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 delaying the formation, growth or / and agglomeration of hydrates of natural gas, petroleum gas or other gases, by using at least one additive.
• the gases which form hydrates can in particular comprise at least one hydrocarbon chosen 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 free state or in the dissolved state in a liquid phase, such as a liquid hydrocarbon, and when the temperature reached by the mixture in particular d water, gas and possibly liquid hydrocarbons, such as oil, becomes lower than the thermodynamic temperature of hydrate formation, this temperature being given for a known composition of gases and when their pressure is fixed.
• Hydrate formation can be feared, especially in the oil and gas industry, for which hydrate formation conditions can be met. Indeed, to reduce the cost of producing crude oil and gas, both from the point of view of investments and from the point of view of exploitation, one way envisaged, in particular in production at sea, is to reduce, even remove, the treatments applied to the crude oil or to the gas to be transported from the deposit to the coast and in particular to leave all or part of the water in the fluid to be transported. These treatments at sea are generally carried out on a platform located on the surface near the deposit, so that the effluent, initially hot, can be treated before the thermodynamic conditions for hydrate formation are reached due to the effluent cooling with seawater.
• hydrate plugs can cause production to stop and thus cause significant financial losses.
• the return to service of the installation especially if it is a question 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 to the formation of hydrates can also be met in the same way on the ground, for pipes which are not (or not deep enough) buried in the ground, when for example the temperature of the ambient air is cold.
• patent application EP-A-323774 in the name of the applicant, which describes the use of nonionic amphiphilic compounds chosen from polyol esters of substituted or unsubstituted carboxylic acids , and the imide functional compounds
• patent application EP-A-323 775 also in the name of the applicant, which describes in particular the use of compounds belonging to the family of diethanolamides of fatty acids or derivatives of fatty acids
• US-A-4956593 which describes the use of surfactant compounds such as organic phosphonates, esters phosphates, phosphonic acids, their salts and esters, inorganic polyphosphates and their esters, as well as homopolyacrylamides and copolymers-acrylamide-acrylates
• patent application EP-A-457375 which describes the use of anionic surfactants, such as alkylarylsulfonic acids and their alkali metal salts.
• Amphiphilic compounds obtained by reaction of at least one succinic derivative chosen from the group formed by polyalkenylsuccinic acids and anhydrides on at least one polyethylene glycol monoether have also been proposed to reduce the tendency for agglomeration of natural gas hydrates, petroleum gas or other gases (patent application EP-A-582507).
• International application WO-A-9519408 more generally describes the use of aliphatic polymers containing carbonylated N-heterocycles in complex formulations.
• international applications WO-A-9517579 and WO-A-9604462 describe the use of ammonium, sulfonium and phosphonium derivatives alkylated either alone or mixed with a corrosion inhibitor.
• water-soluble polymers which may be neutral or positively charged homopolymers or copolymers, or else polyampholytes and which derive from one or more nitrogenous monomers, allow, at low concentrations, to inhibit or retard the formation, growth and / or agglomeration of hydrates of natural gas, petroleum gas or other gases, with an efficiency clearly superior to the compounds described above.
• neutral monomers illustrating these formulas mention may be made of dimethyl-amino-ethyl acrylate and of dimethyl-amino-ethyl methacrylate.
• cationic monomers mention may be made of methacrylate-ethyl-trimethyl ammonium chloride, methacrylamido-N-propyltrimethyl ammonium chloride and diallyl-dimethyl ammonium chloride.
• amphoteric monomers mention may be made of ethyl trimethyl ammonium acrylate methosulfonate.
• the cationic monomers, the amphoteric monomers and the neutral monomers from [A] to [E] defined in the preceding description may be included in the homopolymers or copolymers, in any proportions, that is to say ranging, for each, from 0 to 100 mol%.
• the invention also proposes the use as additives, of copolymers resulting from the combination of at least one of the monomers described above (cationic monomer, amphoteric monomer and / or neutral monomer from [A] to [E]) , with at least one 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 sulfonate groups and more precisely acrylate, methacrylate, itaconate, 2-acrylamido-2-methyl-propane sulfonate, 2-methacryloyloxy ethane sulfonate, 3-acrylamido-3 monomers. -methyl butanoate, styrene sulfonate, styrene carboxylate, vinyl sulfonate, maleic anhydride or maleic acid.
• the proportions of cationic monomers, amphoteric monomers, neutral monomers from [A] to [E], anionic monomers and / or additional neutral monomers can vary, for each of the monomers, for example from 1 to 99%, more particularly from 10 to 70% by moles.
• the cationic monomers, the amphoteric monomers and the neutral monomers from [C] to [E] described above can also be combined with one or more other neutral nitrogenous monomers of the N-vinyl lactam type, in particular N-vinyl-2. -pyrrolidone, N-vinyl- ⁇ -valerolactam and N-vinyl- ⁇ -caprolactam.
• the proportions of cationic monomers, amphoteric monomers, neutral monomers from [C] to [E] and additional neutral monomers can vary, for each of the monomers, for example from 1 to 99%, and more particularly from 10 to 70% by moles.
• the homopolymers and copolymers considered in the invention may consist of neutral, cationic (co) polymers or into polyampholytes (the latter containing both positively charged monomers and negatively charged monomers).
• the polymers described in the invention can be linear or branched. Their mass can vary from 3000 to several million.
• the homo and copolymers as described above can be added to the fluid to be treated alone or in the form of mixtures of two or more of them.
• copolymers may be copolymers which differ from one another, for example by the nature of the units of at least one type and / or by a different composition in at least one unit and / or by their mass molecular.
• the homo or copolymers, as well as their mixtures in all proportions, can be added to the fluid to be treated at concentrations generally ranging from 0.05 to 5% by mass, preferably from 0.1 to 2% by mass, relative at the water.
• the homo or copolymers recommended as additives in the invention can be mixed with one or more alcohols (monoalcohols or polyols) containing, for example, from 1 to 6 carbon atoms, more particularly mono-, di- or tri -ethylene glycol, ethanol or methanol, the latter being the preferred alcohol.
• This alcohol or these alcohols) is (are) added (s) in general in proportions ranging from 0.5 to 20% by mass, preferably from 1 to 10% by mass, relative to the water present in the fluid to be treated.
• the homo (s) or copolymer (s) considered in the invention can then be dissolved beforehand in a hydro-alcoholic medium and then added to the medium to be treated, so as to obtain final concentrations of homo or copolymers generally ranging from 0.05 to 3% by mass, preferably from 0.1 to 1% by mass relative to the water present in the fluid to be treated.
• the water-soluble homopolymers or copolymers considered in the invention can be used either in pure water medium, for example in condensing water, or in saline medium, for example in production water.
• the device used consists of tubes with a diameter of 16 mm, into which are introduced 8 ml of an aqueous solution at 20% by mass of THF optionally containing the additive to be tested. A glass ball with a diameter of 8 mm is introduced into each tube, in order to ensure correct mixing of the solution.
• the tubes are placed on a rotary agitator, which rotates at 20 rpm. The latter is placed in a refrigerated enclosure at 2 ° C.
• This latency time corresponds to the interval measured between the moment when the tubes are introduced into the refrigerated enclosure and the moment when the formation of hydrates is observed (appearance of a cloudiness).
• Each series of tests is carried out in the presence of a reference mixture containing no additive, and the latency times provided for an additive correspond to an average of the times measured over 16 tests.
• the pure water / THF solutions have an average latency time of 35 minutes.
• Example 1 The experimental procedure of Example 1 is repeated, replacing the pure water with a mixture of pure water + 5% methanol by mass and lowering the temperature of the refrigerated enclosure to -1 ° C.
• the average latency time of pure water solutions + 5% methanol / THF in the absence of an additive is 29 minutes.
• Example 1 The experimental procedure of Example 1 is repeated, replacing the pure water with a 3.5% by mass NaCl solution. the temperature of the refrigerated chamber is lowered to 0 ° C. Under these conditions, the average latency time of the NaCl / THF solutions 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% by mole of acrylamide-type units, 25% by mole of acrylamido-methyl-propane sulfonate units (AMPS) and 15% by mole of methacrylamido chloride units -N-propyltrimethyl ammonium (MAPTAC) or 0.3% by mass of a PVP / AMPDAPS copolymer (60/40 in moles) inhibit the formation of THF hydrates for a period greater than 6 hours.
• the apparatus comprises a 6-meter loop made up of tubes with an internal diameter equal to 7.7 mm, a 2-liter reactor comprising an inlet and an outlet for the gas, a suction and a discharge for the water and additive mixture initially introduced. .
• the reactor puts the loop under pressure. Tubes of diameter similar to those of the loop ensure the circulation of the fluid from the loop to the reactor, and vice versa, by means of a gear pump placed between the two.
• a sapphire cell integrated into the circuit allows visualization of the circulating liquid and therefore of the hydrates if they have formed.
• the fluid water and additive
• 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 decrease in temperature (0.5 ° C / min) from 17 ° C to 5 ° C is imposed, 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 on the other hand the lag time preceding their formation.
• the latency time corresponds to the time measured between the start of the test (circulation of the fluid at 17 ° C) and the detection of the formation of hydrates (exotherm, high gas consumption).
• the duration of the tests can vary from a few minutes to several hours: a high-performance additive inhibits the formation of hydrates, or keeps them dispersed in the fluids for several hours.
• methane hydrates are formed at a temperature in the region of 10.0 ° C and after an induction time of 30 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)
• Gas Separation By Absorption (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (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/de not_active Expired - Lifetime
  • 1997-05-13 MX MX9703503A patent/MX9703503A/es active IP Right Grant
  • 1997-05-13 BR BR9703143A patent/BR9703143A/pt not_active IP Right Cessation
  • 1997-05-14 NO NO19972225A patent/NO321773B1/no not_active IP Right Cessation
  • 1997-05-14 CA CA002206918A patent/CA2206918C/fr not_active Expired - Fee Related
  • 1997-05-14 RU RU97107763/04A patent/RU2167846C2/ru not_active IP Right Cessation
  • 1997-05-15 AR ARP970102050A patent/AR007156A1/es unknown
  • 1997-05-15 CN CN97113227A patent/CN1072709C/zh not_active Expired - Fee Related
  • 1997-05-15 US US08/857,048 patent/US5981816A/en not_active Expired - Lifetime

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