Mobil Oil Corporation

James M Paul

Richard L Morris

R Michael Davis

Alfred R Jennings, Jr

Wilton F Espenscheid

Joseph G Savins

Earl S Snavely, Jr

Peggy M Wilson

Edwin T Strom

John B Otto, Jr

Eleanor R Fieler

Robert Mitchell Davis

Wilton F Espenscheid, Deceased

Harold W Hadley

A method for extracting bitumen from crushed mined tar sands comprising contacting the mined tar sands with a solvent in the presence of sonic energy in the frequency range of 0.5 to 2.0 kHz. Specifically, a solvent is first mixed with crushed mined tar sands and the mixture is then formed into a slurry of tar sand suspended in the solvent. Thereafter the tar sand slurry is injected into the top of a vertically disposed, substantially rectangular shaped, hollow acoustic chamber of uniform cross-section. Fresh solvent is injected into the bottom of the acoustic chamber and flows upwardly through the cell. The fresh solvent is injected into the bottom of the acoustic chamber at a rate low enough whereby the tar sand particles in the slurry fall by gravity through the upwardly flowing solvent. The tar sand particles and solvent in the acoustic chamber are subjected to acoustic energy in the frequency range of 0.5 to 2.0 kHz whereby the bitumen is separated from the tar sand and dissolved by the upwardly flowing solvent without cavitation of the solvent. The bitumen dissolved in the solvent is recovered from the top of the acoustic chamber and transferred by pipeline to an off-site refinery. The bitumen-extracted sand particles recovered from the bottom of the acoustic chamber may be recycled to the top of the acoustic chamber to recover additional bitumen after injection of the slurry has been discontinued.

Method for extracting bitumen from tar sands

A method for breaking an emulsion comprising oil and water into oil and water phases comprising treating the emulsion with a chemical demulsifier and passing the mixture through a hollow chamber having a uniform cross-section and subjecting the mixture to acoustic energy in the frequency range of about 0.5 to 10.0 kHz, preferably 1.25 kHz, to enhance breaking the emulsion into a water phase and oil phase. The oil phase is then separated from the water phase by gravity separation and recovered. The sonic energy is generated by a transducer attached to the mid-section of the upper or lower outer surface of the hollow chamber. For emulsions containing light oil having an API gravity greater than 20 and water, the emulsion can be broken by the use of acoustic energy in the frequency range of about 0.5 to 10.0 kHz without the addition of chemical demulsifiers.

Method and apparatus for breaking hydrocarbon emulsions

Heavy crude oil containing at least 1% by weight water is hydrotreated and upgraded while being produced downhole in a production well. During production the heavy crude oil containing water is subjected to sonic energy at a low frequency of 400 Hz to 10 kHz downhole in the presence of a metal hydrogenation catalyst that causes the water in the crude oil to react and form hydrogen which then hydrotreats and upgrades the heavy crude oil during production. In another embodiment, if the heavy crude oil does not contain water, the hydrogen may be formed in-situ by contacting the heavy crude oil downhole with a chemical compound comprising ammonia, hydrazine and formic acid that in the presence of a metal hydrogenation catalyst and sonic energy causes the chemical compound to react and form hydrogen which then hydrotreats the heavy crude oil during production. Suitable catalysts include nickel on zinc dust, platinum on carbon and palladium on carbon, preferably nickel on zinc dust. The hydrotreated and upgraded heavy crude oil has improved properties making it easier to refine and transport by pipeline. The upgrading includes reducing the amount of asphaltenes and resins in the heavy crude oil and increasing the amount of aromatics and saturates.

Method for hydrotreating and upgrading heavy crude oil during production

A method for extracting oil from oil-contaminated soil containing 2 to 5 wt. % oil, comprising contacting the oil-contaminated soil with a solvent in the presence of sonic energy in the frequency range of 0.5 to 2.0 kHz. Specifically, a solvent is first mixed with the oil-contaminated soil and the mixture is then formed into a slurry of oil-contaminated soil particles suspended in the solvent. Thereafter the oil-contaminated soil slurry is passed through a shaker screen to remove soil particles greater than 1/4 inch. The oil-contaminated soil slurry containing the smaller soil particles is then fed into the top of a vertically disposed, substantially rectangular shaped, hollow acoustic chamber of uniform cross-section. Fresh solvent is injected into the bottom of the acoustic chamber that flows upwardly through the acoustic chamber. The fresh solvent is injected at a rate low enough whereby the oil-contaminated soil particles fall by gravity through the upwardly flowing solvent. The oil-contaminated soil particles and solvent in the acoustic chamber are subjected to acoustic energy in the frequency range of 0.5 to 2.0 kHz displaces the oil from the oil-contaminated soil particles that is dissolved by the upwardly flowing solvent without cavitation of the solvent. The substantially oil-free soil particles containing only 0.2 to 0.4 wt. % oil are recovered from the bottom of the acoustic chamber and spread over the land for land farming. The present method may also be used for extracting oil from oily sludge or oil-based drill cuttings.

Method for extracting oil from oil-contaminated soil

The present invention relates to the use of low frequency sonic energy within the range of 1.25 to 6.5 KHz, preferably less than 2.0 KHz and most preferably 1.25 KHz, for enhancing the dissolution of alkaline earth metal scales from well bores using a scale-removing solvent comprising an aqueous alkaline solution having a pH of about 8 to about 14 and containing EDTA or DTPA and a catalyst or synergist, preferably an oxalate anion. When the scale deposit is contacted with the scale removing solvent while simultaneously transmitting low frequency sonic energy through the solvent, substantially more scale is dissolved at a faster rate than previously possible.

Method for removing alkaline sulfate scale

The present invention relates to a method of removing alkaline earth sulfate scale from the interior surface of downhole production tubing comprising contacting the scale with a solvent having a specific gravity of at least 1.2 while simultaneously milling the scale with a rotating mill head connected to a downhole motor.

Method for removing alkaline sulfate scale in downhole tubulars

A method to improve the efficiency of scale dissolution in a formation containing multiple productive intervals where variable density liquids are utilized. Initially, a liquid composition sufficient to solubilize an alkaline-earth metal sulfate scale deposit is directed into a wellbore thereby contacting scale in one productive interval of the formation. Thereafter, a second scale solubilizing liquid having a density of about 0.1 wt % less than the first liquid is directed into the wellbore thereby contacting additional perforations and a higher interval. These scale solubilizing liquids with varying densities are allowed to remain in contact with perforations and productive intervals communicating therewith for a time sufficient to solubilize the scale deposit thereby efficiently removing said scale deposit from perforations and productive intervals at two different levels.

Use of variable density carrier fluids to improve the efficiency of

A method and composition for removing barium and strontium sulfate scale deposits. The composition comprises an aqueous solution having a pH of about 8 to about 14, an EDTA or DTPA chelant, and a catalyst or synergist. Preferred chelants comprise diethylenetriaminepentaacetic acid (DTPA) or ethylenediaminetetraacetic acid (EDTA or alkali salts thereof. Anions of organic and inorganic acids comprise the catalyst. Catalysts which can be used include fluoride, oxalate, persulfate, dithionate, hypochlorite and formate anions. When the solution containing the composition is contacted with a surface containing a scale deposit, the deposit dissolves substantially more scale quicker than heretofore possible.

Composition for removing an alkaline earth metal sulfate scale

Alkaline earth metal scales, especially barium sulfate scale deposits are removed from oilfield pipe and other tubular goods with a scale-removing composition comprising an aqueous alkaline solution having a pH of about 8 to about 14, a polyaminopolycarboxylic acid, preferably EDTA or DTPA and a catalyst or synergist comprising oxalate anion. When the scale-removing solution is contacted with a surface containing a scale deposit, substantially more scale is dissolved at a faster rate than previously possible.

Compositions for dissolution of sulfate scales

Barium sulfate scale is dissolved by contacting the scale with an aqueous solvent having a pH of about 10 to about 14, preferably about 12, and comprising a chelating agent comprising a polyaminopolycarboxylic acid or salt of such an acid, and a synergist anion. The solvent containing the dissolved scale is regenerated by acidifying the solvent in the presence of an anion which forms a precipitate of an insoluble salt of the alkaline earth metal of the dissolved scale. The precipitate is then removed from the solvent. Thereafter, the pH of the solvent is increased to a pH of about 10 to about 14, preferably about 12, to recover a regenerated solvent for reuse, in dissolving scale.

Method for regenerating scale solvent

Alkaline earth metal scales, especially barium sulfate scale deposits are removed from oilfield pipe and other tubular goods with a scale-removing composition comprising an aqueous alkaline solution having a pH of about 8 to about 14, preferably about 11 to 13, of a polyaminopolycarboxylic acid, preferably EDTA or DTPA and a catalyst or synergist comprising a monocarboxylic acid, preferably a substituted acetic acid such as mercaptoacetic, hydroxyacetic acid or aminoacetic acid or an aromatic acid such as salicylic acid. When the scale-removing solution is contacted with a surface containing a scale deposit, substantially more scale is dissolved at a faster rate than is possible without the synergist.

Sulfate scale dissolution

A liquid membrane method for removing scale deposits wherein a novel chelating composition is utilized. The composition used in the external and internal aqueous phases of said membrane comprises an aqueous solution having a pH of about 8 to about 14, and an aminocarboxylic acid or polyamine chelant. Additionally, a catalyst or synergist is used in the external phase only. Preferred chelants comprise diethylenetriamine pentaacetic acid (DTPA) or ethylenediaminetetraacetic acid (EDTA) or alkali salts thereof. Anions of organic and inorganic acids comprise the catalyst used in the external phase. Catalysts which can be used include fluoride, oxalate, persulfate, dithionate, hypochlorite, formate, thio, amino and hydroxy acetate anions. When the solution containing the composition is contacted with a surface containing a scale deposit, the deposit dissolves substantially more scale quicker than heretofore possible.

Method for removing scale via a liquid membrane in combination with an

Alkaline earth metal scales, especially barium sulfate scale is removed from a well (the wellbore and the adjacent formation) by contacting the scale with a scale-removing solvent and thereafter sparging the solvent with air or insert gas to dissolve the scale. The sparging aids in achieving a flushing action by the solvent relative to the scale thereby enabling the solvent to more effectively dissolve the scale in the well. Temperature and caustic compatible surfactuants (anionic and non-ionic) may be used in the solvent to generate a column of foam which increases the extent of cleaning oil from the scale surfaces, enabling the solvent to more effectively remove the scale.

Method for scale removal in a wellbore

Barium sulfate scale is dissolved by contacting the scale with an aqueous solvent having a pH of about 10 to about 14, preferably about 12, and comprising a chelating agent comprising a polyaminopolycarboxylic acid or salt of such an acid, and a synergist anion. The solvent containing the dissolved scale is regenerated by acidifying the spent solvent with an acidic chelating agent such as EDTA or DTPA, preferably DTPA, that release alkaline earth cations which react with sulfate ions present in the solvent to form a precipitate of an insoluble salt of the alkaline earth metal. The precipitate is then removed from the solvent by settling/decanting, filtering, or centrifuging. Thereafter, caustic is added to increase the pH of the solvent to a pH of about 10 to about 14, preferably about 12, to recover a regenerated solvent for reuse, in dissolving scale. The amount of chelating agent added to acidify the spent solvent balances the total amount of dilution caused by adding the caustic thereby maintaining the activity of the chelating agent in the regenerated solvent at least equivalent to or greater than the activity in the spent solvent.

A method for removing calcium sulfate scale from a well comprising mixing carbon dioxide and water at a downhole location within the well to form an acidic solution containing an equilibrium mixture of carbonic acid, bicarbonate and carbonate ions that will convert the calcium sulfate scale to calcium carbonate scale and subsequent in situ dissolution of the calcium carbonate scale into the acidic solution that flows into the formation about the well.

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DeSoto, TX, United States of America

James M Paul