WO2015161812A1 - Compounds, compositions thereof and methods for hydrocarbon extraction using the same - Google Patents

Compounds, compositions thereof and methods for hydrocarbon extraction using the same Download PDF

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WO2015161812A1
WO2015161812A1 PCT/CN2015/077259 CN2015077259W WO2015161812A1 WO 2015161812 A1 WO2015161812 A1 WO 2015161812A1 CN 2015077259 W CN2015077259 W CN 2015077259W WO 2015161812 A1 WO2015161812 A1 WO 2015161812A1
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compound
surfactant
composition
water
dic
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PCT/CN2015/077259
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French (fr)
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Zhijun Wang
Zhenggang CUI
Xiangqiang SHUI
Binglei SONG
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Jiangnan University
Rhodia Operations
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Priority to CN201580035421.0A priority Critical patent/CN107075355B/en
Publication of WO2015161812A1 publication Critical patent/WO2015161812A1/en

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C309/00—Sulfonic acids; Halides, esters, or anhydrides thereof
    • C07C309/01—Sulfonic acids
    • C07C309/02—Sulfonic acids having sulfo groups bound to acyclic carbon atoms
    • C07C309/03—Sulfonic acids having sulfo groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton
    • C07C309/13—Sulfonic acids having sulfo groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton containing nitrogen atoms, not being part of nitro or nitroso groups, bound to the carbon skeleton
    • C07C309/14—Sulfonic acids having sulfo groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton containing nitrogen atoms, not being part of nitro or nitroso groups, bound to the carbon skeleton containing amino groups bound to the carbon skeleton
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C303/00—Preparation of esters or amides of sulfuric acids; Preparation of sulfonic acids or of their esters, halides, anhydrides or amides
    • C07C303/02—Preparation of esters or amides of sulfuric acids; Preparation of sulfonic acids or of their esters, halides, anhydrides or amides of sulfonic acids or halides thereof
    • C07C303/22—Preparation of esters or amides of sulfuric acids; Preparation of sulfonic acids or of their esters, halides, anhydrides or amides of sulfonic acids or halides thereof from sulfonic acids, by reactions not involving the formation of sulfo or halosulfonyl groups; from sulfonic halides by reactions not involving the formation of halosulfonyl groups
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/58—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids
    • C09K8/584—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids characterised by the use of specific surfactants

Definitions

  • the present invention relates to a compound, particularly, a sulfobetaine compound having double fatty alcohol polyalkoxy ether chains, which can be used for extraction of hydrocarbons, in particular, crude oil, from an underground formation.
  • Crude oil remains an important energy source. Crude oil producers typically produce the crude oil by drilling wells into underground reservoirs in a formation. The initial recovery of the crude oil is generally carried out by techniques of “primary recovery” , which mainly relies on the natural pressure present in the underground reservoir for displacing the crude oil to production wells. However, the primary recovery process merely recovers a minor portion of the original oil in place (OOIP) . When the natural pressure is exhausted and the primary recovery is completed, a large portion of the crude oil still remains in the reservoir and is not recovered. Thus, a variety of supplemental recovery techniques have been employed in order to increase the recovery rate of the crude oil from the underground reservoir.
  • the natural pressure present in the underground reservoir drops.
  • the remaining crude oil is usually trapped in porous sandstone reservoir or porous carbonate reservoir as oil droplets due to capillary effect, and therefore, is difficult to be displaced under the natural pressure.
  • the pressure can be increased again or maintained by injecting a fluid, such as water, to the underground reservoir.
  • This is the so-called “secondary recovery” (also known as “water flooding” in the event that water is injected) .
  • the injection of the fluid can supplement the natural pressure and help to displace the crude oil to the production wells.
  • a considerable amount of the crude oil may still be trapped in the porous sandstone reservoir or the porous carbonate reservoir due to the capillary effect.
  • tertiary recovery also known as “enhanced oil recovery”
  • the mobility control process and chemical process are two commonly used enhanced oil recovery processes.
  • the mobility control process primarily relies on a polymer which can modify the viscosity of fluids.
  • an aqueous fluid comprising the polymer is injected into the underground reservoir so as to develop a favourable mobility ratio between the injected fluid and oil/water bank in the underground reservoir.
  • the purpose is to develop a uniform volumetric sweep of the reservoir, both vertically and areally. This can prevent the water from fingering by the crude oil and enhance the sweep efficiency.
  • the chemical process primarily relies on enhancing the microscopic displacement efficiency of the crude oil. It usually involves injecting a displacing fluid (usually an aqueous fluid) that efficiently displace the crude oil because of the phase behaviour properties, which results in decreasing interfacial tension (IFT) between the displacing fluid and the crude oil.
  • a displacing fluid usually an aqueous fluid
  • IFT interfacial tension
  • the crude oil trapped in the porous sandstone reservoir or the porous carbonate reservoir can be displaced more easily through porous channels of the reservoir, and the recovery rate of the crude oil can thus be enhanced.
  • a displacing fluid that has an ultralow IFT (approximately 10 -4 to10 -2 mN/m) with the crude oil is preferred.
  • a displacing fluid comprising suitable surfactant (s) and polymer (s) can be used in the tertiary recovery.
  • displacing fluid possesses a combination of rheological features (e.g., viscosifying properties) and the phase behaviour properties.
  • the displacing fluid may further comprise co-surfactant (s) , oil, electrolytes and alkaline.
  • co-surfactant (s) oil, electrolytes and alkaline.
  • displacing fluids comprising alkaline-surfactant-polymer (ASP) have been used for the tertiary recovery and such technique is called ASP flooding.
  • anionic surfactants are used in the ASP flooding.
  • the alkaline in the displacing fluid may react with minerals and connate water in the underground reservoir, forming water insoluble substances. This will lead to deposition of precipitates on pipelines and equipment, and blocking of the porous channels in the reservoir as well, which may cause severe damage to the oil wells and jeopardize the crude oil recovery.
  • a technique using displacing fluids which comprise surfactant-polymer (SP) and do not comprise any alkaline can be employed and such technique is called SP flooding.
  • CN101549266 B disclosed that methyl carboxyl betaine having double long hydrocarbon chains (such as didodecyl methyl carboxyl betaine) are suitable surfactants for the alkaline-free SP flooding.
  • the compounds have two long hydrocarbon chains in their molecules, and therefore have poor solubility in water and strong interactions with the sandstone reservoir or the carbonate reservoir, which causes problems in their applications for the SP flooding.
  • R 1 and R 2 are independently linear or branched chain, saturated or unsaturated hydrocarbyl groups containing from 8 to 22 carbon atoms;
  • X and Y are independently alkylene groups containing from 2 to 4 carbon atoms;
  • n are independently in the range of 1 to 20;
  • R 3 is an alkyl group containing from 1 to 5 carbon atoms
  • R 4 is a sulfonate containing group.
  • R 4 is one selected from -CH 2 CH 2 SO 3 - , -CH 2 CH 2 CH 2 SO 3 - and
  • X and Y are ethylene.
  • R 1 and R 2 are alkyl groups.
  • R 1 and R 2 are alkyl groups containing from 8 to 18 carbon atoms.
  • m and n are independently in the range of 1 to 5 .
  • composition comprising the compound according to the first aspect of the present invention, a viscosifying polymer and water.
  • the viscosifying polymer is a polyacrylamide or a xanthan gum.
  • the composition further comprises a co-surfactant.
  • the co-surfactant is a zwitterionic surfactant or a nonionic surfactant.
  • the co-surfactant is an alkanol amide.
  • the co-surfactant is a betaine.
  • a method for extracting hydrocarbons from an underground formation comprising the steps of :
  • a method for preparing the compound according to the first aspect of the present invention comprising the step of reacting a compound according to the formula
  • R 1 and R 2 are independently linear or branched, saturated or unsaturated hydrocarbyl groups containing from 8 to 22 carbon atoms;
  • X and Y are independently alkylene groups containing from 2 to 4 carbon atoms;
  • n are independently in the range of 1 to 20;
  • R 3 is an alkyl group containing from 1 to 5 carbon atoms.
  • Fig. 1 shows the surface tension of aqueous solutions comprising various concentrations of diC 12-14 E n HSB at 25 °C.
  • Fig. 2 shows the dynamic IFT between the Daqing oilfield crude oil and aqueous solutions comprising diC 12-14 E n HSB and polyacrylamide (PAM) .
  • Fig. 3 shows the dynamic IFT between the Daqing oilfield crude oil and aqueous solutions comprising a mixture of diC 12-14 E n HSB and myristyldimethyhydroxylpropylsulfobetaine, PAM and Na 2 CO 3 .
  • Fig. 4 shows the dynamic IFT between the Daqing oilfield crude oil and aqueous solutions comprising a mixture of diC 12-14 E n HSB, didodecylmethylhydroxylpropylsulfobetaine and oleamidepropylhydroxylpropylsulfobetaine, and PAM.
  • Fig. 5 shows the adsorption of diC 12-14 E n HSB and diC 12 B at silica/water interface by using SiO 2 nanoparticles as the silica phase.
  • Fig. 6 shows the adsorption of diC 12-14 E n HSB at Daqing sandstone/water interface at 45 °C assessed by using weighing in combination of element analysis in comparison with the adsorption of diC 12 B as measured by two phase titration and HPLC methods.
  • betaine means a chemical compound with a positively charged cationic functional group, such as a quaternary ammonium or phosphoniumcation, which bears no hydrogen atom, and with an anionic group, such as a carboxyl containing group or a sulfonate containing group, which may not be adjacent to the cationic site.
  • a sulfonate containing group is comprised in the molecule of the compound, the compound is also called “sulfobetaine” .
  • surfactant means an amphiphilic compound that comprises a hydrophilic moiety and a hydrophobic moiety and that, when present in water, lowers the surface tension of the water.
  • underground formation As used herein, the term “underground formation” , “underground reservoir” or “reservoir” refers to a place where crude hydrocarbons are found in reservoir forms in the Earth’s crust.
  • secondary recovery refers to the process which usually involves the injection of a fluid (usually an aqueous fluid) into the underground reservoir or the formation.
  • the injected fluid and the injection process supplement natural pressure in the reservoir to displace the hydrocarbons to a production well.
  • the secondary recovery is also called “water flooding” .
  • the secondary recovery is usually conducted after the “primary recovery” is completed which mainly relies on the natural pressure present in the underground reservoir for the displacement of the hydrocarbons to the production well.
  • tertiary recovery also called “enhanced oil recovery” refers to the process applied by the oil industry to further increase displacement of the hydrocarbons from the underground reservoir in supplement to the primary recovery and the secondary recovery processes.
  • the tertiary recovery techniques encompass thermal processes, mobility control processes and chemical processes, such as heat generation, heat transfer, steam drive, steam soak, polymer flooding, surfactant flooding, surfactant-polymer (SP) flooding, alkaline-surfactant-polymer (ASP) flooding, and use of hydrocarbon solvents, high-pressure hydrocarbon gas, carbon dioxide and nitrogen.
  • the term “displacing fluid” refers to an aqueous fluid used for the tertiary recovery (the enhanced oil recovery) in the underground formation.
  • the compound suitable for the present invention has the formula
  • R 1 and R 2 are independently linear or branched chain, saturated or unsaturated hydrocarbyl groups containing from 8 to 22 carbon atoms.
  • the carbon atom numbers of R 1 and R 2 may be same or different.
  • hydrocarbyl groups as used herein, means a substituent or radical containing hydrogen and carbon atoms.
  • the hydrocarbyl group may have any suitable structures including saturated or unsaturated, straight or branched chain.
  • Illustrative hydrocarbyl groups include, but are not limited to: alkyl, such as methyl, ethyl, isopropyl, octyl, dodecyl, octadecyl and so on; alkenyl, such as propenyl, butenyl, pentenyl.
  • R 1 and R 2 are independently alkyl groups containing from 8 to 22 carbon atoms. More preferably, R 1 and R 2 are independently alkyl groups containing from 8 to 18 carbon atoms.
  • X and Y are independently alkylene groups containing from 2 to 4 carbon atoms.
  • X and Y are ethylene or propylene, more preferably, ethylene.
  • Alkoxy moiety in the compound of Formula (I) i.e., (OX) m or (OY) n as illustrated in Formula (I) , may comprise a single species of alkylene group, such as ethylene, propylene or butylene.
  • the alkoxy moiety may comprise a mixture of alkylene groups having different carbon atoms numbers, such as a mixture of ethylene and propylene, a mixture of ethylene and butylene, a mixture of propylene and butylene, and a mixture of ethylene, propylene and butylene.
  • the values of m and n are in the range of 1 to 20, preferably 1 to 10, more preferably 1 to 5.
  • the values of m and n may be same or different.
  • the compound of the present invention may not be a single compound containing a certain copy number of alkylene oxide (i.e. OX and OY) as Formula (I) may suggest. Instead, the compound may be a mixture of several homologs which have different copy numbers of the alkylene oxide while the average copy number of the alkylene oxide of the homologs falls within the ranges as described above.
  • R 3 is an alkyl group containing from 1 to 5 carbon atoms.
  • R 3 is selected from the group consisting of -CH 3 , -CH 2 CH 3 , -CH 2 CH 2 CH 3 , -CH 2 CH 2 CH 2 CH 3 and -CH 2 CH 2 OH.
  • R 4 is a sulfonate containing group.
  • sulfonate containing group refers to a hydrocarbyl group in which one hydrogen is substituted by a sulfonate group (i.e., SO 3 - ) .
  • SO 3 - a sulfonate group
  • the sulfonate containing groups suitable for the present invention include, but are not limited to -CH 2 CH 2 SO 3 - , -CH 2 CH 2 CH 2 SO 3 - and
  • the compound of the present invention possesses a surfactant structure.
  • the compound of the present invention is typically a sulfobetaine compound which has a head group and two fatty alcohol polyalkoxy ether chains linked to the head group.
  • the head group of the compound comprises a cationic site, i.e., the ammonium atom as shown in Formula (I), and an anionic group, i.e., R 4 as shown in Formula (I) .
  • each of the fatty alcohol polyalkoxy ether chains possesses a surfactant structure which is composed of lipophilic groups (R 1 and R 2 ) and hydrophilic groups (the alkoxy moieties) , thus in their designed applications, the performance of the compound is dependent on a balance between the lipophilicity and the hydrophilicity provided by these groups.
  • the compound of the present invention possesses Hydrophilic-Lipophilic Balance (HLB) which is suitable for efficiently reducing interfacial tension (IFT) between crude oil phase and water phase (crude oil-water IFT) .
  • HLB Hydrophilic-Lipophilic Balance
  • IFT interfacial tension
  • the compound of the present invention can be more efficient in reducing the crude oil-water IFT.
  • the compound of the present invention can be used for extracting hydrocarbons, more particularly, the crude oil, from an underground formation.
  • the compound of the present invention can be used for the SP flooding.
  • a composition, more particularly, a displacing fluid, comprising the compound may be delivered to the underground formation to facilitate the displacement of the hydrocarbons (e.g., the crude oil) .
  • the composition may be an aqueous solution, which can be prepared by mixing the compound of the present invention with water.
  • the composition of the present invention may be delivered to the underground formation containing the hydrocarbons (e.g., the crude oil) .
  • the composition may be delivered to the underground formation through an injection system, such as an injection well.
  • the composition can reduce the crude oil-water IFT, forming an oil-water microemulsion locally. This zone of low IFT is then propagated through the underground formation.
  • the hydrocarbons e.g., the crude oil
  • trapped in porous sandstone reservoir or porous carbonate reservoir can be displaced, subsequently be recovered through a production system such as a production well.
  • the injection well is same as the production well.
  • composition of the present invention can reduce the crude oil-water IFT to ultralow (below 10 -2 mN/m) without addition of any alkaline or electrolytes in the composition. Hence, by using the composition of the present invention, recovery rate of the crude oil can be significantly increased.
  • the composition of the present invention may optionally comprise a viscosifying polymer.
  • the viscosifying polymer can increase the viscosity of the composition and reduce its mobility in the reservoir. This will enhance the sweeping efficiency and lead to increasing the recovery efficiency of the hydrocarbons.
  • the displacing fluid when delivered to the underground formation, it tends to bypass lower permeability regions, leaving behind a significant volume of the crude oil because the displacing fluid, which is primarily water based, is much more mobile than the crude oil.
  • the difference between the mobility of the displacing fluid and that of the crude oil can be decreased by adding the viscosifying polymer in the displacing fluid, such that the viscosified displacing fluid will not finger by the oil and the sweep efficiency can be therefore enhanced.
  • the viscosifying polymer may also possess surfactant activities, wherein the polymer contributes to reducing the crude oil-water IFT.
  • the composition may be an aqueous solution of the viscosifying polymer, or an aqueous dispersion of the viscosifying polymer.
  • the polymer is substantially evenly distributed within the composition.
  • the polymer may be supplied as a powder.
  • the powder may be used to prepare a mother solution or dispersion of the polymer in water having a polymer concentration of at least 5%by weight, preferably at least 10%by weight, for example, 5 to 20%by weight. Then, the mother solution or dispersion may be dosed into the composition such that the resulting composition has a suitable viscosity for the applications of the present invention.
  • the polymer may be supplied in the form of a concentrated dispersion, e.g., a colloidal dispersion. Then, the concentrated dispersion of the polymer may be dosed into the composition.
  • a concentrated dispersion e.g., a colloidal dispersion.
  • the polymer may also be supplied in the form of an emulsion comprising a dispersed aqueous phase, in which the polymer is dissolved or dispersed, in a continuous oil phase, e.g., an emulsion in which droplets of the aqueous phase are dispersed in the oil phase.
  • aqueous phase is a highly concentrated solution of the polymer.
  • the final concentration of the viscosifying polymer in the composition may be in the range of 500-2,000 ppm by weight.
  • the composition may comprise 1,500 ppm, 1,250 ppm, 1,000 ppm or 700 ppm of the viscosifying polymer by weight.
  • the viscosifying polymers suitable for the present invention include polymers that are known to be useful for the tertiary recovery, such as polyacrylamide (including partially hydrolyzed polyacrylamide) and xanthan gum.
  • the composition of the present invention may optionally comprise at least one co-surfactant. It is known that it is in the conditions of formation of the oil-water microemulsion that the crude oil recovery efficiency is highest.
  • the conditions of formation of the oil-water microemulsion depend on the type of the surfactant used, the nature of the crude oil (mainly its content of naphthenates or Alkane Carbon Number (ACN) and its density/viscosity) , the salinity of the aqueous phase etc.
  • ACN Alkane Carbon Number
  • the co-surfactant can be included in the composition to optimize the HLB of the resulting composition wherein the optimal HLB is determined based on the characteristics of the oil and of the connate water in the reservoir where the composition will be applied.
  • the co-surfactant may be a small molecule surfactant or a polymeric surfactant.
  • the co-surfactant may be a zwitterionic surfactant, such as a betaine and a sulfobetaine, or a nonionic surfactant, such as an ethoxylated fatty alcohol and an alkanol amide.
  • the composition of the present invention may comprise more than one co-surfactants.
  • the HLB of the composition may also be adjusted by selecting a suitable molar ratio between the compound of the present invention and the co-surfactant (s) in the composition.
  • the molar fraction of the compound of the present invention in the total surfactants may be above 0.1 and below 1.0, preferably, in the range of 0.3 to 0.7 .
  • composition of the present invention may also comprise other additives, in particular, salts, sacrificial agents and an agent for pH adjustment (for example sodium carbonate) .
  • control of the pH is helpful for preventing the composition being trapped by the sandstone reservoir or the carbonate reservoir.
  • the composition of the present invention may be used for the SP flooding or the ASP flooding, in particular, the SP flooding, in the tertiary recovery.
  • the compound of the present invention may also be used for the secondary recovery.
  • water comprising the compound of the present invention may be injected into the underground reservoir to supplement the natural pressure in the reservoir for displacing the hydrocarbons, at the same time, the solution can reduce the crude oil-water IFT.
  • the present invention also relates to the use of the compound or the composition of the present invention as described herein for extracting the hydrocarbons, more particularly, the crude oil, from an underground formation.
  • the present invention provides a suitable compound which may be used as a surfactant for extracting the hydrocarbons from the underground formation, in particular, for the SP flooding.
  • a surfactant for extracting the hydrocarbons from the underground formation, in particular, for the SP flooding.
  • the surfactant should have a sufficient lipophilicity; secondly, the surfactant should have a high adsorption at the oil/water interface; thirdly, the surfactant should have good aqueous solubility so that it will not precipitate easily from the aqueous solution.
  • the conventional surfactants known in the art can hardly fulfil the above requirements at the same time.
  • lipophilic raw materials usually have hydrocarbon chains containing no more than 18 carbon atoms, thus are not sufficiently lipophilic for being used for the SP flooding process.
  • heavy alkylbenzenesulfonates mostly having two alkyls connected to a benzene ring, are relatively lipophilic but exhibit low adsorption due to their large cross section areas at the oil/water interface.
  • CN101549266 B disclosed use of didodecyl methyl carboxyl betaine for the alkaline-free SP flooding.
  • Such compound has double alkyl chains connected to a single head group which comprises a cationic ammonium and an anionic methyl carboxyl group.
  • the compound has poor solubility in water, which may be due to the presence of the two long alkyl chain in the molecule of the compound. Furthermore, it tends to have strong interactions with the sandstone reservoir and/or the carbonate reservoir. This may be problematic when such compound is used for the SP flooding. Surprisingly, it has been of the present invention can solve the above mentioned problems associated with the conventional surfactants used for the tertiary recovery.
  • the compound and the composition of the present invention are particularly suitable for being used for extracting the hydrocarbons (e.g., the crude oil) from the underground formation
  • the compound and the composition can also be used for other applications wherein the compound functions as a surfactant for modifying the phase behaviour properties.
  • Such applications include, but are not limited to detergents, foaming agents, fabric softeners, dyeing and finishing of fabrics.
  • the compound of Formula (I) can be prepared by the following stages :
  • Stage 1 Preparation of fatty alcohol polyalkoxy ether chlorides.
  • fatty alcohol polyalkoxy ether are firstly obtained by reacting fatty alcohols containing 8-22 carbon atoms with ethylene oxide (EO) , propylene oxide (PO) , butylene oxide (BO) or a mixture thereof by using conventional methods.
  • EO ethylene oxide
  • PO propylene oxide
  • BO butylene oxide
  • EO ethylene oxide
  • EO ethylene oxide
  • Selection of the molar ratio between the alkylene oxide and the fatty alcohol can be determined based on the copy number of the alkylene oxide in the desired reaction product. Generally, a higher ratio between the alkylene oxide and the fatty alcohol will lead to a higher copy number of the alkylene oxide in the reaction product.
  • the present invention may employ a single species of fatty alcohol polyalkoxy ether for the synthesis of the compound of the present invention, in such case, the two fatty alcohol polyalkoxy ether chains in the final product synthesized (e. g., the compound of Formula (I) ) will be homogenous.
  • the present invention may employ a mixture of fatty alcohol polyalkoxy ethers for the synthesis of the compound of the present invention, in such case, the two fatty alcohol polyalkoxy ether chains in the final product (e.g., the compound of Formula (I) ) will be heterogeneous.
  • certain species of fatty alcohol polyalkoxy ethers are available from commercial sources thus can be directly used as staring materials for the synthesis of the compound of the present invention.
  • Stage 2 Preparation of the secondary amine intermediate (VI) .
  • a first fatty alcohol polyalkoxy ether chloride i.e., the intermediate (III)
  • a primary alkylamine V
  • the primary alkylamines suitable for the present invention include, but are not limited to NH 2 CH 3 , NH 2 CH 2 CH 3 , NH 2 CH 2 CH 2 CH 3 , NH 2 CH 2 CH 2 CH 3 and NH 2 CH 2 CH 2 OH.
  • the reaction can be illustrated in the following equation :
  • the secondary amine intermediate (VI) typically, for synthesizing the secondary amine intermediate (VI) , certain amount of the intermediate (III) and isopropanol are added into a high pressure reactor, followed by addition of the primary alkylamine (V) .
  • the molar ratio of (III) and (V) is in the range of 2.0 to 2.5.
  • the reaction mixture is stirred and heated to 100-150 °C, preferably, 100-110 °C, and allowed to react at such temperature for 4-7 hours. A typical reaction time is 6 hours.
  • the product mixture is then distillated at vacuum to remove isopropanol.
  • the distillated mixture which mainly comprises the secondary amine intermediate (VI) and R 3 NH 3 Cl, is transferred to a container and water is added to the container to dissolve the R 3 NH 3 Cl solid salt, which is a by-product of the reaction.
  • certain amount of NaOH aqueous solution is added to decompose amine hydrochloride by-products which are possibly produced during the reaction.
  • the product mixture is transferred to a funnel and is allowed to separate into two phases.
  • the upper phase which contains the secondary amine intermediate (VI) is collected.
  • the secondary amine intermediate (VI) obtained in this stage can be further purified if necessary.
  • Stage 3 Preparation of the tertiary amine intermediate (VII) .
  • the secondary amine intermediate (VI) obtained in stage (2) is mixed, in a container (e.g., a four-neck flask) , with a second fatty alcohol polyalkoxy ether chloride (i.e., the intermediate (IV) ) and sodium carbonate.
  • the molar ratio of (VI) , (IV) and sodium carbonate is 1-1.5/1/1-1.5.
  • the reaction mixture is stirred and heated to 100-200 °C, preferably, 150 °C to 180 °C, and allowed to react at such temperature for 20 to 30 hours to yield the tertiary amine intermediate (VII) .
  • a typical reaction time is 24 hours.
  • the tertiary amine intermediate (VII) product may be subject to analysis, such as MS spectra analysis for characterization.
  • Stage 4 Sulfonation of the tertiary amine intermediate (VII) .
  • the tertiary amine intermediate (VII) obtained in stage (3) is subject to the sulfonation reaction, wherein a sulfonate containing group is linked to the ammonium atom in the tertiary amine intermediate (VII) so as to yield the compound of Formula (I) .
  • the sulfonate containing groups suitable for the reaction include, but are not limited to -CH 2 CH 2 SO 3 - , -CH 2 CH 2 CH 2 SO 3 - and
  • the tertiary amine intermediate (VII) may be reacted with a sulfonic acid or sulfonate to yield the compound of Formula (I) .
  • the tertiary amine intermediate (VII) is reacted with 3-chloro2-hydroxyl-propyl sulfonate, as illustrated in the following equation :
  • the sulfonation reaction is carried out under alkaline condition to avoid formation of tertiary amine hydrochloride salt in acidic condition.
  • the reaction is carried out in isopropanol/water mixture solvent.
  • the temperature of the reaction is in the range of 70 °C to 150 °C, preferably in the range of 70 °C to 120 °C.
  • coconut alcohol polyoxyethylene (2) ether was obtained from Solvay (Zhangjiagang) Specialty Chemical CO. Ltd..
  • Didodecyl methyl carboxyl betaine (denoted as “diC 12 B” ) was obtained from Jiangnan University, China. The synthesis and characterization of diC 12 B were disclosed in CN101549266 B. diC 12 B is a methyl carboxyl betaine compound having double C 12 alkyl chains.
  • the Daqing oilfield crude oil samples were obtained from the Daqing oilfield, China.
  • a crude oil sample has an Equivalent Alkane Carbon Number (EACN) and the IFT behaviours of the crude oil sample are similar to those of an n-alkane having an alkane carbon number equal to the EACN. It is known that the Daqing oilfield crude oil has an EACN of approximately 10.
  • the Daqing oilfield connate water samples were obtained from the Daqing oilfield, China.
  • the Daqing oilfield connate water samples comprise certain amounts of ions, including CO 3 2- , HCO 3 - , Cl - , SO 4 2- , Ca 2+ , Mg 2+ and Na + .
  • Example 1 Synthesis and characterization of di-coconut alcohol polyoxyethylene ether methyl hydroxyl propyl sulfobetaine (denoted as diC 12-14 E n HSB)
  • coconut alcohol polyoxyethylene (2) ether was firstly transformed to coconut alcohol polyoxyethylene ether chloride by using the reaction described above.
  • the distillated mixture was transferred to a 1000 cm 3 beaker and 500 cm 3 of pure water was added to dissolve CH 3 NH 3 Cl solid salt, which was a by-product of the reaction. Then certain amount of NaOH aqueous solution (30 wt%) was added to decompose amine hydrochloride by-products possibly produced.
  • the mixture was transferred to a funnel of 1000 cm 3 and allowed to separate into two phases. The upper phase, which contains the desired intermediate, i.e., coconut alcohol polyoxyethylene ether methyl amine was collected.
  • di-coconut alcohol polyoxyethylene ether methyl amine intermediate 0.155 mole of coconut alcohol polyoxyethylene ether methyl amine was mixed with 0.163 mole of coconut alcohol polyoxyethylene ether chloride and 0.163 mole of sodium carbonate. The reaction mixture was added into a 250 cm 3 4-neck flask wherein the molar ratio of coconut alcohol polyoxyethylene ether chloride/coconut alcohol polyoxyethylene ether methyl amine/Na 2 CO 3 was kept at 1.05/1/1.05. The reaction mixture was stirred and heated to 155 °C and allowed to react at this temperature for 24 hours to yield di-coconut alcohol polyoxyethylene ether methyl amine (denoted as diC 12-14 E n A) . The diC 12-14 E n A intermediate was subject to MS spectra (positive model) analysis for its molecular mass.
  • the diC 12-14 E n A obtained in the above step was reacted with 3-chloro-2-hydroxyl propyl sulfonate (ClCH 2 CH (OH) CH 2 SO 3 - N a + ) so as to yield the diC 12-14 E n HSB product. More specifically, 0.12 mole of 3-chloro-2-hydroxylpropylsulfonate was added into a 250 cm 3 3-neck flask equipped with a stirrer, a thermometer and a condenser pipe. Then, water was added into the flask and the mixture was stirred until the solid dissolved completely. Then, isopropanol was added into the flask, wherein the volume ratio of water/isopropanol was 1/6.
  • reaction product was heated to 50 °C and neutralized by adding 5%NaOH aqueous solution.
  • the mixture was then dried by removing the solvent component (isopropanol) by using a rotary evaporator.
  • the dried product was then dissolved in ethyl acetate, and the solution was transferred into a funnel and washed with water.
  • the aqueous phase (lower layer) was removed and the upper layer was washed repeatedly using water for another two times.
  • the trace amount of water present in the final upper layer was dried by using anhydrous sodium sulfate and filtration. Then a crude product was obtained by drying the filtrate at vacuum by using a rotated evaporator.
  • the crude product was dissolved in ethyl acetate and the solution was passed through a column (45cmx7.5 cm) filled with chromatograph silica (FCP300-400 mesh, 40 times of the amount of the crude product to be treated) .
  • Purified diC 12-14 E n HSB product was then obtained by removing solvent at vacuum.
  • the diC 12-14 E n HSB product contains a mixture of homologs with C 12 /C 12 , C 12 /C 14 , and C 14 /C 14 fatty alcohol chains.
  • the average EO copy numbers in the fatty alcohol polyalkoxy ether chains of the homologs in the diC 12- 14 E n HSB product is in the range of 2 to 3.
  • aqueous solutions comprising series concentrations of diC 12-14 E n HSB were measured at 25 °C and the results are shown in Fig. 1. It is found that diC 12-14 E n HSB could efficiently reduce the surface tensions of the aqueous solutions in a dosage dependent manner, and increased concentration of diC 12-14 E n HSB led to decreased surface tension of the aqueous solution.
  • diC 12-14 E n HSB is highly effective and efficient in reducing surface tension ( ⁇ cmc ) . Also, compared to typical surfactants, diC 12-14 E n HSB has a high saturated adsorption at air /water interface ( ⁇ ⁇ ) and a small cross section area (a ⁇ ) , indicating that diC 12-14 E n HSB can have a large adsorption at the oil/water interface and form a dense monolayer, which is beneficial for reducing the crude oil-water IFT.
  • the water phase samples were prepared as below :
  • the diC 12-14 E n HSB solely could reduce the Daqing crude oil/connate water IFT to ultra low at concentrations no less than 2.5 mM without addition of any alkali or electrolyte.
  • the water phase samples were prepared as below :
  • Example 4 an aqueous solution containing 1,000 ppm PAM and 0.5%of Na 2 CO 3 was prepared. Then a mixture of diC 12-14 E n HSB and myristyldimethyhydroxylpropylsulfobetaine was dissolved in the above mentioned aqueous solution at varies total surfactant concentrations. The molar fraction of diC 12-14 E n HSB in the total surfactants was 0.8.
  • Example 5 An aqueous solution containing 1,000 ppm PAM was prepared. Then a mixture of diC 12-14 E n HSB, didodecylmethylhydroxylpropylsulfobetaine and oleamidepropylhydroxylpropylsulfobetaine was dissolved in the above mentioned aqueous solution at varies total surfactant concentrations. The molar ratio of diC 12- 14 E n HSB/didodecylmethylhydroxylpropylsulfobetaine/oleamidepropylhydro xylpropylsulfobetaine was 35/24/41.
  • ultralow (below 10 -2 mN/m) dynamic/equilibrium IFT can be achieved very fast by using a surfactant composite which contains diC 12-14 E n HSB and which has a total surfactant concentration of from 0.625 to 7.5 mM.
  • diC 12- 14 E n HSB could reduce Daqing crude oil/water IFT to ultra low wherein it is mixed with a hydrophobic sulfobetaine, i. e.didodecylmethylhydroxylpropylsulfobetaine, and a hydrophilic sulfobetaine, i.e. oleamidepropylhydroxylpropylsulfobetaine.
  • a hydrophobic sulfobetaine i. e.didodecylmethylhydroxylpropylsulfobetaine
  • a hydrophilic sulfobetaine i.e. oleamidepropylhydroxylpropylsulfobetaine.
  • Example 6 Adsorption of diC 12-14 E n HSB at silica/water interface SiO 2 nanoparticles with a BET area of 200 m 2 /g, which are negatively charged in aqueous media, were used for this experiment and were used to simulate the behaviours of sandstone. It is appreciated that surface tension of a surfactant solution is in direct correlation with the concentration of the surfactant when the concentration of the surfactant is lower than the critical micelle concentration (cmc) . Hence, when the SiO 2 nanoparticles are added into the surfactant solution, the surfactant concentration will decrease due to absorption by the particles, which will in turn lead to an increase of the surface tension.
  • cmc critical micelle concentration
  • the adsorption of the surfactant at silica/water interface can be calculated and assessed.
  • Example 7 Adsorption at Daqing sandstone/water interface measured by weighing in combination of element analysis
  • the adsorption of diC 12-14 E n HSB at Daqing sandstone/water interface at 45 °C was also assessed by using weighing in combination of element analysis.
  • 20 mL aqueous solution of diC 12-14 E n HSB at different concentration was put in a 25 mL bottle, followed by addition of 2g sandstones in the solution.
  • the dispersion was mixed using a rotation mixer for 12 hours at 45 o C, and then settled for more than 48 hours at the same temperature to let the sandstones sediment.
  • the upper liquid phase (without particles) was then transferred to another 25 mL bottle (dried and weighed) and heated to evaporate the water.
  • the bottle was dried at 105 °C for 2 hours, cooled and then weighed. For each concentration, two samples and a blank (without particles) were processed and measured in parallel. Then the dried product was taken for measurement of contents of C, H, N, and S elements. The weight of the surfactant after adsorption was then obtained by correction using the elemental analysis results. Accordingly, the weight of the surfactant that has been adsorbed by the sandstones was calculated.
  • the adsorption of diC 12 B at Daqing sandstone/water interface was also measured by two phase titration and HPLC methods which are known by a person skilled in the art. As shown in Fig. 6, at an equilibrium concentration close to 1 mmol/L, the adsorption of diC 12-14 E n HSB (triangle) and diC 12 B (circle) at Daqing sandstone/water interface at 45 °C was 2.14x10 -3 and 2.41x10 -2 mmol/g, respectively. The adsorption of diC 12- 14 E n HSB at sandstone/water interface was markedly lower than that of diC 12 B.

Abstract

The present invention relates to a compound, more particularly, a sulfobetaine compound having double fatty alcohol polyalkoxy ether chains, which can be used for extraction of hydrocarbons, in particular, crude oil, from an underground formation. The compound is particularly useful for alkaline-free surfactants-polymer (SP) flooding techniques in tertiary recovery. The present invention also relates to a process for preparing the compound, a composition comprising the compound and the use thereof.

Description

Compounds, compositions thereof and methods for hydrocarbon extraction usingthe same
This application claims priority to PCT international application No. PCT/CN2014/076051 filed on April 23, 2014, the whole content of this application being incorporated herein by reference for all purposes.
Technical Field
The present invention relates to a compound, particularly, a sulfobetaine compound having double fatty alcohol polyalkoxy ether chains, which can be used for extraction of hydrocarbons, in particular, crude oil, from an underground formation.
Background of Invention
Crude oil remains an important energy source. Crude oil producers typically produce the crude oil by drilling wells into underground reservoirs in a formation. The initial recovery of the crude oil is generally carried out by techniques of “primary recovery” , which mainly relies on the natural pressure present in the underground reservoir for displacing the crude oil to production wells. However, the primary recovery process merely recovers a minor portion of the original oil in place (OOIP) . When the natural pressure is exhausted and the primary recovery is completed, a large portion of the crude oil still remains in the reservoir and is not recovered. Thus, a variety of supplemental recovery techniques have been employed in order to increase the recovery rate of the crude oil from the underground reservoir.
Over time, as the crude oil is recovered by the primary recovery from the oil wells, the natural pressure present in the underground reservoir drops. In this case, the remaining crude oil is usually trapped in porous sandstone reservoir or porous carbonate reservoir as oil droplets due to capillary effect, and therefore, is difficult to be displaced under the natural pressure. When this happens, the pressure can be increased again or maintained by injecting a fluid, such as water, to the underground reservoir. This is the so-called “secondary recovery” (also known as “water flooding” in the event that water is injected) . The injection of the fluid can supplement the  natural pressure and help to displace the crude oil to the production wells. However, even by means of the secondary recovery, a considerable amount of the crude oil may still be trapped in the porous sandstone reservoir or the porous carbonate reservoir due to the capillary effect.
In order to further enhance the recovery rate of the crude oil, “tertiary recovery” (also known as “enhanced oil recovery” ) techniques may be employed. The mobility control process and chemical process are two commonly used enhanced oil recovery processes. The mobility control process primarily relies on a polymer which can modify the viscosity of fluids. In a typical application, an aqueous fluid comprising the polymer is injected into the underground reservoir so as to develop a favourable mobility ratio between the injected fluid and oil/water bank in the underground reservoir. The purpose is to develop a uniform volumetric sweep of the reservoir, both vertically and areally. This can prevent the water from fingering by the crude oil and enhance the sweep efficiency. On the other hand, the chemical process primarily relies on enhancing the microscopic displacement efficiency of the crude oil. It usually involves injecting a displacing fluid (usually an aqueous fluid) that efficiently displace the crude oil because of the phase behaviour properties, which results in decreasing interfacial tension (IFT) between the displacing fluid and the crude oil. As a consequence, the crude oil trapped in the porous sandstone reservoir or the porous carbonate reservoir can be displaced more easily through porous channels of the reservoir, and the recovery rate of the crude oil can thus be enhanced. In order to achieve high recovery efficiency, a displacing fluid that has an ultralow IFT (approximately 10-4 to10-2 mN/m) with the crude oil is preferred. It has been known that a displacing fluid comprising suitable surfactant (s) and polymer (s) can be used in the tertiary recovery. Such displacing fluid possesses a combination of rheological features (e.g., viscosifying properties) and the phase behaviour properties. The displacing fluid may further comprise co-surfactant (s) , oil, electrolytes and alkaline. Conventionally, displacing fluids comprising alkaline-surfactant-polymer (ASP) have been used for the tertiary recovery and such technique is  called ASP flooding. Mostly, anionic surfactants are used in the ASP flooding. However, the alkaline in the displacing fluid may react with minerals and connate water in the underground reservoir, forming water insoluble substances. This will lead to deposition of precipitates on pipelines and equipment, and blocking of the porous channels in the reservoir as well, which may cause severe damage to the oil wells and jeopardize the crude oil recovery. To avoid such problem, a technique using displacing fluids which comprise surfactant-polymer (SP) and do not comprise any alkaline can be employed and such technique is called SP flooding.
It has been found that in the absence of the alkaline, it is difficult to reduce the IFT between the crude oil and the aqueous fluid to ultralow by using conventional surfactants which are efficient in the ASP flooding, such as petroleum sulfonates, heavy alkylbenzenesulfonates, natural carboxylates, petroleum carboxylates.
CN101549266 B disclosed that methyl carboxyl betaine having double long hydrocarbon chains (such as didodecyl methyl carboxyl betaine) are suitable surfactants for the alkaline-free SP flooding. However, the compounds have two long hydrocarbon chains in their molecules, and therefore have poor solubility in water and strong interactions with the sandstone reservoir or the carbonate reservoir, which causes problems in their applications for the SP flooding.
There is a need to provide a compound which overcomes the drawbacks associated with the known surfactants used for the tertiary recovery, in particular, for the SP flooding.
Summary of Invention
It has been found that the above objective can be solved by the present invention.
In a first aspect of the present invention, there is provided a compound according to the formula
Figure PCTCN2015077259-appb-000001
wherein :
R1 and R2 are independently linear or branched chain, saturated or unsaturated hydrocarbyl groups containing from 8 to 22 carbon atoms；
the carbon atom numbers of R1 and R2 are same or different；
X and Y are independently alkylene groups containing from 2 to 4 carbon atoms；
m and n are independently in the range of 1 to 20；
R3 is an alkyl group containing from 1 to 5 carbon atoms；
R4 is a sulfonate containing group.
Preferably, R4 is one selected from -CH2CH2SO3 －, -CH2CH2CH2SO3 －and
Figure PCTCN2015077259-appb-000002
Preferably, X and Y are ethylene.
Preferably, R1 and R2 are alkyl groups.
Preferably, R1 and R2 are alkyl groups containing from 8 to 18 carbon atoms.
Preferably, m and n are independently in the range of 1 to 5.
In a second aspect of the present invention, there is provided a composition comprising the compound according to the first aspect of the present invention, a viscosifying polymer and water.
Preferably, the viscosifying polymer is a polyacrylamide or a xanthan gum.
Preferably, the composition further comprises a co-surfactant.
Preferably, the co-surfactant is a zwitterionic surfactant or a nonionic surfactant.
In one embodiment of the present invention, the co-surfactant is an alkanol amide.
In another embodiment of the present invention, the co-surfactant is a betaine.
In a third aspect of the present invention, there is provided a use of the compound according to the first aspect of the present invention or the composition according to the second aspect of the present invention for extracting hydrocarbons from an underground formation.
In a forth aspect of the present invention, there is provided a method for extracting hydrocarbons from an underground formation, comprising the steps of :
(a) delivering a composition comprising the compound according to the first aspect of the present invention and water to the underground formation containing the hydrocarbons；
(b) recovering the hydrocarbons through a production system.
In a fifth aspect of the present invention, there is provided a method for preparing the compound according to the first aspect of the present invention, comprising the step of reacting a compound according to the formula
Figure PCTCN2015077259-appb-000003
with a sulfonic acid or sulfonate, wherein :
R1 and R2 are independently linear or branched, saturated or unsaturated hydrocarbyl groups containing from 8 to 22 carbon atoms；
the carbon atom numbers of R1 and R2 are same or different；
X and Y are independently alkylene groups containing from 2 to 4 carbon atoms；
m and n are independently in the range of 1 to 20；
R3 is an alkyl group containing from 1 to 5 carbon atoms.
Brief Description of Drawings
 Fig. 1 shows the surface tension of aqueous solutions comprising various concentrations of diC12-14EnHSB at 25 ℃.
 Fig. 2 shows the dynamic IFT between the Daqing oilfield crude oil and aqueous solutions comprising diC12-14EnHSB and polyacrylamide (PAM) .
Fig. 3 shows the dynamic IFT between the Daqing oilfield crude oil and aqueous solutions comprising a mixture of diC12-14EnHSB and myristyldimethyhydroxylpropylsulfobetaine, PAM and Na2CO3.
Fig. 4 shows the dynamic IFT between the Daqing oilfield crude oil and aqueous solutions comprising a mixture of diC12-14EnHSB, didodecylmethylhydroxylpropylsulfobetaine and oleamidepropylhydroxylpropylsulfobetaine, and PAM.
Fig. 5 shows the adsorption of diC12-14EnHSB and diC12B at silica/water interface by using SiO2 nanoparticles as the silica phase.
Fig. 6 shows the adsorption of diC12-14EnHSB at Daqing sandstone/water interface at 45 ℃ assessed by using weighing in combination of element analysis in comparison with the adsorption of diC12B as measured by two phase titration and HPLC methods.
Detailed Description of the Invention
In the context of the present application, including the claims, the term "comprising" should be understood as being synonymous with the term "comprising at least one" , unless otherwise specified. The terms "between" , “in the range of” should be understood as being inclusive of the limits.
In the context of the present application, the term "betaine" , as used herein, means a chemical compound with a positively charged cationic functional group, such as a quaternary ammonium or phosphoniumcation, which bears no hydrogen atom, and with an anionic group, such as a carboxyl containing group or a sulfonate containing group, which may not be adjacent to the cationic site. In the case that a sulfonate containing group is comprised in the molecule of the compound, the compound is also called "sulfobetaine” .
In the context of the present application, the term "surfactant" means an amphiphilic compound that comprises a hydrophilic moiety and a hydrophobic moiety and that, when present in water, lowers the surface tension of the water.
As used herein, the term “underground formation” , “underground reservoir” or “reservoir” refers to a place where crude hydrocarbons are found in reservoir forms in the Earth’s crust.
As used herein, the term “secondary recovery” refers to the process which usually involves the injection of a fluid (usually an aqueous fluid) into the underground reservoir or the formation. The injected fluid and the injection process supplement natural pressure in the reservoir to displace the hydrocarbons to a production well. The secondary recovery is also called “water flooding” . The secondary recovery is usually conducted after the “primary recovery” is completed which mainly relies on the natural pressure present in the underground reservoir for the displacement of the hydrocarbons to the production well.
As used herein, the term “tertiary recovery” (also called “enhanced oil recovery” ) refers to the process applied by the oil industry to further increase displacement of the hydrocarbons from the underground reservoir in supplement to the primary recovery and the secondary recovery processes. The tertiary recovery techniques encompass thermal processes, mobility control processes and chemical processes, such as heat generation, heat transfer, steam drive, steam soak, polymer flooding, surfactant flooding, surfactant-polymer (SP) flooding, alkaline-surfactant-polymer (ASP) flooding, and use of hydrocarbon solvents, high-pressure hydrocarbon gas, carbon dioxide and nitrogen.
As used herein, the term “displacing fluid” refers to an aqueous fluid used for the tertiary recovery (the enhanced oil recovery) in the underground formation.
In one aspect of the present invention, the compound suitable for the present invention has the formula
Figure PCTCN2015077259-appb-000004
In Formula (I) , R1 and R2 are independently linear or branched chain, saturated or unsaturated hydrocarbyl groups containing from 8 to 22 carbon atoms. The carbon atom numbers of R1 and R2 may be same or different. In the context of the present application, the term "hydrocarbyl groups" , as used herein, means a substituent or radical containing hydrogen and carbon atoms. The hydrocarbyl group may have any suitable structures including saturated or unsaturated, straight or branched chain. Illustrative hydrocarbyl groups include, but are not limited to: alkyl, such as methyl, ethyl, isopropyl, octyl, dodecyl, octadecyl and so on； alkenyl, such as propenyl, butenyl, pentenyl. Preferably, R1 and R2 are independently alkyl groups containing from 8 to 22 carbon atoms. More preferably, R1 and R2 are independently alkyl groups containing from 8 to 18 carbon atoms.
In Formula (I) , X and Y are independently alkylene groups containing from 2 to 4 carbon atoms. Preferably, X and Y are ethylene or propylene, more preferably, ethylene. Alkoxy moiety in the compound of Formula (I) , i.e., (OX) m or (OY) n as illustrated in Formula (I) , may comprise a single species of alkylene group, such as ethylene, propylene or butylene. Alternatively, the alkoxy moiety may comprise a mixture of alkylene groups having different carbon atoms numbers, such as a mixture of ethylene and propylene, a mixture of ethylene and butylene, a mixture of propylene and butylene, and a mixture of ethylene, propylene and butylene. The values of m and n are in the range of 1 to 20, preferably 1 to 10, more preferably 1 to 5. The values of m and n may be same or different.
It should be noted that the compound of the present invention may not be a single compound containing a certain copy number of alkylene oxide (i.e. OX and OY) as Formula (I) may suggest. Instead, the compound may be a mixture of several homologs which have different copy numbers of the alkylene oxide while the average copy number of the alkylene oxide of the homologs falls within the ranges as described above.
In Formula (I) , R3 is an alkyl group containing from 1 to 5 carbon atoms. Preferably, R3 is selected from the group consisting of -CH3, -CH2CH3, -CH2CH2CH3, -CH2CH2CH2CH3 and -CH2CH2OH.
In Formula (I) , R4 is a sulfonate containing group. In the context of the present application, the term “sulfonate containing group” refers to a hydrocarbyl group in which one hydrogen is substituted by a sulfonate group (i.e., SO3 -) . The sulfonate containing groups suitable for the present inventioninclude, but are not limited to -CH2CH2SO3 －, -CH2CH2CH2SO3 －and
Figure PCTCN2015077259-appb-000005
Typically, the compound of the present invention possesses a surfactant structure.
The compound of the present invention is typically a sulfobetaine compound which has a head group and two fatty alcohol polyalkoxy ether chains linked to the head group. The head group of the compound comprises a cationic site, i.e., the ammonium atom as shown in Formula (I), and an anionic group, i.e., R4 as shown in Formula (I) . Also, as shown in Formula (I) , each of the fatty alcohol polyalkoxy ether chains possesses a surfactant structure which is composed of lipophilic groups (R1 and R2) and hydrophilic groups (the alkoxy moieties) , thus in their designed applications, the performance of the compound is dependent on a balance between the lipophilicity and the hydrophilicity provided by these groups. More particularly, the compound of the present invention possesses Hydrophilic-Lipophilic Balance (HLB) which is suitable for efficiently reducing interfacial tension (IFT) between crude oil phase and water phase (crude oil-water IFT) . Compared to betaines which have only one fatty alcohol polyalkoxy ether chain, the compound of the present invention can be more efficient in reducing the crude oil-water IFT.
The compound of the present invention can be used for extracting hydrocarbons, more particularly, the crude oil, from an underground formation. In particular, the compound of the present invention can be used for the SP flooding. For this purpose, a composition, more particularly, a displacing fluid, comprising the compound may be delivered to the underground formation to facilitate the displacement of the  hydrocarbons (e.g., the crude oil) . Accordingly, in one aspect of the present invention, there is provided a composition, more particularly, a displacing fluid, comprising the compound of the present invention as described herein. The composition may be an aqueous solution, which can be prepared by mixing the compound of the present invention with water.
For the extraction of the hydrocarbons (e.g., the crude oil) , the composition of the present invention, preferably in the form of aqueous solution, may be delivered to the underground formation containing the hydrocarbons (e.g., the crude oil) . The composition may be delivered to the underground formation through an injection system, such as an injection well. The composition can reduce the crude oil-water IFT, forming an oil-water microemulsion locally. This zone of low IFT is then propagated through the underground formation. As a consequence, the hydrocarbons (e.g., the crude oil) trapped in porous sandstone reservoir or porous carbonate reservoir can be displaced, subsequently be recovered through a production system such as a production well. In certain embodiment, the injection well is same as the production well. It has been found that the composition of the present invention can reduce the crude oil-water IFT to ultralow (below 10-2mN/m) without addition of any alkaline or electrolytes in the composition. Hence, by using the composition of the present invention, recovery rate of the crude oil can be significantly increased.
According to one aspect of the present invention, the composition of the present invention may optionally comprise a viscosifying polymer. The viscosifying polymer can increase the viscosity of the composition and reduce its mobility in the reservoir. This will enhance the sweeping efficiency and lead to increasing the recovery efficiency of the hydrocarbons. Generally, when the displacing fluid is delivered to the underground formation, it tends to bypass lower permeability regions, leaving behind a significant volume of the crude oil because the displacing fluid, which is primarily water based, is much more mobile than the crude oil. The difference between the mobility of the displacing fluid and that of  the crude oil can be decreased by adding the viscosifying polymer in the displacing fluid, such that the viscosified displacing fluid will not finger by the oil and the sweep efficiency can be therefore enhanced. In certain embodiment, the viscosifying polymer may also possess surfactant activities, wherein the polymer contributes to reducing the crude oil-water IFT.
The composition may be an aqueous solution of the viscosifying polymer, or an aqueous dispersion of the viscosifying polymer. Preferably, the polymer is substantially evenly distributed within the composition.
The polymer may be supplied as a powder. The powder may be used to prepare a mother solution or dispersion of the polymer in water having a polymer concentration of at least 5％by weight, preferably at least 10％by weight, for example, 5 to 20％by weight. Then, the mother solution or dispersion may be dosed into the composition such that the resulting composition has a suitable viscosity for the applications of the present invention.
Alternatively, the polymer may be supplied in the form of a concentrated dispersion, e.g., a colloidal dispersion. Then, the concentrated dispersion of the polymer may be dosed into the composition.
The polymer may also be supplied in the form of an emulsion comprising a dispersed aqueous phase, in which the polymer is dissolved or dispersed, in a continuous oil phase, e.g., an emulsion in which droplets of the aqueous phase are dispersed in the oil phase. Preferably the aqueous phase is a highly concentrated solution of the polymer.
The final concentration of the viscosifying polymer in the composition may be in the range of 500-2,000 ppm by weight. For instance, the composition may comprise 1,500 ppm, 1,250 ppm, 1,000 ppm or 700 ppm of the viscosifying polymer by weight.
The viscosifying polymers suitable for the present invention include polymers that are known to be useful for the tertiary recovery, such as polyacrylamide (including partially hydrolyzed polyacrylamide) and xanthan gum.
According to another aspect of the present invention, the composition of the present invention may optionally comprise at least one co-surfactant. It is known that it is in the conditions of formation of the oil-water microemulsion that the crude oil recovery efficiency is highest. The conditions of formation of the oil-water microemulsion depend on the type of the surfactant used, the nature of the crude oil (mainly its content of naphthenates or Alkane Carbon Number (ACN) and its density/viscosity) , the salinity of the aqueous phase etc. Generally, it is helpful to select a surfactant or a combination of surfactants which has an HLB which matches the physicochemical conditions, in particular the characteristics of the oil and of the connate water in the underground reservoir. The characteristics of the oil and of the connate water can be evaluated by the characterization of the crude oil samples and the connate water samples collected from the reservoir. Accordingly, in the present invention, the co-surfactant can be included in the composition to optimize the HLB of the resulting composition wherein the optimal HLB is determined based on the characteristics of the oil and of the connate water in the reservoir where the composition will be applied. The co-surfactant may be a small molecule surfactant or a polymeric surfactant. The co-surfactant may be a zwitterionic surfactant, such as a betaine and a sulfobetaine, or a nonionic surfactant, such as an ethoxylated fatty alcohol and an alkanol amide. In certain embodiment, the composition of the present invention may comprise more than one co-surfactants.
The HLB of the composition may also be adjusted by selecting a suitable molar ratio between the compound of the present invention and the co-surfactant (s) in the composition. The molar fraction of the compound of the present invention in the total surfactants may be above 0.1 and below 1.0, preferably, in the range of 0.3 to 0.7 .
The composition of the present invention may also comprise other additives, in particular, salts, sacrificial agents and an agent for pH adjustment (for example sodium carbonate) . Control of the pH is helpful for preventing the composition being trapped by the sandstone reservoir or the carbonate reservoir.
Generally, the composition of the present invention may be used for the SP flooding or the ASP flooding, in particular, the SP flooding, in the tertiary recovery. Nevertheless, the compound of the present invention may also be used for the secondary recovery. In such case, water comprising the compound of the present invention may be injected into the underground reservoir to supplement the natural pressure in the reservoir for displacing the hydrocarbons, at the same time, the solution can reduce the crude oil-water IFT.
The present invention also relates to the use of the compound or the composition of the present invention as described herein for extracting the hydrocarbons, more particularly, the crude oil, from an underground formation.
The present invention provides a suitable compound which may be used as a surfactant for extracting the hydrocarbons from the underground formation, in particular, for the SP flooding. For the designing of a successful surfactant for the SP flooding, several factors need to be considered. Firstly, the surfactant should have a sufficient lipophilicity； secondly, the surfactant should have a high adsorption at the oil/water interface； thirdly, the surfactant should have good aqueous solubility so that it will not precipitate easily from the aqueous solution. The conventional surfactants known in the art can hardly fulfil the above requirements at the same time. For example, some industrially available lipophilic raw materials usually have hydrocarbon chains containing no more than 18 carbon atoms, thus are not sufficiently lipophilic for being used for the SP flooding process. Also, heavy alkylbenzenesulfonates, mostly having two alkyls connected to a benzene ring, are relatively lipophilic but exhibit low adsorption due to their large cross section areas at the oil/water interface. CN101549266 B disclosed use of didodecyl methyl carboxyl betaine for the alkaline-free SP flooding. Such compound has double alkyl chains connected to a single head group which comprises a cationic ammonium and an anionic methyl carboxyl group. However, the compound has poor solubility in water, which may be due to the presence of the two long alkyl chain in the molecule of the compound. Furthermore,  it tends to have strong interactions with the sandstone reservoir and/or the carbonate reservoir. This may be problematic when such compound is used for the SP flooding. Surprisingly, it has been of the present invention can solve the above mentioned problems associated with the conventional surfactants used for the tertiary recovery.
Although the compound and the composition of the present invention are particularly suitable for being used for extracting the hydrocarbons (e.g., the crude oil) from the underground formation, the compound and the composition can also be used for other applications wherein the compound functions as a surfactant for modifying the phase behaviour properties. Such applications include, but are not limited to detergents, foaming agents, fabric softeners, dyeing and finishing of fabrics.
The compound of Formula (I) can be prepared by the following stages :
Stage 1: Preparation of fatty alcohol polyalkoxy ether chlorides.
In this stage, fatty alcohol polyalkoxy ether are firstly obtained by reacting fatty alcohols containing 8-22 carbon atoms with ethylene oxide (EO) , propylene oxide (PO) , butylene oxide (BO) or a mixture thereof by using conventional methods. Preferably, a mixture of ethylene oxide (EO) and propylene oxide (PO) is used for the reaction. More preferably, ethylene oxide (EO) is used for the reaction. Selection of the molar ratio between the alkylene oxide and the fatty alcohol can be determined based on the copy number of the alkylene oxide in the desired reaction product. Generally, a higher ratio between the alkylene oxide and the fatty alcohol will lead to a higher copy number of the alkylene oxide in the reaction product. It should be mentioned that the present invention may employ a single species of fatty alcohol polyalkoxy ether for the synthesis of the compound of the present invention, in such case, the two fatty alcohol polyalkoxy ether chains in the final product synthesized (e. g., the compound of Formula (I) ) will be homogenous. Alternatively, the present invention may employ a mixture of fatty alcohol polyalkoxy ethers for the synthesis of the compound of the present invention, in such case, the two fatty alcohol polyalkoxy ether chains in the final product (e.g., the compound of Formula (I) ) will be heterogeneous. It should also be  mentioned that certain species of fatty alcohol polyalkoxy ethers are available from commercial sources thus can be directly used as staring materials for the synthesis of the compound of the present invention.
Then, the fatty alcohol polyalkoxy ethers are transformed to fatty alcohol polyalkoxy ether chlorides. The reaction can be illustrated by the following equations :
Figure PCTCN2015077259-appb-000006
In the above equations and the formula of the intermediate (III) and (IV) , R1, R2, X, Y, m and n have the same meaning as that defined in Formula (I).
Stage 2: Preparation of the secondary amine intermediate (VI) .
In this stage, a first fatty alcohol polyalkoxy ether chloride (i.e., the intermediate (III) ) is reacted with a primary alkylamine (V) , to yield the secondary amine intermediate (VI) . The primary alkylamines suitable for the present invention include, but are not limited to NH2CH3, NH2CH2CH3, NH2CH2CH2CH3, NH2CH2CH2CH2CH3 and NH2CH2CH2OH. The reaction can be illustrated in the following equation :
Figure PCTCN2015077259-appb-000007
In the formula of the intermediates (V) and (VI) , R1, R3, X and m have the same meaning as defined in Formula (I) .
Typically, for synthesizing the secondary amine intermediate (VI) , certain amount of the intermediate (III) and isopropanol are added into a high pressure reactor, followed by addition of the primary alkylamine (V) . The molar ratio of (III) and (V) is in the range of 2.0 to 2.5. The reaction mixture is stirred and heated to 100-150 ℃, preferably, 100-110 ℃, and  allowed to react at such temperature for 4-7 hours. A typical reaction time is 6 hours.
The product mixture is then distillated at vacuum to remove isopropanol. The distillated mixture, which mainly comprises the secondary amine intermediate (VI) and R3NH3Cl, is transferred to a container and water is added to the container to dissolve the R3NH3Cl solid salt, which is a by-product of the reaction. Then certain amount of NaOH aqueous solution is added to decompose amine hydrochloride by-products which are possibly produced during the reaction. Subsequently the product mixture is transferred to a funnel and is allowed to separate into two phases. The upper phase which contains the secondary amine intermediate (VI) is collected. The secondary amine intermediate (VI) obtained in this stage can be further purified if necessary.
Stage 3: Preparation of the tertiary amine intermediate (VII) .
The reaction can be illustrated in the following equation :
Figure PCTCN2015077259-appb-000008
In the formula of the intermediates (VII) , R1, R2, R3, X, Y, m and n have the same meaning as defined in Formula (I) .
In this stage, the secondary amine intermediate (VI) obtained in stage (2) is mixed, in a container (e.g., a four-neck flask) , with a second fatty alcohol polyalkoxy ether chloride (i.e., the intermediate (IV) ) and sodium carbonate. The molar ratio of (VI) , (IV) and sodium carbonate is 1-1.5/1/1-1.5. The reaction mixture is stirred and heated to 100-200 ℃, preferably, 150 ℃ to 180 ℃, and allowed to react at such temperature for 20 to 30 hours to yield the tertiary amine intermediate (VII) . A typical reaction time is 24 hours. The tertiary amine intermediate (VII) product may be subject to analysis, such as MS spectra analysis for characterization.
Stage 4: Sulfonation of the tertiary amine intermediate (VII) .
In this stage, the tertiary amine intermediate (VII) obtained in stage (3) is subject to the sulfonation reaction, wherein a sulfonate containing group is linked to the ammonium atom in the tertiary amine intermediate (VII) so as to yield the compound of Formula (I) . The sulfonate containing groups suitable for the reaction include, but are not limited to -CH2CH2SO3 －, -CH2CH2CH2SO3 －and
Figure PCTCN2015077259-appb-000009
The tertiary amine intermediate (VII) may be reacted with a sulfonic acid or sulfonate to yield the compound of Formula (I) . As an example, the tertiary amine intermediate (VII) is reacted with 3-chloro2-hydroxyl-propyl sulfonate, as illustrated in the following equation :
Figure PCTCN2015077259-appb-000010
Preferably, the sulfonation reaction is carried out under alkaline condition to avoid formation of tertiary amine hydrochloride salt in acidic condition. Preferably, the reaction is carried out in isopropanol/water mixture solvent. The temperature of the reaction is in the range of 70 ℃ to 150 ℃, preferably in the range of 70 ℃ to 120 ℃.
Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.
Other details or advantages of the present invention will become more clearly apparent in the light of the examples below, without a limiting nature.
Examples
Materials: 
Coconut alcohol polyoxyethylene (2) ether was obtained from Solvay (Zhangjiagang) Specialty Chemical CO. Ltd..
Didodecyl methyl carboxyl betaine (denoted as “diC12B” ) was obtained from Jiangnan University, China. The synthesis and characterization of diC12B were disclosed in CN101549266 B. diC12B is a methyl carboxyl betaine compound having double C12 alkyl chains.
The Daqing oilfield crude oil samples were obtained from the Daqing oilfield, China. Generally, a crude oil sample has an Equivalent Alkane Carbon Number (EACN) and the IFT behaviours of the crude oil sample are similar to those of an n-alkane having an alkane carbon number equal to the EACN. It is known that the Daqing oilfield crude oil has an EACN of approximately 10.
The Daqing oilfield connate water samples were obtained from the Daqing oilfield, China. The Daqing oilfield connate water samples comprise certain amounts of ions, including CO3 2-, HCO3 -, Cl-, SO4 2-, Ca2+, Mg2+ and Na+.
Example 1: Synthesis and characterization of di-coconut alcohol polyoxyethylene ether methyl hydroxyl propyl sulfobetaine (denoted as diC12-14EnHSB) 
Coconut alcohol polyoxyethylene (2) ether was firstly transformed to coconut alcohol polyoxyethylene ether chloride by using the reaction described above.
Then, 0.6 mole of coconut alcohol polyoxyethylene ether chloride and 5.5 moles of isopropanol were added into a 1000 cm3 high pressure reactor, followed by addition of 1.5 moles of methyl amine (CH3NH2) . The molar ratio between coconut alcohol polyoxyethylene ether chloride and methyl amine in the reaction mixture was kept between 2.0 and 2.5. Then the reaction mixture was stirred and heated to 100-110 ℃ and allowed to react at this temperature for 6 hours to yield coconut alcohol polyoxyethylene ether methyl amine. The product mixture was then distillated at vacuum to remove isopropanol. The distillated mixture was transferred to a 1000 cm3 beaker and 500 cm3 of pure water was added to dissolve CH3NH3Cl solid salt, which was a by-product of the reaction. Then certain amount of NaOH aqueous solution (30 wt％) was added to  decompose amine hydrochloride by-products possibly produced. The mixture was transferred to a funnel of 1000 cm3 and allowed to separate into two phases. The upper phase, which contains the desired intermediate, i.e., coconut alcohol polyoxyethylene ether methyl amine was collected.
For the synthesis of di-coconut alcohol polyoxyethylene ether methyl amine intermediate, 0.155 mole of coconut alcohol polyoxyethylene ether methyl amine was mixed with 0.163 mole of coconut alcohol polyoxyethylene ether chloride and 0.163 mole of sodium carbonate. The reaction mixture was added into a 250 cm3 4-neck flask wherein the molar ratio of coconut alcohol polyoxyethylene ether chloride/coconut alcohol polyoxyethylene ether methyl amine/Na2CO3 was kept at 1.05/1/1.05. The reaction mixture was stirred and heated to 155 ℃ and allowed to react at this temperature for 24 hours to yield di-coconut alcohol polyoxyethylene ether methyl amine (denoted as diC12-14EnA) . The diC12-14EnA intermediate was subject to MS spectra (positive model) analysis for its molecular mass.
The diC12-14EnA obtained in the above step was reacted with 3-chloro-2-hydroxyl propyl sulfonate (ClCH2CH (OH) CH2SO3 -Na +) so as to yield the diC12-14EnHSB product. More specifically, 0.12 mole of 3-chloro-2-hydroxylpropylsulfonate was added into a 250 cm3 3-neck flask equipped with a stirrer, a thermometer and a condenser pipe. Then, water was added into the flask and the mixture was stirred until the solid dissolved completely. Then, isopropanol was added into the flask, wherein the volume ratio of water/isopropanol was 1/6. Subsequently, 0.1 mole of diC12-14EnA was added into the flask, followed by adding 3 wt％of potassium iodide. The resulting mixture was reacted at 80 ℃ for 48 hrs. The pH value of the reaction mixture was monitored during the reaction, and was kept in the range of 7–9 by adding a basic reagent.
Subsequently, the reaction product was heated to 50 ℃ and neutralized by adding 5％NaOH aqueous solution. The mixture was then dried by removing the solvent component (isopropanol) by using a rotary evaporator. The dried product was then dissolved in ethyl acetate, and the  solution was transferred into a funnel and washed with water. The aqueous phase (lower layer) was removed and the upper layer was washed repeatedly using water for another two times. The trace amount of water present in the final upper layer was dried by using anhydrous sodium sulfate and filtration. Then a crude product was obtained by drying the filtrate at vacuum by using a rotated evaporator. To remove remaining amines in the crude product, the crude product was dissolved in ethyl acetate and the solution was passed through a column (45cmx7.5 cm) filled with chromatograph silica (FCP300-400 mesh, 40 times of the amount of the crude product to be treated) . The column was initially washed using a mixture of methanol/ethyl acetate (v/v＝1/10) (with 1 mL ammonia (25％) in 110 mL mixed solvent) to remove amines, then the adsorbed product was washed off using a mixture of methanol/ethyl acetate (v/v＝1/1) (with 6 mL ammonia (25％) in 500 mL mixture) . Purified diC12-14EnHSB product was then obtained by removing solvent at vacuum.
The diC12-14EnHSB product contains a mixture of homologs with C12/C12, C12/C14, and C14/C14 fatty alcohol chains. The average EO copy numbers in the fatty alcohol polyalkoxy ether chains of the homologs in the diC12- 14EnHSB product is in the range of 2 to 3.
It was found that an aqueous solution comprising 50 mM of the purified diC12-14EnHSB exhibited half transparent appearance, which indicates that diC12-14EnHSB has good solubility in water.
Example 2: Surface activity of diC12-14EnHSB
The surface tensions of aqueous solutions comprising series concentrations of diC12-14EnHSB were measured at 25 ℃ and the results are shown in Fig. 1. It is found that diC12-14EnHSB could efficiently reduce the surface tensions of the aqueous solutions in a dosage dependent manner, and increased concentration of diC12-14EnHSB led to decreased surface tension of the aqueous solution. Other parameters, such as critical micelle concentration (cmc) , effectiveness in reducing surface tension (γcmc) , saturated adsorption at air /water interface (Γ∞) , as well as the cross section area (ɑ∞) of a molecule at air/water interface of diC12- 14EnHSB were measured and the results are listed in Table 1 below. 
Table 1
Figure PCTCN2015077259-appb-000011
Results show that diC12-14EnHSB is highly effective and efficient in reducing surface tension (γcmc) . Also, compared to typical surfactants, diC12-14EnHSB has a high saturated adsorption at air /water interface (Γ∞) and a small cross section area (a∞) , indicating that diC12-14EnHSB can have a large adsorption at the oil/water interface and form a dense monolayer, which is beneficial for reducing the crude oil-water IFT.
Examples 3: Effects of diC12-14EnHSBon reducing the oil-water IFT
The water phase samples were prepared as below :
An aqueous solution of 1,000 ppm polyacrylamide (PAM, molecular weight ＝25,000,000 g/mol) in the Daqing oilfield connate water was prepared. Then diC12-14EnHSB was dissolved in the above mentioned solution at various concentrations.
Subsequently, the dynamic IFTs between the above aqueous solution and the Daqing oilfield crude oil were measured at 45 ℃ for a period of 120 mins by using a spinning drop tensionmeter, respectively.
As shown in Fig. 2, the diC12-14EnHSB solely could reduce the Daqing crude oil/connate water IFT to ultra low at concentrations no less than 2.5 mM without addition of any alkali or electrolyte.
Examples 4 and 5: Effects of diC12-14EnHSBsurfactant composites on reducing the oil-water IFT
The water phase samples were prepared as below :
Example 4: an aqueous solution containing 1,000 ppm PAM and 0.5％of Na2CO3 was prepared. Then a mixture of diC12-14EnHSB and myristyldimethyhydroxylpropylsulfobetaine was dissolved in the above mentioned aqueous solution at varies total surfactant concentrations. The molar fraction of diC12-14EnHSB in the total surfactants was 0.8.
Example 5: An aqueous solution containing 1,000 ppm PAM was prepared. Then a mixture of diC12-14EnHSB, didodecylmethylhydroxylpropylsulfobetaine and oleamidepropylhydroxylpropylsulfobetaine was dissolved in the above mentioned aqueous solution at varies total surfactant concentrations. The molar ratio of diC12- 14EnHSB/didodecylmethylhydroxylpropylsulfobetaine/oleamidepropylhydro xylpropylsulfobetaine was 35/24/41.
Then the dynamic IFT (time course) between the water phase samples (Example 4 and Example 5, respectively) and the Daqing oilfield crude oil were measured at 45 ℃ for a time period of 120 mins by using a spinning drop tensionmeter.
As shown in Fig. 3, ultralow (below 10-2mN/m) dynamic/equilibrium IFT can be achieved very fast by using a surfactant composite which contains diC12-14EnHSB and which has a total surfactant concentration of from 0.625 to 7.5 mM.
As shown in Fig. 4, in the absence of any alkali or electrolyte, diC12- 14EnHSB could reduce Daqing crude oil/water IFT to ultra low wherein it is mixed with a hydrophobic sulfobetaine, i. e.didodecylmethylhydroxylpropylsulfobetaine, and a hydrophilic sulfobetaine, i.e. oleamidepropylhydroxylpropylsulfobetaine.
Example 6: Adsorption of diC12-14EnHSB at silica/water interface SiO2 nanoparticles with a BET area of 200 m2/g, which are negatively charged in aqueous media, were used for this experiment and were used to simulate the behaviours of sandstone. It is appreciated that surface tension of a surfactant solution is in direct correlation with the concentration of the surfactant when the concentration of the surfactant is lower than the critical micelle concentration (cmc) . Hence, when the SiO2 nanoparticles are added into the surfactant solution, the surfactant concentration will decrease due to absorption by the particles, which will in turn lead to an increase of the surface tension. Thus by measuring the surface tensions of the surfactant solution which contains the SiO2 nanoparticles and the surface tensions of the surfactant solution which does not contain the SiO2 nanoparticles, the adsorption of the surfactant at silica/water interface can be calculated and assessed.
As shown in Fig. 5, at the maximum concentration measured (3.07x10-6 molL-1, or 0.83 cmc) , the adsorption of diC12B was 1.35 mmol/g. On the other hand, for diC12-14EnHSB at the maximum concentration measured (3.90x10-6 molL-1, or 0.85 cmc) , the adsorption was 0.0623 mmol/g, approximately 4.6％of that of diC12B. At very low equilibrium concentration, e.g., 1.0x10-6 molL-1, the adsorptions were 1.08x10-3 mmol g-1 and 2.27x10-4 mmol g-1 for diC12B and diC12-14EnHSB, respectively. These data indicated that diC12-14EnHSB has markedly lower absorption than diC12B.
Example 7 : Adsorption at Daqing sandstone/water interface measured by weighing in combination of element analysis
The adsorption of diC12-14EnHSB at Daqing sandstone/water interface at 45 ℃ was also assessed by using weighing in combination of element analysis. For this experiment, 20 mL aqueous solution of diC12-14EnHSB at different concentration was put in a 25 mL bottle, followed by addition of 2g sandstones in the solution. The dispersion was mixed using a rotation mixer for 12 hours at 45 oC, and then settled for more than 48 hours at the same temperature to let the sandstones sediment. The upper liquid phase (without particles) was then transferred to another 25 mL bottle (dried and weighed) and heated to evaporate the water. After that the bottle was dried at 105 ℃ for 2 hours, cooled and then weighed. For each concentration, two samples and a blank (without particles) were processed and measured in parallel. Then the dried product was taken for measurement of contents of C, H, N, and S elements. The weight of the surfactant after adsorption was then obtained by correction using the elemental analysis results. Accordingly, the weight of the surfactant that has been adsorbed by the sandstones was calculated.
The adsorption of diC12B at Daqing sandstone/water interface was also measured by two phase titration and HPLC methods which are known by a person skilled in the art. As shown in Fig. 6, at an equilibrium concentration close to 1 mmol/L, the adsorption of diC12-14EnHSB (triangle) and diC12B (circle) at Daqing sandstone/water interface at 45 ℃ was 2.14x10-3 and 2.41x10-2mmol/g, respectively. The adsorption of diC12- 14EnHSB at sandstone/water interface was markedly lower than that of diC12B.

Claims (15)

  1. A compound according to the formula
    Figure PCTCN2015077259-appb-100001
    wherein
    R1 and R2 are independently linear or branched chain, saturated or
    unsaturated hydrocarbyl groups containing from 8 to 22 carbon atoms；
    the carbon atom numbers of R1 and R2 are same or different；
    X and Y are independently alkylene groups containing from 2 to 4 carbon atoms；
    m and n are independently in the range of 1 to 20；
    R3 is an alkyl group containing from 1 to 5 carbon atoms；
    R4 is a sulfonate containing group.
  2. The compound according to claim 1, wherein R4 is one selected from -CH2CH2SO3 －, -CH2CH2CH2SO3 －and
    Figure PCTCN2015077259-appb-100002
  3. The compound according to claim 1 or 2, wherein X and Y are ethylene.
  4. The compound according to any one of claims 1 to 3, wherein R1 and R2 are alkyl groups.
  5. The compound according to any one of claims 1 to 4, wherein R1 and R2 are alkyl groups containing from 8 to 18 carbon atoms.
  6. The compound according to any one of claims 1 to 5, wherein m and n are independently in the range of 1 to 5.
  7. A composition comprising the compound according to any one of claims 1 to 6, a viscosifying polymer and water.
  8. The composition according to claim 7, wherein the viscosifying polymer is a polyacrylamide or a xanthan gum.
  9. The composition according to claim 7 or 8, wherein the composition further comprises a co-surfactant.
  10. The composition according to claims 9, wherein the co-surfactant is a zwitterionic surfactant or a nonionic surfactant.
  11. The composition according to claim 9 or 10, wherein the co-surfactant is an alkanol amide.
  12. The composition according to claim 9 or 10, wherein the co-surfactant is a betaine.
  13. Use of the compound according to any one of claims 1 to 6 or the composition according to any one of claims 7 to 12 for extracting hydrocarbons from an underground formation.
  14. A method for extracting hydrocarbons from an underground formation, comprising the steps of :
    (a) delivering a composition comprising water and the compound according to any one of claim 1 to 6 to the underground formation containing the hydrocarbons；
    (b) recovering the hydrocarbons through a production system.
  15. A method for preparing the compound of claim 1, comprising the step of reacting a compound according to the formula
    Figure PCTCN2015077259-appb-100003
    with a sulfonic acid or sulfonate, wherein
    R1 and R2 are independently linear or branched chain, saturated or
    unsaturated hydrocarbyl groups containing from 8 to 22 carbon atoms；
    the carbon atom numbers of R1 and R2 are same or different；
    X and Y are independently alkylene groups containing from 2 to 4 carbon atoms；
    m and n are independently in the range of 1 to 20；
    R3 is an alkyl group containing from 1 to 5 carbon atoms.
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CN114540002B (en) * 2020-11-24 2023-04-25 中国石油天然气股份有限公司 Salt-resistant low-interfacial tension foam oil displacement agent
CN112939821A (en) * 2021-02-09 2021-06-11 山东达维石油技术有限公司 Phase permeation regulating penetrant for developing compact oil and preparation method thereof
CN115385870A (en) * 2022-09-29 2022-11-25 胜利油田物华化工厂 Surfactant for improving crude oil recovery ratio and preparation method thereof
CN115385870B (en) * 2022-09-29 2023-10-03 胜利油田物华化工厂 Surfactant for improving crude oil recovery ratio and preparation method thereof

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