Composition of gas hydrate formation retarders

Abstract

The present invention relates to a composition for retarding or preventing the formation and / or agglomeration of gas hydrates in installations for producing, transporting and storing fluids during oil and / or gas exploitation, comprising: - at least one polyol of the following formula (I): (I) - at least one kinetic hydrate inhibitor chosen from polymers in which at least one of the repeating units comprises at least one amide function.

Description

COMPOSITION OF GAS HYDRATE FORMATION RETARDANTS

[0001] The present invention relates to the field of hydrocarbon extraction, and more particularly to the field of additives used to facilitate the extraction and transport of said hydrocarbons to the surface. The present invention particularly relates to a method for inhibiting and / or delaying the formation of gas hydrates which are commonly known to disrupt the flow of hydrocarbons in pipelines for extracting and transporting said hydrocarbons.

[0002] Hydrocarbon extraction, mainly oil, gas, condensates and others, is currently carried out in a wide variety of environments, including offshore and subsea sites, or sites experiencing cold weather periods. These diverse environments can often lead to significant cooling of the extracted fluids in contact with the cold walls of the transport pipes.

[0003] Extracted fluids (or produced fluids, or production fluids) are understood to mean fluids including oil, gas, condensates, water and their mixtures.

[0004] For the purposes of the present invention, oil means crude oil, i.e. unrefined oil, originating from a deposit.

[0005] For the purposes of the present invention, gas means raw natural gas, i.e. untreated, directly extracted from a deposit, such as, for example, hydrocarbons, such as methane, ethane, propane, butane, hydrogen sulfide, carbon dioxide and other gaseous compounds under operating conditions, as well as mixtures thereof.

[0006] The composition of extracted natural gas varies considerably depending on the well. Thus, the gas can include gaseous hydrocarbons, water, and other gases.

[0007] For the purposes of the present invention, condensates means hydrocarbons of intermediate density. Condensates generally comprise mixtures of hydrocarbons which are liquid under operating conditions.

[0008] It is known that these production fluids most often contain an aqueous phase, in greater or lesser quantities. The origin of this aqueous phase can be endogenous and / or exogenous to the underground reservoir containing the hydrocarbons, the exogenous aqueous phase generally coming from an injection of water, also called injection water.

[0009] The depletion of previously discovered sites is leading the oil and gas industry to extract from new sites at ever greater depths.

[0010] Particularly on offshore sites, the pipelines for transporting the produced fluids are often laid on the seabed, at increasingly greater depths, where the seawater temperature is often below 15°C, more often below 10°C, or even close to or equal to 4°C.

[0011] Similarly, it is not uncommon to find extraction sites located in geographical areas where the air and / or surface water may be at relatively cold temperatures, typically below 15°C or even below 10°C. At such temperatures, the produced fluids undergo significant cooling during transport. This cooling can be further amplified in the event of a production shutdown or slowdown, in which case the contact time between the produced fluids and the cold pipe walls can increase, often considerably.

[0012] One of the disadvantages directly linked to a more or less sudden drop in the temperatures of the produced fluids is the formation of clathrates, also called hydrate crystals, gas hydrates or simply hydrates. This phenomenon is for example described in the work of Malcolm A. Kelland, Production Chemicals For The OU And Gas Industry, Second Edition, (2014), CRC Press, Taylor&Francis Group, Chapter 9, Gas hydrate Control, pages 224-235.

[0013] The risk of formation of such hydrates in production fluids, particularly during oil, gas and condensate extraction, is greater when the temperature of the production fluids is low and the pressure of these fluids is high.

[0014] These clathrates are solid crystals (similar to those of water in the form of ice) formed by water molecules, also called "receivers", around one or more gas molecules, also called "guests", such as methane, ethane, propane, butane, carbon dioxide or hydrogen sulfide.

[0015] The formation and growth of these crystals are most often induced by a lowering of the temperature of the production fluids that come out hot from the geological reservoirs that contain them and that enter a cold zone. These crystals can grow more or less quickly and agglomerate and can cause clogging or blockages of production pipes, hydrocarbon transport pipes (oil, condensates, gas), valves, flaps and other elements likely to be totally or at least partially blocked.

[0016] These blockages / pluggings can lead to losses in oil, condensate and / or gas production, resulting in significant or even very significant economic losses. Indeed, these blockages and / or pluggings will result in a reduction in the production flow rate, or even a shutdown of the production unit. In the event of a blockage, searching for the area of ​​the plug and removing it will result in a loss of time and profit for this unit. These blockages and / or pluggings can also lead to malfunctions in safety elements (safety valves for example).

[0017] These problems of hydrate formation and / or agglomeration can also be encountered within drilling muds or within completion fluids, during a drilling operation or a completion operation.

[0018] To reduce, delay or inhibit the formation and / or agglomeration of hydrates, various solutions have already been proposed or considered. Among these, we can notably cite a first solution which consists of dehydrating the production fluid, crude oil or gas, upstream of the zone of the pipe where the temperature favors the formation of said hydrates. This solution is however difficult, if not impossible, to implement under satisfactory economic conditions.

[0019] A second approach, also very expensive, consists of maintaining the temperature of the pipe at a temperature higher than the temperature of formation and / or agglomeration of hydrates, at a given pressure.

[0020] A third, frequently used approach is to add an additive called a "thermodynamic hydrate inhibitor" (or "THI"), generally an alcohol or alcohol derivative, for example methanol or glycol, to the produced fluids containing the water / guest gas mixture. It is now commonly recognized that the addition of such an additive can shift the equilibrium temperature for hydrate formation. To achieve acceptable efficiency, approximately 30% by weight of alcohol, relative to the amount of water, is generally introduced. However, the toxicity of alcohols or alcohol derivatives and the large amount of additive used are increasingly leading manufacturers to adopt a fourth approach.

[0021] This fourth solution consists of adding a low-dose additive, called LDHI (Low Dosage Hydrate Inhibitor) to the produced fluids comprising the water / guest gas mixture. This additive is also called an anti-hydrate and is introduced at a low dosage, generally between 0.2% and 4% by weight, relative to the weight of the water, it being understood that higher or lower quantities are of course possible. Two types of anti-hydrate additives are currently known, anti- agglomerants and kinetic hydrate inhibitors (or “KHI” in English).

[0022] As previously stated, hydrate formation depends primarily on temperature and pressure, as well as the composition of the guest gas(es).

[0023] Anti-caking agents do not inhibit the formation of hydrate crystals, but rather have the property of dispersing them, which consequently prevents the said hydrate crystals from agglomerating together. The hydrate crystals thus dispersed can no longer clog the pipelines transporting oil and gas production fluids, thus increasing production, in particular oil and gas extraction.

[0024] Anti-caking agents remain effective even at low temperatures. In particular, they help prevent problems with pipe blockages at temperatures generally 15°C below the minimum temperature at which hydrate crystals form, for a given pressure.

[0025] Kinetic antihydrates, on the other hand, act on the germination and growth of hydrate crystals, delaying crystal formation by several hours or even days. However, unlike anti-caking agents, kinetic antihydrates have difficulty working at low temperatures, for example below 10°C, below several tens of bars, these values ​​depending on the composition of the fluids present.

[0026] Document CN104357034 discloses a gas hydrate inhibitor comprising a mixture of two homopolymers: polyvinylpyrrolidone and polyvinylcaprolactam combined with polypropylene glycol. This mixture has kinetic anti-hydrate properties. However, relatively significant foaming of this mixture is observed under the conditions of use. In addition, the polymers in this mixture lead to a cloud point at a relatively low temperature, which may be insufficient, in particular, during hot injections.

[0027] Also known from document WO2020089554 is a composition for delaying the formation of gas hydrates, comprising at least one specific copolymer and at least one specific polyether. However, the performance of these compositions can still be improved.

[0028] There is therefore a real need to develop additives that can delay the formation of hydrates (kinetic anti-hydrates) that are even more effective at low temperatures. In other words, there remains a real need for kinetic anti-hydrates that have the longest possible induction times (hydrate formation times).

[0029] Another objective of the present invention is to provide a kinetic hydrate inhibitor which is effective under usual conditions of use, i.e. for a dosage of between 0.05% and 10% by weight, relative to the total weight of the aqueous phase in a production fluid. Yet another objective is to provide a kinetic hydrate inhibitor which is not only not very toxic to the environment, but also inexpensive and easy to produce.

[0030] It has now been surprisingly discovered that a composition comprising polyols of specific structure and specific kinetic hydrate inhibitors makes it possible to satisfy the above-mentioned objectives and in particular to behave as kinetic anti-hydrates having relatively long induction times, and in particular longer than those observed with the kinetic anti-hydrates known from the prior art. This composition also proves to be environmentally friendly and easy to prepare with entirely reasonable production costs.

[0031] Other objectives, characteristics, aspects and advantages of the invention will appear even more clearly on reading the description and the examples which follow. In what follows, and unless otherwise indicated, the limits of a range of values ​​are included in this range, in particular in the expressions "between... and..." and "ranging from... to...".

[0032] Thus, the invention relates to a composition comprising: -at least one polyol of formula (I) as described below, and - at least one hydrate kinetic inhibitor chosen from polymers, at least one of the repeating units of which comprises at least one amide function.

[0033] The invention also relates to a method for delaying or preventing the formation and / or agglomeration of gas hydrates in fluid production, transport and storage installations during oil and / or gas exploitation using the composition according to the invention.

[0034] The invention finally relates to the use of the composition according to the invention for delaying or preventing the formation and / or agglomeration of gas hydrates in installations for the production, transport and storage of fluids during oil and / or gas exploitation.

[0035] For the purposes of the present invention, gas hydrates are understood to mean clathrates or solid crystals (similar to those of water in the form of ice) formed by water molecules, also called "receivers", around one or more gas molecules, also called "guests", such as methane, carbon dioxide, hydrogen sulfide possibly forming in production fluids.

[0036] For the purposes of the present invention, the term “production fluid” means a fluid comprising an aqueous phase and one or more gases, and optionally comprising oil, gas, such as methane, ethane, propane, butane, hydrogen sulfide, carbon dioxide, condensates, water and mixtures thereof. Composition

[0037] The invention relates to a composition comprising: - at least one polyol of the following formula (I): in which: HAS 1 , HAS 2 , HAS3 and A 4 represent, independently of each other, a hydrogen atom, a hydrocarbon chain, linear or branched, saturated or unsaturated, comprising from 1 to 30 carbon atoms, preferably from 1 to 18, preferably from 1 to 8, more preferably from 1 to 5 carbon atoms, even more preferably from 1 to 4 carbon atoms inclusive, Z denotes a carbon atom, a linear, saturated or unsaturated hydrocarbon chain comprising from 2 to 10 carbon atoms, a monocyclic or polycyclic, aliphatic or aromatic hydrocarbon cycle with 4 to 10 vertices, preferably 5 to 10 vertices, and more particularly 6 to 10 vertices, optionally comprising one or more heteroatoms chosen from oxygen, nitrogen and sulfur, when present, R 1 , R 2 , R 3 and R 4represent, independently of one another, a hydrocarbon chain, linear or branched, saturated or unsaturated, comprising from 1 to 30 carbon atoms, preferably from 1 to 18, preferably from 1 to 8, more preferably from 1 to 5 carbon atoms, even more preferably from 1 to 4 carbon atoms inclusive, optionally carrying one or more hydroxyl groups, when present, T 1 , T 2 , T 3 and T 4represent, independently of each other, a linear or branched, saturated or unsaturated hydrocarbon chain, comprising from 1 to 30 carbon atoms, preferably from 1 to 18, preferably from 1 to 8, more preferably from 1 to 5 carbon atoms, even more preferably from 1 to 4 carbon atoms inclusive, a, b, d and e represent, independently of each other, an integer, identical or different, between 0 and 200, preferably between 0 and 100, more preferably between 0 and 60, more preferably between 1 and 60, and most preferably between 2 and 60, m, n, o and p represent, independently of each other, an integer equal to 0 or 1, the sum m + n + p + o being equal to 2, 3 or 4, preferably equal to 3 or 4, qi, q2, qa and q4 represent, independently of each other, an integer equal to 0 or 1, the sum qi + q2 + qs + q4 being equal to 2, 3 or 4, and Z is not directly linked to an oxygen atom,the polyol of formula (I) comprising at least two terminal hydroxyl functions, and, - at least one hydrate kinetic inhibitor chosen from polymers of which at least one of the repeating units comprises at least one amide function.

[0038] For the purposes of the present invention, the term terminal hydroxyl function means an OH function located at the end of a hydrocarbon chain. Polyol of formula (I)

[0039] Preferably, Z is chosen from a carbon atom or a monocyclic or polycyclic, aliphatic or aromatic hydrocarbon ring with 4 to 10 vertices, preferably 5 to 10 vertices, and more particularly 6 to 10 vertices, optionally comprising one or more heteroatoms chosen from oxygen, nitrogen and sulfur. More particularly, Z is chosen from a carbon atom, a cyclopentane, a furan, a tetrahydrofuran, a thiophene, a tetrahydrothiophene, a pyrrole, a pyrroline, a pyrrolidine, an oxazole, a cyclohexane, a benzene, a pyridine, a piperidine, a pyrimidine, a pyrazine, an indole, a pyrazine, a naphthalene, a quinoline. More particularly, Z is a carbon atom.

[0040] Preferably T 1 , T 2 , T 3 and T 4represent, independently of each other, bivalent hydrocarbon groups (alkylene radicals) comprising from 1 to 4 linear or branched carbons. Preferably, T 1 , T 2 , T 3 and T 4 independently represent methylene, ethylene, propylene, butylene groups. More particularly, T 1 , T 2 , T 3 and T 4 represent a methylene group or an ethylene group.

[0041] Preferably R 1 , R 2 , R 3 and R 4 represent, independently of each other, bivalent hydrocarbon groups (alkylene radicals) comprising 2 to 4 linear or branched carbons. Preferably, R 1 , R 2 , R 3 and R 4 independently represent butylene, propylene, ethylene groups and their mixtures.

[0042] In other words, the branches of the polyol of formula (I) according to the invention may comprise oxy-ethylene chains, hereinafter referred to as OE, oxy-propylene chains, hereinafter referred to as OP, and / or oxy-butylene chains, hereinafter referred to as OB.

[0043] According to one embodiment, the polyol according to the invention may comprise the same oxy-alkylene (or alkylenoxy) group on all of the branches, i.e. only oxy-ethylene or only oxy-propylene or only oxy-butylene.

[0044] According to another embodiment, the polyol according to the invention may comprise on each branch a mixture of two or three alkyleneoxy groups. Preferably, the branches of the polyol comprise the following block or statistical chains: OE / OP, OE / OB, OP / OB, OE / OP / OB.

[0045] Preferably, the sum a + b + d + e is between 0 and 200, preferably between 0 and 100, more preferably between 0 and 60, advantageously between 1 and 200, preferably between 1 and 100, more preferably between 1 and 60, and very particularly preferably between 2 and 60.

[0046] According to one embodiment, the polyol according to the invention may comprise on each branch the same alkylenoxy group different from that of the other branches.

[0047] Preferably A 1 , HAS 2 , HAS 3 and A 4 each represent a hydrogen atom.

[0048] Preferably, in the polyol of formula (I), Z denotes a carbon atom, HAS 1 , HAS 2 , HAS 3 and A 4 each represent a hydrogen atom.

[0049] According to a preferred embodiment, in the polyol of formula (I), Z denotes a carbon atom, HAS 1 , HAS 2 , HAS 3 and A 4 each represent a hydrogen atom, when present, T 1 , T 2 , T 3 and T 4 represent, independently of each other, a methylene group or an ethylene group, when present, R 1 , R 2 , R 3 and R 4 represent, independently of one another, an ethylene group, a propylene group, a butylene group, preferably butylene, a, b, d and e represent, independently of one another, an integer, identical or different, between 0 and 100, more preferably between 0 and 60, more preferably between 1 and 60, and very particularly preferably between 2 and 60, m, n, o and p represent, independently of each other, an integer equal to 0 or 1, with m + n + p + o is greater than or equal to 3, qi, q2, qa and q4 represent, independently of each other, an integer equal to 0 or 1, with qi + q2 + qs + q4 is greater than or equal to 2, the polyol of formula (I) comprises at least two terminal hydroxyl functions.

[0050] According to a first more preferred embodiment, in the polyol of formula (I), Z denotes a carbon atom, HAS 1 , HAS 2 , HAS 3 and A 4 represent a hydrogen atom, m + n + p + o is 4, T 1 represents an ethylene group and T 2 , T 3 and T 4 each represent a methylene group, qi is 0 and q2 + qa + q4 is 3, a + b + d + e is 0.

[0051] According to a second more preferred embodiment, in the polyol of formula (I), Z denotes a carbon atom, HAS1 , HAS 2 , HAS 3 and A 4 represent a hydrogen atom, m + n + p + o is 4, T 1 represents an ethylene group and T 2 , T 3 and T 4 each represent a methylene group, qi is 0 and q2 + qs + q4 is 3, R 2 , R 3 and R 4 represent, independently of one another, an ethylene group, a propylene group, a butylene group, preferably butylene, b + d + e is between 1 and 200, preferably between 1 and 100, more preferably between 1 and 60, most preferably between 2 and 60.

[0052] According to a third preferred embodiment, in the polyol of formula (I), Z denotes a carbon atom, HAS 1 , HAS 2 , HAS 3 and A 4 represent a hydrogen atom, m + n + p + o is 4, T 1 , T 2 , T 3 and T 4each represent a methylene group, qi + q2 + qs + q4 is 2, 3 or 4, a + b + d + e is 0.

[0053] According to an even more preferred embodiment, in the polyol of formula (I), Z denotes a carbon atom, HAS 1 , HAS 2 , HAS 3 and A 4 represent a hydrogen atom, m + n + p + o is 4, T 1 , T 2 , T 3 and T 4 each represent a methylene group, qi + q2 is 0 and q3+ q4 is 2, and d + e is 0.

[0054] According to an even more preferred embodiment, in the polyol of formula (I), Z denotes a carbon atom, HAS 1 , HAS 2 , HAS 3 and A 4 represent a hydrogen atom, m + n + p + o is 4, T 1 , T 2 , T 3 and T 4 each represent a methylene group, qi + q2 is 0 and q3+ q4 is 2, R 3 and R4 represent, independently of one another, an ethylene group, a propylene group, or a butylene group, preferably butylene, d + e is between 1 and 200, preferably between 1 and 100, more preferably between 1 and 60, most preferably between 2 and 60.

[0055] According to another even more preferred embodiment, in the polyol of formula (I), Z denotes a carbon atom, HAS 1 , HAS 2 , HAS 3 and A 4 represent a hydrogen atom, m + n + p + o is 4, T 1 , T 2 , T 3 and T 4 each represent a methylene group, qi + q2 + qa + q4 is 4, and a + b + d + e is 0.

[0056] According to another even more preferred embodiment, in the polyol of formula (I), Z denotes a carbon atom, HAS 1 , HAS 2 , HAS 3 and A 4represent a hydrogen atom, m + n + p + o is 4, T 1 , T 2 , T 3 and T 4 each represent a methylene group, qi + q2 + qs + q4 is 4, and R 1 , R 2 , R 3 and R 4 represent, independently of one another, an ethylene group, a propylene group, a butylene group, preferably butylene, a + b + d + e is between 1 and 200, preferably between 1 and 100, more preferably between 1 and 60, and most preferably between 2 and 60.

[0057] Preferably, the polyol of formula (I) is chosen from propoxylated trimethylolpropane, ethoxylated trimethylolpropane, butoxylated trimethylolpropane, propoxylated neopentyl glycol, ethoxylated neopentyl glycol, butoxylated neopentyl glycol.

[0058] More particularly, the polyol of formula (I) is chosen from trimethylolpropane comprising from 2 to 100 alkyleneoxy units, preferably from 2 to 60 alkyleneoxy units and neopentyl glycol comprising from 2 to 100 alkyleneoxy units, preferably from 2 to 60 alkyleneoxy units.

[0059] Alternatively, the polyol of formula (I) is chosen from trimethylolpropane comprising from 1 to 60 alkyleneoxy units, preferably from 2 to 60 alkyleneoxy units and neopentyl glycol comprising from 1 to 60 alkyleneoxy units, preferably from 2 to 60 alkyleneoxy units.

[0060] The polyols according to the invention are commercial products or easily synthesized using operating methods known from scientific literature and patent literature. Kinetic hydrate inhibitor

[0061] The composition according to the invention comprises at least one hydrate kinetic inhibitor chosen from polymers of which at least one of the repeating units comprises at least one amide function. The amide functions are branched onto the polymer chain (so-called "pendant" amide functions). The nitrogen atoms of said amide functions may be substituted, and are preferably substituted, more preferably mono-substituted, more preferably di-substituted. The substituents are identical or different and are, independently of one another, chosen from the hydrogen atom and aliphatic groups comprising from 1 to 30 carbon atoms, preferably from 1 to 8 carbon atoms, more preferably from 1 to 4 carbon atoms, and optionally comprise 1, 2, 3 or 4, preferably 1 or 2 heteroatoms, independently chosen from oxygen, nitrogen and sulfur.

[0062] The substituents of the di-substituted amide functions may also, and according to another embodiment of the present invention, form a hydrocarbon or hetero-hydrocarbon ring comprising from 4 to 7 carbon atoms, and optionally comprising 1, 2, 3 or 4, preferably 1 or 2, heteroatoms independently chosen from oxygen, nitrogen and sulfur, preferably with a maximum of two heteroatoms in the ring, the ring itself being able to be substituted by one or more saturated, linear or branched alkyl chains, comprising one or more heteroatoms independently of each other chosen from oxygen, nitrogen and sulfur, or a combination of these groups with the hetero-hydrocarbon ring comprising from 4 to 7 carbon atoms. Such monomers are for example described in detail in patent applications US2017321050 and US2017321108.

[0063] According to another embodiment of the present invention, when the nitrogen atoms of the pendant amide functions are di-substituted, the two substituents can form together and with the nitrogen atom which carries them, a cycle and possibly form a lactam with the amide chain.

[0064] The substituents of the nitrogen atoms of the pendant amide functions may also comprise one or more nitrogen atom(s), preferably one nitrogen atom. This or these nitrogen atom(s) substituents of the nitrogen atoms of the pendant amide functions may also have reacted with one or more alkylating agent(s), so as to form an ammonium cation, the anion being able to be chosen from all the anions known to those skilled in the art, and in particular from halides (for example chloride, bromide), sulfonates (for example methanesulfonate, para-toluenesulfonate), sulfates (for example methyl sulfate, ethyl sulfate), carbonates (for example methyl carbonate), and others.

[0065] In this invention, the term polymer is understood to mean a polymer resulting from the polymerization of one (1), two, three or more different monomers, the polymer then being able to be a homopolymer, a copolymer or a terpolymer. In particular, the term copolymer or terpolymer in the present invention means a polymer resulting from the polymerization of two or three different monomers.

[0066] The copolymers or terpolymers that can be used in the context of the present invention may be block or graft copolymers or terpolymers, random, periodic or statistical, preferably of low molecular mass. By low molecular mass is meant a mass of between 1000 and 5000 atomic mass units (uma) and preferably between 1500 and 4000 amu.

[0067] According to yet another embodiment of the invention, the monomers which can be used to form the polymers with amide-functional monomers can be chosen from monomers comprising an amine functional group. These amine functional groups can be primary amines (-NH2), secondary amines (-NHR a ) or tertiary (-NRaRb), preferably secondary or tertiary amines. The radicals R a and Rb substituents of secondary or tertiary amines may be identical or different and independently of each other chosen from saturated or partially unsaturated, linear or branched hydrocarbon chains comprising from 1 to 30 carbon atoms, preferably from 1 to 20 carbon atoms, more preferably from 1 to 8 carbon atoms.

[0068] The R radicals aand Rb can optionally and with the nitrogen atom which carries them form a hetero-hydrocarbon cycle comprising from 3 to 8, preferably from 4 to 7, vertices with optionally 1, 2, 3 or 4 heteroatoms independently chosen from oxygen, nitrogen and sulfur, preferably with a maximum of 2 heteroatoms in the cycle, the cycle being able to be substituted by one or more entities chosen from linear or branched, saturated or partially unsaturated hydrocarbon chains and from the heteroatoms independently chosen from oxygen, nitrogen and sulfur. Such monomers are notably described in detail in the publications of patent applications US2017321050 and US2017321108 cited above.

[0069] The R substituents a and R bnitrogen atoms of the aforementioned pendant amine functions may also comprise one or more nitrogen atom(s), preferably one (1) nitrogen atom. This or these nitrogen atom(s) substituents of the nitrogen atoms of the pendant amine functions may also have reacted with one or more alkylating agent(s), so as to form an ammonium cation, the anion being able to be of any type well known to those skilled in the art and preferably chosen from halides (for example chloride, bromide), sulfonates (for example methanesulfonate, para-toluenesulfonate), sulfates (for example methyl sulfate, ethyl sulfate), carbonates (for example methyl carbonate), and others.

[0070] According to one embodiment of the invention, the monomer(s) which can be used to form the polymers explained above can be of any type and are advantageously chosen from the monomers of formula (II): in which: R D represents -H or -CH3, and R E is chosen from the hydrogen atom, and an alkyl, alkoxy, hydroxy, N-alkylaminoalkoxy, N,N-dialkylaminoalkoxy, hydroxyalkoxy radical, cyclic radical, saturated or partially or totally unsaturated, comprising from 3 to 8 vertices, preferably 4 to 7 vertices, and optionally one or more heteroatoms, identical or different, chosen from oxygen, nitrogen and sulfur, and optionally substituted by one or more groups chosen from alkyl, halogen, carbonyl, hydroxy, alkoxy, amino, nitro and cyano.

[0071] The monomers of formula (II) may be, for example and in a non-limiting manner, chosen from acrylic acid, alkyl acrylates, N-alkylaminoalkyl acrylates and N,N-dialkylaminoalkyl acrylates as well as their halides, in particular the corresponding quaternary alkyl chlorides, hydroxyalkyl acrylates, methacrylic acid, alkyl methacrylates, N-alkylaminoalkyl methacrylates and N,N-dialkylaminoalkyl methacrylates, as well as their halides, in particular the corresponding quaternary alkyl chlorides, hydroxyalkyl methacrylates, and others, as well as mixtures of two or more of them in all proportions.

[0072] In the present description, the term "alkyl" or "alkyl" represents, unless otherwise indicated, a saturated, linear or branched hydrocarbon radical comprising from 1 to 10 carbon atoms, preferably from 1 to 6 carbon atoms, more preferably from 1 to 4 carbon atoms.

[0073] Still other monomers may be involved in the formation of the aforementioned polymers, and among these, mention may be made, without being limiting, of monomers containing at least one hydroxyl function and / or at least one functional group convertible into a hydroxyl function. Such monomers are notably described in detail in international application WO2010117660. Among these monomers, mention may be made in particular of vinyl acetate.

[0074] In the composition according to the present invention, the polymer of which at least one of the repeating units comprises at least one amide function is a polymer obtained by polymerization of at least one monomer comprising a pendant amide function, and preferably the polymer is a copolymer obtained by polymerization of two or more monomers comprising a pendant amide function, for example chosen from substituted or unsubstituted (meth)acrylamides, vinyl monomers with lactam groups, in particular vinylpyrrolidones, vinylcaprolactams.

[0075] According to a preferred embodiment of the present invention, the monomers used for the preparation of the polymer of which at least one of the repeating units comprises at least one amide function (polymer a) of the composition of the present invention) are chosen from monomers of vinylcaprolactam (VCap) type and vinylpyrrolidone (VP) type.

[0076] By polymers resulting from the copolymerization of at least one vinyl monomer with amide and / or cyclic amide groups (lactams) with a monomer containing a hydroxyl function and / or a functional group convertible into a hydroxyl function, we mean polymers resulting for example from the polymerization of monomers of the vinylpyrrolidones (VP), vinylcaprolactams (VCap), acrylamides and / or methacrylamides type with monomers containing a hydroxyl function and / or a functional group convertible into a hydroxyl function and in particular the monomers thus described in detail in the international application WO2010117660 cited above.

[0077] According to one embodiment of the present invention, the polymers are obtained by copolymerization of vinylcaprolactam (VCap) and / or vinylpyrrolidone (VP) with vinyl acetate and more preferably by copolymerization of vinylcaprolactam (VCap) with vinyl acetate. These copolymers are known and commercially available or easily prepared from known procedures and described in the scientific literature, on the internet, in patent applications, and for example in the aforementioned document WO2010117660.

[0078] More particularly, non-limiting examples of the aforementioned monomers are vinylpyrrolidone (VP), vinylcaprolactam (VCap), acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N,N-dialkylacrylamide, N,N-dialkylmethacrylamide, N,N-dialkylaminoalkylacrylamide, N,N-dialkylaminoalkylmethacrylamide, as well as their quaternary alkylammonium salts (halides, sulfonates, sulfates, carbonates and others).

[0079] According to one embodiment of the invention, the polymer a) is a copolymer obtained by copolymerization of vinylcaprolactam (VCap) and vinylpyrrolidone (VP) monomers. For example, when the vinylcaprolactam (VCap) monomer is copolymerized in the presence of a vinylpyrrolidone (VP) monomer, the VCap / VP mass ratio is advantageously between 95 / 5 and 30 / 70, preferably between 75 / 25 and 50 / 50 and even more preferably between 60 / 40 and 50 / 50.

[0080] According to another preferred embodiment of this invention, the polymer a) of the composition according to the present invention is a VCap / VOH copolymer obtained by polymerization of N-vinyl-2-caprolactam and vinyl acetate. This copolymerization is advantageously carried out in a suitable solvent known to those skilled in the art (butyl glycol for example) followed by hydrolysis of the polymer in an alkaline medium. The VCap / VOH mass ratio in the final copolymer is between 30 / 70 and 95 / 5, preferably between 60 / 40 and 85 / 15 and even more preferably between 65 / 35 and 75 / 25. Among the copolymers of interest for this invention, mention may be made, for example, of the product sold by the company Ashland Inc. under the trade name Inhibex BIO 800.

[0081] Preferably, the mass ratio between the polyol of formula (I) and the hydrate kinetic inhibitor is between 100:1 and 1:100, preferably between 80:1 and 1:80, preferably between 50:1 and 1:50, and more particularly between 1:20 and 20:1, limits included. Solvent

[0082] The composition according to the invention may comprise one or more solvents. This solvent may be water, one or more organic solvents or their mixtures. The organic solvents that can be used are advantageously chosen from alkyl alcohols comprising from 1 to 4 carbon atoms, glycol ethers and mixtures thereof. According to a preferred aspect, the organic solvent used is a glycol or a mixture of glycols, and very particularly preferably, the organic solvent is butyl glycol, also called butoxyethanol.

[0083] The total amount of organic solvent(s) present in the composition of the invention is generally between 10% and 90%, preferably between 50% and 90%, and more preferably between 60% and 85% by weight, relative to the total weight of the composition.

[0084] The composition according to the present invention may also comprise one or more other additives commonly used in oil and gas production, such as, for example, those chosen from corrosion inhibitors, roof corrosion inhibitors, kinetic anti-hydrates other than those mentioned above, hydrate anti-agglomerants, mineral anti-deposits, demulsifiers, biocides, de-oilers, anti-foam additives, paraffin inhibitors and dispersants, asphaltene inhibitors and dispersants, oxygen, hydrogen sulfide or mercaptan scavengers, drag or friction inhibitors (drag reducers) and other colorants, flavors, preservatives, if necessary or if desired.

[0085] According to a preferred embodiment of the invention, the composition comprises: - at least one polyol of formula (I) in which the polyol of formula (I), Z denotes a carbon atom, HAS 1 , HAS 2 , HAS 3 and A 4 each represent a hydrogen atom, when present, T 1 , T 2 , T 3 and T 4 represent, independently of each other, a methylene group or an ethylene group, when present, R 1 , R 2 , R 3 and R 4represent, independently of each other, an ethylene group, a propylene group, a butylene group, preferably butylene, a, b, d and e represent, independently of each other, an integer, identical or different, between 0 and 100, more preferably between 0 and 60, more preferably between 1 and 60, and very particularly preferably between 2 and 60, m, n, o and p represent, independently of each other, an integer equal to 0 or 1, with m + n + p + o being greater than or equal to 3, qi, q2, qa and q4 represent, independently of each other, an integer equal to 0 or 1, with the sum qi + q2 + qs + q4 being equal to 2, 3 or 4, the polyol of formula (I) comprising at least two terminal hydroxyl functions, - at least one selected kinetic hydrate inhibitor comprising at least one monomer selected from vinylpyrrolidone (VP), vinylcaprolactam (VCap), acrylamide, methacrylamide, vinyl alcohol, N-alkylacrylamide, N-alkylmethacrylamide, N,N-dialkylacrylamide, N,N-dialkylmethacrylamide, N,N-dialkylaminoalkylacrylamide, N,N-dialkylaminoalkylmethacrylamide, as well as their quaternary alkylammonium salts and - water and / or one or more organic solvents chosen from alkyl alcohols containing from 1 to 4 carbon atoms, glycol ethers and their mixtures, the mass ratio between the polyol of formula (I) and the kinetic hydrate inhibitor being between 100:1 and 1:100, preferably between 50:1 and 1:50, and more particularly between 1:20 and 20:1, limits included.

[0086] The composition according to the present invention can be easily prepared, for example, by mixing the various components, according to any means well known to those skilled in the art, in any order, depending on the compatibilities and miscibilities of the components with each other. The compositions can thus be prepared by mixing using a stirrer, at room temperature and atmospheric pressure.

[0087] It has been observed, quite surprisingly, that the polyol according to the invention makes it possible to delay the formation and / or agglomeration of hydrate crystals by several hours, or even several days. A direct consequence is that the polyol according to the present invention thus makes it possible to work at lower temperatures than current temperatures while increasing the extraction yield and in particular the oil and / or gas production yield.

[0088] It has further been discovered that this composition is effective at low concentrations, for example at dosages of between 0.05% and 10% by weight, preferably between 0.2% and 7% by weight, more preferably between 0.2% and 5% by weight and even better between 1% and 4% by weight, relative to the total weight of the aqueous phase present in a production fluid, and very particularly between 0.2% and 4%, typically between 0.2% and 3%, in particular between 1% and 3% by weight. Process

[0089] Thus, and according to another aspect, the present invention relates to a method for delaying, or even preventing, the formation and / or agglomeration of gas hydrates, comprising a step of adding the composition as defined above to a production fluid, to a drilling mud or to a completion fluid.

[0090] More specifically, the total content of the aqueous phase, present in the production fluid, is generally between 10% and 90% by weight, relative to the total weight of the production fluid, i.e. relative to the total weight of the fluids (phase aqueous and hydrocarbons). However, the treatment of fluid with a very high aqueous phase content or containing less than 10% aqueous phase, or even less than 1% aqueous phase, would not fall outside the scope of the invention.

[0091] The total aqueous phase content defined above corresponds to the total proportion of aqueous phase initially present in the production fluid, i.e. in the initial mixture (aqueous phase and other raw extraction liquids such as hydrocarbons, condensates, etc.).

[0092] The aqueous phase of the production fluid further comprises one or more gases capable of forming gas hydrates with water at a given temperature and pressure. Some of the gases present in the aqueous phase of the production fluid are the so-called "guest" gases, as defined above, and generally include methane, ethane, propane, butane, carbon dioxide, hydrogen sulfide, and mixtures thereof.

[0093] The composition according to the invention is added in an amount between 0.05% and 10% by weight, preferably between 0.2% and 7% by weight, more preferably between 0.2% and 5% by weight and better still between 1% and 4% by weight, relative to the total weight of the aqueous phase in a production fluid, and very particularly between 0.2% and 4%, typically between 0.2% and 3%, in particular between 1% and 3% by weight.

[0094] The composition according to the invention is added in an amount between 0.001% and 10% by weight, preferably between 0.02% and 7% by weight, more preferably between 0.2% and 5% by weight and better still between 1% and 4% by weight, relative to the total weight of the production fluid, and very particularly between 0.2% and 4%, typically between 0.2% and 3%, in particular between 1% and 3% by weight.

[0095] The composition according to the invention can be introduced into the production fluid continuously, discontinuously, or temporarily, in one or more times. The introduction of the composition is generally carried out upstream of the zone at risk of the presence of hydrates, whether on the surface, at the wellhead or at the bottom of the well.

[0096] According to another embodiment of the method of the invention, the fluid treated by the composition according to the invention is a drilling mud or a completion fluid. In this embodiment, the composition is introduced into the drilling mud or into the completion fluid, before or during the injection of the drilling mud or the completion fluid. Use

[0097] Finally, according to another aspect, the present invention relates to a use of the composition according to the invention for delaying or preventing the formation and / or agglomeration of gas hydrates in installations for the production, transport and storage of fluids during oil and / or gas exploitation.

[0098] Preferably, the use of the composition according to the invention aims to delay, or even prevent the formation and / or agglomeration of gas hydrates, in a production fluid comprising an aqueous phase and one or more gases, in a drilling mud or in a completion fluid.

[0099] The invention will be better understood in light of the following examples, given for illustrative purposes only and which are not intended to restrict the scope of the invention, defined by the appended claims. EXAMPLES Example 1 1.1. Compositions tested: The following compositions are prepared. Compositions 1, 2 and 3 are comparative compositions, while compositions 4 and 5 are compositions according to the invention. The contents are expressed in Table 1 as a mass percentage. -- Table 1 -- 1VP / VCap copolymer: Vinylpyrrolidine / vinylcaprolactam copolymer sold under the trade name Inhibex™ 501 by Ashland. 2 Polypropylene glycol with a molar mass of 446 g / mol sold under the trade name Polypropylene Glycol by Sigma-Aldrich. 1.2. Evaluation of compositions:

[0100] The kinetic efficiency of different anti-hydrate compositions was tested on a mixture comprising: a gas phase, consisting of 98% (molar) methane, and 2% (molar) propane, and a liquid phase comprising: - 8 cm 3 of an aqueous phase comprising a 1 gL NaCl solution 1 And - 2 cm 3 condensate from the Malaysian West Coast field in the South China Sea, taken from the KIMANIS Offshore Terminal.

[0101] The tests were carried out at a pressure of 98.5 bar (9.85 MPa), a pressure value that is characteristic of operating conditions where there is a risk of hydrate formation. The equilibrium temperature of the hydrates of this mixture at 98.5 bar (9.85 MPa) is approximately 18.5 °C. In other words, at 98.5 bar (9.85 MPa), gas hydrates form, when the temperature becomes lower than or equal to 18.5 °C.

[0102] The tests are carried out in a device called "rocking cells RC5", available from PSL Systemtechnik, comprising 5 cells mechanically agitated by movements ranging from +45° to -45° and temperature controlled by a double jacket. Each cell is cylindrical in shape with an internal volume of approximately 20 cm 3, with an internal diameter of 27 mm. It is made of steel resistant to 200 bars (20 MPa) and contains a 17 mm ball ensuring the agitation of the fluids during its movement. The cell is instrumented to continuously monitor the internal pressure and temperature. The cells are immersed in a glycol water bath cooled by a HUBER brand cooling bath.

[0103] In order to carry out the evaluations of the different products, we start by introducing 10 cm into the cells 3 liquid phase containing the additive to be evaluated, or without additive (reference). The cells are closed, connected to the RC5 device and purged 3 times with nitrogen. After temperature equilibration at 18.5°C, the gas mixture is charged, with stirring, into the cell until a stable pressure of 98.5 bars (9.85 MPa) is obtained.

[0104] The whole is then heated and maintained at 30°C for 12 hours to erase the thermal history of the mixture and then lowered in 30 minutes to 20°C. A 30 min hold at 20°C is maintained then the temperature is lowered at a rate of 1°C / h to a temperature of 1°C.

[0105] The performance of anti-hydrate compositions is measured by recording the temperature at which the hydrate forms when the temperature drops from 20°C to 1°C. Hydrate formation is detected by a rapid decrease in pressure not related to the cooling of the gas phase. The products are evaluated at different dosages. The dosage here corresponds to the quantity by weight of anti-hydrate composition introduced into the aqueous phase relative to the weight of the water. 1.2. Results:

[0106] The results are shown in Table 2 below: -- Table 2 --

[0107] Compositions 4 and 5 according to the invention make it possible to delay the formation of the hydrate compared to the test without additive or compared to the test using a polyol alone. Example 2 2.1. Compositions tested: The following compositions are prepared. Compositions 6 and 7 are comparative compositions, while composition 8 is according to the invention. The contents are expressed as a mass percentage in Table 3. -- Table 3 -- 1 VP / VCap copolymer: Vinylpyrrolidine / vinylcaproactam copolymer sold under the trade name Inhibex™ 501 by Ashland 2.2. Evaluation of compositions:

[0108] The operating conditions are the same as in Example 1. The tested compositions are added to the aqueous phase at a content of 1% by weight. The quantity of hydrate formed between the start of its formation and the moment when the system reaches 0.5°C is measured. 2.3. Results: The results are shown in Table 4 below. The contents are expressed as a percentage by mass. -- Table 4 --

[0109] The results presented in Table 4 show that the composition according to the invention makes it possible to significantly reduce the quantity of gas hydrate formed, whether compared to the addition of a hydrate kinetic inhibitor alone or compared to the addition of a polyol alone. Example 3 3.1. Compositions tested: The following compositions are prepared. Compositions 9 to 11 are comparative compositions, while compositions 12 to 17 are compositions according to the invention. The contents are expressed as a mass percentage in Table 5. -- Table 5 -- 1 VP / VCap copolymer: Vinylpyrrolidone / vinylcaprolactam copolymer sold under the trade name Inhibex™ 501 by Ashland 2 PolyVCap sold under the trade name Luvicap® BIO by BASF 3 Polyvinylpyrrolidone with an average molar mass of 10,000 g / mol sold under the trade name PVP 10 by Sigma Aldrich 3.2. Evaluation of compositions:

[0110] The conditions used for this example are the same as in Example 1. 3.3. Results:

[0111] The results are shown in Table 6 below. The composition was added to the liquid phase at a content of 1% by weight. - Table 6 --

[0112] The addition of the composition according to the invention in the formulation allows a loss of pressure of a factor close to 2. Conclusion The examples show the very marked improvement when the polyol of formula (I) and the hydrate inhibitors as claimed are combined with each other.

Claims

DEMANDS 1. Composition including: -at least one polyol with the following formula (I): in which: HAS 1 , HAS 2 , HAS 3 and A 4 represent, independently of each other, a hydrogen atom, a hydrocarbon chain, linear or branched, saturated or unsaturated, comprising from 1 to 30 carbon atoms, preferably from 1 to 18, preferably from 1 to 8, preferably still from 1 to 5 carbon atoms, even more preferably from 1 to 4 carbon atoms inclusive, Z denotes a carbon atom, a linear hydrocarbon chain, saturated or unsaturated, comprising from 2 to 10 carbon atoms, a hydrocarbon ring, monocyclic or polycyclic, aliphatic or aromatic, of 4 to 10 vertices, preferably of 5 to 10 vertices, and more particularly of 6 to 10 vertices, possibly comprising one or more heteroatoms selected from oxygen, nitrogen and sulfur, when present, R 1 , R 2 , R 3 and R 4 represent, independently of each other, a linear or branched, saturated or unsaturated hydrocarbon chain comprising from 1 to 30 carbon atoms, preferably from 1 to 18, preferably from 1 to 8, preferably from 1 to 5 carbon atoms, and even more preferably from 1 to 4 carbon atoms inclusive, optionally bearing one or more hydroxyl groups, when present, T 1 , T 2 , T 3 and T 4represent, independently of each other, a hydrocarbon chain, linear or branched, saturated or unsaturated, comprising from 1 to 30 carbon atoms, preferably from 1 to 18, preferably from 1 to 8, preferably from 1 to 5 carbon atoms, and even more preferably from 1 to 4 carbon atoms inclusive, a, b, d, and e represent, independently of each other, an integer, identical or different, from 0 to 200, preferably from 0 to 100, preferably from 0 to 60, preferably from 1 to 60, and most preferably from 2 to 60, m, n, o, and p represent, independently of each other, an integer equal to 0 or 1, the sum m + n + p + o being equal to 2, 3, or 4, preferably equal to 3 or 4, q1, q2, q1, and q4 represent, independently of each other, an an integer equal to 0 or 1, the sum qi + q2 + qs + q4 being equal to 2, 3 or 4, and Z is not directly bonded to an oxygen atom,the polyol of formula (I) comprising at least two terminal hydroxyl functions, and at least one kinetic hydrate inhibitor selected from polymers in which at least one of the repeating motifs comprises at least one amide function.

2. Composition according to claim 1, characterized in that, in the polyol of formula (I), Z denotes a carbon atom and A 1 , HAS 2 , HAS 3 and A 4 each represent a hydrogen atom.

3. Composition according to claim 2, characterized in that in the polyol of formula (I), when present, T 1 , T 2 , T 3 and T 4 independently represent a methylene group or an ethylene group; when present, R 1 , R 2 , R 3 and R 4represent, independently of each other, an ethylene group, a propylene group, a butylene group, preferably butylene; a, b, d, and e represent, independently of each other, an integer, identical or different, between 0 and 100, preferably again between 0 and 60, preferably again between 1 and 60, and most preferably between 2 and 60; m, n, o, and p represent, independently of each other, an integer equal to 0 or 1, with m + n + p + o greater than or equal to 3; qi, q2, qa, and q4 represent, independently of each other, an integer equal to 0 or 1, with the sum qi + q2 + qs + q4 equal to 2, 3, or 4; when m + n + p + o equals 3, then qi + q2 + qs + q4 is not equal to 4; the polyol of formula (I) comprises at least two terminal hydroxyl functions. Composition according to any one of claims 1 to 3, characterized in that the polyol of formula (I) is selected from trimethylolpropane comprising from 1 to 60 alkylenoxy motifs, preferably from 2 to 60 alkylenoxy motifs and neopentyl glycol comprising from 1 to 60 alkylenoxy motifs, preferably from 2 to 60 alkylenoxy motifs. Composition according to any one of claims 1 to 4, wherein the polymer of which at least one of the repeating motifs comprises at least one amide function is a polymer in which the amide functions are branched onto the polymer chain (so-called "pending" amide functions), the nitrogen atoms of said amide functions can be substituted, and are preferably substituted, more preferably monosubstituted, more preferably disubstituted.

6. Composition according to any one of claims 1 to 5, wherein the monomer(s) which can be used to form the polymers a) are selected from monomers of formula (II): in which: R D represents -H or -CH3, and R E is chosen from the hydrogen atom, and an alkyl, alkoxy, hydroxy, N-alkylaminoalkoxy, N,N-dialkylaminoalkoxy, hydroxyalkoxy, cyclic radical, saturated or partially or totally unsaturated, having 3 to 8 vertices, preferably 4 to 7 vertices, and possibly one or more heteroatoms, identical or different, chosen from oxygen, nitrogen and sulfur, and possibly substituted by one or more groups chosen from alkyl, halogen, carbonyl, hydroxy, alkoxy, amino, nitro and cyano.

7. Composition according to any one of claims 1 to 6, wherein the polymer, at least one of whose repeating units comprises at least one amide function, is a polymer obtained by polymerization of at least one monomer having a pendant amide function, preferably obtained by polymerization of two or more monomers having a pendant amide function, preferably chosen from substituted or unsubstituted (meth)acrylamides, vinyl monomers with lactam groups, in particular vinylpyrrolidones, vinylcaprolactams.

8. Composition according to any one of claims 1 to 7, wherein the polymer, at least one of whose repeating units comprises at least one amide function, is a polymer obtained by polymerization of one or more monomers selected from vinylpyrrolidone (VP), vinylcaprolactam (VCap), acrylamide, methacrylamide, vinyl alcohol, N-alkylacrylamide, N-alkylmethacrylamide, N,N-dialkylacrylamide, the N,N-dialkylmethacrylamide, N,N-dialkylaminoalkylacrylamide, N,N-dialkylaminoalkyl-methacrylamide, and their quaternary alkylammonium salts.

9. Composition according to any one of claims 1 to 8, characterized in that the mass ratio between the polyol of formula (I) and the kinetic hydrate inhibitor is between 10:1 and 1:10, preferably between 5:1 and 1:

5.

10. Composition according to any one of claims 1 to 9, characterized in that it comprises water and / or one or more organic solvents selected from alkyl alcohols comprising 1 to 4 carbon atoms, glycol ethers and mixtures thereof.

11. A method for delaying or preventing the formation and / or agglomeration of gas hydrates in fluid production, transport and storage facilities during oil and / or gas production, comprising a step of adding the composition as defined in any one of claims 1 to 10 into a production fluid, drilling mud or completion fluid.

12. A process according to claim 11, wherein the composition is added in an amount of between 0.001% and 10% by weight, preferably between 0.002% and 7% by weight, more preferably between 0.2% and 5% by weight, and even more preferably between 1% and 4% by weight, relative to the total weight of the production fluid, and particularly between 0.2% and 4%, typically between 0.2% and 3%, especially between 1% and 3% by weight.

13. A method according to claim 11 or claim 12, wherein the composition is introduced into the production fluid continuously, discontinuously, or temporarily, in one or more stages.

14. Use of the composition as defined in any one of claims 1 to 10 to delay or prevent the formation and / or agglomeration of gas hydrates in fluid production, transport and storage facilities during oil and / or gas operations, and in particular in a production fluid, drilling mud or completion fluid.

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