93 results about "Asphaltene precipitation" patented technology

The present invention provides a down hole spectrometer for determination of dew point pressure to determine an associated optimal pumping rate during sampling to avoid precipitation of asphaltenes in a formation sample. A sample is captured at formation pressure in a controlled volume. The pressure in the controlled volume is reduced. Initially the formation fluid sample appears dark and allows less light energy to pass through a sample under test. The sample under test, however, becomes lighter and allows more light energy to pass through the sample as the pressure is reduced and the formation fluid sample becomes thinner or less dense under the reduced pressure. At the dew point pressure, however, the sample begins to darken and allows less light energy to pass through it as apshaltenes begin to precipitate out of the sample. Thus, the dew point is that pressure at which peak light energy passes through the sample. The dew point pressure is plugged into an equation to determine the optimum pumping rate for a known mobility, during sampling to avoid dropping the pressure down to the dew point pressure to avoid asphaltene precipitation or dew forming in the sample. The bubble point can be plugged into an equation to determine the optimum pumping rate for a known mobility, during sampling to avoid dropping the pressure down to the bubble point pressure to avoid bubbles forming in the sample.

Trunk piston marine engine lubrication, when the engine is fueled by heavy fuel oil, is effected by a composition comprising a major amount of an oil of lubricating viscosity containing at least 50 mass % of a basestock containing greater than or equal to 90% saturates and less than or equal to 0.03% sulphur or a mixture thereof, and respective minor amounts of an over-based metal hydrocarbyl-substituted hydroxybenzoate detergent other than such a detergent having a basicity index of less than two and a degree of carbonation of 80% or greater and at least 1 mass % of a hydrocarbyl-substituted carboxylic acid, anhydride, ester or amide thereof. Asphaltene precipitation in the lubricant, caused by the presence of contaminant heavy fuel oil, is prevented or inhibited.

The invention comprises an apparatus and method for simple fluorescence spectrometry in a downhole environment using a UV light source and UV fluorescence to determine a parameter of interest for a sample downhole. The UV light source illuminates the fluid, which in turn fluoresces light. The fluoresced light is transmitted back towards the UV light source and through the pathway towards an optical spectrum analyzer. API gravity is determined by correlation the wavelength of peak fluorescence and brightness of fluorescent emission of the sample. Asphaltene precipitation pressure is determined by monitoring the blue green content ratio for a sample under going depressurization.

Compositions comprising at least one C₄-C₃₀ olefin or oxidation product thereof and kerosene or an aromatic solvent are particularly effective for use in removing asphaltene and asphaltene-containing organic deposits and in preventing or reducing the precipitation and deposition of asphaltenes from hydrocarbon fluids. When added to heavy oils comprising asphaltenes, alone or in combination with dispersants and further inhibitors, the invented compositions lower viscosity and pour point, and aid in preventing asphaltene precipitation during transport and in combustion.

The recovery of oil from a reservoir is assisted by injecting a diluent into the reservoir formation to reduce the viscosity of the crude oil. This diluent is a mixture of a material which is an asphaltene precipitant, especially supercritical carbon dioxide, and a more polar material which comprises at least one aliphatic compound which includes at least one of a cycloaliphatic ring, an olefinic unsaturation, an ester or ether group. The inclusion of such an aliphatic compound which is more polar than the asphaltene precipitant reduces asphaltene precipitation and can enhance the efficiency of oil recovery when the precipitant is by supercritical carbon dioxide.

The present invention relates to formulations of asphaltenes' inhibitor-dispersant additives based on oxazolidine derived from polyalkyl or polyalkenyl N-hydroxyalkyl succinimides. Said formulations can contain inert organic solvents, preferably including: toluene, mixtures of xylene, o-xylene, p-xylene, kerosene, turbo-fuel; or inert hydrocarbon solvents having boiling points within the range of gasoline and diesel; or inert hydrocarbon or organic solvents having a boiling point within a range from 75 to 300° C. The ratio in weight of inert organic solvents to additive that prevents and controls the precipitation and deposition of asphaltenes ranges from 1:9 to 9:1, preferably from 1:3 to 3:1.

The present invention provides a downhole method and apparatus using a flexural mechanical resonator, for example, a tuning fork to provide real-time direct measurements and estimates of the viscosity, density and dielectric constant of formation fluid or filtrate in a hydrocarbon producing well. The present invention additionally provides a method and apparatus for monitoring cleanup from a leveling off of viscosity or density over time, measuring or estimating bubble point for formation fluid, measuring or estimating dew point for formation fluid, and determining the onset of asphaltene precipitation. The present invention also provides for intercalibration of plural pressure gauges used to determine a pressure differential downhole. A hard or inorganic coating is placed on the flexural mechanical resonator (such as a tuning fork) to reduce the effects of abrasion from sand particles suspended in the flowing fluid in which the flexural mechanical resonator is immersed.

Trunk piston marine engine lubrication, when the engine is fueled by heavy fuel oil, is effected by a composition comprising a major amount of an oil of lubricating viscosity and a minor amount of one or more phenolic compounds comprising distilled cashew nut shell liquid or hydrogenated distilled cashew nut shell liquid. Asphaltene precipitation in the lubricant, caused by the presence of contaminant heavy fuel oil, is prevented or inhibited.

Disclosed herein is a method for determining the effectiveness of one or more asphaltene dispersant additives for inhibiting or preventing asphaltene precipitation in a hydrocarbon-containing material subjected to elevated temperature and pressure conditions.

The invention relates to asphaltene deposition solid inhibitor in the exploitation of light oil which can effectively reduce and control asphaltene to gather and deposit in the light oil exploitation process, which is used on the crude oil exploitation, and can solve the problems of asphaltene deposition and precipitation in the light oil exploitation process. The technical scheme is that the inhibitor is formed by high-pressure polyethylene, diesel fuel and other auxiliary agent, and the product of asphaltene deposition solid inhibitor can be obtained through conducting molten agglutination reaction for 20-60% high-pressure polyethylene, 10-40% diesel fuel and 20-40% other auxiliary agent which comprises three medicaments of polyoxyethylene ether, sodium dodecylbenzene sulfonate and 2,6-ditrertiarybutyl p-methyl phenyl under the temperature of 100-130 DEG C to form even mixture before molding. The product can be direct thrown into drug-carrying container or be thrown by means of a drug-adding pipe, is slowly released as the scouring of bottom hole oil stream, which can effectively inhibit the gathering and growth of asphaltene, solves the problem of pipe column plugging-up problem in well, and has the advantages of high inhibiting efficiency, long cycle, small additive dose and low cost.

A paraffinic solvent recovery process for treating high paraffin diluted bitumen includes supplying the latter to flashing apparatus; separating into flashed paraffinic solvent and diluted bitumen underflow; and returning a portion of the underflow as returned diluted bitumen into the high paraffin diluted bitumen prior to introduction into the flashing apparatus, at temperature and amount to shift asphaltene precipitation equilibrium to reduce asphaltene precipitation. The process includes pre-heating the high paraffin diluted bitumen by transferring heat from hot dry bitumen, flashed paraffinic solvent and/or a portion of diluted bitumen underflow. Flashed paraffinic solvent may contain residual light end bitumen contaminants that increase asphaltenes solubility and the process may include removing contaminants to produce reusable paraffinic solvent at given solvent-to-bitumen ratio range to maintain given asphaltene precipitation. The process may also include a bitumen fractionation column producing hot dry bitumen underflow containing at most 0.5 wt % paraffinic solvent.

Disclosed is a method for transporting blended crude oils comprising the steps of; (a) admixing a first crude oil with a second, different crude oil to form a crude oil admixture; (b) determining a first value representing the content of unprecipitated asphaltenes in the admixture; (c) holding the admixture for a period of time at standard conditions; (d) determining a second value representing the content of unprecipitated asphaltenes in the admixture; and (e) either: (i) transporting the admixture if the second value is the same as or within a predetermined range of the first value; or (ii) taking remedial action to prevent asphaltene precipitation prior to transporting if the second value is outside a predetermined range from the first value. Also disclosed is a method for estimating the storage stability of stored crude oils and crude oil admixtures.

A method of inhibiting asphaltene precipitation and/or deposition in a hydrocarbon, preferably crude oil, by adding to the hydrocarbon a polyester asphaltene dispersing agent which is the reaction product of an alk(en)yl substituted succinic anhydride wherein the average number of succinic groups per alk(en)yl group is less than 2.0, and at least one polyol.

An additive comprising, dissolved in a solvent, an asphaltene dispersant selected from the group consisting of α-olefin/vinyl pyrrolidinone copolymers. The copolymer can comprise at least one α-olefin selected from the group consisting of mono-α-olefins, at least one α-olefin selected from the group consisting of linear α-olefins and/or at least one α-olefin is selected from the group consisting of 1-hexadecene, 1-octadecene, 1-eicosene, 1-docosene, 1-tetracosene, 1-hexacosene, 1-octacosene and 1-triacontene. The additive can comprise a copolymer of 2-pyrrolidinone, 1-ethenyl monomer. The copolymer can have a Hansen Solubility Parameter (HSP), δ, of greater than 16, 17 or 18 MPa^1/2. The solvent can be selected from the group consisting of aromatic solvents, such as 1-methyl naphthalene, bis-(m-phenoxyphenyl)ether, o-xylene, toluene and heavy aromatic solvents. Also provided is a method of inhibiting asphaltene precipitation in a fluid by introducing into the fluid an asphaltene dispersant selected from the group consisting of α-olefin/vinyl pyrrolidinone copolymers.

A method predicts the asphaltene precipitation envelope of a fluid consisting of stock tank oil and dissolved gas. The method comprises comparing a solubility parameter of the fluid, δ_fluid, and an onset solubility parameter of the fluid, δ_onset(fluid), across a range of pressures, to predict pressures at which asphaltene precipitation will be observed, δ_fluid and δ_onset(fluid) are calculating using a correction factor, F_correction. F_correction is determined according to formula (1):

F_correction=δ_{STO(physical)}/δ_{STO(solvent power)}  (1)

• • where: δ_{STO(physical)} is an estimate of the solubility parameter of the stock tank oil based on a physical property of the stock tank oil, and
  •  δ_{STO(solvent power)} is an estimate of the solubility parameter of the stock tank oil based on the solvent power of the stock tank oil.

The magnitude of asphaltic precipitation when injecting a viscosity reducing diluent into a reservoir formation, notably to assist oil recovery therefrom, is forecast by (i) determining a relationship between asphaltic precipitation and a solubility parameter for the diluted oil, and then (ii) utilizing that relationship to forecast the magnitude of asphaltic precipitation when injecting a predetermined viscosity reducing diluent into the formation. Making this forecast may be followed by injecting a viscosity reducing diluent into the formation to assist oil recovery. The diluent may in particular be supercritical carbon dioxide or other asphaltene precipitant mixed with a more polar material in proportions designed by forecasting asphaltic precipitation by candidate materials in possible proportions.