Additive composition comprising a mixture of carboxylic acids as scale inhibitor in petroleum products and / or oil production installation

Abstract

The present invention deals with an oil soluble additive composition comprising: (a) at least one fatty carboxylic acid comprising at least one fatty chain containing at least 8 carbon atoms, (b) at least one mono- or polycarboxylic acid comprising at least one hydrocarbon chain containing from 1 to 7 carbon atoms. The instant invention further pertains to the use of such a composition as an additive in an oil production installation and / or in a petroleum product such as a crude oil or any product which results therefrom by any refining and / or extraction process. The additive composition of the invention is especially useful as calcium carbonate CaCO3 scale inhibitor. In addition, the invention aims at providing a petroleum product comprising such an additive composition, as well as a method for cleaning an oil production installation production, especially for cleaning an electric submersible pump (ESP), implementing such an additive composition.

Description

[0001] DESCRIPTION

[0002] TITRE : Additive composition comprising a mixture of carboxylic acids as scale inhibitor in petroleum products and / or oil production installation

[0003] The present invention deals with an oil soluble additive composition comprising at least a mixture of carboxylic acids as defined hereafter.

[0004] The instant invention further pertains to the use of such a composition as an additive in an oil production installation and / or in a petroleum product such as a crude oil or any product which results therefrom by any refining and / or extraction process. The additive composition of the invention i s especially useful as a calcium carbonate CaCCh scale inhibitor.

[0005] In addition, the invention aims at providing a petroleum product compri sing such an additive composition, as well as a method for reducing the content of calcium carbonate present in a petroleum product, and a method for cleaning an oil production installation, including any part of an oil production installation and / or an artificial lift system, preferably an electric submersible pump (ESP).

[0006] PRIOR ART AND BACKGROUND OF THE INVENTION

[0007] Oil production well s are often equipped with an artificial lift system to optimize oil production and extend their lifetime. Some of the most common types of artificial lift systems are for example Progressive Cavity Pump (often denoted PCP), Rod Lift, Plunger Lift, and Electric Submersible Pumps (often denoted ESPs).

[0008] Electric Submersible Pumps are parti cularly advantageous as they can handle a wide range of flow rates, especially from moderate to high volumes of oil, fulfil a large string of lift requirements, and be implemented in harsh environments.

[0009] However, these electric submersible pumps di splay a specific geometry that i s very sensitive to solid fouling, especially to mineral scale deposits on their surfaces, which may cause the pumps to malfunction.

[0010] It bespeaks that when such fouling occurs, operators need to stop the oil production for several days and initiate a chemical treatment for cleaning the pumps, especially the pumps internal s including their surfaces, with a scale dissolver.

[0011] Such a maintenance operation is time-consuming, so as the costs as the oil production must be halted for a long period of time and the cleaning treatment must be carried out several times, and risks damaging not only the pumps but also any part of the oil production installation. Indeed, the oil production installation and / or the electric submersible pumps may be impaired, especially during shutdown, cleaning, and / or restarting.

[0012] This maintenance operation may also have the drawback of having to be performed several times.

[0013] Hence, scale deposition, especially calcium carbonate CaCCh scale, may hinder oil productivity, lead to heavy financial losses, and shorten the lifetime of the pumps and / or the oil production installation. In addition, scale can build-up on the surfaces of any part of the oil production installation in the same conditions as in the ESPs.

[0014] In general, calcium carbonate CaCCh can be formed by reaction of calcium ions, issued from calcium sulphate, with the presence of carbon dioxide CO2 in water.

[0015] Several attempts related in the art have therefore been developed to address this issue. For instance, phosphonate- and / or phosphonic acid-based scale inhibitors are commonly and widely used in the oil and gas industry to prevent the formation of calcium carbonate CaCOs scale. Such scale inhibitors are namely water-soluble compounds and are usually applied when the water content is strictly higher than 5% by volume compared to oil .

[0016] These scale inhibitors may be chosen among amine phosphonate- based compounds, such as ethylenediaminetetramethylene phosphonic acid or aminotrimethylene phosphonic acid, and prevent the formation of calcium carbonate CaCCh scale by reacting with calcium ions present in water, which may result in the formation of a calcium-phosphonate precipitate.

[0017] In other words, such scale inhibitors prevent the formation of calcium carbonate CaCCh scale by acting directly on the calcium ions present in water and issued from calcium sulphate, in order to make them precipitate.

[0018] However, calcium carbonate CaCCh can form even if the water content is low, especially lower than 5% by volume compared to oil, and can therefore be present within the oil phase leading to the formation of scale deposits on pump surfaces and / or any part of the oil production installation.

[0019] As a result, it remains a real need to provide a novel additive which is soluble in crude oils as well as in products deriving therefrom which is efficient to reduce the content of calcium carbonate CaCCh present within the oil phase and the calcium carbonate CaCOs scale deposits formed on the pumps and / or any part of the oil production installati on.

[0020] Indeed, one of the purposes of the present invention is to provide an improved calcium carbonate CaCCH scale inhibitor which is soluble in crude oils as well as in products deriving therefrom, and allows to maintain artificial lift systems, such as electric submersible pumps (ESPs), clean toward calcium carbonate CaCCh scale, as well as any part of an oil production installation, over a long period of production in order to limit the maintenance operations, especially their duration and their numbers, and avoid shutdown of the oil production.

[0021] More specifically, one of the goals of the present invention is to provide an improved calcium carbonate CaCCH scale inhibitor having a good ecotoxicity profile ensuring safety conditions for the environment, specifically to the marine environment, while allowing a better oil production optimization.

[0022] OBJECT OF THE INVENTION

[0023] The present invention namely results from the unexpected findings, by the inventors, that an oil soluble additive composition compri sing at least a mixture of carboxylic acids, as defined below, is particularly efficient to reduce the formation of CaCCh deposit that may forms in the oil under certain conditions to lessen the calcium carbonate CaCCh scale deposits formed on artificial lift systems, such as electric submersible pumps (ESPs), and / or on any part of an oil production installation.

[0024] Therefore, the present invention relates to an oil soluble additive composition comprising:

[0025] (a) at least one fatty carboxylic acid comprising at least one fatty chain containing at least 8 carbon atoms, and

[0026] (b) at least one mono- or polycarboxylic acid comprising at least one hydrocarbon chain containing from 1 to 7 carbon atoms.

[0027] The composition according to the present invention exhibits the asset of being soluble in crude oil s as well as in products deriving therefrom, especially in oil phases wherein the water content is less than or equal to 5% by volume related to the total volume of the oil phase.

[0028] The composition of the present invention allows the compatibilization of calcium carbonate CaCCh in crude oils as well as in products deriving therefrom, and the solubilization of calcium carbonate CaCCh scale deposited on surfaces.

[0029] Said composition is therefore particularly advantageous to maintain the cleanliness of artificial lift system or to clean artificial lift systems, such as electric submersible pumps (ESPs), and / or on any part of an oil production installation.

[0030] Hence, said composition namely prevents the malfunction of artificial lift systems, preferably electric submersible pumps (ESPs), and enhances their lifetime, as well as the lifetime of an oil production installation.

[0031] Especially, said composition makes it possible to improve the performances of an artificial lift system, preferably an electric submersible pump .

[0032] More specifically, said composition allows to maintain the pressure gradient of an electric submersible pump over time, ensuring its proper functioning.

[0033] Thus, said composition helps to improve oil productivity of an oil production installation. Moreover, said composition allows to keep the artificial lift systems, such as electric submersible pumps (ESPs), and / or on any part of an oil production installation, clean over a long period of production so as to limit the number and duration of maintenance operati ons, avoid shutdown of the oil production, and avert loss of oil production.

[0034] The composition of the present invention can further i nclude one or more further additives, and therefore can be effective against other types of solid fouling which might impede the proper functioning of an artificial list system and / or an oil production installation.

[0035] In other words, said mixture of carboxylic acids is compatible with one or more further additives, especially with one or more asphaltene inhibitors.

[0036] Especially, asphaltene inhibitors are stable in the composition of the present invention.

[0037] In still other terms, said composition can be a multifunctional additive composition as several types of solid fouling can be treated.

[0038] It ensures from this asset that said composition can be implemented for multipronged purposes.

[0039] In particul ar, said composition may be a bifunctional additive composition acting against calcium carbonate scale and asphaltene formation in a petroleum product, such as a crude oil .

[0040] The composition according to the invention further di splays a good ecotoxicity profile ensuring safety conditions for the environment, specifically to the marine environment.

[0041] Indeed, said composition advantageously encompasses bio-based compounds, especially vegetable-based compounds.

[0042] Another subj ect-matter of the present invention relies on the use of said composition as an additive in a petroleum product and / or an oil production installation.

[0043] The petroleum product preferably compri ses 5% or less of water, more preferably less than 5% of water in volume related to the total volume of said petroleum product.

[0044] Preferably, the subj ect-matter of the present invention relies on the use of said composition as an additive in a petroleum product such as a crude oil or any product which results therefrom by any refining and / or extraction process, preferably as a scale inhibitor, especially for reducing the formation of calcium carbonate precipitate and deposit in petroleum and installation.

[0045] As previously outlined, said composition advantageously reduces the content of calcium carbonate deposit in a petroleum product containing 5% or less of water in volume, related to the total volume of the petroleum product, which allows for better separation of the aqueous phase from the oil phase and results in a better aqueous phase quality.

[0046] Indeed, said composition allows to reduce the content of calcium carbonate in the organic phase, which leads to an increase in the concentration of calcium ions in the aqueous phase, giving it an increased conductivity.

[0047] The instant invention further pertains to the use of said composition as an additive in an oil production installation, preferably as a scale inhibitor, preferably for reducing calcium carbonate CaCOs scale deposition in an oil production installation.

[0048] Once again, as previously mentioned, the composition as defined hereafter is particularly efficient to reduce and / or remove calcium carbonate CaCOs scale deposited on one or more surfaces of any part of an oil production installation, including an artificial lift system especially an electric submersible pump (ESP).

[0049] Another subj ect-matter of the present invention concerns a petroleum product comprising such an additive composition.

[0050] The instant invention also concerns a method for reducing the content of calcium carbonate and optionally the content of asphaltene present in a petroleum product comprising adding an additive composition to said petroleum product.

[0051] A further subj ect-matter of the present invention deals with a method for cleaning an oil production installation, preferably at least one artificial lift system, more preferably an electric submersible pump (ESP), comprising adding to said part of the oil production installation at least one additive composition as previously defined.

[0052] This method can advantageously be implemented to clean one or more surfaces of any part of an oil production installation, including any part of an oil production installation and / or an artificial lift system. Other obj ects, features, aspects and advantages of the invention will become more apparent upon reading the following description and examples.

[0053] In the following, and at least one other indication, the limits of a value range are included within this range, particularly in the expressions "between" and "ranging from ... to ... " .

[0054] Moreover, the expressions " at least one" and " at least" used in the present description are respectively equivalent to the expressions "one or more" and "more than or equal to" .

[0055] Finally, in a manner known per se, Cncompound or group designates a compound or a group containing in its chemical structure n carbon atoms.

[0056] DETAILED DESCRIPTION

[0057] Additive composition

[0058] As previously defined, the oil soluble additive composition compri ses:

[0059] (a) at least one fatty carboxylic acid comprising at least one fatty chain containing at least 8 carbon atoms, and

[0060] (b) at least one mono- or polycarboxylic acid comprising at least one hydrocarbon chain containing from 1 to 7 carbon atoms.

[0061] According to the present invention, the term “oil soluble” means that the additive composition is soluble in an organic phase comprising 5% or less of water by volume related to the total volume of said organic phase.

[0062] Preferably, the additive composition is soluble in an oil phase compri sing 5% or less of water by volume, more preferably less than 5% of water, related to the total volume of said oil phase.

[0063] Especially, the additive composition is soluble in a petroleum product as defined hereafter; the petroleum product comprising 5% or less of water by volume.

[0064] The fatty chain of the carboxylic acid (a) may contain from 8 to 30 carbon atoms, preferably from 12 to 24 carbon atoms, more preferably from 12 to 20 carbon atoms, even more preferably from 14 to 20 carbon atoms.

[0065] The fatty carboxylic acid (a) may be chosen among the group consisting of the compounds having the formula Ri -C(O)OH wherein Ri denotes a hydrocarbon group containing at least 8 carbon atoms.

[0066] The fatty carboxylic acid (a) may be chosen among the group consisting of the compounds having the formula Ri -C(O)OH wherein Ri represents a linear or branched, saturated or unsaturated, alkyl group compri sing at least 8 carbon atoms, preferably from 8 to 30 carbon atoms, more preferably from 12 to 24 carbon atoms, especially from 12 to 20 carbon atoms and specifically from 14 to 20 carbon atoms.

[0067] Preferably, the fatty carboxylic acid (a) is chosen among the group consisting of the compounds having the formula Ri-C(O)OH wherein Ri represents a linear, saturated or unsaturated, alkyl group compri sing at least 8 carbon atoms, preferably from 8 to 30 carbon atoms, more preferably from 12 to 24 carbon atoms, especially from 12 to 20 carbon atoms and specifically from 14 to 20 carbon atoms.

[0068] More preferably, the fatty carboxylic acid (a) is chosen among the group consisting of the compounds having the formula Ri -C(O)OH wherein Ri represents a linear, saturated or unsaturated, alkyl group compri sing from 12 to 24 carbon atoms, especially from 12 to 20 carbon atoms and specifically from 14 to 20 carbon atoms.

[0069] Even more preferably, the fatty carboxylic acid (a) is chosen among the group consisting of the compounds having the formula Ri- C(O)OH wherein Ri represents a linear and unsaturated alkyl group compri sing from 12 to 24 carbon atoms, especially from 12 to 20 carbon atoms and specifically from 14 to 20 carbon atoms.

[0070] The fatty carboxylic acid (a) is preferably a liquid fatty carboxylic acid.

[0071] For the purposes of the present invention, the term “liquid fatty acid” means a fatty carboxylic acid having a melting point below or equal to 25 °C, preferably below or equal to 20°C at atmospheric pressure (1 .013 >< 105Pa). The fatty carboxylic acid (a) may be chosen among the group consisting of oleic acid, linoleic acid, arachidonic acid, i sostearic acid, isopalmitic acid, and mixtures thereof, preferably oleic acid.

[0072] The fatty carboxylic acid (a) is advantageously from natural origin, preferably based on bio-based fatty carboxylic acids.

[0073] The fatty carboxylic acid (a) is especially chosen from plantbased fatty carboxylic acids.

[0074] As previously defined, the mono- or polycarboxylic acid (b) compri ses at least one hydrocarbon group containing from 1 to 7 carbon atoms.

[0075] Preferably, the mono- or polycarboxylic acid (b) comprises at least one hydrocarbon group containing from 1 to 5 carbon atoms, especially from 1 to 4 carbon atoms.

[0076] According to the present invention, the mono- or polycarboxylic acid (b) may be chosen from monocarboxylic acids, polycarboxylic acids, and mixtures thereof.

[0077] Preferably, the mono- or polycarboxylic acid (b) may be chosen among mono- or dicarboxylic acids, preferably from the group consisting of monocarboxylic acids.

[0078] The monocarboxylic acid (b) may be chosen among the group consisting of the compounds having the formula R2-C(O)OH wherein R2 represents a linear or branched, saturated or unsaturated, alkyl group compri sing from 1 to 6 carbon atoms, preferably from 1 to 5 carbon atoms, more preferably from 1 to 3 carbon atoms.

[0079] The monocarboxylic acid (b) is preferably chosen among the group consisting of propionic acid, acetic acid, or mixture thereof, especially propionic acid.

[0080] The dicarboxylic acid (b) may be chosen among the group consisting of the compounds having the formula HO(O)C-R’2-C(O)OH wherein R’ 2 represents a linear or branched, saturated or unsaturated, alkylene group comprising from 1 to 5 carbon atoms, preferably from 1 to 4 carbon atoms, more preferably from 1 to 2 carbon atoms or a covalent bond between the two carboxylic groups (-C(O)OH).

[0081] The dicarboxylic acid (b) is preferably chosen among the group consisting of propanedioic acid, pentanedioic acid, butanedioic acid, ethanedioic acid, or mixture thereof, especially chosen among the group consisting of propanedioic acid, ethanedioic acid, or mixture thereof.

[0082] The mono- or polycarboxylic acid (b) may preferably be chosen among the group consisting of propionic acid, acetic acid, propanedioic acid, pentanedioic acid, butanedioic acid, ethanedioic acid, or mixture thereof, especially chosen among the group consisting of propionic acid, acetic acid, or mixture thereof, specifically propionic acid.

[0083] The composition according to the present invention may compri se said fatty carboxylic acid (a) and mono- or polycarboxylic acid (b) in a ratio by mass (a) : (b) ranging from more than 50 : 50 to 95 : 5 , preferably from 60 :40 to 90 : 10, more preferably from 70 : 30 to 85 : 15, even more preferably is in a ratio of 80 :20.

[0084] The composition according to the present invention may preferably comprise said fatty carboxylic acid (a) and monocarboxylic acid (b) in a ratio by mass (a): (b) ranging from more than 50 : 50 to 95 : 5 , preferably from 60 :40 to 90 : 10, more preferably from 70 : 30 to 85 : 15, even more preferably is in a ratio of 80 :20.

[0085] The composition according to the present invention may further compri se (c) at least one organic additive different from the mixture of carboxylic acids as previously defined.

[0086] The organic additive may be chosen among the group consisting of asphaltene inhibitors, wax inhibitors, demulsifiers, surfactants, corrosion inhibitors, antioxidants, antifoam agents, foaming agents, friction reducers, and their mixtures.

[0087] Preferably, the composition according to the present invention may further comprise (c) at least one additive chosen among the group consisting of asphaltene inhibitors, wax inhibitors or demulsifiers, and mixtures thereof.

[0088] Preferably, the composition according to the present invention compri ses (c) at least one asphaltene inhibitor.

[0089] The asphaltene inhibitor may be chosen from the group consisting of alkylphenol formaldehyde resins, modified alkylphenol aldehyde resins and mixtures thereof.

[0090] Alkyl phenol may be from fossil origin or renewable origin (cardanol for example). Preferably, the asphaltene inhibitor comprises at least one modified alkylphenol-aldehyde resin capable of being obtained by a Mannich reaction of an alkylphenol-aldehyde condensation resin with: at least one aldehyde and / or ketone having from 1 to 8 carbon atoms, preferably from 1 to 4 carbon atoms, and at least one hydrocarbon compound having at least one alkylamine group (alkylmonoamine or alkylpolyamine) having between 1 to 30 carbon atoms, preferably between 4 and 30 carbon atoms, the said alkylphenol-aldehyde condensati on resin being itself capable to be obtained by condensation of:

[0091] • at least one alkylphenol substituted by at least one linear or branched alkyl group having from 1 to 30 carbon atoms with

[0092] • at least one aldehyde and / or ketone having from 1 to 8 carbon atoms, preferably from 1 to 4 carbon atoms.

[0093] Such modified alkyphenol-aldehyde resins are for example disclosed in the patent application WO2016 / 162392.

[0094] According to a particular embodiment, the asphaltene inhibitor may compri se a resin obtainable by condensation of a phenol compound or derivative thereof with at least one aldehyde having from 1 to 8 carbon atoms.

[0095] More particularly, the asphaltene inhibitor may comprise at least one resin obtainable by condensation of at least one phenol substituted by a hydrocarbon group having from 12 to 24 carbon atoms with at least one aldehyde having from 1 to 8 carbon atoms. Such alkylphenol formaldehyde resins are different from alkylphenol-aldehyde resins obtainable by a Mannich reaction as described hereabove.

[0096] Said phenol is preferably substituted in meta position, and more preferably corresponds to formula (I) below: wherein X denotes a linear of branched, saturated on unsaturated hydrocarbon group containing from 12 to 24 carbon atoms, preferably from 12 to 18 carbon atoms and more preferably from 14 to 16 carbon atoms. Most preferably, X denotes an alkyl or alkenyl group.

[0097] A particularly preferred compound is cardanol, which i s a compound of formula (I) wherein X denote an alkenyl group with an average number of 15 carbon atoms and 1 to 3 double bonds.

[0098] Cardanol can be obtained in a known manner from an oil that i s itself obtained from the shell of cashew kernels also known as cashew nutshell liquid.

[0099] The aldehyde used for obtaining said resin preferably contains from 1 to 4 carbon atoms. Said aldehyde is preferably chosen from formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, 2- ethylhexanal, benzaldehyde and mixtures thereof, and more preferably from formaldehyde.

[0100] According to a particular embodiment, the composition according to the present invention may further comprise (c) at least one cardanol-formaldehyde resin.

[0101] The composition according to the present invention may compri se said mixture of carboxylic acids (a) + (b) and the asphaltene inhibitor (c) in a ratio by mass (a)+(b) : (c) ranging from 50 : 50 to 95 : 5, more preferably from 50 : 50 to 90 : 10, even more preferably from 50 : 50 to 80 :20.

[0102] According to a preferred embodiment, the additive composition of the present invention further contains one or more liquid organic solvent(s). By liquid, it is meant a solvent which is in liquid form at ambient temperature (20°C) and atmospheric pressure ( 1 ,013. 105Pa).

[0103] Such solvents may in particular be chosen from poly alkyl ethers, aliphatic hydrocarbons such as alkanes, aromatic solvents such as aromatic hydrocarbons and aromatic hetero-compounds, and mixtures thereof.

[0104] Preferred organic solvents are chosen from aromatic solvents, such as N-methylpyrrolidone, xylene, toluene, benzene; and poly alkyl ethers such as butyl carbitol (diethylene glycol monobutyl ether); as well as mixtures thereof.

[0105] Other preferred organic solvents include those derived from biomass, such as oils of vegetable origin. A particularly preferred solvent is cashew nutshell liquid, also known as CSNL, which is a widely available vegetable oil derived from cashew nutshell . CNSL can be used as a mixture with any other solvent such as those described herein.

[0106] Preferably, the additive composition comprises one or more organic solvent chosen among the group consisting of oils of vegetable origin, especially cashew nutshell liquid.

[0107] The composition of the invention may contain an amount of solvent ranging from 5 to 80% by weight, preferably from 5 to 40% by weight, more preferably from 10 to 25% by weight, relative to the total weight of the composition.

[0108] Preferably, the composition according to the present invention compri ses:

[0109] (a) at least one fatty carboxylic acid having the formula Ri- C(O)OH wherein Ri denotes a hydrocarbon group containing from 12 to 24 carbon atoms, more preferably from 12 to 20 carbon atoms, even more preferably from 14 to 20 carbon atoms,

[0110] (b) at least one monocarboxylic acid having the formula R2- C(O)OH wherein R2 represents a linear or branched, saturated or unsaturated, alkyl group comprising from 1 to 7 carbon atoms, preferably from 1 to 5 carbon atoms, more preferably from 1 to 4 carbon atoms and / or dicarboxylic acid (b) may be chosen among the group consisting of the compounds having the formula HO(O)C-R’ 2-C(O)OH wherein R’ 2 represents a linear or branched, saturated or unsaturated, alkylene group comprising from 1 to 5 carbon atoms, preferably from 1 to 4 carbon atoms, more preferably from 1 to 2 carbon atoms or a covalent bond between the two carboxylic groups (-C(O)OH). According to thi s preferred embodiment, said fatty carboxylic acid (a) and mono- or polycarboxylic acid (b) are preferably in a ratio by mass (a) : (b) ranging from 60 :40 to 90 : 10, more preferably from 70 : 30 to 85 : 15.

[0111] Preferably, the composition according to the present invention compri ses:

[0112] (a) at least one fatty carboxylic acid having the formula Ri- C(O)OH wherein Ri denotes a hydrocarbon group containing from 12 to 24 carbon atoms, more preferably from 12 to 20 carbon atoms, even more preferably from 14 to 20 carbon atoms,

[0113] (b) at least one monocarboxylic acid having the formula R2- C(O)OH wherein R2 represents a linear or branched, saturated or unsaturated, alkyl group comprising from 1 to 7 carbon atoms, preferably from 1 to 5 carbon atoms, more preferably from 1 to 4 carbon atoms.

[0114] According to thi s preferred embodiment, said fatty carboxylic acid (a) and monocarboxylic acid (b) are preferably in a ratio by mass (a) : (b) ranging from 60 :40 to 90 : 10, more preferably from 70 : 30 to 85 : 15.

[0115] According to this preferred embodiment, said composition may further comprise (c) at least one organic additive as previously defined, especially at least one asphaltene inhibitor.

[0116] Preferably, the composition according to the present invention compri ses:

[0117] (a) at least one fatty carboxylic acid having a fatty chain chosen in the group consisting of oleic acid, linoleic acid, arachidonic acid, isostearic acid, isopalmitic acid, and mixtures thereof, preferably oleic acid,

[0118] (b) at least one mono-or polycarboxylic acid chosen among the group consisting of propionic acid, acetic acid, propanedioic acid, pentanedioic acid, butanedioic acid, ethanedioic acid, or mixture thereof, especially chosen among the group consisting of propionic acid, acetic acid, or mixture thereof, specifically propionic acid.

[0119] According to this preferred embodiment, said composition may further comprise (c) at least one organic additive as previously defined, especially at least one asphaltene inhibitor.

[0120] According to this preferred embodiment, said composition may compri se said mixture of carboxylic acids (a) + (b) and the asphaltene inhibitor (c) in a ratio by mass (a)+(b): (c) ranging from 50 : 50 to 90 : 10, even more preferably from 50 : 50 to 80 :20.

[0121] According to thi s preferred embodiment, said composition preferably comprises (a) at least one fatty carboxylic acid having a fatty chain chosen in the group consisting of oleic acid, linoleic acid, arachidonic acid, isostearic acid, isopalmitic acid, and mixtures thereof, preferably oleic acid, and (b) at least one monocarboxylic acid chosen from propionic acid, acetic acid, or mixture thereof, especially propionic acid.

[0122] According to a preferred embodiment, the composition i s devoid of water-soluble scale inhibitors.

[0123] Use of said composition

[0124] As previously indicated, said composition is advantageously useful as an additive in a petroleum product such as a crude oil or any product which results therefrom by any refining and / or extraction process, preferably as a calcium carbonate (CaCCU) scale inhibitor, especially for reducing the content of calcium carbonate in said petroleum product.

[0125] According to an embodiment, said composition is free of asphaltene inhibitor and is used as an additive in a petroleum product as previously defined simultaneously or sequentially to at least one asphaltene inhibitor as previously defined.

[0126] In other words, when the additive composition is free of asphaltene inhibitor, said composition may advantageously be used sequentially, especially before and / or after, or simultaneously with at least one asphaltene inhibitor (c) as previously defined, for example with an alkylphenol-aldehyde resin. In particular, according to this embodiment, the additive composition and the at least one asphaltene inhibitor (c) as previously defined may preferentially be used sequentially, especially before and / or after, more specification before or after.

[0127] The petroleum product may be a crude oil or any product which derives therefrom by any refining and / or extraction process. The petroleum product may also be a bitumen, such as bitumens of natural origin such as those present in natural bitumen or natural asphalt deposits, or bituminous sands, the bitumens originating from the refining of crude oil, in particular from the atmospheric and / or vacuum distillation of oil, it being possible for these bitumens to optionally be blown, visbroken and / or deasphalted and / or mixed.

[0128] The petroleum product is especially selected from crude petroleum oils; hydrocarbon fractions and residues deriving from the distillation thereof such as in heavy fuel oils, heavy residues; and bitumens.

[0129] The petroleum product preferably comprises 5% or less of water in volume related to the total volume of said petroleum product, even more preferably 2% or less of water in volume related to the total volume of said petroleum product.

[0130] The petroleum product preferably comprises from more than 0% to 5% or less of water in volume.

[0131] Preferably, said composition is advantageously used for reducing the content of calcium carbonate deposit in a petroleum product as previously defined, and therefore enhances the quality of the water phase of the petroleum product.

[0132] Another subj ect-matter of the present invention is the use of said composition as an additive in an oil production installation, especially as a calcium carbonate (CaCCh) scale inhibitor, preferably for reducing calcium carbonate (CaCCh) scale deposition in an oil production installation.

[0133] Preferably, said composition i s used as a calcium carbonate scale inhibitor on at least one surface, especially at least one metallic surface, of an oil production installation, including any part of an oil production installation and / or an artificial lift system, specifically an artificial lift system.

[0134] The oil production installation may be chosen among the group consisting of a tank, a drilling well, a refining plant, a transportation plant, a treatment plant, a pipeline, any type of pipes, a storage vessel, a transportation equipment, a filter and / or an artificial lift system.

[0135] Preferably, the oil production installation is an artificial lift system.

[0136] According to a preferred embodiment, said composition is used as a calcium carbonate scale inhibitor in an artificial lift system, preferably on one or more internal parts of an artificial lift system, more preferably on at least one surface of an artificial lift system, even more preferably on at least one metallic surface of an artificial lift system.

[0137] The artificial lift system may be chosen among the group consisting of a pressure cavity pump (PCP), a rod lift, a plunger lift, and an electric submersible pump.

[0138] Preferably, the artificial lift system is an electric submersible pump.

[0139] According to a preferred embodiment, said composition is used as a calcium carbonate scale inhibitor in an electric submersible pump, preferably on one or more internal parts of an electric submersible pump, more preferably on at least one surface of an electric submersible pump, even more preferably on at least one metallic surface of an electric submersible pump.

[0140] Preferably, said composition i s used to clean an oil production installation as previously defined, especially one or more internal parts of an oil production installation as previously defined.

[0141] More preferably, said composition is used to clean an artificial lift system as previously defined, especially one or more internal parts of an artificial lift system.

[0142] Advantageously said composition is used to clean at least one surface, especially at least one metallic surface of an artificial lift system as previously described, in particular of an electric submersible pump.

[0143] According to a preferred embodiment, said composition is used to reduce the content of calcium carbonate deposited on one or more internal parts of an oil production installation as previously defined, especially of an artificial lift system such as an electric submersible pump.

[0144] Preferably, said composition is used to reduce the content of calcium carbonate deposited on at least one surface, especially on at least one metallic surface, of an oil production installation as previously defined, especially of an artificial lift system such as an electric submersible pump .

[0145] According to a preferred embodiment, said composition is used to protect one or more internal parts of an oil production installation as previously defined against calcium carbonate scale deposit, especially on at least one surface of an artificial lift system such as an electric submersible pump .

[0146] According to a preferred embodiment, said composition is used to protect at least one metallic surface of an electric submersible pump against calcium carbonate scale deposit.

[0147] The additive composition is advantageously used in an amount ranging from 10 to 1000 ppm by weight, preferably from 10 to 500 ppm, more preferably from 10 to 300 ppm and more preferably still from 10 to 150 ppm, expressed as total weight of said mixture of carboxylic acids (a) and (b) with respect to the total weight of the petroleum product.

[0148] Petroleum product

[0149] The petroleum product contains a crude oil or a product which results therefrom by any refining and / or extraction process, and an additive composition as described above.

[0150] The petroleum product may also contain a bitumen, such as bitumen of natural origin such as those present in natural bitumen or natural asphalt deposits, or bituminous sands, the bitumen originating from the refining of crude oil, in particular from the atmospheric and / or vacuum distillation of oil, it being possible for these bitumen to optionally be blown, visbroken and / or deasphalted and / or mixed.

[0151] The petroleum product preferably contains a crude petroleum oil and / or at least one hydrocarbon fraction or at least one residue deriving from the distillation of crude petroleum oil, such as heavy fuel oil s, heavy residues and / or at least one bitumen.

[0152] The petroleum product preferably comprises 5% or less of water in volume related to the total volume of said petroleum product.

[0153] The petroleum product preferably comprises from more than 0% to 5% or less of water in volume.

[0154] The petroleum product advantageously contains at least one mixture of said carboxylic acids (a) and (b) at an amount ranging from 10 to 800 ppm by weight, preferably from 10 to 400 ppm, more preferably from 10 to 210 ppm and more preferably still from 10 to 100 ppm, with respect to the total weight of the petroleum product.

[0155] Methods

[0156] Another subj ect-matter is a method for reducing the content of calcium carbonate and optionally the content of asphaltene present in a petroleum product comprising adding at least an additive composition as defined herein to said product.

[0157] The additive composition pursuant to the present invention optionally compri ses at least one asphaltene inhibitor (c) as previously defined, preferably comprises at least one asphaltene inhibitor (c) as previously defined.

[0158] In other words, the additive composition implemented in the method of the present invention may comprise at least one asphaltene inhibitor (c) as previously defined or may be free of said asphaltene inhibitor (c).

[0159] According to an embodiment, said method comprises adding to said product at least one asphaltene inhibitor (c) as previously defined and at least one additive composition comprising at least said fatty carboxylic acid (a), as previously defined, and at least said mono- or polycarboxylic acid (b), as previously defined.

[0160] According to thi s embodiment, the at least one asphaltene inhibitor (c) may be added to the petroleum product sequentially, especially before and / or after, or simultaneously with said additive composition, preferentially sequentially to the additive composition, more preferentially before or after the additive composition.

[0161] In other words, according to an embodiment, said method compri ses adding to the petroleum product: at least one asphaltene inhibitor (c), at least one additive composition as previously defined, devoid of any asphaltene inhibitor (c), the at least one asphaltene inhibitor (c) may be added to said product sequentially, especially before and / or after, or simultaneously with the additive composition, preferentially sequentially.

[0162] In still other words, said method may comprise adding to said product: at least a composition C comprising at least one asphaltene inhibitor (c), at least one additive composition AB comprising at least said fatty carboxylic acid (a), as previously defined, and at least said mono- or polycarboxylic acid (b), as previously defined, said composition C and said additive composition AB may be added to said product simultaneously or sequentially, preferentially sequentially, especially before and / or after, more specifically before or after.

[0163] The petroleum product i s advantageously chosen from those described above.

[0164] The petroleum product preferably comprises 5% or less of water in volume related to the total volume of said petroleum product.

[0165] The petroleum product preferably comprises from more than 0% to 5% or less of water in volume.

[0166] The additive composition is preferably added in an amount ranging from 10 to 1000 ppm by weight, preferably from 10 to 250 ppm and more preferably still from 10 to 125 ppm, with respect to the total weight of the petroleum product.

[0167] According to a preferred embodiment, the method of the invention compri ses at least two steps :

[0168] ( 1 ) the introduction of an additive composition as described above into the petroleum product, and

[0169] (2) a treatment step chosen from : a rise in pressure, a rise in temperature and a mixing with at least one other fluid. According to a most preferred embodiment, steps ( 1 ) and (2) are carried out successively (step 1 and then step 2).

[0170] According to a preferred variant, step (2) is chosen from : an extraction of a crude oil from a reservoir, a stage of refining a crude oil or a derived product, a transportation of a crude oil or of a derived product, a filtration of a crude oil or of a derived product, an inj ection of gas into a crude oil or into a derived product, a mixing of crude oils or of derived products, and a mixing of a crude oil or of a derived product with a solvent.

[0171] Step (2) can for example correspond to a pressurization, for example in a pipeline or any type of pipe, or through a filter; it can compri se a heating in a refining plant, an inj ection of a gas or a mixing with another variety of crude oil or with another grade of heavy oil resulting from the refining.

[0172] Such treatments results in a reduction of the calcium carbonate CaCCh scale in said petroleum product and / or in an oil production installation, especially on one or more internal parts of an oil production installation.

[0173] The method of the invention makes it possible to compatibilize calcium carbonate in said petroleum product and reduce calcium carbonate scale deposited on any part of an oil production installation, including an artificial lift system such as an electric submersible pump.

[0174] The present invention further pertains to a method for cleaning an oil production installation, as previously defined, comprising applying to said oil production installation at least said additive composition.

[0175] The method may be implemented to clean one or more internal parts of the oil production installation, preferably at least one surface, especially at least one metallic surface, of said oil production installation.

[0176] Accordingly, said composition may be applied to one or more internal parts, particularly to at least one surface, and more particularly to at least one metallic surface of said oil production installation.

[0177] As previously indicated, the oil production installation includes any part of an oil production, installation and / or an artificial lift system, especially an artificial lift system .

[0178] The oil production installation is as defined above and is preferably an artificial lift system.

[0179] The artificial lift system is as defined above and preferably corresponds to an electric submersible pump.

[0180] The method is advantageously implemented to clean calcium carbonate scale deposited on an oil production installation, as previously defined, especially deposited on one or more internal parts of said oil production installation, preferably on at least one surface, especially on at least one metallic surface, of said oil production installation.

[0181] Accordingly, the method may comprise applying said composition to at least one or more internal parts, especially to at least one or more surfaces, particularly to at least one or more metallic surfaces of said oil production installation, on which calcium carbonate scale is present.

[0182] According to the present invention, the term “clean” means that said composition makes it possible to decrease, reduce, inhibit and / or remove calcium carbonate scale deposit, as well as to protect said oil production installation against calcium carbonate scale.

[0183] According to a preferred embodiment, the method is for cleaning one or more internal parts of an electric submersible pump, preferably at least one surface, especially at least one metallic surface of an electric submersible pump.

[0184] More preferably, the method is for protecting one or more internal parts, in particular at least one surface, especially at least one metallic surface, of an electric submersible pump against calcium carbonate scale deposition.

[0185] According to a preferred embodiment, the method is for cleaning one or more internal walls of an artificial lift system, preferably an electric submersible pump.

[0186] According to a preferred embodiment, the method is for protecting one or more internal walls of an artificial lift system, preferably an electric submersible pump, against calcium carbonate scale deposition. According to a further preferred embodiment, the method is for improving and / or maintaining the performances of an artificial lift system, preferably an electric submersible pump.

[0187] Especially, the method is for maintaining the pressure gradient of an electric submersible pump over time.

[0188] The methods as defined herein are able to improve the recovery of the crude oils while decreasing and / or removing calcium carbonate scale deposits on an oil production installation.

[0189] The examples hereafter only aim at illustrating the present invention and shall not be interpreted so as to limit its scope.

[0190] EXAMPLES

[0191] Example 1 : Assessment of calcium carbonate deposit

[0192] Preparation of an additive composition

[0193] An additive composition (A l ) according to the present invention is prepared by mixing (a) an oleic acid and (b) a propionic acid in a weight ratio (a) / (b) of 80 / 20.

[0194] The additive composition (Al ) exhibits a good ecotoxi city profile ensuring safety conditions for the environment.

[0195] Protocol for assessing the content of calcium carbonate

[0196] A mixture of crude oil and diesel in a weight ratio of 50 / 50, 500 ppm of calcium carbonate and 2% by volume of demineralized water related to said mixture were added to a centrifuge tube. The resulting solution was allowed to stand for one hour and then was centrifuged at 1500 rpm for 30 minutes.

[0197] After the centrifugation, the resulting solution was observed for phase separation and measurement of phases.

[0198] The content of calcium carbonate settled down at the bottom of the centrifuge tube is measured.

[0199] At the same time, a mixture of crude oil and diesel in a weight ratio of 50 / 50, 500 ppm of calcium carbonate, 2% by volume of water related to said mixture and 500 ppm of said composition (Al ) were added to a centrifuge tube. The resulting solution was allowed to stand for one hour and then was centrifuged at 1500 rpm.

[0200] After the centrifugation, the resulting solution was allowed to stand for 30 minutes.

[0201] The content of calcium carbonate settled down at the bottom of the centrifuge tube is measured.

[0202] Result of the assessment

[0203] The results display that:

[0204] - 0.075 ml of calcium carbonate had settled down at the bottom of the centrifuge tube in which no additive composition was used,

[0205] - less than 0.05ml of calcium carbonate had settled down at the bottom of the centrifuge tube in which 500 ppm of composition (Al ) was used.

[0206] These result show that the quantity of calcium carbonate CaCCh deposited after centrifugation was significantly reduced with the addition of composition (Al ).

[0207] Furthermore, one can observe that water was better separated from the oil / diesel mixture and its quality was also enhanced.

[0208] Example 2 : APT assessment

[0209] An additive composition (A2) was prepared by mixing (a) an oleic acid, (b) a propionic acid, and (c) an asphaltene inhibitor in a weight ratio [(a)+(b)] / (c) corresponds to 75 / 25.

[0210] The asphaltene inhibitor is an alkylphenol formaldehyde resin according to the patent application WO2016 / 162392.

[0211] A conventional additive composition (B) was prepared by dissolving an asphaltene inhibitor with xylene as a solvent. The amount of the asphaltene inhibitor in composition (B) is 50% by weight to the total weight of the composition. The same asphaltene inhibitor has been used in composition (B).

[0212] The performances in terms of preventing asphaltene precipitation of the tested composition was assessed on a mixture of crude oil / diesel (50 / 50), 2% of water and 500 ppm of calcium carbonate, using an asphaltene dispersancy test (ATD) described below. The ADT is a rapid test method which allows to assess the performance of an additive composition in preventing asphaltene precipitation in a crude oil . The test allows to compare the relative effectiveness of additive compositions in keeping asphaltene dispersed in a non-solvent medium. The ADT takes advantage of the insolubility of asphaltenes in an alkane diluent (n-heptane). Dilution of a fixed volume of crude oil in a fixed volume of alkane diluent results in precipitation of asphaltenes. Dilution of the same fixed volume of crude oil properly dosed with an effective additive composition in the same fixed volume of alkane diluent results in minimal precipitation of asphaltenes during a controlled testing period. An effective additive composition will prevent the agglomeration and eventual precipitation of asphaltenes when the crude oil sample i s diluted in the alkane diluent.

[0213] The protocol of the ADT test is described below:

[0214] A mixture of crude oil and diesel in a weight ratio of 50 / 50, 500 ppm of calcium carbonate and 2% by volume of water related to said mixture were added to four centrifuge tubes.

[0215] In the first centrifuge tube, no additive composition was used.

[0216] In the second centrifuge tube, 50 ppm of composition (A2) was added to the above-described mixture.

[0217] In the third centrifuge tube, 50 ppm of composition (Al ) was added to the above-described mixture.

[0218] In the fourth centrifuge tube, 50 ppm of composition (B) was added to the above-described mixture.

[0219] In each tube, the resulting solution was mixed manually and allowed to stand. Crude oil having asphaltenes slowly phases out asphaltenes which settles down at the bottom of the centrifuge tube typically within 30 minutes to 60 minutes.

[0220] The presence of sediments was assessed by visual observations of the tubes after 48 hours at room temperature.

[0221] The results display that asphaltene deposit was ob served at the bottom of the first centrifuge tube and the fourth centrifuge tube.

[0222] The results al so show that no asphaltene deposit was observed in the tubes wherein the additive composition (Al ) and (A2) were introduced. It bespeaks that the additive compositions (Al ) and (A2) do not allow the asphaltene present in the crude oil to settle down in the tube.

[0223] Furthermore, it exhibits that compositions (Al ) and (A2) are effective on calcium carbonate scale deposit as well as on asphaltene deposit.

[0224] Example 3 : Performances assessment of an ESP

[0225] The additive composition (A l ) was inj ected downhole a production well equipped with an electric submersible pump (ESP).

[0226] The additive composition was inj ected upfront the ESP aspiration in front of the ESP. The oil well was producing 6420 bbl / d and additive composition inj ected at 100 ppm (4,2 L / h) over a period of one month.

[0227] The pressure gradient at the pump inlet and outlet was measured over a period of one month.

[0228] The results show the gradient of pressure remains the same over this period of time which exhibits that no calcium carbonate deposit was able to hinder the functioning of the pump.

[0229] An increase of the delta Pressure of about 1 bar / month was even observed.

[0230] Furthermore, a better separation of water with an increase of conductivity in the water phase shows the ability of the additive composition to avoid deposition of calcium carbonate in the ESP.

Claims

CLAIMS1. An oil soluble additive composition comprising:(a) at least one fatty carboxylic acid comprising at least one fatty chain containing at least 8 carbon atoms,(b) at least one mono- or polycarboxylic acid compri sing at least one hydrocarbon chain containing from 1 to 7 carbon atoms.

2. The composition as defined in the preceding claim, wherein said fatty carboxylic acid has a fatty chain comprising from 8 to 30 carbon atoms, preferably from 12 to 24 carbon atoms, more preferably from 12 to 20 carbon atoms, and even more preferably from 14 to 20 carbon atoms.

3. The composition according to Claim 1 or 2, wherein said fatty carboxylic acid is a bio-based compound, preferably a vegetablebased compound.

4. The composition according any of the preceding claims, wherein said fatty carboxylic acid is chosen among the group consisting of oleic acid, linoleic acid, arachidonic acid, isostearic acid, isopalmitic acid, and mixtures thereof, preferably oleic acid.

5. The composition according to any of the preceding claims, wherein said mono- or polycarboxylic acid is chosen among the group consisting of propionic acid, acetic acid, propanedioic acid, pentanedioic acid, butanedioic acid, ethanedioic acid, or mixture thereof, especially chosen among the group consisting of monocarboxylic acid, and more preferably from propionic acid, acetic acid, or mixture thereof, specifically propionic acid.

6. The composition according to any of the preceding claims, wherein said fatty carboxylic acid (a) and mono-or polycarboxylic acid (b) are present in a ratio by mass (a) : (b) ranging from more than 50 : 50 to 95 : 5, preferably from 60 : 40 to 90 : 10, more preferably from 70 : 30 to 85 : 15, even more preferably is in a ratio of 80 :20.

7. The composition according to any of the preceding claims, wherein it further comprises (c) at least one additive chosen among the group consisting of asphaltene inhibitors, wax inhibitors ordemulsifiers, and mixtures thereof, preferably at least one asphaltene inhibitor.

8. The composition according to any of the preceding claims, wherein said mixture of carboxylic acids (a) + (b) and the asphaltene inhibitor (c) in a ratio by mass (a)+(b) : (c) ranging from 50 : 50 to 95 : 5, more preferably from 50 : 50 to 90 : 10, even more preferably from 50 : 50 to 80 :20.

9. The composition according to any of the preceding claims, wherein it further comprises one or more liquid organic solvent(s) chosen in the group consisting of:- poly alkyl ethers, aliphatic hydrocarbons such as alkanes, aromatic solvents such as aromatic hydrocarbons and aromatic hetero-compounds;- organic solvents derived from biomass, in particular oils of vegetable origin and more preferably cashew nutshell liquid;- and mixtures thereof10. A petrol eum product containing:- a crude oil and / or at least one hydrocarbon fraction or at least one residue deriving from the distillation of a crude petroleum oil, and / or at least one bitumen; and- an additive composition as defined in any of the preceding claims.1 1. Use of a composition as defined in any of claims 1 to 9 as an additive in a petroleum product and / or an oil production installation, especially for reducing the content of calcium carbonate in a petroleum product and / or an oil production installation.

12. Use according to claim 1 1 , wherein the oil production installation includes any part of an oil production installation and / or an artificial lift system, preferably an artificial lift system, more preferably an electric submersible pump.

13. Use of a composition as defined in any of claims 1 to 9 to protect one or more internal parts of an oil production installation against calcium carbonate scale deposit, especially on at least one surface of an artificial lift system such as an electric submersible pump .

14. Method for reducing the content of calcium carbonate, and optionally the content of asphaltene, present in a petroleum productcompri sing adding an additive composition as defined in any of claims 1 to 9, to said petroleum product.

15. Method according to claim 14 comprising adding an additive composition as defined in any of claims 1 to 6 or 9, and at least one asphaltene inhibitor (c); said at least one asphaltene inhibitor being added to said petroleum product sequentially, before and / or after, or simultaneously with said additive composition, preferentially sequentially to said additive composition.

16. Method for cleaning an oil production installation, compri sing applying to said oil production installation at least one additive composition as defined in any of claims 1 to 9.

17. Method according to claim 16, wherein said composition is applied to one or more internal parts, especially to at least one surface of an oil production installation, including any part of an oil production installation and / or an artificial lift system, preferably an electric submersible pump .

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