Texaco Inc.

Getty Oil Company

Other

Robert H Friedman

Billy W Surles

Philip D Fader

Bertram E Eakin

Carlos W Pardo

Maria Friedman

Pedicured toe sock

Disclosed are methods for treating wells to form a permeable barrier around the well for consolidating unconsolidated mineral particles such as sand in a subterranean petroleum formation penetrated by a well, or for forming an impermeable barrier for fluid entry control, or for plugging the well for abandonment. A fluid containing a polymerizable resin such as furfuryl alcohol, a polar organic diluent such as butyl acetate and an oil soluble acid catalyst to cause polymerization of the resin at formation temperatures is prepared. The acid should have a pK in the range of 0.4 to 6.0. The acid and acid concentration are selected to cause the polymerization reaction to be essentially complete in from 0.75 to 4.0 hours and preferably 1.0-2.0 hours at the formation temperature. Usually the selected acid concentration will be in the range of from 0.2 to 5.0 percent. This fluid is injected into the formation to saturate at least a portion of the formation adjacent to the well. In one embodiment, when it is desired to form a permeable treated zone for sand control, an aqueous fluid comprising water which is from 70 to 100% saturated with inorganic salts including sodium chloride is injected into the same portion of the formation contacted by the resin containing fluid. The injected resin-containing fluid is allowed to remain in the formations for at least four hours to accomplish at least partial polymerization of the resin, forming a permeable or impermeable mass around the wellbore.

Formation treating methods

Methods are provided for consolidating unconsolidated mineral grains such as sand within a subterranean oil formation to form a fluid permeable barrier which restrains the movement of sand particles when oil passes through the barrier. A quantity of an organic solvent, preferably an ester such as butyl acetate is injected into the formation as a preflush. Next, a liquid comprising a polymerizable oligomer such as furfuryl alcohol oligomer, an ester such as butyl acetate, and an acid catalyst such as toluene sulfonic acid is provided, then mixed with a noncondensable gas to form a multiphase or aerosol treating fluid, and the treating fluid is injected into the formation to be consolidated. The well is shut in for sufficient period of time for polymerization to convert the injected fluids into a permeable barrier around the wellbore.

Sand consolidation methods

Methods are provided for selectively consolidating naturally occurring mineral grains such as sand grains within a subterranean formation to form a fluid permeable barrier, which restrains the movement of sand particles when oil passes through the barrier. A sand consolidation fluid usually containing a monomer or oligomer of furfuryl alcohol is injected, either mixed with steam to form a multiphase treating fluid or injected as a liquid phase into the formation. The fluid contains an acid catalyst and an ester and an effective amount of a swelling polymer to reduce shrinkage of the furfuryl alcohol when it polymerizes in the formation. A preferred swelling polymer is a copolymer of starch and an acrylamides or acrylates.

Wells penetrating oil-producing and water-producing intervals may be treated in order to reduce the flow rate of water into the well by isolating the water-producing interval and introducing into it a volume of treating fluids sufficient to invade at least six inches into the water-producing interval. Cased wells may be treated to plug holes in the casing caused by corrosion or casing breaks by introducing a treating fluid into the formation adjacent to the break. The treating fluid comprises a material which can be acid catalyzed in a period of from 1 to 16 hours at formation conditions, preferably a monomer or oligomer of furfuryl alcohol. The treating fluid contains from 40 to 60 percent furfuryl alcohol and from 40 to 60 percent of an ester, preferably ethyl acetate or butyl acetate. The catalyst is preferably orthonitrobenzoic acid or toluene sulfonic acid in a concentration of from 1 to 4 percent by weight, selected to produce a set time at the formation temperature in the range of from 1 to 16 hours. The treating fluid also contains an effective amount in the range of 0.5 to 1.5 percent of a water swelling polymer, preferably a copolymer of starch and synthetic polymer (acrylates or acrylamides) to prevent shrinkage of the furfuryl alcohol on polymerization.

Treating underground formations

Wells penetrating oil-producing and water-producing intervals may be treated in order to reduce the flow rate of water into the well by isolating the water-producing interval and introducing into it a volume of treating fluids sufficient to invade at least six inches into the permeable formation comprising the water-producing interval. Cased wells may be treated to plug holes in the casing caused by corrosion or casing breaks by introducing a treating fluid into the formation adjacent to the break. The treating fluid comprises a material which can be acid catalyzed in a period of from 1 to 16 hours at formation conditions, preferably a monomer or oligomer of furfuryl alcohol. The treating fluid contains from 40 to 60 percent furfuryl alcohol and from 40 to 60 percent of an ester, preferably ethyl acetate or butyl acetate. The catalyst is preferably orthonitrobenzoic acid or toluene sulfonic acid in a concentration of from 1 to 4 percent by weight. The acid and concentration of acid are selected to produce a set time at the formation temperature in the range of from 1 to 16 hours, so the treating fluid will flow into and saturate the pore space of the portion of the formation being treated.

Methods are provided for selectively consolidating naturally occurring mineral grains such as sand grains within a subterranean formation to form a fluid permeable barrier, which restrains the movement of said particles when oil passes through the barrier. When applied to formations in which at least a portion of the sand grains are coated with a viscous oily residue of crude oil, or where the pore spaces between the sand grains contain excessive quantities of water, either of which interfere with the polymerization of the polymerizable monomer employed for said consolidation, a preflush is utilized which functions both to remove the oily residue from the said grains and to remove water from the pore spaces of the formation adjacent to the wellbore. the preflush is preferably an ester such as ethyl acetate or butyl acetate in an amount sufficient to occupy substantially all of the pore space of the formation into which the polymerizable component employed for sand consolidation are subsequently injected. In one preferred embodiment and acid catalyst such as sulfuric acid is added to the preflush. After injection of the preflush, the sand consolidation fluid usually containing a monomer or oligomer of furfuryl alcohol is injected, either mixed with steam to form a mulitphase treating fluid or injected as a liquid phase into the formation.

Methods are provided for selectively consolidating naturally occurring mineral grains such as sand within a subterranean formation to form a fluid permeable barrier which restrains the movement of sand particles when oil passes through the barrier. A fluid comprising a polymerizable monomer such as furfural alcohol and as a diluent, a polar organic solvent such as methanol and a strong, non-volatile acid catalyst such as sulfuric acid is provided, mixed with steam to form a multiphase or aerosol treating fluid, and injected into the formation to be consolidated. An ester such as butyl acetate is incorporated in the fluid when the steam quality is less than 80 percent. The well is shut in for sufficient period of time for polymerization to convert the injected fluids into a permeable barrier around the wellbore.

We have found that it is possible to produce resin coated particular matter having uniform coating of resin to protect the particles against erosion or dissolution on contact with high pH fluids. The coated sand or other particles is produced by introducing the particles into a mixing device, to which is added a resin mixture comprising a urea formaldehyde resin and a furfural alcohol resin. The sand and resin mixture is mixed for sufficient time to accomplish uniform coating of the sand particle with the resin mixture. Next a foaming aqueous surfactant containing fluid is added which causes the resin-coated sand particles to be suspended in the foaming aqueous mixture. The surfactant fluid also contains acid catalyst. This mixture is allowed to set for a period of time after which the coated particles are washed and then cured at 300.degree. C. to accomplsih drying and complete the polymerization reaction. Coated sand grains are highly resistant to prolonged contact with strong alkaline fluids such as are encountered in subterranean formations being stimulated by injection of hot alkaline fluids.

Processes for forming and using particles coated with a resin which is

Disclosed are fluid and method for suspending resin coated sand in order to place the sand adjacent to a production well for the purpose of forming a permeable consolidated gravel pack. The fluid contains a viscosifying amount of hydroxyethylcellulose, sufficient fluorescent dye to increase the viscosity of the fluid, sodium chloride, and an acid forming component such as phthalic anhydride or succinic anhydride. As fluid containing the resin coated gravel particles is pumped down the injection string and positioned where it is desired to form the consolidated gravel pack, the acid forming material slowly reacts with water to form an acid, reducing the pH of the fluid, and thereby reducing the viscosity of the carrier fluid which facilitates the resin coated sand grains coming together in order to form the desired gravel pack.

Method and fluid for placing resin coated gravel or sand in a producing

Methods are provided for selectively consolidating naturally occurring mineral grains such as sand within a subterranean formation to form a fluid permeable barrier which restrains the movement of sand particles when oil passes through the barrier. A fluid comprising a polymerizable resin such as an oligomer of furfuryl alcohol and as a diluent, a polar organic solvent such as butylacetate and an oil soluble, slightly water-soluble acid catalyst such as orthonitrobenzoic acid is provided and injected into the formation to be consolidated. Water which is at least 70% saturated with respect to sodium chloride or other effective inorganic salt is then injected into the resin fluid saturated formation to open flow paths within the portion of the formation invaded by the polymerizable resin fluid. The well is shut in for sufficient period of time for polymerization to convert the injected fluids into a permeable barrier around the wellbore.

Our invention pertains to a method of treating an oil well completed in an oil containing consolidated limestone or dolomite formation, to form a fluid impermeable barrier in the formation some distance from the oil well. The barrier may be a cone or pancake shaped barrier below the perforation to prevent bottom water coning, or a cylindrical barrier may be formed opposite portions of the well perforations. An aqueous hydrcarbon emulsion treating fluid is used which comprises a hydrocarbon, water and surfactant, whose pH is in the rqnge of from 2 to 6 and preferably adjusted to a level determined experimentally to cause precipitation of hydrocarbon after exposure to the formation from 7 to 14 days. First the emulsion and then the displacement fluid are injected into the formation at a predetermined injection rate which causes the polyvalent metal ions to be extracted from said formation and accumulated in the treating fluid at a controlled rate. The level of polyvalent metal ions in the treating fluid reaches a critical concentration for precipitating hydrocarbon from the treating fluid after the treating fluid has been displaced away from the wellbore to the desired location.

Method for forming a barrier to fluid flow in an oil formation adjacent

Disclosed is a method for controlling sand flow in an producing well by forming a permeable consolidated gravel pack. Gravel is coated with a resin such as an oligomer of furfuryl alcohol containing an ester and as a catalyst an oil soluble, slightly water soluble organic acid such as anthranilic acid. The resin coated gravel is suspended in a carrier fluid comprising saturated brine and optionally a viscosity increasing polymer. The fluid comprising resin coated gravel and the carrier fluid are pumped through the well into the formation adjacent to the producing well. Heat or pressure cause joining of adjacent coated gravel to form the consolidated gravel pack.

Consolidatable gravel pack method

Hydrocarbons may be recovered from subterranean oil shale deposits by penetrating the deposit with a well, applying hydraulic and/or explosive fracturing to the portion of the formation adjacent the well to form a zone of rubberized and/or fractured oil shale material and then introducing it to the treated portion of the formation a hydrogen doner solvent, preferably tetralin, in a sufficient volume to essentially fill all of the void spaces in the formation within the rubberized and fractured portion of the formation, and then applying hydrogen to the well and maintaining the hydrogen at a pressure range of from 50 to 500 and preferably from 250 to 350 pounds per square inch for a period of time in the range of from 50 to 600 and preferably 250 to 350 days, which causes a disintegration of the oil shale minerals. After this first stage pretreatment, the hydrogen is removed and a free-oxygen containing gas such as air is introduced into the pretreated portion of the oil shale deposit which removes organic fragments from the polymeric kerogen component of the oil shale by oxidative scission. A suitable solvent for the organic fragments is also present with the free oxygen containing gas. Fluids are recovered from the formation, since fluids including solvent and the organic fractions, which are separated by sublimation with the solvent being recycled.

In situ method for recovering hydrocarbon from subterranean oil shale

Hydrocarbons may be recovered from crushed oil shale by contacting the coarsely crushed oil shale material with a hydrogen doner solvent such as tetralin, alone or in combination with high pressure gaseous hydrogen for a period of time sufficient to cause disintegration of the oil shale lumps, after which the pretreated material is introduced into a vessel containing a free oxygen containing gas such as air in a fluid environment at a temperature range from 30.degree. to 43.degree. C. to remove organic fragments from the polymeric kerogen component of oil shale by oxidative scissions. The oxidation is conducted using a liquid phase solvent for the organic fractions removed from the kerogen. Preferred solvents are naphthalene, tetralin and phenanthracene. The solvent-organic fraction solution is then separated into solvent and organic fraction by sublimation with the solvent being recycled. The residual solids comprising oil shale material and unoxidized kerogen is then subjected to a bake-off to recover additional organic material from the kerogen. In addition to recovering a portion of the organic content from the kerogen, the oxidative scission reaction increases the susceptibility of the kerogen to recovery by pyrolysis under milder conditions than the unoxidized oil shale material. The pyrolysis is conducted at a temperature from 400.degree. F. to 750.degree. F. for a time period up to 2 hours.

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Houston, TX, United States of America

Robert H Friedman