Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
  • C09K8/52—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
  • C09K8/524—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning organic depositions, e.g. paraffins or asphaltenes

Definitions

• the present invention relates to methods and means for removing solid asphalt residues from the surface of production plants or the formation surrounding the borehole in petroleum production and processing, and the use of certain fatty acid esters for this purpose.
• Crude oil is a complex mixture of different paraffinic and aromatic hydrocarbons, whereby the individual components have very different chemical and physical properties. In the distillation of crude oil, therefore, both highly volatile, low-viscosity components and waxy, highly viscous fractions are obtained. This last group includes petroleum resins and predominantly asphaltenes, which are colloidally disperse in the oil phase.
• the asphaltenes consist of a mixture of different, saturated, unsaturated and aromatic hydrocarbons, especially naphthalene derivatives. There are also heterocyclic hydrocarbons, some of which also contain complexed metal ions. Asphaltenes are also rich in sulfur, nitrogen and oxygen compounds. Due to the complex composition, asphaltenes are generally characterized by their solubility.
• the heptane or pentane insoluble but toluene soluble petroleum fraction is called asphaltenes, whereby the "dissolving" of the asphaltenes is a complex process for which a complete theoretical description does not yet exist (cf.
• Asphaltenes exist as micelle colloids in the oil phase of the crude oil, whereby the individual micelles each consist of several different molecules.
• the micelles have different sizes depending on the temperature and composition of the oil phase. For example, it is known that lighter aromatic hydrocarbons in crude oil stabilize the asphaltene micelles. Under the conditions of oil production or demand, however, the asphaltenes often precipitate, which leads to the formation of highly viscous, waxy to solid residues on the surface of the production facilities and the petroleum-containing formation surrounding the borehole.
• Asphaltene residues on the surfaces of the production plants for example the conveyor pipe or the walls of the casing of pipelines or separators, can also significantly hinder the production.
• the present application therefore relates in a first embodiment to the use of fatty acid esters of the general formula (I)
• R 1 represents an alkyl radical having 6 to 22 C atoms or a radical (CH 2 ) m -COOR 4 , where R 2 and R 4 independently of one another represent an alkyl radical having 1 to 8 C atoms, n is a number 2 or 3 and m represents a number from 1 to 6 and x is 0 or a number between 1 and 12, for removing solid asphalt residues from the surfaces of production plants or the petroleum-containing formation surrounding the borehole during petroleum production and processing .
• asphaltenes are understood to mean those constituents of crude oil which, in accordance with DIN 51595 (Dec. 1983), precipitate out at 30-2 times the volume of heptane at 18-28 ° C. when the petroleum is dissolved and are soluble in benzene.
• Solid asphaltene residues are residues which, at the respective working temperature to which the surface is exposed, have a solid or waxy consistency and consist of more than 50% by weight of asphaltenes.
• the solid residues can also contain petroleum resins or other solids.
• the solid asphalt residues can form on the surfaces of production plants during the extraction of oil, whereby production plants are understood to mean all technical plants that come into direct contact with the oil.
• production plants include, for example, the production pipe, the lining of the borehole, the so-called casing, and all other oil-carrying lines, pipelines, separators, pumps and valves.
• the surface of these production plants is usually made of metal, in particular steel, while the casing is usually made of concrete.
• Production plants are also understood to mean the processing steps of the crude oil downstream of the actual production, for example in the processing of the crude oil fractions by distillation. Asphaltene residues can also occur during the transportation of crude oil through pipelines or its storage and thus hinder production.
• fatty acid esters which are used according to the invention for removing the solid asphaltene residues can be synthesized by all methods known to the person skilled in the art. For this purpose, alcohol and fatty acid are usually reacted in the presence of acidic or basic catalysts, if appropriate under pressure.
• Another possibility for obtaining fatty acid esters of the general formula (I) is the transesterification of natural fats and oils with methanol in the presence of a catalyst. Suitable natural oils are, for example, rapeseed, sunflower, soybean, linseed or coconut oil.
• Suitable alcohols which can be used in the synthesis of the esters used according to the invention are either unbranched, such as methanol, ethanol, propanol, butanol, pentanol, hexanol, or branched, such as isopropanol, isobutanol, 2-methyl or 2-ethylhexanol.
• Capronic, caprylic, lauric, myristic, palmitic, stearic, arachic or behenic acids are suitable as saturated fatty acids.
• Unsaturated fatty acids are, for example, lauroleic, palmitoleic, oleic, ricinoleic, linoleic and linolenic acid.
• esters of dicarboxylic acids such as maleic, succinic or adipic acid can also be used for the synthesis.
• esters of the formula (I) are also suitable, which can be obtained, for example, by esterifying the preliminary fatty acids obtained in the purification of fatty acid mixtures by distillation. Any mixtures of esters of the formula (I) can also be used.
• esters of the general formula (I) in which R 1 is an alkyl radical having 6 to 10 C atoms and R 2 is a methyl radical and x is 0. Mixtures of these esters are preferably used, which are obtained by esterifying pre-fatty acids with 6 to 10 carbon atoms with methanol.
• fatty acid ester alkoxylates of the general formula (I) in which n denotes a number from 2 or 3 and x denotes a number from 1 to 12 can also be used for the purposes of the invention.
• Such compounds are prepared by reacting fatty acid derivatives with alkoxylated methanol or by heterogeneously catalyzed direct alkoxylation of fatty acid alkyl esters with alkylene oxide, especially ethylene oxide. This synthesis method is described in detail in WO 90/13533 and WO 91/15441. Such are preferred
• R ! represents an alkyl radical with 8 to 16 carbon atoms
• R 2 stands for a short-chain alkyl radical with 1 to 4 carbon atoms, preferably a methyl radical
• n is 2 and x is a number between 2 and 6.
• Asphalt deposits occur during the production of petroleum on the surface of production facilities or the formation surrounding the borehole, which is usually found in If the delivery rate drops, the affected area of the production plant or the borehole is brought into contact with the fatty acid esters. It is expedient to pump the esters in liquid form at temperatures of at least 50 ° C. through the production facilities or the borehole in order to remove the deposits.
• Another object of the present invention therefore relates to a method for removing solid asphaltene residues from the surface of production plants or the petroleum-containing formation surrounding the borehole during petroleum production and processing by the asphaltene residues with an ester of formula (I) in liquid form and a Temperature of at least 50 ° C are brought into contact until the residues have at least partially dissolved.
• the time in which the deposit is removed depends on the amount of asphalt deposits and the operating temperature.
• the asphaltene deposits dissolve faster under the conditions that prevail on the surface of the petroleum-containing formation, namely high pressure and high temperatures (150 to 300 ° C) than, for example, deposits that occur in the production pipe because lower temperatures ( ⁇ 100 ° C) prevail.
• dissolving the residue is to be understood as a complex process in which the asphaltenes colloidally dissolve in the form of micelles.
• esters it is possible, but not preferred for reasons of cost, to rinse the production facilities only with liquid ester. Depending on the operating temperature and melting point of the esters, there may also be viscosity problems when storing the pure ester. At low temperatures, for example in winter, heated tanks must be used for higher melting joints. It is therefore preferred to use the esters in a mixture with a suitable solvent in order to avoid the described problems in handling. It has proven to be particularly advantageous to use the esters in admixture with crude oil or petroleum - the fraction which passes over during crude oil distillation at 180-225 ° C. In principle, any mixtures with a weight ratio of crude oil or petroleum: ester between 1:99 and 99: 1 are possible. For the purposes of the present invention, however, mixtures with certain proportions of esters are preferred.
• Another object of the invention therefore relates to a liquid crude oil or petroleum-containing agent for removing solid asphalt residues from the surface of production plants or the petroleum-containing formation surrounding the borehole during petroleum production and processing, which more than 25 wt .-% at least one Contains fatty acid esters of the general formula (I).
• Crude oil or petroleum-containing agents which contain more than 50% by weight of esters of the formula (I) are particularly preferred.
• the esters are dissolved or dispersed in the crude oil or petroleum and can then be stored and used without any problems.
• compositions can also contain other ingredients, for example corrosion inhibitors or other known solvents for asphaltenes, and asphaltene inhibitors which prevent precipitation, such as imidoamides, imidazolines or aromatic sulfonic acids, as described in US Pat. No. 5,504,063 .
• a method for removing solid asphalt residues from the surface of production plants or the petroleum-containing formation surrounding the borehole during petroleum production and processing is claimed, wherein the asphaltene deposits with a crude oil- or petroleum-containing liquid medium with a temperature of at least 50 ° C, that contains at least 25% by weight of ester of the formula (I) until the residues have at least partially dissolved.
• a defined amount of an asphaltene deposit (residue from the Laque refinery / France) was stirred with a weighed amount of a fatty acid ester A - D in a beaker at temperatures between 50 and 10 ° C for 1.5 hours. The liquids were then filtered and the remaining asphaltene residue was washed with heptane. The solubility was determined by comparing the weighed-in amount of asphaltenes with the amount of filtered asphaltene residue. The results are shown in Table 1. To detect the asphaltenes in the filtrate, 30 times the volume of heptane was added to the filtrate in accordance with DIN 51595 (December 1983). The asphaltenes failed as intended.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Fats And Perfumes (AREA)
• Working-Up Tar And Pitch (AREA)

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• 1997
  • 1997-03-03 DE DE19708499A patent/DE19708499A1/de not_active Withdrawn
• 1998
  • 1998-02-21 WO PCT/EP1998/001010 patent/WO1998039549A1/de not_active Application Discontinuation
  • 1998-02-21 CA CA002282322A patent/CA2282322A1/en not_active Abandoned
  • 1998-02-21 EP EP98910717A patent/EP0966593A1/de not_active Withdrawn
  • 1998-02-21 US US09/380,699 patent/US6368422B1/en not_active Expired - Fee Related
  • 1998-02-21 BR BR9808137-3A patent/BR9808137A/pt unknown
  • 1998-02-27 AR ARP980100883A patent/AR010900A1/es not_active Application Discontinuation
• 1999
  • 1999-09-02 NO NO994254A patent/NO994254L/no not_active Application Discontinuation

Non-Patent Citations (1)

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