Classifications

• • 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
  • C09K8/588—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 polymers
• • 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
  • C09K2208/00—Aspects relating to compositions of drilling or well treatment fluids
  • C09K2208/24—Bacteria or enzyme containing gel breakers
• • 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
  • C09K2208/00—Aspects relating to compositions of drilling or well treatment fluids
  • C09K2208/26—Gel breakers other than bacteria or enzymes

Definitions

• the present invention relates to the field of exploration and exploitation of an underground formation.
• the invention relates more particularly to the treatment of a fluid recovered from the underground formation.
• the invention relates in particular to the field of enhanced oil recovery (EOR) and the field of treatment of production water.
• EOR enhanced oil recovery
• This additive can take the form of a formulation of organic molecules, such as polymers, copolymers and / or surfactants, etc.
• This formulation can also contain inorganic molecules such as minerals (clays, barite, etc.), oxide particles (titanium oxides, iron oxides, etc.) etc.
• additive poses certain problems linked in particular to the presence of the additive or of molecules constituting it in the water produced.
• additive generally polymers, copolymers and surfactants, is found in the water produced, in order to carry out an adequate water treatment .
• tertiary assisted recovery There are several methods of enhanced oil recovery.
• the injected fluid also called sweeping fluid
• compounds this is called tertiary assisted recovery.
• These chemical compounds are polymers, surfactants, alkaline compounds, or mixtures of these compounds.
• the advantage of the presence of a polymer is to increase the viscosity of the sweeping fluid and consequently to improve the mobility ratio between the injected fluid and the hydrocarbons. in place in the underground formation.
• the hydrocarbon recovery yield is increased using a better formation sweeping efficiency (Han DK & al, Recent Development of Enhanced oil Recovery in China, J. Petrol. Sci. Eng. 22 (1-3 ): 181-188; 1999).
• the polymers used in this method are generally polymers of high molecular weights chosen for their viscosifying properties at moderate concentrations.
• Crude oil and water must be separated.
• the petroleum is transported to its refining place and the water is treated to remove unwanted compounds and comply with discharge standards.
• Different techniques are applied to treat the production water, in particular to remove the dispersed crude drops: sedimentation by gravity separation, centrifugation, flotation with or without gas injection and filtration.
• a production effluent comprising a mixture of aqueous fluid and hydrocarbons in the form of an emulsion, the water / hydrocarbon ratio of which varies as a function of the duration of production.
• the presence of polymer in the production effluent due to the viscosifying effect of the latter, makes it more difficult to separate the different fluids (oil / gas / water) and, in particular, the secondary treatment of water.
• the viscosity of the water in the production effluent becomes an obstacle to the separation between water and hydrocarbons.
• This problem has led operators in the field to consider means for reducing the viscosity of the water produced, that is to say of the aqueous phase in the production effluent, in order to improve the separation between the water. and hydrocarbons.
• the degradation of the viscosifying polymer or polymers in the water produced is envisaged and is described in the prior art.
• the conventional polymers used for enhanced petroleum recovery are polymers of high molar masses which generally belong to the family of polyacrylamides (PAM) or partially hydrolyzed polyacrylamides (HPAM).
• Polyacrylamides are obtained by radical polymerization of acrylamide according to the following general scheme. polymerization
• the partially hydrolyzed polyacrylamides are copolymers of acrylamide with either acrylic acid or an acrylate, for example an acrylate of an alkaline element, for example sodium. They can be represented for example by the following general formula in which the alkaline element is sodium.
• the acrylamide monomer unit is generally in the majority.
• the partially hydrolyzed polyacrylamides can be obtained for example by copolymerization of acrylamide with acrylic acid, the carboxylic acid function of which can optionally be neutralized according to the carboxylate function of an alkaline element such as, for example, sodium.
• the partially hydrolyzed polyacrylamides can also be obtained by copolymerization of the acrylamide with an acrylate of an alkaline element such as for example sodium acrylate.
• Partially hydrolyzed polyacrylamides can also be obtained by polymerization of acrylamide to polyacrylamide followed by partial hydrolysis of the amide functions according to carboxylic acid functions or into carboxylate functions of alkaline salts.
• the HPAMs can be random or block copolymers.
• Figure 1 summarizes the synthetic routes of partially hydrolyzed polyacrylamides of the prior art in the case where the alkaline element is sodium.
• the conventional polymers used in EOR are polymers of high molar masses which generally belong to the family of polyacrylamides (PAM) or partially hydrolyzed polyacrylamides (HPAM). They may optionally contain monomeric units of the N-vinylpyrrolidone or acrylamido-tert-butyl sulfonate (ATBS) type.
• PAM polyacrylamides
• HPAM partially hydrolyzed polyacrylamides
• ATBS acrylamido-tert-butyl sulfonate
• the means appearing in the prior art for degrading the polymer are essentially based on the use of chemical reagents, in particular oxidizing agents (Ahmadum &al; Review of technologies for oil and gas produced water management; J. Hazard Mater., 170 (2 -3): 530-551. 2009).
• the effectiveness of the treatment essentially depends on the specific reactivity of these oxidizing agents, their concentration and the conditions under which the degradation will be carried out, in particular the temperature and the reaction time.
• the improvements described in the prior art consist of starting from a polymer which is a conventional HPAM, optimizing the choice and the concentration of the oxidizing agent as well as the reaction conditions.
• the Applicant has surprisingly discovered that it is possible to inject an aqueous fluid containing a particular polymer as an additive making it possible to increase the viscosity of the fluid in order to optimize the enhanced recovery of hydrocarbons and that it was also possible to reduce the viscosity of the fluid once it has reproduced on the surface in order to promote the separation between the hydrocarbons and the water, and to facilitate subsequent water treatment operations.
• the invention relates to a process for the enhanced recovery of hydrocarbons in an underground formation, in particular crude oil, comprising at least the following steps: a) at least one fluid is injected into said underground formation, said injected fluid comprising at least one water-soluble terpolymer in aqueous solution, said water-soluble terpolymer being a partially hydrolyzed polyacrylamide of formula (I)
• X is an alkaline cation chosen from sodium, lithium or potassium, or an ammonium cation
• limits included is greater than or equal to 0.50, preferably between 0.5 and 0.8, limits included, is less than 0.50, preferably between 0.1 and 0.4, limits included is between 0, 01 and 0.20, preferably between 0.02 and 0.15, limits included
• At least one production effluent from said underground formation is recovered comprising at least one aqueous phase and one organic phase.
• the method can comprise a step c) in which a chain-cutting reaction of said water-soluble terpolymer is caused in order to reduce the viscosity of the aqueous phase of said production effluent to allow the separation and / or the subsequent treatment of said aqueous phase.
• the chain cutting reaction of said terpolymer is caused by oxidation using an oxidizing agent.
• the oxidizing agent is chosen from: a periodate for example a sodium, potassium or ammonium periodate, a hypochlorite such as for example a sodium or potassium hypochlorite, a persulfate such as for example a sodium persulfate or potassium, a peroxide such as for example hydrogen peroxide or an organic peroxide, a permanganate such as for example potassium permanganate, a Fenton's reagent.
• Said biodegradation can be carried out under aerobic conditions and catalyzed by alcohol oxidases or hydrolases or dehydrogenases.
• biodegradation can be carried out under anaerobic conditions using heterotrophic fermentative bacteria, sulfato-reducing bacteria and methanogenic bacteria.
• the chain cutting reaction of said terpolymer is caused during step c) by oxidation using an oxidizing agent coupled with biodegradation and / or photodegradation.
• the method can comprise a step d) of separation of the aqueous phase and the organic phase of said production effluent.
• Steps c) and d) can be reversed and / or repeated.
• Said terpolymer preferably consists of the chain of three monomer units derived from the following monomers:
• Said water-soluble terpolymer can be prepared by terpolymerization of acrylamide with acrylic acid and vinyl acetate, followed by a hydrolysis reaction under basic conditions.
• Said water-soluble terpolymer can also be prepared by terpolymerization of acrylamide with the acrylate of an alkaline element, for example sodium, and vinyl acetate, followed by a hydrolysis reaction under basic conditions.
• an alkaline element for example sodium, and vinyl acetate
• said water-soluble terpolymer can be prepared by copolymerization of acrylamide with vinyl acetate followed by a hydrolysis reaction under basic conditions.
• the copolymerization or terpolymerization reactions are carried out in the aqueous phase and initiated by one or more radical polymerization initiators such as peroxides or organic hydroperoxides, azo compounds such as 2,2'-azobis (2-methylpropionitrile), ammonium or alkali metal persulfates, at a temperature generally between 20 ° C and 100 ° C, most generally between room temperature and 80 ° C, preferably under an inert atmosphere, for a period of between 2 minutes and 12 hours.
• radical polymerization initiators such as peroxides or organic hydroperoxides, azo compounds such as 2,2'-azobis (2-methylpropionitrile), ammonium or alkali metal persulfates
• the water-soluble terpolymer is isolated at the end of the copolymerization or terpolymerization reactions, and at the end of the hydrolysis step by precipitation in an antisolvent preferably chosen from organic solvents known to those skilled in the art , especially acetone or methanol, to obtain a precipitated polymer.
• an antisolvent preferably chosen from organic solvents known to those skilled in the art , especially acetone or methanol, to obtain a precipitated polymer.
• the precipitated polymer is then dissolved in water, then a second precipitation is carried out in an antisolvent.
• the invention also relates to the use of a water-soluble terpolymer as an additive to the fluid injected in a process for the enhanced recovery of hydrocarbons in an underground formation, in particular of crude oil, said water-soluble terpolymer being a partially hydrolyzed polyacrylamide of formula (I)
• X is an alkaline cation chosen from sodium, lithium or potassium, or an ammonium cation NH 4 + .
• a b + c is greater than or equal to 0.50, preferably between 0.5 and 0.8, limits included, is less than 0.50, preferably between 0.1 and 0.4, limits included - -— is between 0.01 and 0.20, preferably between 0.02 and 0.15, limits included all the reports having a sum equal to 1.
• production effluent is understood to mean in particular complex fluids comprising, alone or as a mixture, production water, hydrocarbons, drilling fluids, fracturing fluids, water from geological formations, etc.
• the present invention relates to the use of a family of viscosifying polymers for enhanced oil recovery, said polymers being particularly suitable for being more sensitive to degradation, in particular under the action of oxidizing agents, than the polymers conventionally used in EOR such as HPAM.
• the greater sensitivity of these polymers to the action of oxidizing agents allows, by better degradation, to obtain a better reduction in the viscosity of the aqueous phase of the production effluent which contains them. It can also make it possible to obtain this reduction in viscosity more quickly and / or under milder conditions.
• FIG. 1 presents the diagram of the routes of synthesis of partially hydrolyzed polyacrylamides of the prior art.
• FIG. 3 shows the diagram of three synthetic routes for the partially hydrolyzed polyacrylamides which contain at least one monomer unit of vinyl alcohol type used in the process according to the invention.
• the terpolymers present in the fluid injected in the enhanced recovery process according to the invention are partially hydrolyzed polyacrylamides which contain at least one monomer unit of vinyl alcohol type.
• Said terpolymers comprise the chain of three monomer units derived from the following monomers: 1) acrylamide, 2) acrylic acid or acrylate of an alkaline element such as for example sodium acrylate and 3) vinyl alcohol.
• the distribution of these monomer units along the polymer chain can be random or block.
• Said terpolymers can be represented by the following general formula (I) in which the element X is an alkaline cation, chosen from the cations of alkaline elements such as sodium, lithium or potassium, preferably sodium (see Figure 2 ).
• the alkaline element can optionally be replaced by an ammonium cation NH 4 + .
• a b + c is greater than or equal to 0.50, preferably between 0.5 and 0.8, limits included, b
• the applicant has discovered that the presence of at least one monomer unit of vinyl alcohol type within the chain of such a polymer increases the sensitivity of the polymer chain to break, in particular under the action of reactants. oxidants.
• the terpolymer used in the invention is prepared by radical terpolymerization of acrylamide with acrylic acid and vinyl acetate, the terpolymerization reaction being followed by a hydrolysis reaction in basic conditions, for example in the presence of sodium hydroxide, which hydrolyzes the ester function provided by the vinyl acetate monomer unit in alcohol function and simultaneously neutralizes the carboxylic acid function present in the acrylic acid monomer unit in carboxylate function, for example sodium.
• the hydrolysis reaction can also affect the amide functions provided by the acrylamide monomer unit into carboxylate functions. This latter reaction can be limited by operating under moderate hydrolysis conditions, in particular by operating at moderate temperatures, for example at room temperature, taking into account the greater stability of the amide functions with respect to hydrolysis. compared to the ester functions.
• the terpolymer used in the invention is prepared by radical terpolymerization of acrylamide with the acrylate of an alkaline element, for example sodium, and vinyl acetate, the terpolymerization reaction being followed by a hydrolysis reaction under basic conditions, for example in the presence of sodium hydroxide which hydrolyzes the ester function provided by the vinyl acetate monomer unit in alcohol function.
• the hydrolysis reaction can also affect the amide functions provided by the acrylamide monomer unit into carboxylate functions. This latter reaction can be limited by operating under moderate hydrolysis conditions, taking into account the greater stability of the amide functions with respect to the hydrolysis compared to the ester functions.
• the terpolymer used in the invention is prepared by radical copolymerization of acrylamide with vinyl acetate, the copolymerization reaction being followed by a hydrolysis reaction under basic conditions, for example in presence of a base such as sodium hydroxide which hydrolyzes the ester functions provided by the vinyl acetate monomer unit in alcohol function.
• a base such as sodium hydroxide which hydrolyzes the ester functions provided by the vinyl acetate monomer unit in alcohol function.
• the base hydrolyzes during the same step the amide functions provided by the acrylamide monomer unit into carboxylate functions.
• the three synthetic routes can be represented by the diagram of Figure 3 in which the base is sodium hydroxide and the alkaline element X is sodium Na, but it can be any other alkaline element such as, for example, lithium or potassium.
• the alkaline element can optionally be replaced by the ammonium cation NH4 +.
• the polymerization, copolymerization or terpolymerization reactions are generally carried out in water.
• the reactions are initiated by one or more radical polymerization initiators belonging to well-known chemical families such as, for example, peroxides or organic hydroperoxides, azo compounds such as 2,2'-azobis (2-methylpropionitrile), ammonium persulfates or alkaline cations.
• radical polymerization initiators belonging to well-known chemical families such as, for example, peroxides or organic hydroperoxides, azo compounds such as 2,2'-azobis (2-methylpropionitrile), ammonium persulfates or alkaline cations.
• the polymerization reactions are carried out at a temperature generally between 20 ° C and 100 ° C, most generally between room temperature and 80 ° C.
• the polymerization reactions are preferably carried out under an inert atmosphere.
• the polymerization time is generally between a few minutes and a few hours, preferably between 2 minutes and 12 hours, preferably between 1 and 6 hours, very preferably between 30 minutes and 4 hours.
• the monomers are preferably placed in aqueous solution, in the proportions making it possible to obtain the ratios between the indices a, b, c sought.
• the solution can be degassed with argon beforehand to obtain an inert atmosphere.
• the radicalization initiator chosen in proportions known to those skilled in the art to initiate the polymerization.
• the mixture is optionally heated to obtain a temperature above ambient, and optionally subjected to stirring.
• the mixture is advantageously cooled to room temperature.
• the polymer obtained is isolated by precipitation in the anti-solvent.
• the polymer is advantageously washed, preferably with the same anti-solvent, then advantageously dried at a temperature between 20 and 100 ° C. for a period of between 1 to 24 hours. ues
• the dried polymer is dissolved in an alkaline aqueous solution, preferably water containing sodium hydroxide, so that the pH of the solution is strictly greater than 7, advantageously greater than 9, preferably greater than 11, of very preferably between 12.0 and 13.5, even more preferably between 12.5 and 13.0.
• the medium is advantageously degassed with argon to be placed in an inert atmosphere, then stirred at room temperature for a period between 1 and 48 hours, preferably between 2 and 36 hours, very preferably between 12 and 24 hours .
• the pH of the solution is then advantageously strictly greater than 7, very preferably greater than 8, even more preferably between 9 and 11.
• the partially hydrolysed polymer obtained is isolated by precipitation in the anti-solvent.
• the polymer is advantageously washed, preferably with the same anti-solvent, then advantageously dried at a temperature between 20 and 100 ° C. for a period of between 1 to 24 hours.
• the hydrolysis reaction is carried out under basic conditions by dissolving the polymer obtained in the presence of a basic compound, such as sodium hydroxide.
• a basic compound such as sodium hydroxide.
• the pH of the mixture is strictly greater than 7, preferably greater than 9, very preferably greater than 11, and even more preferably between 11.5 and 13.5, very advantageously between 12.0 and 13, 5, terminals included.
• the polymer obtained is isolated, most often by precipitation in an antisolvent which is preferably chosen from organic solvents known to those skilled in the art, in particular acetone or methanol.
• an antisolvent which is preferably chosen from organic solvents known to those skilled in the art, in particular acetone or methanol.
• This precipitation operation can optionally be doubled after precipitation of the polymer obtained in the anti-solvent, the precipitated polymer is dissolved in water, then a second precipitation is carried out in an anti-solvent.
• the polymer is advantageously washed, preferably with the same anti-solvent, then dried at a temperature between 20 and 100 ° C., for a period advantageously between 1 and 24 hours.
• the nitrogen / carbon mass ratio, N / C, of the water-soluble terpolymer obtained is advantageously between 0.1 and 0.5, preferably between 0.2 and 0.4.
• the chain-cutting reaction of the polymer of the invention can be caused by the action of an oxidant known to break covalent bonds between two carbon atoms, for example without being limiting:
• hypochlorite such as for example a sodium or potassium hypochlorite
• a persulfate such as for example a sodium or potassium persulfate
• a peroxide such as, for example, oxygen peroxide or an organic peroxide
• a permanganate such as for example potassium permanganate
• the chain-cutting reaction of the polymer of the invention can advantageously be carried out by biodegradation.
• Biodegradation can be carried out under aerobic conditions and catalyzed by alcohol oxidases or hydrolases responsible for endo-type cleavages.
• the ultimate reaction product is CO2. It can be catalyzed by dehydrogenases, which lead to the formation of intermediates of the poly (vinyl) ketone type, then cleaved by hydrolases to give as final product of biodegradation of methyl ketone or of carboxylates.
• Biodegradation can be carried out under anaerobic conditions, by the synergistic action of bacterial consortia composed of heterotrophic fermentative bacteria, sulfato-reducing bacteria and methanogens. This degradation chain leads to the production of acetate, CH4 and CO2. At the industrial level, these operations can be envisaged in anaerobic digesters.
• the chain-cutting reaction of the polymer of the invention can be carried out by photodegradation. This involves the rupture of covalent bonds under the action of photons, for example by subjecting the polymer solution to ultraviolet radiation, or the rupture of bonds following an ionization, for example caused by subjecting the sample to radiation. of accelerated electrons.
• the method according to the invention may comprise at least one step d) of separation of the aqueous phase and of the organic phase of said production effluent, before or after the treatment step making it possible to cut the chain of the water-soluble terpolymer previously described, from preferably before.
• the aqueous phase can then be subjected to any type of conventional secondary water treatment as described above.
• Example 1 Synthesis of a HPAM-vinyl co-alcohol terpolymer according to the invention
• Example 4 (comparative): synthesis of a polyacrylamide
• Example 5 (comparative): synthesis of an HPAM copolymer
• Example 6 tests of oxidative degradation
• Each polymer resulting from examples 1 to 3 (according to the invention) and examples 4 and 5 (comparative) is dissolved in water in order to obtain 40 g of polymer solution at a concentration of 1.00% in mass except for the polymer from Example 1 for which the concentration is 0.21% by mass.
• Each solution is divided into two fractions of 20g each.
• 100 mg of sodium sulfite are introduced, except for the polymer from Example 1 for which the amount of sodium sulfite is 25 mg, then the medium is degassed with the argon and the sample are kept away from air as a reference sample.
• each second fraction constituting the test sample 145 mg of sodium periodate are introduced, then the medium is stirred in the presence of air for 5 hours at 50 ° C. After returning to ambient temperature, 100 mg of sodium sulfite are introduced into each second fraction. except for the polymer from Example 1 for which the amount of sodium sulfite is 25 mg, then the medium is degassed with argon and the sample is stored in the absence of air as a test sample.
• the added sodium sulfite stabilizes the samples until analysis.
• a viscosity measurement is carried out on each sample (reference and test) for each example using a rotary rheometer (DHR3 from TA Instruments). Double cylinder geometry is used. A flow logarithmic sweep is performed between 1 and 200s 1 . The values are measured at 10s 1 .

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• 2018
  • 2018-06-25 FR FR1855631A patent/FR3082849B1/fr not_active Expired - Fee Related
• 2019
  • 2019-06-19 CA CA3099883A patent/CA3099883A1/fr not_active Abandoned
  • 2019-06-19 WO PCT/EP2019/066255 patent/WO2020002105A1/fr unknown
  • 2019-06-19 BR BR112020023087-1A patent/BR112020023087A2/pt not_active Application Discontinuation
  • 2019-06-19 US US17/254,051 patent/US20210253941A1/en not_active Abandoned
  • 2019-06-19 EP EP19730824.0A patent/EP3810716A1/de not_active Withdrawn
  • 2019-06-21 AR ARP190101727A patent/AR115603A1/es unknown
• 2021
  • 2021-01-22 CO CONC2021/0000606A patent/CO2021000606A2/es unknown

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