COMPOSITION OF ADDITIVES CONTAINING A COPOLYMER AND A RESIN

Description

technical field

[0001] The present invention relates to an additive composition comprising at least a first compound selected from ethylene and vinyl acetate (EVA) copolymers, optionally grafted with at least one alkyl (meth)acrylate or from polymers comprising at least 90 mole percent of motifs derived from alkyl (meth)acrylate monomer; and at least a second compound selected from alkylphenol-aldehyde resins modified with an alkylpolyamine.

[0002] The invention also relates to the use of this composition to reduce the viscosity of a liquid petroleum product and / or to limit the formation of paraffin deposits on the walls of a pipeline transporting a liquid petroleum product (pipe).

[0003] The invention further relates to a method for reducing the viscosity of a liquid petroleum product and / or limiting the phenomena of aggregation of paraffins, and / or dispersion of paraffins and / or delaying the crystallization of paraffins, in a liquid petroleum product. Prior art

[0004] Underground crude oil formations, also commonly referred to as "crude mineral oil" or "crude oil," have relatively high temperatures. After being extracted from the underground formation to the surface, the crude oil cools. This cooling process varies depending on the production temperature and the storage or transportation conditions.

[0005] The extracted crude oil comprises mainly two classes of products: maltenes and asphaltenes. The main constituents of maltenes are resins and waxes. These waxes are composed of paraffins (saturated hydrocarbon compounds) and aromatics. Paraffins consist of linear or branched alkanes and can be liquid, oily, or solid.

[0006] Depending on their origin, crude oils have varying proportions of waxes, which are primarily composed of long-chain n-paraffins. Depending on the type of crude oil, the proportion of these paraffins can typically range from 1 to 30% by weight of the crude oil.

[0007] During crude oil extraction from a well, temperature drops, such as in subsea wells or in harsh climatic conditions, cause the extracted crude oil to cool. As a result, paraffins crystallize, typically as platelets or platelet aggregates, and the oil's viscosity (dynamic) increases. These platelet-shaped n-paraffin crystals can form a sort of house-of-cards structure that traps the crude oil, causing it to stop flowing even though the majority of the oil remains liquid. The crystallized paraffins, and therefore the highly viscous crude oil, can clog filters, pumps, pipelines, the well, and other equipment, or be deposited in tanks, thus requiring extensive cleaning.The crystallization of these paraffins, and therefore the increase in viscosity, can occur in oil production wells and pumping facilities. These crystallized paraffins significantly impair the oil's fluidity, increasing its viscosity and making pumping and transport operations more difficult and costly, particularly because they require more energy.

[0008] This phenomenon also leads to a loss of productivity and a reduction in well life. Without treatment to prevent this phenomenon, drilling equipment must be frequently dismantled for cleaning, and the frequency of maintenance operations at production sites represents a significant economic burden.

[0009] The main factors that promote the crystallization of paraffins, and therefore the increase in the viscosity of crude oil, are a decrease in temperature and an increase in pressure relative to the "initial pressure" during oil extraction or during transport and / or storage.

[0010] The lowest temperature at which an oil sample still flows during cooling is called the pour point. Standardized test methods are used to measure the pour point.

[0011] Crude oils can have pour points above ambient temperature, so they can solidify during or after production. The pour point of crude oils can be lowered by appropriate additives. This can prevent paraffins from crystallizing during the cooling of the produced crude oil. Appropriate additives first prevent the formation of the so-called "house of cards" structures of paraffins, thus lowering the temperature at which the crude oil solidifies. Furthermore, the additives can promote the formation of fine, well-crystallized, non-agglomerating paraffin crystals, ensuring uninterrupted oil transport. These additives are called pour point depressants (PPDs) or flow enhancers.

[0012] To avoid paraffin crystallization problems, especially at low temperatures, one solution is to add additives to the crude oil, particularly crystallization-modifying additives that alter the morphology and size of the crystals. These additives can also have a dispersing effect, limiting the agglomeration of paraffin crystals.Known additives include modified alkylphenol-aldehyde resins, obtained by Mannich reaction of an alkylphenol-aldehyde condensation resin with at least one aldehyde and at least one hydrocarbon compound having at least one alkylamine group, for dispersing asphaltenes and / or preventing and / or delaying and / or inhibiting and / or reducing asphaltene precipitation in crude oil compositions (WO2016162392), or in fuel compositions as WASA anti-sedimentation additives (WO2012085865), for low-temperature stability (WO2013189868), and as antioxidants (WO2014173844). These additives are added directly to fuel compositions to improve their properties. In documents WO2012085865 and WO2013189868, the technical effect described is to prevent the formation and crystallization, or sedimentation, of paraffin crystals, particularly at low temperatures.

[0013] However, current pour point lowering additives and dispersants do not allow for a cumulative positive effect on the rheology of crude oil (its viscosity, its shear stress) as well as on paraffin deposits and their aggregation.

[0014] The applicant thus discovered that a particular combination of two additives made it possible to lower the pour point and viscosity of crude oils more effectively than conventional additives, to limit the formation of paraffin deposits on the walls and to limit the aggregation of paraffins. Summary of the invention

[0015] The invention primarily relates to a composition of additives comprising: (1) at least one first compound selected from: (i) ethylene-vinyl acetate copolymers having a molar mass Mn in the range of 10,000 to 60,000 g.mol-1, optionally grafted with at least one alkyl (meth)acrylate group having a saturated alkyl chain and containing 12 to 30 carbon atoms; and (ii) polymers comprising at least 90 mole percent of motifs derived from alkyl (meth)acrylate monomer having a saturated alkyl chain and containing 18 to 22 carbon atoms; (2) at least one second compound selected from modified alkylphenol-aldehyde resins; said modified alkylphenol-aldehyde resins being capable of being obtained by Mannich reaction of an alkylphenol-aldehyde condensation resin: with at least one aldehyde and / or ketone having from 1 to 8 carbon atoms, and at least one hydrocarbon compound comprising at least one alkylpolyamine group having from 1 to 30 carbon atoms;said alkylphenol-aldehyde condensation resin being itself capable of being obtained by condensation: of at least one alkylphenol substituted by at least one alkyl group, linear or branched, having from 1 to 30 carbon atoms, preferably from 14 to 26 carbon atoms, and even more preferably having from 18 to 22 carbon atoms; with at least one aldehyde and / or a ketone having from 1 to 8 carbon atoms; and wherein the mass ratio of the quantity of the first compound (1) to the quantity of the second compound (2) is in the range of 1 to 10, preferably in the range of 1 to 6, more preferably from 1 to 5, and even better from 1.5 to 4.

[0016] The invention also relates to the use of the composition of additives to reduce the dynamic viscosity of a liquid petroleum product, preferably at a temperature less than or equal to 30°C, more preferably less than or equal to 25°C, more preferably less than or equal to 20°C, more preferably less than or equal to 15°C, more preferably less than or equal to 10°C, more preferably less than or equal to 5°C, more preferably still less than or equal to 0°C, better less than or equal to -5°C, and better still less than or equal to -15°C; and / or to limit the aggregation phenomena of paraffins and / or to disperse them and / or delay their crystallization in a liquid petroleum product; and / or to lower the pour point of a liquid petroleum product; and / or to limit the formation of paraffin deposits on the walls of a pipeline transporting a liquid petroleum product.

[0017] Preferably, the liquid petroleum product is diesel, crude oil or heavy fuel oil, preferably crude oil.

[0018] According to a preferred embodiment of the invention, the polymers (ii) comprise at least 95% by moles, preferably at least 98%, and better 100% of motifs derived from alkyl (meth)acrylate monomer having a saturated alkyl chain and containing 18 to 22 carbon atoms.

[0019] According to a preferred embodiment of the invention, the modified alkylphenol-aldehyde resin can be obtained from p-nonylphenol, formaldehyde and at least one hydrocarbon compound having at least one alkylpolyamine group.

[0020] According to a preferred embodiment of the invention, said modified alkylphenol-aldehyde resin can be obtained by Mannich reaction of an alkylphenol-aldehyde condensation resin: with at least one aldehyde and / or ketone having from 1 to 4 carbon atoms; and at least one hydrocarbon compound comprising at least one alkylpolyamine group having from 4 to 30 carbon atoms, said alkylphenol-aldehyde condensation resin being itself capable of being obtained by condensation: of a monoalkylphenol with at least one aldehyde and / or ketone having 1 to 4 carbon atoms.

[0021] According to a preferred embodiment of the invention, the modified alkylphenol-aldehyde resin can be obtained from p-nonylphenol, formaldehyde and at least one hydrocarbon compound.

[0022] According to a preferred embodiment of the invention, the modified alkylphenol-aldehyde resin can be obtained from p-nonylphenol, and the average number of phenolic nuclei per molecule of modified p-nonylphenol-aldehyde resin is in the range of 6 to 25, preferably in the range of 8 to 17, and even more preferably in the range of 9 to 16.

[0023] According to a preferred embodiment of the invention, the hydrocarbon compound having at least one alkylpolyamine group comprises at least two primary amine groups and a fatty chain having from 12 to 24 carbon atoms, preferably from 12 to 22 carbon atoms, and preferably said hydrocarbon compound is tallow dipropylenetriamine.

[0024] According to a preferred embodiment of the invention, the additive composition further comprises an organic solvent, preferably selected from an aromatic solvent, such as xylene; a liquid hydrocarbon cut such as a diesel cut; and mixtures of such solvents.

[0025] According to a preferred embodiment of the invention, the first polymeric compound (1) comprises in its main chain an average number of acrylate motifs or ethylene motifs per polymer molecule in the range of 5 to 30, preferably 8 to 25, and even more preferably 9 to 15.

[0026] According to a preferred embodiment of the invention, the modified alkylphenol-aldehyde resin is introduced into the composition of additives (comprising additives 1 and 2 and the optional solvent) in an amount of between 100 and 20,000 ppm by weight, preferably between 1,000 and 15,000 ppm, preferably between 2,000 and 12,000 ppm, preferably between 3,000 and 10,000 ppm, preferably between 4,000 and 5,000 ppm by weight relative to the total weight of the composition.

[0027] According to another embodiment, the invention relates to a method for reducing the viscosity of a liquid petroleum product and / or limiting the phenomena of paraffin aggregation, and / or dispersion of paraffins and / or delaying the crystallization of paraffins, in a liquid petroleum product, comprising at least the following steps: the preparation of an additive composition as defined above, and then the introduction of said additive composition into a liquid petroleum product, preferably crude oil.

[0028] Preferably, the additive composition is introduced into the liquid petroleum product in such a quantity that the total content of the two compounds (1) and (2) is between 10 and 2500 ppm by weight, preferably between 20 and 1800 ppm, preferably between 50 and 1500 ppm, preferably between 70 and 1000 ppm, preferably between 100 and 800 ppm, more preferably between 400 and 700 ppm, more preferably between 550 and 650 ppm by weight.

[0029] In what follows, and unless otherwise indicated, the boundaries of a range of values ​​are included in that range, in particular in the expressions "between" and "ranging / goes / extends from ... to ...".

[0030] Furthermore, the expressions "at least one" and "at least" used in this description are respectively equivalent to the expressions "one or more" and "greater than or equal to".

[0031] In the present invention, the number average molar masses (M n ) and mass average molar masses (M w ) are determined by gel permeation chromatography or size exclusion chromatography (GPC in English for "Gel Permeation Chromatography"). Detailed description of the invention The first compound

[0032] The composition according to the invention comprises a first compound (1) selected from: (i) ethylene and vinyl acetate copolymers having a molar mass Mn in the range of 10,000 to 60,000 g.mol-1, optionally grafted with at least one alkyl (meth)acrylate whose alkyl chain is saturated and contains from 12 to 30 carbon atoms; and (ii) polymers comprising at least 90 mole percent of motifs derived from alkyl (meth)acrylate monomer whose alkyl chain is saturated and contains from 18 to 22 carbon atoms.

[0033] In a preferred embodiment, the alkyl (meth)acrylate grafts of the polymers (i) comprise a saturated alkyl chain having from 14 to 26 carbon atoms, and preferably having from 18 to 22 carbon atoms.

[0034] Preferably, the polymers (ii) comprise at least 95 mole percent, preferably at least 98 percent, and better still 100 percent of motifs derived from said alkyl (meth)acrylate monomer. The ungrafted copolymer (i)

[0035] The invention implements a copolymer comprising a repeating motif of the following formula (I):

[0036] This pattern is derived from the ethylene monomer.

[0037] It preferably represents 75 to 95% by moles, relative to the total number of moles of motifs in the copolymer.

[0038] Preferably, the copolymer comprises 77 to 92 mole percent of formula (I) motifs relative to the total number of moles of motifs in the copolymer, more preferably 80 to 88 mole percent, and even better 82 to 87 mole percent.

[0039] The copolymer (i) also comprises one or more repeating vinyl acetate unit(s) corresponding to the following formula (II): in which R1, R2, and R3 represent a hydrogen atom, and R4 represents a C1 alkyl group.

[0040] The motif(s) of formula (II) preferably represent 5 to 25% by moles, relative to the total number of moles of motifs of the copolymer.

[0041] Preferably, the copolymer (i) comprises 8 to 23 mole percent of formula motifs (II), more preferably 12 to 20 mole percent and better still 13 to 18 mole percent.

[0042] The motifs of formula (II) are derived from monomers of the C1 carboxylic acid ester and vinyl alcohols, i.e. the vinyl acetate ester of the following formula (IIA): in which R1, R2, R3 and R4 are as defined above.

[0043] The copolymer (i) used in the present invention is advantageously a statistical copolymer.

[0044] The molar mass Mn of the copolymers (i) not grafted according to the invention is in the range of 10,000 to 60,000 g.mol -1< , preferably of 10,000 to 40,000 g.mol -1< , better of 10,000 to 20,000 g.mol -1< .

[0045] The molar mass Mw of the copolymers (i) not grafted according to the invention is preferably in the range of 31,000 to 190,000 g.mol -1< , preferably of 31,000 to 125,000 g.mol -1< , better of 31,000 to 62,000 g.mol -1< .

[0046] When not grafted, the copolymer (i) used in the present invention contains only formula (I) motifs and formula (II) motifs.

[0047] Copolymers (i) can be prepared by polymerization processes known per se. The various techniques and conditions of polymerization are widely described in the literature and fall within the general knowledge of those skilled in the art.

[0048] They can notably be synthesized by conventional radical polymerization as described in US patent 3627838: the process generally involves mixing the different monomers in a suitable solvent, such as benzene, and the copolymerization is initiated using a radical polymerization initiator, such as a peroxide like tert-butyl hydroperoxide. The copolymerization reaction temperature is preferably between 260 and 350°C, even more preferably 300°C, and the pressure is preferably from 10 to 140 bar, preferably from 40 to 70 bar.

[0049] In the case where the copolymer is prepared by conventional radical polymerization, it may be necessary to proceed after the actual polymerization to a purification by any appropriate separation technique (in particular by chromatography) in order to isolate a copolymer having the required characteristics in terms of molar mass and dispersity.

[0050] According to a preferred embodiment, the copolymer according to the invention is prepared using controlled radical polymerization (CRP) techniques. Controlled radical polymerization techniques, known per se, have the advantage of being able to directly lead to copolymers having the required molar mass and dispersity characteristics, such that a separating purification may, depending on the conditions used, not be necessary.

[0051] Among these techniques, we can notably mention polymerizations governed by reversible termination or by reversible transfer (or degenerative transfer). Among these PRC techniques, those controlled by degenerative transfer are preferred, and among these, reversible addition-fragmentation chain transfer (RAFT) is even more preferred. The grafted copolymer (i)

[0052] In another embodiment, the copolymer (i) used in the present invention is grafted by at least one alkyl (meth)acrylate whose alkyl chain is saturated and contains from 12 to 30 carbon atoms.

[0053] In this embodiment, the copolymer (i) comprises a basic skeleton consisting of the ungrafted copolymer (i) as described above, onto which are grafted at least one alkyl (meth)acrylate having a saturated alkyl chain and containing 12 to 30 carbon atoms. Such a graft typically corresponds to the following formula (III): in which R 5 , R 6, identical or different, represent a hydrogen atom or an alkyl group at C 1 to C 4; R 7 represents a hydrogen atom or a methyl group and R 8 represents a saturated alkyl chain at C 12 to C 30.

[0054] In a preferred embodiment, the alkyl (meth)acrylate graft(s) comprise at least one saturated alkyl chain having 14 to 26 carbon atoms, and preferably having 18 to 22 carbon atoms.

[0055] In a preferred embodiment, R5, R6, and R7, whether identical or different, represent a hydrogen atom or a methyl group. In a particularly preferred embodiment, R5, R6, and R7 all represent a hydrogen atom; or R5 and R6 represent a hydrogen atom and R7 represents a methyl group.

[0056] According to a preferred embodiment, R8 represents a linear saturated alkyl chain. More preferably, R8 is chosen from the groups nC18H37, nC19H39, nC20H41, nC21H43, and nC22H45.

[0057] According to a particularly preferred embodiment: R 5 , R 6 , and R 7 all represent a hydrogen atom, and R 8 is chosen from the groups nC 18 H 37 , nC 19 H 39 nC 20 H 41 , nC 21 H 43 , and nC 22 H 45 .

[0058] Most preferably, R 8 is chosen from a mixture of the nC 18 H 37, nC 20 H 41, and nC 22 H 45 groups, that is to say that the alkyl (meth)acrylate is the behenyl acrylate.

[0059] Alkyl (meth)acrylate grafting can be achieved by any grafting process known per se, such as classical radical grafting or controlled radical grafting, or by ATRP (atom transfer polymerization).

[0060] The various grafting techniques and conditions are widely described in the literature and fall within the general knowledge of a person skilled in the art.

[0061] Radical grafting is particularly preferred. Grafting takes place at the level of the vinyl acetate: either on the methyl group of the acetate, or on the tertiary carbons of the copolymer skeleton, depending on the nature of the polymerization initiator.

[0062] If the initiating agent is benzoyl peroxide, grafting is initiated instead on the methyl group of the acetate.

[0063] If the initiating agent is dicumyl peroxide, grafting is initiated rather on the tertiary carbons of the copolymer skeleton, or the methyl group of the acetate.

[0064] In the case of the grafted copolymer (i), the motif of formula (I) preferably represents 71 to 94% by moles, relative to the total number of moles of motifs of the copolymer, more preferably, the copolymer comprises 78 to 88% by moles of motifs of formula (I) relative to the total number of moles of motifs of the copolymer, more preferably still 80 to 88% by moles, and better still 82 to 87% by moles.

[0065] And, the motif(s) of formula (II) preferably represent 5 to 25% by moles, relative to the total number of moles of motifs of the copolymer, more preferably, the copolymer comprises 10% to 15% by moles of motifs of formula (II).

[0066] The formula graft(s) (III) preferably represent 1 to 4% by moles, relative to the total number of moles of motifs of the copolymer, more preferably, the copolymer comprises 1.5 to 3% by moles of motifs of formula (II).

[0067] The molar mass Mn of the copolymers (i) grafted according to the invention is preferably in the range of 12,000 to 50,000 g.mol -1< , preferably of 12,000 to 40,000 g.mol -1< , better of 12,000 to 32,000 g.mol -1< .

[0068] The molar mass Mw of the copolymers (i) grafted according to the invention is preferably in the range of 23,500 to 230,000 g.mol-1, preferably of 46,500 to 190,000 g.mol-1, better of 55,000 to 150,000 g.mol-1. The polymer (ii)

[0069] The first component of the additive composition may also be chosen from polymers (ii) comprising at least 90 mole percent of motifs derived from alkyl (meth)acrylate monomer whose alkyl chain is saturated and contains 18 to 22 carbon atoms.

[0070] Alkyl (meth)acrylate monomers correspond to the following formula (IV): in which R 5 , R 6, whether identical or different, represent a hydrogen atom or an alkyl group at C 1 to C 4; R 7 represents a hydrogen atom or a methyl group; and R 8 represents a saturated alkyl chain at C 18 to C 22.

[0071] In a preferred embodiment, R5, R6, and R7, whether identical or different, represent a hydrogen atom or a methyl group. In a particularly preferred embodiment, R5, R6, and R7 all represent a hydrogen atom; or R5 and R6 represent a hydrogen atom and R7 represents a methyl group.

[0072] According to a preferred embodiment, R8 represents a linear saturated alkyl chain. More preferably, R8 is chosen from the groups nC18H37, nC19H39, nC20H41, nC21H43, and nC22H45.

[0073] According to a particularly preferred embodiment: R 5 , R 6 , and R 7 all represent a hydrogen atom, and R 8 is chosen from the groups nC 18 H 37 , nC 19 H 39 nC 20 H 41 , nC 21 H 43 , and nC 22 H 45 .

[0074] Most preferably, R8 is chosen from a mixture of the nC18H37, nC20H41, and nC22H45 groups. Also preferably, the alkyl (meth)acrylate is behenyl acrylate.

[0075] In a preferred embodiment, the polymers (ii) comprise at least 95 mole percent, preferably at least 98 percent, and better 100 percent of motifs derived from alkyl (meth)acrylate monomer having a saturated alkyl chain and containing 18 to 22 carbon atoms. The second compound (resin)

[0076] The composition according to the invention comprises a second compound selected from modified alkylphenol-aldehyde resins; said modified alkylphenol-aldehyde resin being capable of being obtained by Mannich reaction of an alkylphenol-aldehyde condensation resin: with at least one aldehyde and / or ketone having from 1 to 8 carbon atoms, and at least one hydrocarbon compound having at least one alkylpolyamine group, having from 1 to 30 carbon atoms; said alkylphenol-aldehyde condensation resin being itself capable of being obtained by condensation: of at least one alkylphenol substituted by at least one alkyl group, linear or branched, having from 1 to 30 carbon atoms, with at least one aldehyde and / or ketone having from 1 to 8 carbon atoms.

[0077] In a preferred embodiment, said modified alkylphenol-aldehyde resin can be obtained by Mannich reaction of an alkylphenol-aldehyde condensation resin: with at least one aldehyde and / or ketone having from 1 to 4 carbon atoms; and at least one hydrocarbon compound comprising at least one alkylpolyamine group having from 4 to 30 carbon atoms, said alkylphenol-aldehyde condensation resin being itself capable of being obtained by condensation: of a monoalkylphenol, with at least one aldehyde and / or ketone having 1 to 4 carbon atoms.

[0078] The alkylphenol-aldehyde condensation resin can be chosen from any resin of this type already known and in particular those described in documents EP857776, EP1584673.

[0079] The modified alkylphenol-aldehyde resin according to the invention is advantageously obtained from p-nonylphenol, formaldehyde and at least one hydrocarbon compound comprising at least one alkylpolyamine group.

[0080] According to one embodiment, the resin can be obtained from p-nonylphenol and the average number of phenolic nuclei per molecule of modified p-nonylphenol-aldehyde resin is in the range of 6 to 25, preferably 8 to 17, and even more preferably 9 to 16.

[0081] The number of phenolic nuclei can be determined by nuclear magnetic resonance (NMR) or gel permeation chromatography (GPC).

[0082] Advantageously, the modified alkylphenol-aldehyde resin is obtained by using the same aldehyde or ketone at both stages of its preparation.

[0083] According to a preferred embodiment, the modified alkylphenol-aldehyde resin can be obtained from at least one aldehyde and / or ketone selected from formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, 2-ethylhexanal, benzaldehyde, and / or acetone. Preferably, the modified alkylphenol-aldehyde resin can be obtained from at least one aldehyde, preferably at least formaldehyde (or methanal).

[0084] According to a particular embodiment, the modified alkylphenol-aldehyde resin is obtained from at least one hydrocarbon compound having at least one alkylpolyamine group having at least two primary and / or secondary amine groups. In particular, the alkylpolyamine is advantageously chosen from primary or secondary polyamines substituted by, respectively, one or two alkyl groups comprising, preferably, from 12 to 24 carbon atoms, more preferably from 12 to 22 carbon atoms.

[0085] According to a preferred variant, the modified alkylphenol-aldehyde resin is obtained from at least one hydrocarbon compound having at least one alkylpolyamine group having at least two primary amine groups.

[0086] In particular, the modified alkylphenol-aldehyde resin can advantageously be obtained from at least one alkylpolyamine in which all the amine groups are primary amines.

[0087] According to another preferred variant, the modified alkylphenol-aldehyde resin is obtained from at least one alkylpolyamine having at least two primary amine groups, preferably three primary amine groups, and comprising a fatty chain having 12 to 24 carbon atoms, preferably 12 to 22 carbon atoms.

[0088] The alkylpolyamine is preferably fat-chain with 12 to 24 carbon atoms, preferably with 12 to 22 carbon atoms.

[0089] Commercial alkylpolyamines are generally not pure compounds but mixtures. Among the commercially available alkylpolyamines that are suitable, we can mention in particular the fat-chain alkylpolyamines marketed under the names Trinoram ®< , Duomeen ®< , Dinoram ®< , Triameen ®< , Armeen ®< , Polyram ®< , Lilamin ®< and Cemulcat ®< .

[0090] A preferred example is Trinoram ®< S, which is a tallow dipropylenetriamine, also known as N-(Tallowalkyl)dipropylenetriamine (CAS 61791-57-9). The composition of additives

[0091] The composition according to the invention is such that the mass ratio of the quantity of the first compound (1) to the quantity of the second compound (2) is within the range of 1 to 10, preferably 1 to 6, more preferably 1 to 5, and even better 1.5 to 4.

[0092] According to one embodiment, the composition further comprises an organic solvent.

[0093] As an example, the organic solvent is chosen from aliphatic and / or aromatic hydrocarbons, and / or chosen from mixtures of hydrocarbons, for example fractions of gasoline, diesel, kerosene, decane, pentadecane, toluene, xylene, ethylbenzene, polyethers.

[0094] Preferably, the solvent mixture is a mixture of aromatic solvents comprising aromatic compounds having 10 carbon atoms, and / or aromatic compounds having 9 carbon atoms, and / or xylene.

[0095] In one embodiment, compound (2) is introduced into the composition previously diluted in a mixture of solvents: 50% by volume of an organic solvent mentioned below such as Solvarex, and 50% by volume of xylene.

[0096] In this case, preferably, the mixture of aromatic solvents is introduced into the modified alkylphenol-aldehyde resin solution (which already contains 50%v of solvent) and (co)polymers in a volume quantity of between 5 and 90% v / v relative to the mixture of aromatic solvents (C10, C9 and / or xylene), preferably between 10-80% v / v, even more preferably between 30-80% v / v, and very preferably between 35-70% v / v.

[0097] The organic solvent comprises a majority (at least 80% by weight) of aromatic compounds typically having 10 carbon atoms. As examples, the solvent is chosen from: Solvarex 10 ®< , Solvarex 10 LN ®< , Solvent Naphta ®< , Shellsol AB ®< , Shellsol D ®< , Solvesso 150 ®< , Solvesso 150 ND ®< .

[0098] Preferably, the first compound (1) is present in the composition of additives in an amount of between 2 and 50% by mass, preferably between 3 and 40, more preferably between 5 and 35%, by mass relative to the total mass of the composition.

[0099] Preferably, the second compound (2) (the modified alkylphenol-aldehyde resin) is present in the composition of additives in an amount of between 1 and 50% by mass, preferably between 2 and 40%, more preferably from 5 to 30%, by mass relative to the total mass of the composition. Other additives in the composition

[0100] The composition of additives may also include one or more additional additive(s), different from said additives according to the invention.

[0101] Examples of additional additives that may be incorporated into the composition include: dispersants / detergents, corrosion inhibitors, biocides, demulsifiers or antifoaming agents, paraffin deposit inhibitors; pour point depressants, paraffin anti-sedimentation additives; H2S scavengers, organic deposit inhibitors such as naphthenic acids, mineral deposit inhibitors, markers, thermal stabilizers, emulsifiers, friction reducers, surfactants, and mixtures thereof.

[0102] Other additional additives include, in particular: a) antifoaming additives, including (but not limited to) those selected from polysiloxanes, oxyalkylated polysiloxanes, and fatty acid amides derived from vegetable or animal oils; b) detergent and / or anti-corrosion additives, including (but not limited to) those selected from the group consisting of amines, succinimides, alkenylsuccinimides, polyalkylamines, polyalkyl polyamines, polyetheramines; imidazolines; and quaternary ammonium salts derived from the aforementioned compounds; c) lubrication additives or anti-wear agents, including (but not limited to) those selected from the group consisting of fatty acids and their ester or amide derivatives, including glycerol monooleate, and mono- and polycyclic carboxylic acid derivatives; d) crystallization modifying additives, paraffin deposit inhibitor additives, pour point lowering additives;low temperature rheology modifiers such as ethylene / vinyl propionate (EVP) copolymers, ethylene / vinyl acetate / vinyl versatate (EA / AA / EOVA) terpolymers; ethylene / vinyl acetate / alkyl acrylate terpolymers; polyacrylates; acrylate / vinyl acetate / maleic anhydride terpolymers; amidated maleic anhydride / alkyl(meth)acrylate copolymers that can be obtained by reacting a maleic anhydride / alkyl(meth)acrylate copolymer with an alkylamine or polyalkylamine having a hydrocarbon chain of 4 and 30 carbon atoms, preferably 12 to 24 carbon atoms;Amidified alpha-olefin / maleic anhydride copolymers obtainable by reacting an alpha-olefin / maleic anhydride copolymer with an alkylamine or polyalkylamine, the alpha-olefin being selectable from C10-C50 alpha-olefins, preferably C16-C20, and the alkylamine or polyalkylamine advantageously having a hydrocarbon chain of 4 to 30 carbon atoms, preferably 12 to 24 carbon atoms. Examples of terpolymers include those described in EP01692196, WO2009106743, WO2009106744, US4758365 and US4178951, e) acid neutralizers.

[0103] In one embodiment, the additive composition includes a dispersing agent. This embodiment is preferred when said additive composition includes a solvent, such as, in particular, a liquid hydrocarbon fraction.

[0104] For example, the dispersant is chosen from among surfactants, sulfonates, sulfonic acids (naphthalene, dodecylbenzene, etc.)... The petroleum product

[0105] According to one embodiment, the additive composition is introduced into a liquid petroleum product in such a quantity that the total content of the two compounds (1) and (2) is between 10 and 2500 ppm by weight, preferably between 20 and 1800 ppm, preferably between 50 and 1500 ppm, preferably between 70 and 1000 ppm, preferably between 100 and 800 ppm, more preferably between 400 and 700 ppm, more preferably between 550 and 650 ppm by weight, relative to the total weight of the petroleum product.

[0106] According to one embodiment, the additive composition is introduced into a liquid petroleum product in such a quantity that the content of compound (1) is between 5 and 2495 ppm by weight, preferably between 10 and 2200 ppm, preferably between 30 and 2000 ppm, preferably between 100 and 1500 ppm, by weight, relative to the total weight of the petroleum product.

[0107] According to one embodiment, the additive composition is introduced into a liquid petroleum product in such a quantity that the content of compound (2) is between 5 and 1000 ppm by weight, preferably between 10 and 800 ppm, preferably between 20 and 700 ppm, preferably between 10 and 500 ppm by weight, preferably between 10 and 300 ppm by weight, relative to the total weight of the petroleum product.

[0108] In the invention, the expression "liquid petroleum product" is synonymous with crude oil or crude petroleum (extracted from an oil well, or in an oil well, or in a pipeline...), fuel (preferably diesel), fuel oil / heavy fuel...

[0109] By "liquid" petroleum product we mean that such a petroleum product is in a liquid state at ambient temperature (25°C) and atmospheric pressure (1.03.10 5< Pa).

[0110] The liquid petroleum product is preferably crude oil or crude oil.

[0111] Crude oil (or crude petroleum) comes from a natural reserve or rock formation, preferably underground, or underground ore. It is extracted via a well or "drilling well," which is a hole or shaft penetrating into the rock formation containing the oil.

[0112] Crude oils from the well may be alone or mixed with other components, such as water, gas and / or brine, or other additives used during drilling (anti-scale...). The use

[0113] Another object of the invention is the use of the composition of additives, to decrease the dynamic viscosity of a liquid petroleum product, preferably at a temperature less than or equal to 30°C, more preferably less than or equal to 25°C, more preferably less than or equal to 20°C, more preferably less than or equal to 15°C, more preferably less than or equal to 10°C, more preferably less than or equal to 5°C, more preferably still less than or equal to 0°C, better less than or equal to -5°C, and better still less than or equal to -15°C.

[0114] Dynamic viscosity, well known to those skilled in the art, characterizes the resistance to laminar flow of an incompressible fluid.

[0115] Viscosity is measured using an Anton Paar MCR 302 rheometer, with 27mm coaxial cylinders and CSR (controlled shear rate) control: the flow curves are determined, and the viscosity is obtained. This method of determination is well known to those skilled in the art.

[0116] The composition of additives according to the invention is also used to limit the aggregation / crystallization phenomena of paraffins; and / or to disperse them and / or delay their crystallization in a liquid petroleum product.

[0117] Another object of the invention is the use of the composition of additives to limit the formation of paraffin deposits on the walls of a pipeline transporting a liquid petroleum product (pipeline).

[0118] The additive composition according to the invention is also used to lower the pour point of a liquid petroleum product. The pour point is the minimum temperature at which a substance (crude oil) will still flow. It is measured according to ASTM D5853.

[0119] The additive composition according to the invention is also used to reduce shear stress, yield stress, and / or viscosity during the flow of a liquid petroleum product, preferably at a temperature less than or equal to 85°C, more preferably less than or equal to 75°C, more preferably less than or equal to 65°C, better less than or equal to 55°C, more preferably less than or equal to 45°C, more preferably less than or equal to 35°C, more preferably less than or equal to 25°C, more preferably less than or equal to 10°C, more preferably less than or equal to 5°C, more preferably less than or equal to 0°C, better less than or equal to -5°C, and better still less than or equal to -15°C.

[0120] Shear stress is the ratio of a tangential force applied to a surface to the area of ​​the cross-sectional area of ​​the surface tangential to the force. Shear stress is measured using an Anton Paar MCR 302 rheometer, with a 27mm coaxial cylinder geometry and CSR control. The flow curves allow the shear stress to be deduced.

[0121] The liquid petroleum product is preferably diesel, crude oil or heavy fuel oil, preferably crude oil.

[0122] The invention aims to facilitate crude oil extraction, in particular by preventing / inhibiting / delaying / reducing crystallization and therefore the aggregation phenomena of paraffins. This phenomenon can affect compositions with very varied paraffin contents. The process of reducing the viscosity of a liquid petroleum product

[0123] The invention also relates to a method for reducing the viscosity of a liquid petroleum product and / or limiting the phenomena of paraffin aggregation, and / or dispersion of paraffins and / or delaying the crystallization of paraffins, in a liquid petroleum product, comprising at least the following steps: the preparation of an additive composition as defined above, and then the introduction of said additive composition into a liquid petroleum product, preferably crude oil.

[0124] The introduction of said composition of additives into the liquid petroleum product is carried out at a sufficiently high temperature, i.e. when the paraffins are still dissolved in the petroleum product matrix, i.e. between 45 and 90°C, preferably between 60 and 90°C.

[0125] According to the process of the invention, said composition of additives is introduced into a liquid petroleum product in such a quantity that the total content of the two compounds (1) and (2) is between 10 and 2500 ppm by weight, preferably between 20 and 1800 ppm, preferably between 50 and 1500 ppm, preferably between 70 and 1000 ppm, preferably between 100 and 800 ppm, more preferably, from 400 to 700 ppm, more preferably from 550 to 650 ppm by weight.

[0126] The following examples serve to illustrate the invention without being intended to be limiting. Examples:

[0127] In the following examples, the concentrations expressed in ppm correspond to ppm by mass. The abbreviation "ma" means active substance. Example 1: Additives used

[0128] The examples implement the following additives: As the first compound (1) according to the invention: a homopolymer obtained by radical polymerization of behenyl acrylate monomers, and having a molar mass Mw of 20,000 g / mol, hereinafter referred to as C1; compound C1 consists of a solution of the polyacrylate polymer at a concentration of 32% by mass in a C10 aromatic solvent; an ungrafted ethylene and vinyl acetate (EVA) copolymer, comprising 33% by mass of vinyl acetate, and having molar masses Mn=15,440 g / mol, Mw=48,025 g / mol (polydispersity index Ip=3.1), hereinafter referred to as C2; compound C2 consists of a solution of the EVA copolymer at a concentration of 20% by mass in a C10 aromatic solvent; a grafted ethylene-vinyl acetate (EVA) copolymer, comprising 5% by mass of vinyl acetate and 74% by mass of behenyl acrylate, and having molar masses of Mn=24.471 g / mol, Mw=118.528 g / mol (polydispersity index Ip=4.8), hereinafter referred to as C3; compound C3 consists of a solution of the EVA copolymer grafted at a concentration of 38% by mass in a C10 aromatic solvent.

[0129] As a second compound (2) according to the invention: a modified alkylphenol-aldehyde resin, hereinafter referred to as Res1, and whose method of synthesis is detailed below.

[0130] For comparison, the examples also implement a polyisobutylene succinimide additive, hereinafter referred to as PIBSI, obtained by condensation of succinic anhydride grafted by a polyisobutylene group with a molecular mass Mw of 1000 g / mol with tetraethylenepentamine.

[0131] The number-average molar masses (Mn) and mass-average molar masses (Mw) were determined using a size-exclusion chromatography system by gel permeation of AGILENT PL-GPC50-Plus. The elution solvent was tetrahydrofuran, and the standards consisted of polystyrene. Synthesis of the modified alkylphenol-aldehyde resin (Res1)

[0132] Step 1: In a first step, an alkylphenol-aldehyde resin is prepared by condensation of para-nonylphenol and formaldehyde (for example according to the procedure described in EP857776), with a viscosity at 50°C between 1800 and 4800 mPa.s (viscosity measured at 50°C using a dynamic rheometer with a shear rate of 10 s -1< on the resin diluted with 30% by mass of aromatic solvent (Solvesso 150 ®< )).

[0133] Step 2:In a second step, the alkylphenol-aldehyde resin from the first step is modified by Mannich reaction by adding 2 molar equivalents of formaldehyde and 2 molar equivalents of tallow dipropylenetriamine, known as N-(Tallowalkyl)dipropylenetriamine and marketed for example under the name Trinoram S ®< , compared to the alkylphenol-aldehyde resin from the first step.

[0134] The characteristics of the resin (named Res1) obtained at the end of step 2 are listed in the following table 1: [Table 1] Alkylpolyamine Dry matter (1g / 30 min / 200°C) Kinematic viscosity (mm² / s) (1) N Phe (2) Trinoram S ®< 50% 120 14,1 (1) Kinematic viscosity measured in accordance with standard NF EN ISO3405 at 40°C, on the resin diluted with 50% mass of Solvesso 150 ®< solvent, (2) Evaluation of the average number of phenolic nuclei per resin molecule or N Phe: measured by proton nuclear magnetic resonance. Example 2: Additive compositions comprising C1 + Res1 2.1 Shear stress measurements

[0135] Compound C1 and / or Res 1 resin were incorporated into crude oil, and the shear stress at different temperatures was measured with an Anton Paar MCR 302 rheometer, 27mm coaxial cylinder geometry, CSR piloting. It is measured at a shear rate of 90 s⁻¹.

[0136] The values ​​of the shear stresses obtained (expressed in Pa) are gathered in Table 2 below. [Table 2] Temperature Comparison 1: Unadditized crude oil Comparison 2: Crude oil + 1000 ppm C1 (equivalent to 320 ppm in ma) Invention: Crude oil + 1000 ppm additive = 800 ppm C1 + 200 ppm Res1; or in mA: 256 ppm C1 + 100 ppm Res1; mA / C1 / Res1 weight ratio of 2.56:1 65°C 4,61 4,31 3,96 55°C 7,93 7,10 6,39 45°C 13,68 12,05 10,78 35°C 23,63 20,64 18,25 25°C 48,97 40,14 34,83

[0137] The above results show that the shear stress of crude oil including the composition of additives according to the invention is lower than the shear stresses of crude oil alone (comparative 1) and of the mixture of crude oil and compound C1 (comparative 2). 2.2. Dynamic viscosity measurements

[0138] The following additive compositions according to the invention were prepared from compound C1 and resin Res1, diluted in an organic solvent consisting of a mixture of C9 aromatic compounds and xylene: Composition of additive A1: C1 + Res 1 with a weight ratio C1 / Res1 of 4:1 (i.e. in ma 2.56:1); Composition of additive A2: C1 + Res 1 with a weight ratio C1 / Res1 of 3:1 (i.e. in ma 1.92:1).

[0139] Each composition comprises 35% by weight of additives and 65% by weight of organic solvent.

[0140] These compositions A1 and A2 were incorporated into crude oil, and the dynamic viscosity was measured with an Anton Paar MCR 302 rheometer, 27mm coaxial cylinder geometry, CSR piloting. It is measured at a shear rate of 38 s⁻¹.

[0141] The viscosity values ​​obtained (expressed in mPa.s) are summarized in Table 3 below. [Table 3] Viscosity at 23°C Viscosity at 18°C Comparison: unadditized crude oil 2540 5290 Invention: Crude oil + 2000 ppm A1 2214 5111 Invention: crude oil + 2000 ppm A2 2113 4688

[0142] The above results show that the dynamic viscosity of crude oil including the additive compositions according to the invention is lower than the dynamic viscosity of crude oil alone (comparative).

[0143] Tests were also carried out, comparing composition A1 to the Res.1 resin alone. The dynamic viscosity was measured with an Anton Paar MCR 302 rheometer, 27mm coaxial cylinder geometry, CSR piloting. It was measured at a shear rate of 38 s⁻¹.

[0144] The viscosity values ​​obtained (expressed in mPa.s) are summarized in Table 4 below. [Table 4] Viscosity at 23°C Viscosity at 18°C Comparison: unadditized crude oil 2540 5290 Comparison: crude oil + 520 ppm Res.1 (260 ppm ma) 2240 4820 Comparison: crude oil + 1300 ppm Res.1 (650 ppm of ma) 2370 4950 Invention: crude oil + 1040 ppm C1 + 260 ppm Res.1 (332.8 ppm ma C1 + 130 ppm ma Res1; weight ratio C1 / Res1 = 2.56 :1) 2170 4690

[0145] The results above show that adding the resin alone does not sufficiently lower the viscosity, and that increasing the resin content tends to worsen the viscosity. It is the synergy between the two compounds, C1 and Res1, that allows for a substantial reduction in viscosity. Example 3: Additive compositions comprising C2 + Res1 3.1. Dynamic viscosity measurements

[0146] The additives C2, Res 1 and PIBSI were incorporated into a crude oil, and the dynamic viscosity at different temperatures was measured with an Anton Paar MCR 302 rheometer, 27mm coaxial cylinder geometry, CSR piloting. It is measured at a fixed shear rate of 0.02 s⁻¹.

[0147] The viscosity values ​​obtained (expressed in Pa.s) are summarized in Table 5 below. [Table 5] Temperature Crude oil Crude oil + 500 ppm C2 (i.e., 100 ppm ma) Crude oil + 400 ppm C2 + 100 ppm PIBSI (i.e., in m³: 80 ppm C2 + 50 ppm PIBSI; weight ratio 1.6:1) Crude oil + 400 ppm C2 + 100 ppm Res.1 (i.e. in m³: 80 ppm C2 + 50 ppm Res.1; weight ratio 1.6:1) 25°C 124,38 3,43 8,74 2,11 20°C 448,83 38,03 48,16 25,55 15°C 2029,30 128,93 164,17 94,16 10°C 4738,80 269,10 584,25 258,30

[0148] Measurements were also carried out at a fixed temperature of 10°C, and by varying the shear rate from 10 to 500 s -1.

[0149] The viscosity values ​​obtained (expressed in Pa.s) are gathered in Table 6 below. [Table 6] Shear rate Crude oil Crude oil + 500 ppm C2 (i.e., 100 ppm ma) Crude oil + 400 ppm C2 + 100 ppm PIBSI (i.e., in m³: 80 ppm C2 + 50 ppm PIBSI; weight ratio 1.6:1) Crude oil + 400 ppm C2 + 100 ppm Res.1 (i.e. in m³: 80 ppm C2 + 50 ppm Res.1; weight ratio 1.6:1) 10 s -1< 22,45 0,65 1,61 1,02 100 s -1< 6,30 0,19 0,55 0,18 500 s -1< 1,01 0,16 0,39 0,18

[0150] These results presented in Tables 5 and 6 above show that the composition of additives according to the invention (C2 + Res.1 combination) makes it possible to significantly reduce viscosity, compared to the three comparators.

[0151] The composition according to the invention also makes it possible to reduce the amount of EVA active material used (compound C2), while improving viscosity reduction performance during cooling, which is not possible with PIBSI doping at equivalent total rates of additives used. 3.2. Yield strength measurements

[0152] Threshold measurements at 10°C were also carried out, on the same crude oil added with the same compounds as in example 3.1 above.

[0153] The measurements were carried out with an Anton Paar MCR 302 rheometer, 27mm coaxial cylinder geometry, CSR piloting, at a shear rate of 38 s -1.

[0154] The yield threshold values ​​obtained (expressed in Pa) are gathered in Table 7 below. [Table 7] Crude oil Crude oil + 500 ppm C2 (i.e., 100 ppm ma) Crude oil + 400 ppm C2 + 100 ppm PIBSI (i.e., in m³: 80 ppm C2 + 50 ppm PIBSI; weight ratio 1.6:1) Crude oil + 400 ppm C2 + 100 ppm Res.1 (i.e. in m³: 80 ppm C2 + 50 ppm Res.1; weight ratio 1.6:1) 52,31 3,16 6,84 3,43

[0155] These results show that the composition of additives according to the invention (C2 + Res.1 combination) makes it possible to significantly reduce the yield threshold, compared to the three comparators.

[0156] The composition according to the invention also makes it possible to reduce the amount of EVA active material used (compound C2), while improving performance in reducing the yield point, which is not possible with PIBSI doping at equivalent total rates of additives used. Example 4: Additive compositions comprising C3 + Res1 4.1. Dynamic viscosity measurements

[0157] An additive composition according to the invention was prepared, from compound C3 and Res1 resin, diluted in an organic solvent consisting of a mixture of C9 aromatic compounds and xylene: Composition of additive A3: C3 + Res 1 with a weight ratio C3 / Res1 of 4:1 (i.e. in ma 3.04:1).

[0158] This A3 composition comprises 12% by weight of additives and 88% by weight of organic solvent.

[0159] Composition A3 was incorporated into a crude oil, having a density at 15°C of 0.911 g / cm3 and a pour point of +15°C.

[0160] Dynamic viscosity measurements were performed with an Anton Paar MCR 302 rheometer, 27mm coaxial cylinder geometry, CSR piloting, and at a shear rate of 38 s -1.

[0161] The viscosity values ​​obtained (expressed in mPa.s) are summarized in Table 8 below. [Table 8] Viscosity at 23°C Viscosity at 18°C Comparison: unadditized crude oil 1000 2000 Invention: crude oil + 1250 ppm A3 500 1000

[0162] The above results show that the dynamic viscosity of crude oil including the composition of additives according to the invention is lower than the dynamic viscosity of crude oil alone (comparative).

[0163] Tests were also carried out, comparing composition A3 to Res.1 resin alone.

[0164] The viscosity values ​​obtained (expressed in mPa.s) are summarized in Table 9 below. [Table 9] Viscosity at 23°C Viscosity at 18°C Comparison: unadditized crude oil 1000 2000 Comparison: crude oil + 50 ppm Res.1 (25 ppm of ma) 1000 2000 Invention: crude oil + 9.6 ppm C3 + 2.4 ppm Res.1 (3.65 ppm ma C3 + 1.2 ppm ma Res1; weight ratio C1 / Res1 = 3.04 :1) 700 1500

[0165] The results above show that adding the resin alone does not lower the viscosity of this crude oil. It is the synergy between the two compounds, C3 and Res1, that allows for a substantial reduction in viscosity.

Claims

1. Additive composition comprising: (1) at least one first compound selected from: (i) copolymers of ethylene and vinyl acetate having a molar mass Mn in the range from 10 000 to 60 000 g.mol-1, optionally grafted with at least one alkyl (meth)acrylate group in which the alkyl chain is saturated and contains from 12 to 30 carbon atoms; and (ii) polymers comprising at least 90 mol% of units derived from alkyl (meth)acrylate monomer in which the alkyl chain is saturated and contains from 18 to 22 carbon atoms; (2) at least one second compound selected from modified alkylphenol-aldehyde resins; said modified alkylphenol-aldehyde resins being obtainable by Mannich reaction of an alkylphenol-aldehyde condensation resin: • with at least one aldehyde and / or ketone having from 1 to 8 carbon atoms, and • at least one hydrocarbon compound comprising at least one alkylpolyamine group having between 1 and 30 carbon atoms, said alkylphenol-aldehyde condensation resin being itself obtainable by condensation: • of at least one alkylphenol substituted by at least one linear or branched alkyl group having from 1 to 30 carbon atoms, with • at least one aldehyde and / or ketone having from 1 to 8 carbon atoms, and wherein the mass ratio of the amount of the first compound (1) to the amount of the second compound (2) is in the range from 1 to 10.

2. Composition according to Claim 1, wherein the mass ratio of the amount of the first compound (1) to the amount of the second compound (2) is in the range from 1 to 6, more preferably from 1 to 5, and even better from 1.5 to 4.

3. Composition according to either of Claims 1 and 2, wherein the alkyl (meth)acrylate grafts of the polymers (i) comprise a saturated alkyl chain having from 14 to 26 carbon atoms, and preferably having from 18 to 22 carbon atoms.

4. Composition according to any one of Claims 1 to 3, wherein the polymers (ii) comprise at least 95 mol%, preferably at least 98 mol%, and better still 100 mol% of said units derived from alkyl (meth)acrylate monomer.

5. Composition according to any one of Claims 1 to 4, wherein said modified alkylphenol-aldehyde resins are obtainable by Mannich reaction of an alkylphenol-aldehyde condensation resin: • with at least one aldehyde and / or ketone having from 1 to 4 carbon atoms, and • at least one hydrocarbon compound comprising at least one alkylpolyamine group having between 4 and 30 carbon atoms, said alkylphenol-aldehyde condensation resin being itself obtainable by condensation: • of a monoalkylphenol with • at least one aldehyde and / or ketone having from 1 to 4 carbon atoms.

6. Composition according to any one of the preceding claims, wherein the modified alkylphenol-aldehyde resins are obtainable from p-nonylphenol, formaldehyde and at least one hydrocarbon compound comprising at least one alkylpolyamine group.

7. Composition according to any one of the preceding claims, wherein the modified alkylphenol-aldehyde resins are obtainable from p-nonylphenol and the average number of phenolic rings per molecule of modified p-nonylphenolaldehyde resin is in the range from 6 to 25, preferably from 8 to 17, and even more preferably from 9 to 16.

8. Composition according to any one of the preceding claims, wherein the hydrocarbon compound having at least one alkylpolyamine group comprises at least two primary amine groups and a fatty chain having from 12 to 24 carbon atoms, preferably from 12 to 22 carbon atoms, and preferably said hydrocarbon compound is tallow dipropylenetriamine.

9. Composition according to any one of the preceding claims, characterized in that it further comprises an organic solvent, preferably selected from an aromatic solvent, such as xylene; a liquid hydrocarbon fraction such as a gas oil fraction; and mixtures of such solvents.

10. Use of the composition defined in any one of the preceding claims for reducing the dynamic viscosity of a liquid petroleum product, preferably at a temperature less than or equal to 30°C, more preferably less than or equal to 25°C, more preferably less than or equal to 20°C, more preferably less than or equal to 15°C, more preferably less than or equal to 10°C, more preferably less than or equal to 5°C, more preferably still less than or equal to 0°C, better still less than or equal to -5°C, and even better still less than or equal to -15°C.

11. Use of the composition defined in any one of Claims 1 to 9 for limiting paraffin aggregation phenomena, and / or for dispersing paraffins and / or retarding their crystallization in a liquid petroleum product.

12. Use of the composition defined in any one of Claims 1 to 9 for lowering the pour point of a liquid petroleum product.

13. Use of the composition defined in any one of Claims 1 to 9 for limiting the formation of paraffin deposits on the walls of a pipe for transporting a liquid petroleum product.

14. Use according to any one of Claims 10 to 13, wherein the liquid petroleum product is a gas oil, a crude oil or a heavy fuel oil, preferably a crude oil.

15. Use according to any one of Claims 10 to 14, wherein the modified alkylphenol-aldehyde resin is introduced into the additive composition in an amount of between 100 and 20 000 ppm by weight, preferably between 1000 and 15 000 ppm, preferably between 2000 and 12 000 ppm, preferably between 3000 and 10 000 ppm, preferably between 4000 and 5000 ppm by weight relative to the total weight of the composition.

16. Method for decreasing the viscosity of a liquid petroleum product and / or for limiting paraffin aggregation phenomena, and / or for dispersing paraffins and / or for retarding paraffin crystallization, in a liquid petroleum product, preferably a crude oil, comprising at least the following steps: - the preparation of an additive composition as defined in any one of Claims 1 to 9, then - the introduction of said additive composition into said liquid petroleum product in an amount such that the total content of the two compounds (1) and (2) is in the range from 10 to 2500 ppm by weight, preferably from 20 to 1800 ppm, preferably from 50 to 1500 ppm, preferably from 70 to 1000 ppm, preferably from 100 to 800 ppm, more preferably from 400 to 700 ppm, more preferably still from 550 to 650 ppm by weight.