Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
  • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas

Definitions

• the invention relates to a method for inhibiting or retarding the formation, growth and / or agglomeration of hydrates of natural gas, petroleum gas or other gases by using at least one additive.
• the gases that form hydrates may in particular comprise at least one hydrocarbon selected from methane, ethane, ethylene, propane, propene, n-butane and iso-butane, and optionally H 2 S and / or CO 2 .
• hydrates are formed when the water is in the presence of gas, either in the state free, either in the dissolved state in a liquid phase, such as a liquid hydrocarbon, and when the temperature reached by the mixture including water, gas and liquid hydrocarbons, such as oil, becomes lower than the thermodynamic temperature of formation of hydrates, this temperature being given for a known gas composition and when their pressure is fixed.
• thermodynamics required to form hydrates are met, agglomeration hydrates causes the blocking of the transport pipes by creating plugs which prevent any passage of crude oil or gas.
• hydrate corks can lead to a cessation of production and thus cause significant financial losses.
• the return to service of the installation especially in the case of production or transport at sea, can be long, because the decomposition of the hydrates formed is very difficult to achieve.
• the temperature at the bottom of the sea can be, for example, 3 or 4 ° C.
• Conditions favorable for the formation of hydrates can also be combined with the same way on land, for pipes not (or not deep enough) buried in the terrestrial soil, when for example the temperature of the ambient air is cold.
• Amphiphilic compounds obtained by reaction of at least one derivative succinic selected from the group consisting of acids and anhydrides polyalkenylsuccinic acids on at least one polyethylene glycol monoether have also been proposed to reduce the tendency to agglomerate gas hydrates natural gas, petroleum gas or other gases (EP-A-582507).
• water-soluble polymers that can be neutral or positively charged homopolymers or copolymers, or polyampholytes and which are derived from one or more nitrogenous monomers, allow, at low concentrations, to inhibit or delay formation, growth and / or agglomeration of hydrates of natural gas, petroleum gas or other gases, with an efficiency very much higher than the compounds previously described.
• the invention provides a method for inhibiting or delaying formation, growth and / or agglomeration of hydrates within a fluid comprising water and a gas, under conditions where hydrates can form (from the water and of gas), characterized in that at least one homopolymer or water-soluble copolymer generally defined as deriving from at least a nitrogenous monomer selected from neutral monomers, cationic monomers positively charged) and the amphoteric monomers (i.e. times a positive charge and a negative charge) defined below.
• neutral monomers illustrating these formulas include dimethylaminoethyl acrylate and dimethylaminoethyl methacrylate.
• cationic monomers examples include methacrylate-ethyl-trimethyl ammonium, methacrylamido-N-propyl-trimethyl chloride ammonium and diallyl dimethyl ammonium chloride.
• amphoteric monomers mention may be made of methosulphonate of ethyl trimethylammonium acrylate.
• Cationic monomers, amphoteric monomers and monomers neutrals from [A] to [K] defined in the foregoing description may be included in homopolymers or copolymers, in all proportions, that is to say ranging, for each, from 0 to 100 mol%.
• the invention also proposes the use of copolymers as additives resulting from the combination of at least one of the monomers described above (monomer cationic, amphoteric monomer and / or neutral monomer of [A] to [K]), with at least an anionic (or negatively charged) monomer and / or at least one neutral monomer other than those already described above.
• the anionic monomers considered are more particularly monomers containing carboxylate groups or sulphonate groups and more precisely monomers acrylate, methacrylate, itaconate, 2-acrylamido-2-methylpropane sulfonate, 2-methacryloyloxy ethane sulfonate, 3-acrylamido-3-methyl butanoate, styrene sulfonate, styrene carboxylate, vinyl sulfonate, anhydride maleic or maleic acid.
• cationic monomers amphoteric monomers and / or the neutral monomers of [A] to [K] described above, also one or more other neutral nitrogen-containing monomers such as acrylamide, alkyl-type monomers acrylamide or vinyl acetamide.
• the proportions of cationic monomers, in amphoteric monomers, in monomers neutral from [A] to [K], in monomers anionic and / or additional neutral monomers may vary, for each monomers, for example from 1 to 99%, more particularly from 10 to 70% by weight. mol.
• Cationic monomers, amphoteric monomers and monomers Neutrals of [C] to [K] described above may still be associated with one or more other N-vinyl lactam neutral nitrogenous monomers, in particular N-vinyl-2-pyrrolidone, N-vinyl- ⁇ -valerolactam and N-vinyl- ⁇ -caprolactam.
• the proportions of cationic monomers, in amphoteric monomers, in neutral monomers of [C] to [K] and in the monomers additional neutrals may vary, for each of the monomers, for example from 1 to 99%, and more particularly from 10 to 70 mol%.
• homopolymers and copolymers in relation to the nature of the monomers that can enter their homopolymers and copolymers considered in the invention may consist of neutral, cationic (co) polymers or polyampholytes (these latter containing both positively charged monomers and negatively charged monomers).
• the polymers described in the invention may be linear or branched. Their mass can vary from 3000 to several millions.
• the homo and copolymers as described above can be added to the fluid to be treated alone or as mixtures of two or more of them.
• copolymers may be copolymers which differ from each other for example by the nature of the patterns of at least one type and / or composition different in at least one pattern and / or by their molecular weight.
• Homo or copolymers, as well as their mixtures in all proportions may be added to the fluid to be treated at concentrations generally ranging from 0.05 to 5% by weight, preferably 0.1 to 2% by weight, based on water.
• the homo or copolymers recommended as additives in the invention may be mixed with one or more alcohols (monoalcohols or polyols) containing for example from 1 to 6 carbon atoms, more particularly the mono-, the di- or tri-ethylene glycol, ethanol or methanol, the latter being the preferred alcohol.
• This alcohol or these alcohols is (are) added in general in proportions ranging from 0.5 to 20% by weight, preferably 1 to 10% by weight, relative to the water present in the fluid to be treated.
• the homo or copolymer (s) considered in the invention can then be dissolved beforehand in a hydro-alcoholic medium and then added in the medium to be treated, so as to obtain final concentrations of homo or copolymers generally ranging from 0.05 to 3% by weight, preferably from 0.1 to 1% by weight. mass with respect to the water present in the fluid to be treated.
• the water-soluble homo or copolymers considered in the invention can be used either in pure water medium, for example in water of condensation, or in saline medium, for example in production water.
• the device used consists of 16 mm diameter tubes, in which are 8 ml of a 20% by weight aqueous solution of THF containing optionally the additive to be tested. Each tube is filled with a glass ball of one diameter of 8 mm, to ensure proper mixing of the solution.
• the tubes are placed on a rotary shaker, which rotates at 20 rpm. The latter is placed in a refrigerated chamber at 2 ° C.
• This test is to determine the lag time before the training hydrates. This latency corresponds to the interval measured between the moment when the tubes are introduced into the refrigerated chamber and the moment when the hydrate formation (appearance of a disorder).
• Each series of tests is conducted in the presence of a reference mixture not containing no additive, and the lag times provided for an additive correspond to an average of the times measured over 16 tests.
• the solutions of pure water / THF have an average latency of 35 minutes.
• Example 1 The experimental procedure of Example 1 is repeated replacing pure water with a mixture of pure water and 5% of methanol by mass and lowering the temperature of the refrigerated chamber at -1 ° C.
• Example 1 The experimental procedure of Example 1 is repeated replacing pure water With a solution of NaCl 3.5% by weight, the temperature of the refrigerated chamber is lowered to 0 ° C. Under these conditions, the average latency of the solutions NaCl / THF in the absence of additive is 42 minutes.
• DMAC diallyl dimethyl ammonium chloride
• AMPDAPS poly [3- (2-acrylamido-2-methyl-propyl-dimethyl-ammonio) -1-propane sulfonate]
• a terpolymer containing 60 mol% of acrylamide type units, 25 mol% of acrylamido-methyl-propane units sulfonate (AMPS) and 15 mol% of methacrylamido-N-propyl-trimethyl chloride units ammonium (MAPTAC) or 0.3% by weight of a copolymer NVP / AMPDAPS (60/40 mol) inhibit the formation of THF hydrates during a period longer than 6 hours.
• the apparatus includes a loop of 6 meters consisting of tubes of diameter 7.7 mm, a 2-liter reactor with an inlet and an outlet for gas, suction and discharge for the water and additive mixture initially introduced.
• the reactor makes it possible to put the loop under pressure.
• Diameter tubes analogous to those of the loop ensure the circulation of the fluid from the loop to the reactor, and conversely, via a gear pump placed between the two.
• a sapphire cell integrated in the circuit allows a visualization of the liquid in circulation and therefore hydrates if they formed.
• the fluid is introduced (water and additive) in the reactor.
• the installation is then brought under a pressure of 7 MPa.
• the solution is homogenized by its circulation in the loop and the reactor, then the loop is isolated from the reactor.
• the pressure is kept constant by adding methane, and a gradual reduction of the temperature (0.5 ° C / min) of 17 ° C to 5 ° C, which corresponds to the chosen experimental temperature.
• the principle of these tests is to determine, on the one hand, the temperature of formation of methane hydrates in the loop, and secondly the lag time preceding their formation.
• the latency time corresponds to the measured time between beginning of the test (fluid circulation at 17 ° C) and detection of hydrate formation (exothermic, high gas consumption).
• the duration of the tests may vary from a few minutes to several hours: a powerful additive inhibits the formation of hydrates, or keeps them dispersed in fluids for several hours.
• the methane hydrates are form at a temperature of 10.0 ° C. and after an induction time of 30.degree. minutes.
• the formation of hydrates leads to an immediate blockage of the circulation of the fluid + hydrate mixture in the loop.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Separation Of Suspended Particles By Flocculating Agents (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Gas Separation By Absorption (AREA)

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• 1996
  • 1996-05-15 FR FR9606200A patent/FR2748773B1/fr not_active Expired - Fee Related
• 1997
  • 1997-05-05 EP EP97401004A patent/EP0807678B1/fr not_active Expired - Lifetime
  • 1997-05-13 BR BR9703143A patent/BR9703143A/pt not_active IP Right Cessation
  • 1997-05-13 MX MX9703503A patent/MX9703503A/es active IP Right Grant
  • 1997-05-14 NO NO19972225A patent/NO321773B1/no not_active IP Right Cessation
  • 1997-05-14 RU RU97107763/04A patent/RU2167846C2/ru not_active IP Right Cessation
  • 1997-05-14 CA CA002206918A patent/CA2206918C/fr not_active Expired - Fee Related
  • 1997-05-15 US US08/857,048 patent/US5981816A/en not_active Expired - Lifetime
  • 1997-05-15 AR ARP970102050A patent/AR007156A1/es unknown
  • 1997-05-15 CN CN97113227A patent/CN1072709C/zh not_active Expired - Fee Related

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