thereof. The amount of oil remaining in the aqueous phase was considerably higher in each stage oE the testing indicating inferior results by reversing the order of use of the demulsifier compositions.
Example 3 (Control sample forming no part of this invention~
The procedure of Example 1 was modified so that a mixture of Demulsifier A and B were utilized in the amount of 2.4 cc of Demulsifier A and 0.8 cc of Demulsifier B. The mixture was added to 800 cc of the oil-in-water emuls.ion produced fluid utilized in Examples 1 and 20 After shaking the sample includinq the combination of demulsifiers for 100 times, an oil phase and a water phase were allowed to form and the oil phase was pippetted off. The remaining produced water phase was found to have substantially greater oil content than that obtained after the process of Example 1.
While this invention has been described with reference to certain specific embodiments, it will be recognized by those skilled in this art that many variations are possible without departing from the scope and spirit of the invention and it will be understood that it is intended to cover all changes and modifications oE the invention disclosed herein or the purposes of illustration which do not constitute departures from the spirit and scope o the invention.
Where the oil is recovered by tertiary methods in combination with a large amount o water, as is the case generally with methods such as micellar-polymer flooding techniques, the separation of the produced oil and water mixture into two phases is generally accomplished by the addition of demulsifying agents~ These vary in effective-ness with various crude mineral oils and with the type of surfactant utilized to reduce oil-water interfacial tension in recovering the oil by tertiary methods. As demulsifying i5 agents, alkyl sulfates and alkyl aryl sulfonates as well as petroleum sulfonates in the form of amine salts already have been proposed. Also, the addition products of ethylene oxide with active hydrogen compounds such as alkyl phenols, fatty acids, fatty alcohols, and alkyl phenol aldehyde resins have also been proposed. Despite the large number of demulsifiers available on the market, it has not been possible to obtain efficient recovery of the petroleum oil contained in emulsion form in aqueous media from tertiary oil recovery processes. The alkyl phenol aldehyde resin alkoxylates as a class are more particularly described in U.S. 2,49g,370 for use in a process for breaking petroleum emulsions~
Summarv of the Invention . _ ~ .
It has been found that petroleum emulsions of the oil-in-water type obtained by tertiary petroleum oil recovery methods, particularly micellar-polymer flooding enhanced oil recovery techniques, can be effectively separated into oil and water phases by subjecting the oil-in-water emulsion obtained from a producing well to the action of at least one first nonionic demulsifier selected from the group consisting of the reaction product of ethylene oxidP and at least one other lower alkylene oxide with an alkyl phenol aldehyde resin and thereafter separating and recovering a water phase and an oil phase.
Thereafter, the water phase is subjected to at least one second nonionic demulsifier selected from the group consisting o the reaction product of ethylene oxide with an alkyl phenol aldehyde resin and thereafter the oil phase is recovered therefrom.
Detailed Description of the Invention The demulsifiers o the invention are suitable for demulsifying oil-in-water emulsions generally, but are particularly suitable for demulsifying those petroleum ~
sul~onate-derived oil-water-emulsions obtained by tertiary recovery methods, particularly micellar-polymer flooding methods of tertiary oil recovery. In the micellar-polymer flooding process, it is common to proceed in three stages, namely, preflush, micellar-flood (displacing fluid), and mobility control ~polymer) flood and brine or water as driving fluid.
The preflush is used to adjust the salini~y oE the reservoir brine and cause precipitation and removal of divalent ions from the brine which would otherwise cause increased adsorption of surfactant onto the rock.
Sacrificial agents such as sodium tripolyphosphate, sodium carbonate, nitrilotriacetic acid and pyridines are also sometimes introduced into the well to Eurther reduce surfactant adsorption and improve wetting of the reservoir rock surfaces.
The micellar-flood is the primary active chemical component utilized in micellar-polymer flooding processes~
Generally a petroleum sulfonate surfactant is utilized at a concentration of about 2 to about 17 percent active i5 ingredient in water in order to reduce oil~water interfacial tension from roughly 35 to less than 0.01 dynes per centi-meter. As interfacial tension is reduced in the well, micelles (micro-emulsions) of oil and water are Eormed.
This allows the oil to be carried along in the surfactant-water flood as a stable, single-phase, low-viscosity medium. In addition to aqueous mixtures of petroleum sulfonater the petroleum sulfonate can be utilized in the well in combination with soluble oil rather than water as a carrier.
The amount of petroleum sulfonate utilized in the well is determined by the rate of dilution by the oil in the brine of the well and adsorption on the well rock surfaces. The petroleum sulfonates are anionic and there-fore the negative:Ly charged hydrophilic end of the molecule will be attracted to the positively charged sites on the reservoir surfaceO The duration of flood and the quantity of surfactant employed is a function of the pore volume which is equal to the volume of all pores and fractures in a reservoir which can be contacted by fluids. Usually the petroleum sulfonate constitutes 0.1 to about 12% of the pore volume at a 5 to about 11% by weight active petroleum sulfonate concentration in water.
Flooding of the well is typically designed to be at an injection rate of one foot per day through the reservoir but the actual rate can be much less should injection problems occur. In the well, the formation of micelles ~micro-emulsions) by the contact of the petroleum sulfonate with the oil can in itself increase the viscosity of the mixture of petroleum sulfonate and water or oil carrier enough to positively influence sweep efficiency.
However, it is occasionally necessary to enhance the viscosity of the petroleum sulfonate and carrier mixture in order to avoid by-passing of residual oil.
The petroleum sulfonates generally used in the formation of microemulsions within the well in tertiary oil recovery processes are selected from compounds having the following general formulaD
R -o-(cnH2no)m~R2-so3x wherein Rl is a henzene, toluene or xylene monovalent radical having a linear or branched alkyl substituent containing from about 6 to about 24 carbon atoms; R2 is an alkyl, cycloalkyl~ alkene or aryl radical containing up to about 8 carbon atoms; R3 is a hydrogen atom, a hydroxyl radical, or an aliphatic radical containing from 1 to about 8 carbon atoms; n has a value of 2 or 3; m generally has a value of from 1 to about 20; and X is a cation selected from ammonium and alkali metal ions.
Petroleum sulfonates have classically been produced as by-products of white oil manufacture. They are characterized as the oil-soluble, monosulfated "mahogany"
sulfonates and, as the water-soluble, disulfonated "green acid sulfonates". Typical mahogany sulfonates have a broad equivalent-weight distribution. The equivalent weight for sulfonates is the molecular weight divided by the number of sulfonate groups present in the molecule. The water-soluble, low equivalent weight compounds in these products tend to solubilize the higher molecular weight, oil-soluble compounds. The available range of average equivalent weights (about 350 to 550) provides sufficient variety for blending to obtain the optimum surfactant system. Recently, replacements of the traditional mahogany sulfonates have become available. Thus, petroleum sulfonates can be produced as by-products of linear alkyl benzene manufacture by reacting a suitable olefin with benzene and then sulfonating. They can also be manufactured by treating a petroleum product with SO3.
Generally, the petroleum sulfonates are utilized in combination with co~surfactants and co-solvents. Co-surfactants can be oxyalkylated linear or branched chain alcohols, sulfated ethoxylated alcohols, ethoxylated alkyl phenols, naphthylene sulfonates, ligno-sulfonates~ or tall oil sulfonates. Useful co-solvents are alcohols having 3 to about 8 carbon atoms such as isopropyl, isobutyl, amyl, and hexyl alcohols. The co-solvents reduce the surface tension of small drops of oil so they become more mobile through the pores of the rock strata.
Sodium tripolyphosphate and other agents are oEten advantageously used in conjunction with the petroleum sulfonates as so-called "sacrificial agents" to tie up multivalent ions 50 as to lower the adsorption of petroleum sulfonate onto the rock and increase the tolerance of the petroleum sulfonate to oil reservoir brines. An additional advantage is the increase in reservoir pH which occurs upon adding these agents to the reservoir. This effect is important because generally alkaline conditions increase the tertiary oil recovery efficiency of surfactant solutions.
Alternatively, sodium carbonate has also been utilized to precipitate divalent ions within the well. In addition, ligno-sulfonates are alternatively useful sacrificial agents. These materials can be used to impart a negative charge to rock surfaces, les~ening the loss of the anionic petroleum sulfonates. Ligno-sulfonates also lower inter-facial tension as well as reduce surfactant adsorption thus increasing oil recovery.
Tertiary oil recovery methods often utilize a mobility control (polymer) flood. Instead of the usual brine or surface water, polymer thickened water can be used as the driving fluid to move the petroleum sulfonate water mixture toward the production well from the injection well in which it is added. Usually, the drive Eluid is injected following the injection of the micellar flood containing the petroleum sulfonate surfactant. In polymer flooding, the molecular weight of the polymer is generally tailored to the i5 conditions of the reservoir. A high molecular weight polymer will yield hiyh viscosities at low concentrations but may cause excessive plugging in low permeabili~y formations or may not be injectable readily enough for economic development. Typically, in a medium specific gravity crude reservior, about 1.5 times the pore volume of polymer solution is injected. Polymers that are effective water thickeners are acrylamide/acrylic a~id copolymers, acrylamide/acrylic acid~vinyl terpolymers, polysaccharides, polyethylene oxide, polycarboxymethyl cellulose, and hydroxyethyl cellulose.
In addition to the effect of all the above additives on the emulsion stability of the mixture of oil and water recovered from the producing well in tertiary oil recovery methods, the stability of the emulsion is also affected by the formation of surfactants by the various alkaline materials added in the injection well upon reaction with the acids normally present in the petroleum oil reservolr .
The alkoxylated alkyl phenol aldehyde demulsifiers and the ethoxylated alkyl phenol aldehyde demulsifiers employed in accordance with the process of the present invention are liquid substances which can be dispersed or dissolved in water and certain organic solvents. They can be added to the oil-in-water petroleum emulsion obtained from the producing well either directly or in the form of concentrated solutions or dispersions. Good results are also obtained when the demulsifiers useful in the process of the invention are dissolved in small amounts of organic solvents such as, for example, toluene or methanol or high aromatic naphtha and subsequently added directly to the petroleum emulsion or further diluted with wa~er prior to addition to the petroleum emulsion. Generally, the surfactant demulsifiers are added to the oil-in-water produced mixtures as about 10 to about 50 percent, prefer-ably abou~ 20 to about 40 percent, most preferably about 25 to abou~ 30 percen~, all by weight~ active aqueous solutions.
The alkoxylated phenol aldehyde resin demulsifiers useful in the process of the present invention are reaction products of ethylene oxide and at least one other lower three to four carbon atom alkylene oxide such as propylene oxide, butylene oxide and tetrahydrofuran with an alkyl phenol aldehyde resin. The useful alkyl phenol aldehyde resins are soluble in organic solvents and contain free hydroxyl groups. These are in turn reacted with ethylene oxide, or ethylene oxide and at least one other lower alkylene oxide as recited above to prepare the demulsifiers useful in the process of the invention.
Generally, alkyl phenols are required to prepare the alkyl phenol aldehyde resins. These are preferably monoalkyl phenols with straight chain or branched alkyl groups having about 4 to about 18, preferably about 6 to about 14, carbon atoms in the ortho or para position. These g_ monoalkyl phenols are converted into resins preferably by reaction with formaldehyde or substances which yield formaldehyde under the conditions of the acid or alkaline condensation reaction utilized. For instance, acetaldehyde and higher aldehydes such as propionaldehyde or butyr-aldehyde can also be used alone or in combination with other of said aldehydes or with formaldehyde in the preparation of these resins. The quantity of aldehyde utilized during condensation generally amounts to approximately 0.5 to about 2~0 moles, preferably about 0.9 to about 1.1 moles, per mole of phenol. The reaction takes place in a known manner in the presence of an acid or an alkaline catalyst with or without the addition oE inert solvents.
The alkyl phenol-formaldehyde resins are oxy-ethylated or oxyalkylated using oxyalkylation or oxyethyla-tion agents, the amount of which is employed depends partly upon the length of the alkyl groups contained in the starting alkyl phenol aldehyde resin. Generally, about 2 to about 20 moles, preferably about 4 to about 12 moles, and most preferably about 4 to about 10 moles, of ethylene oxide or a combination of ethylene oxide and one other lower alkylene oxide per single hydroxyl equivalent of the alkyl phenol aldehyde resin are used so as to obtain a demulsifier having a molecular weight of about 500 to about 25,000, preferably about 1000 to about 15,000, and most preferably about 1000 to about 5000. These contain about 10 percent to about 90 percent, preferably about 20 to about 80 percent, by weight of ethylene oxide residue or mixed alkylene oxide residues based upon the total weight of the demulsifier.
A preferred de~ulsifier is a block copolymer prepared by first oxypropylating the reaction product of an alkyl phenol aldehyde such as the reaction product of nonyl phenol and formaldehyde to add about 4 to about 12 moles of the residue of propylene oxide per hydroxyl equivalent of said reaction product and second oxyethylating said oxy-propylated reaction product to add about 4 to about 12 moles of ethylene oxide residue per hydroxyl equivalent.
Both block and heteric polymerizates of ethylene oxide and one other lower alkylene oxide as well as ethoxylates of said alkyl phenol aldehyde resin are useful demulsifiers. Methods for the preparation of these demulsi-fiers are generally described in U.S. 2,499,370 .
The following examples illustrate the various aspects of the process of the invention. Where not other-wise specified throughout this specification and claims, temperatures are given in degrees centigrade and parts, percentages, and proportions are by weight.
Example 1 Utilizing a crude petroleum-water ~oil-in-water) mixture obtained by tertiary oil recovery means at the Gary Energy Micellar Flood Project in the Belle Creek field, Belle Creek, Montana, the process of the invention was evaluated by bottle testing.
Normal production data is as follows for the well.
Volume of produced fluid 2000 barrels per day Volume of produced oil 240 barrels per day Volume of produced water 1760 barrels per day The bottle testing procedure was as follows:
utilizing a sample size of 800 cc and a demulsifier solution active concentration of 10 percent by weight, 2.4 cc of a first demulsifier under test was injected into the 800 cc sample of produced oil-in-water emulsion fluid. The sample was shaken 100 times and the oil was allowed to separate from an aqueous layer. The oil phase was pippetted off and the remaining produced water was treated by injecting 0.8 cc of a second 10 percent by weight demulsifier solution under test and shaken 100 times. The oil phase produced was removed and the amount of oil remaining in the water determined.
The demulsifiers utilized are described as follows:
Demulsifer A is a block copolymer of a nonylphenol formaldehyde reaction product (resin) containing 4O3 moles of propylene oxide per phenol (hydroxyl) equivalent of said nonylphenol formaldehyde reaction product and 5.7 moles of ethylene oxide per phenol equivalent of the nonylphenol formaldehyde resin. The block copolymer is first oxy-propylated and then oxyethylated in the preparation thereof.
Demulsifier B is an ethoxylated nonylphenol formaldehyde resin containing 7.8 moles of ethylene oxide residue per phenol equivalent of the nonylphenol formaldehyde resin. Both the nonylphenol formaldehyde resin and the alkoxylated or ethoxylated derivatives thereof are produced by known processes using an acid or a basic catalyst.
The use of a 10 percent by weight aqueous solutions of these demulsifiers in accordance with the test procedure described above resulted in 2000 parts per million of oil remaining in the aqueous phase subsequent to the addition and shaking of the sample with Demulsifier A
included therein and 40 parts per million of oil remaining in the aqueous phase subsequent to the addition of Demulsifier B and the shaking of the sample prior to evaluation.
Example 2 (Comparative axample forming no part of this invention) Example 1 was repeated utilizing the same demulsifiers ~ut reversing the order in which they are used, namaly, Demulsifier B was utilized first in the amount oE
2.4 cc and Demulsifier A was utilizad second in the amount of 0.8 cc of the 10 percent by weight aqueous solutions thereof. The amount of oil remaining in the aqueous phase was considerably higher in each stage oE the testing indicating inferior results by reversing the order of use of the demulsifier compositions.
Example 3 (Control sample forming no part of this invention~
The procedure of Example 1 was modified so that a mixture of Demulsifier A and B were utilized in the amount of 2.4 cc of Demulsifier A and 0.8 cc of Demulsifier B. The mixture was added to 800 cc of the oil-in-water emuls.ion produced fluid utilized in Examples 1 and 20 After shaking the sample includinq the combination of demulsifiers for 100 times, an oil phase and a water phase were allowed to form and the oil phase was pippetted off. The remaining produced water phase was found to have substantially greater oil content than that obtained after the process of Example 1.
While this invention has been described with reference to certain specific embodiments, it will be recognized by those skilled in this art that many variations are possible without departing from the scope and spirit of the invention and it will be understood that it is intended to cover all changes and modifications oE the invention disclosed herein or the purposes of illustration which do not constitute departures from the spirit and scope o the invention.
Claims (11)
1. A process for breaking petroleum emulsions of the oil-in-water type obtained by tertiary oil recovery methods comprising (A) subjecting an oil in-water emulsion obtained by tertiary oil recovery methods to the action of at least one first nonionic demulsifier selected from the group consisting of the reaction product of ethylene oxide and at least one other lower alkylene oxide with the reaction product of an alkyl phenol and an aldehyde, thereafter (B) separating a water phase and an oil phase and recovering said oil phase, thereafter (C) subjecting said water phase to at least one second nonionic demulsifier selected from the group consisting of the reaction product of ethylene oxide with the reaction product of an alkyl phenol and an aldehyde, and thereafter (D) separating and recovering an oil phase therefrom.
2. The process of claim 1 wherein said alkyl phenol is a monoalkyl phenol having straight or branched chain alkyl groups having about 4 to about 18 carbon atoms in the ortho or para position.
3. The process of claim 2 wherein said aldehyde is selected from at least one of the group consisting of formaldehyde or substances which yield formaldehyde under acid or basic condensation conditions.
4. The process of claim 3 wherein said reaction product of an alkyl phenol and an aldehyde is prepared by reacting about 0.5 to about 2.0 moles of aldehyde per mole of phenol in the presence of an acid or alkaline catalyst and said aldehyde is selected from the group consisting of at least one of acetaldehyde, butyraldehyde, and propion-aldehyde or mixtures thereof with formaldehyde.
5. The process of claim 1 wherein said first nonionic demulsifier is prepared by oxyalkylation in the presence of an acid or an alkaline catalyst with or without the presence of inert solvents.
6. The process of claim 5 wherein said other lower alkylene oxide is selected from at least one of the group consisting of propylene oxide, butylene oxide, and tetrahydrofuran.
7. The process of claim 6 wherein said first nonionic demulsifier has a molecular weight about 500 to about 25,000 and contains about 10 percent to about 90 percent by weight of alkylene oxide residue.
8. The process of claim 1 wherein said second nonionic demulsifier is prepared by oxyethylating in the presence of an acid or an alkaline catalyst with or without the presence of inert solvents.
9. The process of claim 8 wherein said second nonionic demulsifier has a molecular of about 500 to about 25,000 and contains about 10 to about 90 percent by weight of ethylene oxide.
10. The process of claim 7 wherein said first nonionic demulsifier is a block copolymer prepared by first oxypropylating said alkyl phenol aldehyde reaction product to add about 4 to about 12 moles of the residue of propylene oxide per hydroxyl equivalent of the alkyl phenol aldehyde reaction product, and second oxyethylating the product obtained to add about 4 to about 12 moles of ethylene oxide residue per hydroxyl equivalent.
11. The process of claim 9 wherein about 4 to about 12 moles of ethylene oxide is added per hydroxyl equivalent of said alkyl phenol aldehyde reaction product.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US28134881A | 1981-07-08 | 1981-07-08 | |
| US281,348 | 1981-07-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1184865A true CA1184865A (en) | 1985-04-02 |
Family
ID=23076903
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000404726A Expired CA1184865A (en) | 1981-07-08 | 1982-06-08 | Process for breaking petroleum emulsions |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1184865A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4812225A (en) * | 1987-02-10 | 1989-03-14 | Gulf Canada Resources Limited | Method and apparatus for treatment of oil contaminated sludge |
| DE4009760A1 (en) * | 1990-03-27 | 1991-10-02 | Bayer Ag | METHOD FOR SEPARATING OIL IN WATER EMULSIONS |
| DE10057044A1 (en) * | 2000-11-17 | 2002-05-29 | Clariant Gmbh | Resins from alkylphenols and glyoxalic acid derivatives, and their use as emulsion breakers |
| DE10057043A1 (en) * | 2000-11-17 | 2002-05-29 | Clariant Gmbh | Alkylphenol glyoxal resins and their use as emulsion breakers |
| US7026363B2 (en) | 2001-02-20 | 2006-04-11 | Clariant Gmbh | Alkoxylated polyglycerols and their use as demulsifiers |
| WO2018129228A1 (en) * | 2017-01-06 | 2018-07-12 | Saudi Arabian Oil Company | Methods and systems for optimizing demulsifier and wash water injection rates in gas oil separations plants |
| CN111303350A (en) * | 2020-04-01 | 2020-06-19 | 广东石油化工学院 | Polyether demulsifier based on alcohol amine modified phenolic resin and synthetic method thereof |
-
1982
- 1982-06-08 CA CA000404726A patent/CA1184865A/en not_active Expired
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4812225A (en) * | 1987-02-10 | 1989-03-14 | Gulf Canada Resources Limited | Method and apparatus for treatment of oil contaminated sludge |
| DE4009760A1 (en) * | 1990-03-27 | 1991-10-02 | Bayer Ag | METHOD FOR SEPARATING OIL IN WATER EMULSIONS |
| EP0448821A1 (en) * | 1990-03-27 | 1991-10-02 | Bayer Ag | Process for breaking oil-in-water emulsions |
| DE10057044A1 (en) * | 2000-11-17 | 2002-05-29 | Clariant Gmbh | Resins from alkylphenols and glyoxalic acid derivatives, and their use as emulsion breakers |
| DE10057043A1 (en) * | 2000-11-17 | 2002-05-29 | Clariant Gmbh | Alkylphenol glyoxal resins and their use as emulsion breakers |
| DE10057044B4 (en) * | 2000-11-17 | 2004-05-06 | Clariant Gmbh | Resins from alkylphenols and glyoxalic acid derivatives, and their use as emulsion breakers |
| DE10057043B4 (en) * | 2000-11-17 | 2004-05-06 | Clariant Gmbh | Alkylphenol glyoxal resins and their use as emulsion breakers |
| US7026363B2 (en) | 2001-02-20 | 2006-04-11 | Clariant Gmbh | Alkoxylated polyglycerols and their use as demulsifiers |
| WO2018129228A1 (en) * | 2017-01-06 | 2018-07-12 | Saudi Arabian Oil Company | Methods and systems for optimizing demulsifier and wash water injection rates in gas oil separations plants |
| US10370599B2 (en) | 2017-01-06 | 2019-08-06 | Saudi Arabian Oil Company | Methods and systems for optimizing demulsifier and wash water injection rates in gas oil separation plants |
| US10472576B2 (en) | 2017-01-06 | 2019-11-12 | Saudi Arabian Oil Company | Methods and systems for optimizing demulsifier and wash water injection rates in gas oil separation plants |
| CN111303350A (en) * | 2020-04-01 | 2020-06-19 | 广东石油化工学院 | Polyether demulsifier based on alcohol amine modified phenolic resin and synthetic method thereof |
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