Abstract: Methods and compositions for sealing subterranean zones having temperatures in the range of from about 80° F. to about 300°F. are provided. A method of the invention is basically comprised of the steps of providing a subterranean zone sealing composition that becomes substantially rigid when exposed to subterranean zone temperatures above about 80° F. and has a pH above about 8.5 comprised of water, a substantially fully hydrated depolymerized polymer and a cross-linking agent. The sealing composition is introduced into the subterranean zone whereby it becomes rigid and seals the zone. The sealing composition can subsequently be removed by contact with a fluid having a pH below about 8 when a boron compound is utilized as the cross-linking agent.

Abstract: A method of sealing casing or liners in a wellbore is described. The stands of casing or liner receive a jacket bonded to the outer surface. Preferably, the jacket is a rubber compound bonded to the outer wall. The formulation responds to well fluids to swell at a predetermined rate. The casing or liner can also be expanded with a swage preferably prior to the onset of significant jacket swelling. Packers and sealing hangers can be optionally added at the extremes of the casing or liner string to further secure against channeling between adjacent formations.

Abstract: A method is provided for reducing loss of drilling fluid and for stabilizing a wellbore during drilling through depleted sands in a subterranean formation comprising depleted sands. The method comprises introducing into said wellbore and into said depleted sands an aqueous fluid comprising silicate or siliconate and resilient graphitic carbon in an amount effective at substantially plugging pores in said depleted sands.

Abstract: This patent relates to a process whereby two, or more, filter/sieves or water blockages are produced by injecting the interactive chemicals used to form gels and polymers at reservoir temperatures independently and sequentially into a well in such a manner that the chemicals only come into contact with each other at the desired depth of penetration in the formation. At this location in the reservoir, which can be determined by appropriate calculation, the injection is stopped and the intermixed and superimposed chemicals are allowed to react to form the filter/sieves of a gel or polymer depending upon the nature of the individual chemicals injected.

Abstract: The present invention generally relates to compositions of matter and methods of using those compositions. More particularly, and as part of one of the preferred embodiments, the present invention relates to compositions and methods of use of fluids useful for sealing formation fractures and/or inhibiting downhole fluid loss. The present invention is useful as a pill or series of pills that can be formulated and spotted to a particular formation zone.

Abstract: The present invention relates to a wellbore fluid comprising a particulate material composed of the reaction product of A) one or more water soluble organic compound having possessing a molecular weight of less than 30,000 and possessing at least two hydroxyl groups and B) any other organic compound(s) capable of forming acetal or hemiacetal cross-links with the hydroxyl groups of compound A. The invention relates also to the specific particulate material itself and to applications of the wellbore fluid of the invention for well processes such as drilling, under-reaming, completing, working over, sealing loss zones, sealing fractures, sealing cavities or other very high permeability conduits in a rock formation, or hydraulic fracturing to stimulate a hydrocarbon-producing zone.

Abstract: Methods of cementing in subterranean zones, improved cement compositions and improved additives are provided. The compositions are basically comprised of a hydraulic cement, sufficient water to form a slurry and an additive for providing improved rheology, fluid loss control and set retardation comprised of carboxymethylhydroxyethylcellulose having in the range of from about 0.62 to about 2.21 moles of hydroxyethyl substitution and in the range of from about 0.44 to about 0.52 degrees of carboxymethyl substitution and a 2% by weight aqueous solution of the carboxymethylhydroxyethylcellulose has a Höppler viscosity in the range of from about 55 mPa.s to about 359 mPa.s.

Abstract: Methods of cementing in wellbores using cement compositions having elasticity or high compressive strength and low permeability are provided. The cement compositions are basically comprised of particulate acid degradable glass, water, at least one water soluble polymerizable alkenoic acid monomer and a water soluble free-radical initiator.

Abstract: Methods of forming permeable sand screens in long, open hole well bores within fluid producing zones are provided. The methods basically comprise the steps of placing a perforated pipe in the open hole well bore, providing a hardenable composition which after being placed in a desired location cures into a hard mass, placing the hardenable composition in the well bore adjacent to the fluid producing zone within the interior of the perforated pipe therein, between the perforated pipe and the walls of the open hole well bore and within voids or fractures in the producing zone, causing the hardenable composition to cure into a hard permeable mass and drilling the hard permeable mass out of the interior of the perforated pipe.

Abstract: Compositions and methods are provided for reducing the permeability of subterranean zones. More particularly, water-soluble polymeric compositions which form cross-linked gels in the zones. In general, the composition comprises (a) at least one water-soluble polymer; (b) at least one organic gelling agent capable of cross-linking the water-soluble polymer; and (c) at least one water-soluble formate. More preferably, the water-soluble polymer is a copolymer of (i) at least one non-acidic ethylenically unsaturated polar monomer, and (ii) at least one copolymerisable ethylenically unsaturated ester. The gelling agent is preferably selected from the group consisting of a polyalkyleneimine, polyfunctional aliphatic amine, an aralkylamine, and a heteroaralkylamine. The preferred water-soluble formate is selected from the group consisting of ammonium formate, lithium formate, sodium formate, potassium formate, rubidium formate, cesium formate, and francium formate.

Abstract: Methods of reducing the water permeability of a water producing zone in a subterranean formation are provided. The methods basically comprise introducing a polymeric surfactant and an inert gas into the water producing zone to thereby form a water permeability reducing foam therein. The polymeric surfactant has the property of facilitating the formation of the foam and the additional property of stabilizing the foam in the presence of flowing formation water.

Abstract: A novel microorganism producing a nontoxic, non-antigenic exopolysaccharide is taught. The exopolysaccharide has neutral sugars migrating at the same rate as mannose, fucose, fructose and galactose, acidic sugars migrating at the same rate as fucose and amine sugars migrating at the same rate as glucose and fucose, and wherein the ratio of galactose:fucose:glucose:mannose is about 1:2:3:6. The microbe and the exopolysaccharide have uses as a biofilm in geologic applications and have several consumer uses as food and drug polymers and use as a plasma extender.

Abstract: For well plug treatment to plug an abandoned well, a well plug additive including a dry mixture of water soluble crosslinkable polymer, a crosslinking agent, and filter aid, and optionally, a reinforcing material preferably of fibers and/or comminuted plant materials. The method of forming a well plug fluid includes contacting the additive with water or an aqueous solution, with a method of plugging the well further including the step of injecting the fluid into the wellbore.

Abstract: For conformance treatment to plug an opening in subterranean hydrocarbon bearing formation, a conformance additive including water soluble crosslinkable polymer, a crosslinking agent, a filter aid that is preferably diatomaceous earth, and optionally a reinforcing material. The method of forming a conformance fluid includes contacting the additive with water or an aqueous solution, with a method of conforming the formation further including the step of injecting the fluid into the formation to plug the opening.

Abstract: The present invention provides methods of cementing subterranean zones penetrated by well bores using biodegradable dispersants. A cement composition of the invention comprises a hydraulic cement, sufficient water to form a slurry and a water soluble biodegradable cement dispersant comprising a polyamide graft copolymer containing at least o e side chain formed from aldehydes and sulfur-containing acids or their salts.

Abstract: Low concentrations, 1-10% of potassium salt, especially potassium formate, are used in a drilling fluid in oil production. Preferably they are used with guar derivatives, most preferably carboxymethyl hydroxypropyl guar. The concentration of potassium formate is maintained at the desired level by adjusting the potassium formate to maintain a desired Zeta potential in the circulating drilling fluid. The potassium formate/guar derivative composition may be used in the substantial absence of hydrophilic clay additive.

Abstract: The present invention provides methods of treating subterranean zones penetrated by well bores wherein the static temperatures of the zones are as high as 400° F. and greater. The aqueous treating fluids are basically comprised of an aqueous liquid containing one or more inorganic monovalent salts, multivalent salts or both in an amount no greater than about 5% by weight of said aqueous liquid and one or more synthetic hectorite clay gelling and thixotropy imparting agents selected from the group of a synthetic hectorite clay having the composition by weight on a dry basis of 59.5% SiO2, 27.5% MgO, 0.8% Li2O and 2.8% Na2O, a synthetic hectorite clay having the composition by weight on a dry basis of 54.5% SiO2, 26.0% MgO, 0.8% Li2O, 5.6% Na2O and 4.1% P2O5 and a synthetic hectorite clay having the composition by weight on a dry basis of 54.5% SiO2, 26.0% MgO, 0.8% LiO2, 5.6% Na2O, 4.1% P2O5 and also containing inorganic polyphosphate peptizers.

Abstract: The present invention generally relates to compositions of matter and methods of using those compositions. More particularly, and as part of one of the preferred embodiments, the present invention relates to compositions and methods of use of fluids useful for sealing formation fractures and/or inhibiting downhole fluid loss. The present invention is useful as a pill or series of pills that can be formulated and spotted to a particular formation zone.

Abstract: The improved recovery of hydrocarbons from subterranean formations by hydraulically fracturing a subterranean formation is accomplished. Fracturing fluids using a viscosifying surfactant fluid containing viscosifying micelles, for example, wormlike micelles, are useful to improve recovery of hydrocarbons and limit the loss of fracturing fluid into the formation fracture face. The invention further relates to novel fracturing and acidizing methods useful for increasing hydrocarbon production, limiting water production, resisting fracturing fluid loss into the subterranean formation, and reducing the equipment requirements in mixing and pumping fracturing fluid. The action of viscosifying micelles of surfactant in aqueous zones of the subterranean formation diverts fracturing fluid or acid from the aqueous zones to the hydrocarbon-bearing zones and also facilitates the flowback of increased amounts of hydrocarbons once a fractured well is placed back on production.

Abstract: The invention relates to a cement slurry for cementing an oil well or the like, the slurry having a density lying in the range 0.9 g/cm3 to 1.3 g/cm3, and being constituted by a solid fraction and a liquid fraction, having porosity (volume ratio of liquid fraction over solid fraction) lying in the range 38% to 50%. The solid fraction is constitued by a mixture of lightweight particles, microcement and optionally portland cement and gypsum. Such cements have remarkable mechanical properties due to their very low porosity in spite of having very low density.

Abstract: This patent relates to a method for re-establishing oil and/or gas production from an underground formation from a well that has experienced water breakthrough, the method comprising: injecting a first carrier fluid containing a reactive chemical into the well; injecting a spacer fluid into the well; injecting a gel or polymer progenitor fluid into the well, wherein the reactive chemical fluid is injected before or after the progenitor fluid and the spacer is injected between the injections of the reactive chemical fluid and progenitor fluid, and re-establishing oil and/or gas production from the well.

Abstract: Disclosed is a method and gellable composition for decreasing the loss of fluid during well drilling or servicing operations. The gellable composition comprises a superabsorbent polymer in an acidic aqueous liquid in which the superabsorbent is not swellable. Preferably the gellable composition also contains a viscosifier, preferably chitosan. The method is practiced by forming the gellable composition, placing it at the location of fluid loss in a well, and mixing it with a basic aqueous liquid to raise the pH and thus allow the superabsorbent to expand in volume. Advantageously, the superabsorbent, chitosan, and an acid, preferably a solid acid, preferably sulfamic acid, are admixed to form an additive for preparing the gellable composition.

Abstract: An improved composition and method is provided for preventing or alleviating lost circulation during the drilling of wellbores in subterranean formations, and particularly during the drilling of oil and gas wells. The method is suited for horizontal and directional wells as well as more vertical wells. The composition of the invention comprises a synergistic blend of resilient, angular, carbon-based material and a water-swellable, crystalline synthetic polymer. The method employs the composition of the invention in preventing lost circulation.

Abstract: The present invention provides improved compositions and methods for sealing pipe in a well bore. The compositions which harden into highly resilient solid masses having high strengths are basically comprised of a hydraulic cement, an aqueous rubber latex, an aqueous rubber latex stabilizing surfactant and silica hydrophobicized with silicon oil.

Abstract: This invention discloses methods for reducing lost circulation in wellbores. The invention utilizes certain selected water swellable polymers that swell at a rate slow enough to reach the lost circulation zone of a well before those polymers have swollen to an extent that disrupts the drilling process. These selected polymers may be used alone or in conjunction with other lost circulation materials which do not swell or also swell slowly enough to reach the lost circulation zone without interfering with the drilling operation. Mixtures of such materials are also disclosed.

Abstract: The present invention provides oil based compositions and methods of using the compositions for temporarily sealing subterranean zones. The compositions are basically comprised of oil, a hydratable polymer, an organophilic clay, a water-swellable clay, and an acid soluble material such as calcium carbonate. These compositions will form a viscous gel when contacted with water. The gelled mass may then be dissolved with an acidic fluid, such as 15% hydrochloric acid.

Abstract: A plugging fluid for plugging a subterranean formation zone surrounding a drill hole comprises an emulsion comprising a dispersed aqueous phase containing an aqueous base and a continuous hydrophobic phase containing a polymer consisting of a grafted cellulose ether derivative, a surfactant and a crosslinking activator of the polymer. The polymer is preferably 2-hydroxyethyl cellulose grafted with vinyl phosphonic acid. Upon shearing, preferably through the drilling bit, the emulsion inverts so that the rupture of the emulsion droplets releases the crosslinking activator into the water phase thus forming a gel structure.

Abstract: A plugging fluid for plugging a subterranean formation zone surrounding a drill hole comprises an emulsion comprising a dispersed aqueous phase containing an aqueous base and a continuous hydrophobic phase containing a polymer consisting of a grafted cellulose ether derivative, a surfactant and a crosslinking activator of the polymer. The polymer is preferably 2-hydroxyethyl cellulose grafted with vinyl phosphonic acid. Upon shearing, preferably through the drilling bit, the emulsion inverts so that the rupture of the emulsion droplets releases the crosslinking activator into the water phase thus forming a gel structure.

Abstract: The present invention provides stable well cementing methods and compositions for sealing subterranean zones penetrated by well bores. The improved thermally stable and degradation resistant well cement compositions are basically comprised of a hydraulic cement, sufficient water to form a pumpable slurry, an aqueous hydrogenated styrene-butadiene rubber latex and a latex stabilizer present in an amount sufficient to stabilize the hydrogenated styrene-butadiene latex.

Abstract: A water shut-off is provided in a hydrocarbon well by injecting a first chemical composition, effective as a relative permeability modifier polymer, into the hydrocarbon and a water zone of the well followed immediately by the injection of a second chemical composition, which forms a flow blocking polymer composition, into the zones and, after a shut-in period for reaction of the relative permeability modifier polymer, back producing the polymer compositions from they hydrocarbon zones to provide a path for the hydrocarbons from the zones while allowing the flow blocking polymer compositions to form the water shut-off in the water zones.

Abstract: A method is disclosed for consolidating an unconsolidated formation, which method includes the steps of providing a well drilled to an unconsolidated formation, providing a consolidation fluid in the form of a fluid suspension of nanoparticles, and flowing said consolidation fluid through the well and into the unconsolidated formation so as to position the nanoparticles between grains of the unconsolidated formation whereby the formation is consolidated over time.

Abstract: Clay is stabilized in the drilling of wells and other formation treatment for hydrocarbon production by the addition to the drilling or other fluid fluid of potassium formate together with a cationic formation control additive.

Abstract: This patent application relates to a process whereby a filter/sieve is produced by injecting the interactive chemicals used to form gels and polymers at reservoir temperatures independently and sequentially into a well in such a manner that the chemicals only come into contact with each other at the desired depth of penetration in the formation. At this location in the reservoir, which can be determined by appropriate calculation, the injection is stopped and the intermixed and superimposed chemicals are allowed to react to form the filter/sieve of a gel or polymer depending upon the nature of the individual chemicals injected.

Abstract: Improved well cement additives, compositions and methods of using the compositions are provided. The well cement additives are basically comprised of a first monomer selected from the group of 2-acrylamido-2-methylpropane sulfonic acid, 2-allyloxy-2-hydroxy-1-propane sulfonic acid and vinylsulfonic acid, a second monomer selected from the group of N,N-dimethylacrylamide, acrylamide, N-vinylpyrrolidone, N-vinylacetamide and acrylonitrile and a third monomer selected from the group of C6 to C22 dimethylaminopropylmethacrylamide bromide, chloride and iodide and C6 to C22 dimethylaminoethylmethacrylate bromide, chloride and iodide.

Abstract: A well fracturing fluid comprising one or more anionic viscoelastic surfactants and one or more polymers is described. The fluids can contain an aqueous or non-aqueous fluid and/or a buffer for adjusting the pH of the fracturing fluid. The well service fluid can be used as a fracturing fluid in order to control water production from a well, while simultaneously increasing the oil production from the well.

Abstract: The present invention provides methods of cementing subterranean zones using cement compositions comprising calcium aluminate, fly ash, sodium polyphosphate and water.

Abstract: Clay is stabilized in the drilling of wells for hydrocarbon production by the addition to the drilling fluid of potassium formate together with an amount of guar effective to inhibit clay and shale swelling and sloughing.

Abstract: This patent relates to a process whereby a filter/seive is produced by injecting the interactive chemicals used to form gels and polymers at reservoir temperatures independently and sequentially into a well in such a manner that the chemicals only come into contact with each other at the desired depth of penetration in the formation. At this location in the reservoir, which can be determined by appropriate calculation, the injection is stopped and the intermixed and superimposed chemicals are allowed to react to form the filter/seive of a gel or polymer depending upon the nature of the individual chemicals injected.

Abstract: The invention provides a method and fluid for drilling or servicing a well in a subterranean formation, particularly containing lost circulation zones or depleted, low pressure reservoirs. A method of decreasing the density of the fluid circulated in a borehole, decreasing the invasion of fluid into formations contacted by the fluid, or decreasing the lost circulation potential of the fluid is provided by using as the fluid an aqueous liquid having dispersed therein a polymer which increases the low shear rate viscosity of the fluid to the extent that the shear thinning index of the fluid is at least about 10, a surfactant, and aphrons, wherein the aphrons are preferably generated by the turbulence and pressure drop as the fluid exits the drill bit in the vicinity of the formation, the fluid having a low shear rate viscosity of at least 40,000 centipoise.

Abstract: Environmentally acceptable well cement fluid loss control additives, cement compositions including the additives and methods of using the compositions are provided. The environmentally acceptable fluid loss control additives are comprised of ethoxylated hydroxyethylcellulose having a reduced molecular weight.

Abstract: A degradable compound, which may be used as a ball sealer and as an fluid loss additive for use in the oil and gas industry is disclosed. The compound comprises a particular composition of matter and injection molding technique that provides a ball sealer which will dissolve in stimulation or wellbore fluids after stimulation operations are complete. In a similar manner the compound may be used as a fluid loss additive which enhances the fracture filter cake and will dissolve completely after use in fracturing operations. Used as a ball sealer, the surface of the ball sealer softens slightly assuring a solid seal between the ball and the casing perforation. The pure composition when dissolved into wellbore fluids does not pose a hazard and has excellent dispersion in aqueous based wellbore fluids. The same composition, may be combined with fiber-glass to manufacture a high temperature ball sealer.

Abstract: A method for treating a subterranean sand formation adjacent to a bore hole forms a permeable solid barrier which restrains the movement of sand particles while maintaining the permeability of the formation. The method includes the step of forming a consolidation fluid containing an asphaltene and a hydrocarbon solvent such as naphtha or reformate with a concentration of between about 40-80 grams of asphaltene per 100 ml of solvent. The consolidation fluid is injected into the sand formation to saturate the sand in a zone around the bore hole for a distance of 1 to 2 feet. This is followed by injecting an oxygen-containing gas at a temperature of between about 100° C. to about 150° C. for a period of time of between about 24 to about 72 hours. In one embodiment of the invention, the oxygen concentration of the effluent gas is monitored and the injection of oxygen-containing gas is continued until he oxygen concentration of the effluent gas is equal to the oxygen concentration of the injected gas.

Abstract: A settable thixotropic material comprises a thixotrope and a settable substance, the material being capable of gelling reversibly in a gelling time of less than 60 seconds. The thixotrope conveniently comprises a fine grained clay, especially smectite clays, e.g. hectorites. It is preferred to use synthetic smectite type clay colloids, and goods results have been obtained with the synthetic clay known as Laponite RDS. The settable material conveniently comprises cement, particularly Portland cement. The thixotropic material finds use generally in oilwell applications, e.g. to plug lost circulation zones, to repair damaged or corroded casing, as grouts, and to limit annular gas migration. The material also finds particular application in techniques for completion of horizontal wells completed with slotted or pre-drilled liners.

Abstract: A method for strengthening a subterranean formation by injecting an aqueous gellable composition containing a cross-linkable polymer into the subterranean formation through a wellbore to increase the strength of the subterranean formation while retaining the ability of the subterranean formation to produce fluids.

Abstract: Aluminum silicate and/or fibrous mineral-containing cement compositions for cementing wellbores in high stress environments, such as for cementing multi-lateral completions. The cement compositions typically comprise a mixture of a reactive aluminum silicate and/or fibrous mineral such as wollastonite, and may include one or more other additives. The cement compositions may be used to produce set cements offering improved compressive strength, flexural strength, and/or tensile strength over conventional cement compositions.

Abstract: Apparatus for use in operations performed in conjunction with a subterranean well is provided by the present invention. In one described embodiment, a plug apparatus includes a soluble polymer material, which is utilized in a plug member for blocking flow through a fluid passage. In another described embodiment, a soluble polymer material is utilized in a blocking member for blocking displacement of a displacement member of an apparatus.

Abstract: Method for carrying out well construction, repair and/or abandonment operations using an addition-curing silicone formulation, in particular for forming a permanent plug in a well bore or in one or more subterranean formations penetrated by the well bore by placing a mixture of cement and an addition-curing silicone formulation in the one or more subterranean formations or in the well bore at a desired location therein or placing an addition-curing silicone formulation on top of an existing non-gas tight plug and allowing the silicone formulation to set thereby producing a gas tight plug.

Abstract: The present invention provides methods of sealing subterranean zones using high density sealing compositions. The methods are basically comprised of introducing a sealing composition into the subterranean zone comprised of a high density aqueous salt solution, a polymerizable monomer and a polymerizable initiator and allowing said sealing composition to form a sealing gel in said zone.

Abstract: A composition and uses of said composition are described for a latex based setting system for remedial and other operations within a wit bore. The composition comprises a pH-reducing agent and/or a coagulant. By controlling the amount of agent, the setting time of the system can be controlled in a range of 0.5 h to 15 h.

Abstract: The present invention provides improved methods of sealing a subterranean zone to remedy the uncontrolled flow of fluids into and out of the zone. The methods basically comprise preparing a sealing composition and placing the composition into the zone to be sealed. The placement of the composition is controlled in a manner whereby portions of the sealing composition are continuously converted to sealing masses which are successively diverted into permeable portions of the zone until all of the permeable portions are sealed.