Polyol for delaying gas hydrate formation

Abstract

The present invention relates to the use of a polyol of the following formula (I): (I) for delaying or preventing the formation and / or agglomeration of gas hydrates in production fluids present in facilities during oil and gas extraction.

Description

POLYOL TO DELAY THE FORMATION OF GAS HYDRATE

[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 use 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 cases the contact time between the produced fluids and the cold walls of the pipeline 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 OIL 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 “KHIs”).

[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] There is therefore a real need to develop additives that can delay hydrate formation (kinetic anti-hydrates) even more effectively 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).

[0027] 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.

[0028] It has now been surprisingly discovered that polyols of specific structure make it possible to satisfy the above-mentioned objectives and in particular to behave as kinetic anti-hydrates exhibiting relatively long induction times, and in particular longer than those observed with the known kinetic anti-hydrates of the prior art. These polyols are also environmentally friendly and easy to prepare with very reasonable production costs.

[0029] 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...".

[0030] Thus, the invention relates to the use of a polyol of formula (I) as defined below 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.

[0031] The invention also provides a method for delaying or preventing the formation and / or agglomeration of hydrates in an oil and / or gas and / or condensate extraction process.

[0032] 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.

[0033] For the purposes of the present invention, the term “production fluid” means a fluid comprising one or more gases, water, and possibly oil and / or condensates. The use

[0034] The invention relates to the use of a polyol of the following formula (I): in which: HAS1 , 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, 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 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, 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, for delaying or preventing the formation and / or agglomeration of gas hydrates in fluid production, transport and storage facilities during oil and / or gas exploitation, and preferably in a production fluid, in a drilling mud or in a completion fluid.,

[0035] For the purposes of the present invention, the term terminal hydroxyl function means an OH function located at the end of a hydrocarbon chain.

[0036] Preferably, Z is chosen from a carbon atom or 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.

[0037] More particularly, Z is selected 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.

[0038] Preferably T 1 , T 2 , T 3 and T 4 represent, 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Preferably A 1 , HAS 2 , HAS 3 and A 4 each represent a hydrogen atom.

[0046] Preferably, in the polyol of formula (I), Z denotes a carbon atom, A 1 , HAS 2 , HAS 3 and A 4 each represent a hydrogen atom.

[0047] 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 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 qi + q2 + qs + q4 being greater than or equal to 2, the polyol of formula (I) comprises at least two terminal hydroxyl functions.

[0048] 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 4represent 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.

[0049] According to a second 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 + 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.

[0050] 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 4 each represent a methylene group, qi + q2 + qs + q4 is 2, 3 or 4, a + b + d + e is 0.

[0051] 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 4each represent a methylene group, qi + q2 is 0 and qs + q4 is 2, d + e is 0.

[0052] 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 qs + q4 is 2, R 3 and R 4 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.

[0053] According to another even 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 , T 2 , T 3 and T 4 each represent a methylene group, qi + q2 + qs + q4 is 4, a + b + d + e is 0.

[0054] 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, qi + q2 + qs + q4 is 4, R 1 , R 2 , R 3 and R 4represent, 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.

[0055] Preferably, the polyol of formula (I) is chosen from propoxylated trimethylolpropane, ethoxylated trimethylolpropane, butoxylated trimethylolpropane, propoxylated neopentyl glycol, ethoxylated neopentyl glycol, butoxylated neopentyl glycol.

[0056] 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.

[0057] Alternatively, the polyol of formula (I) is chosen from trimethylolpropane comprising from 1 to 200, better still from 1 to 100, better still from 1 to 60 alkyleneoxy units, more preferably from 2 to 60 alkyleneoxy units and neopentyl glycol comprising from 1 to 200, better still from 1 to 100, better still from 1 to 60 alkyleneoxy units and more preferably from 2 to 60 alkyleneoxy units.

[0058] The polyols according to the invention are commercial products or easily synthesized using operating methods known from scientific literature and patent literature.

[0059] The polyol of formula (I) can be used pure or in one or more solvent(s).

[0060] It has further been discovered that the polyol of formula (I) 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 most particularly between 0.2% and 4%, typically between 0.2% and 3%, in particular between 1% and 3% by weight.

[0061] The polyol of formula (I) may be included in a composition comprising, as solvent for water, one or more organic solvents or mixtures thereof. The organic solvents that can be used are advantageously chosen from alkyl alcohols containing 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.

[0062] The total quantity of solvent(s) present in the composition 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.

[0063] The composition may also comprise one or more kinetic hydrate inhibitors other than the polyol according to the invention.

[0064] The kinetic inhibitors of hydrates other than the polyol according to the invention may be chosen from kinetic inhibitors of hydrates well known to those skilled in the art and more specifically from polymers obtained from one or more monomers chosen from N-vinylpyrrolidone, N-vinylcaprolactam, diethylaminoethylmethacrylate, saccharides, vinyl alcohol, N-vinylamine, anhydride monomer, dicarboxylic acid, diester, diol, amine, diamine, N-methyl-N-vinylacetamide, acrylamides such as, for example, methacrylamide, N,N-dimethylacrylamide, N-isopropylmethacrylamide, N-vinylpyridine, polyethoxylated methacrylamides, vinyl acetate, methacrylamidopropyltrimethylammonium chloride, 2-(N,N-dimethylamino)ethylmethacrylamide, 3-(acryloylamino)propyltrimethylammonium chloride, 2-acryloyloxyethyltrimethylammonium chloride, 2-methacryloyloxyethyltrimethylammonium chloride,diallyldimethyl ammonium chloride, acryloyloxyethyldimethylbenzylammonium chloride, methacryloyloxyethyldimethylbenzylammonium chloride, 2-acrylamido-2-methylpropane sulfonic acid or its sodium salt, polymers derived from vinyl monomers grafted onto a polyalkylene glycol backbone, polyalkyleneimine polyesters, polyurethanes, so-called hyperbranched polymers such as hyperbranched polyesteramides obtained from di-isopropanolamine and carboxylic anhydrides such as, for example, but not limited to, c / s-1,2-cyclohexanedicarboxylic anhydride, optionally an imide such as, for example, 3,3-imino-bis-(N,N-dimethylpropylamine) or 1-methylpiperazine, alkylamides derived from maleic copolymers, polymaleimides, polyalkyloxazolines, polyvinyloxazolines, polyallylamides, copolymers (poly alkanoate / N-methyl-N-vinyl-acetamide), polyaspartamides, starch derivatives, polyvinylalkanamides,modified polymers of acryamidopropylsulfinic acid.,

[0065] Preferably, the kinetic inhibitors of hydrates other than the polyol according to the invention may be chosen from polyvinylpyrrolidone, polyvinylcaprolactams, copolymers of poly(N-vinylpyrrolidone / N-vinylcaprolactam), poly(N-vinylcaprolactam / diethylaminoethylmethacrylate), poly(N-vinylpyrrolidone / N-vinylcaprolactam / 2-(N,N-dimethylamino)ethylmethacrylate), poly(vinylcaprolactam / vinyl alcohol), poly(N-methyl-N-vinylacetamide / N-vinylcaprolactam), poly(N-methyl-N-vinylacetamide / isopropylmethacrylamide) poly-N-iso-propylmethacrylamide, poly(methacryloylpyrrolidine), pyroglutamate polyester, poly(vinylphosphonate) diesters, poly(alkylethylene phosphonates), poly(amine oxides), poly(vinyloxazoline), poly(isopropenyl-oxazoline).

[0066] The polyacrylamides described in patents US10189986, US10550215, US2020148828, and the succinimide-based copolymers described in patent US11060042 can be combined with the polyol according to the invention.

[0067] Also suitable are the hydrate kinetic inhibitors described in Malcolm A. Kelland's Production Chemicals For The Oil And Gas Industry, Second Edition, (2014), CRC Press, Taylor&Francis Group, Chapter 9, Gas hydrate Control, pages 224-235.

[0068] The composition may also comprise one or more other additives commonly used in oil and gas production, such as, for example, those selected 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.

[0069] The useful 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.

[0070] 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 the current temperatures while increasing extraction efficiency and in particular oil and / or gas production efficiency.

[0071] It has further been discovered that this polyol 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 in a production fluid, and most particularly between 0.2% and 4%, typically between 0.2% and 3%, in particular between 1% and 3% by weight. Process

[0072] 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 polyol of formula (I) as defined above to a production fluid, to a drilling mud or to a completion fluid.

[0073] 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 (aqueous phase 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 0.1% aqueous phase, would not fall outside the scope of the invention. Indeed, for gas production / transport pipes, when the temperature of the pipe drops, water can condense, increasing the risk of hydrate formation on this condensed water. In these systems, the water / hydrocarbon ratio can be very low.

[0074] 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.).

[0075] 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.

[0076] The polyol of formula (I) according to the invention is added in an amount of between 0.001% and 10% by weight, preferably between 0.01% and 7% by weight, preferably still between 0.1% and 5% by weight and better still 0.2% and 4%, typically between 0.2% and 3%, in particular between 1% and 3% by weight relative to the total weight of the production fluid.

[0077] The polyol of formula (I) according to the invention can be introduced into the production fluid continuously, discontinuously, or temporarily, in one or more times. The introduction of the polyol is generally carried out upstream of the zone at risk of the presence of hydrates, whether at the surface, at the wellhead or at the bottom of the well. For example, it is possible to inject the additives of the invention continuously, i.e. all year round 24 hours a day. Depending on the locations of the installations, it may be possible to inject the additives of the invention 24 hours a day continuously during the winter months, but not the rest of the year when it is warmer. Another example is an injection only for a few days in the year when the forecast weather will drop below a certain temperature.Finally, an injection may only be occasional when a production shutdown is expected and the fluids will stagnate for a certain time in “cold” areas.

[0078] According to another embodiment of the method of the invention, the fluid treated with the polyol according to the invention is a drilling mud or a completion fluid. In this embodiment, the polyol is introduced into the drilling mud or into the completion fluid, before or during the injection of the drilling mud or the completion fluid.

[0079] 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 and are detailed in Table 1. Compositions 1 and 2 are comparative compositions, while composition 3 is a composition according to the invention. The contents are expressed as a mass percentage in Table 1. - Table 1 - 1 PPG: polypropylene glycol with a molar mass of 400 g / mol, available from Sigma Aldrich 2 PPG: polypropylene glycol with a molar mass of 2000 g / mol, available from Sigma Aldrich 3 Polyether amine sold under the trade name Jeffamine SD 401 available from Huntsman. 1.2. Evaluation of compositions:

[0080] 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 an aqueous phase comprising a 1 g NaCl solution. 1 .

[0081] 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.

[0082] 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.

[0083] In order to carry out the evaluations of the different products, we start by introducing 10 cm into the cells 3 aqueous 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.

[0084] 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.

[0085] 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 unrelated 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. 1.3. Results:

[0086] The results are shown in Table 2 below. The composition was added to the liquid phase at a content of 2% by weight. -- Table 2 -- The composition according to the invention makes it possible to reduce the hydrate formation temperature compared to the test without additive or compared to the tests using kinetic inhibitors of hydrates with a structure different from that of the claimed polyol. Example 2 2.1. Compositions tested: The compositions detailed in Table 3 below are prepared. Composition 4 is a comparative composition, while compositions 5 to 10 are compositions according to the invention. The contents are expressed as a percentage by mass. -- Table 3 -- 2.2. Evaluation of compositions:

[0087] The operating conditions are the same as in Example 1 except for the composition of the liquid phase. In this example, the liquid part added to the cell is composed of: - 8 cm 3 of an aqueous phase comprising a 1 gL NaCl solution1 And - 2 cm 3 condensate from the Malaysian West Coast field in the South China Sea, taken from the KIMANIS Offshore Terminal. 2.3. Results:

[0088] The results are shown in Table 4 above: -- Table 4 --

[0089] Compositions 5 to 10 make it possible to delay the formation of the hydrate compared to the test without additive or compared to the test using a hydrate kinetic inhibitor of structure different from that of the claimed polyol. Example 3 3.1. Compositions tested: The compositions detailed in Table 5 below are prepared. Composition 11 is a comparative composition, while composition 12 is according to the invention. The contents are expressed as a mass percentage. -- Table 5 -- 1Vp / VCap copolymer: Vinylpyrrolidine / vinylcaprolactam copolymer sold under the trade name Inhibex™ 501 by Ashland. 3.2. Evaluation of compositions:

[0090] The operating conditions are the same as in Example 2. 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. 3.3. Results:

[0091] The results are shown in Table 6 below: -- Table 6 --

[0092] The results presented in Table 6 show that the addition of a polyol according to the invention (test 12) makes it possible to significantly reduce the quantity of gas hydrate formed compared to the addition of a kinetic inhibitor of hydrates with a structure different from that of the claimed polyol.

Claims

CLAIMS 1. Use of the polyol of formula (I) following: 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, 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, R1 , R 2 , R 3 and R 4 represent, 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, 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 4 represent, 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 still from 1 to 5 carbon atoms, even more preferably from 1 to 4 carbon atoms, limits included 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 a oxygen atom, the polyol of formula (I) comprising at least two terminal hydroxyl functions, to delay or prevent the formation and / or agglomeration of gas hydrates in production facilities,transport and storage of fluids during oil and / or gas exploitation., 2. Use 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. Use according to claim 2, characterized in that in the polyol of formula (I), when they are 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 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 3 or 4, q1, q2, q3 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, the polyol of formula (I) comprises at least two terminal hydroxyl functions.

4. Use according to any one of claims 1 to 3, characterized in that 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.

5. Use according to any one of claims 1 to 4, characterized in that the polyol of formula (I) is included in a composition comprising, as solvent, water and / or one or more organic solvents chosen from alkyl alcohols containing from 1 to 4 carbon atoms, glycol ethers and their mixtures.

6. Use according to claim 5, characterized in that the composition comprises between 10% and 90% by weight of solvent, preferably between 50% and 90%, and more preferably between 60% and 85% by weight, relative to the total weight of the composition.

7. Use according to claim 5 or 6, characterized in that it comprises at least one kinetic hydrate inhibitor of structure different from that of the polyol defined in claims 1 to 4.

8. 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 exploitation comprising a step of adding a polyol as defined in any one of claims 1 to 4 or the composition as defined in any one of claims 5 to 7 in a production fluid, in a drilling mud or in a completion fluid.

9. Process according to claim 8, in which the polyol as defined in any one of claims 1 to 4 or the composition as defined in any one of claims 5 to 7 is added in an amount of between 0.001% and 10% by weight, preferably between 0.01% and 7% by weight, more preferably between 0.1% and 5% by weight and better still 0.2% and 4%, typically between 0.2% and 3%, in particular between 1% and 3% by weight relative to the total weight of the production fluid.

10. A method according to claim 8 or claim 9, wherein the polyol or composition is introduced into the production fluid continuously, discontinuously, or temporarily, in one or more times.

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