Abstract: Methods of consolidating formations include drilling a well bore with a drilling fluid that comprises water, a polymeric cationic catalyst which is adsorbed on minerals and rocks in weak unconsolidated zones or formations and then further contacting the unconsolidated formation with a treating fluid comprising a water soluble or dispersible polymer which is cross-linked by a thermoset resin and causes the resin to be hard and tough when cured, and a water soluble or dispersible thermoset resin which cross-links the polymer, is catalyzed and cured by the catalyst and consolidates the weak zone or formation so that sloughing is prevented.

Abstract: A dense drilling fluid additive used to control lost circulation, fluid loss and/or seepage loss of drilling fluid during drilling operations is disclosed. Such additive is formed from ground base materials, such as inorganic matter, and may be used to manage the rheological properties of drilling fluid.

Abstract: Methods of consolidating unconsolidated weak zones or formations and forming chemical casings include drilling a well bore with a drilling fluid having a pH in the range of from about 6 to 10 and that comprises water, a polymeric cationic catalyst which is adsorbed on the mineral surfaces in the weak zone, a particulate curable solid thermoset resin and a delay acid catalyst for curing the solid resin, and forming a filter cake on the walls of the well bore. The filter cake is then contacted with a treating fluid comprising a water soluble or water dispersible polymer which is capable of being cross-linked by a thermoset resin and causing the resin to be hard and tough when cured, and a water soluble or dispersible thermoset resin, whereby the treating fluid components deposit on the filter cake and the thermoset resin cures into a hard and tough cross-linked chemical casing thereon.

Abstract: A method for drilling a borehole employing a drilling fluid including an additive comprising a glucose derivative with pH lowering acid, buffers and surface active agents. The drilling fluid additive preferably exhibits the following properties: activity of approximately 30%-45% in water solution; pH of about 4.5 to 5.5; a light amber to clear liquid appearance and a density of approximately 1.200 grams per cubic centimeter.

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 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: Methods and compositions for wellbore treating fluids, especially settable spotting fluids, that include zeolite and at least one carrier fluid.

Abstract: Zeolite compositions having enhanced compressive strength and methods therefor are provided. In particular, methods and compositions for wellbore treating fluids, especially settable spotting fluids having enhanced compressive strength are provided.

Abstract: The present invention provides a well treatment fluid containing water, a amine-based polymer, and an oxidized polysaccharide-based polymer. The oxidized polysaccharide-based polymer is able to crosslink with the amine-based polymer and produce a gel having a viscosity of greater than about 20 cp, measured at a pH of about 4 to about 7 and at STP. The present invention also provides a method of treating a subterranean formation penetrated by a wellbore comprising the steps of: (a) forming the well treatment fluid, and (b) contacting the subterranean formation with the fluid.

Abstract: High fluid loss acid soluble lost circulation material and spotting pill comprising the lost circulation material. The spotting pill preferably is weighted to a density substantially the same as the drilling fluid used to treat the formation.

Abstract: The current invention provides methods of using and drilling and servicing fluid compositions for depositing and removing filter cake from the walls of a well bore. The compositions make use of particulate solid bridging agent comprised of a salt of an organic acid. The bridging particles are dissolvable by a clean-up solution comprised of a mild solvent that is less corrosive than the conventional strong mineral acids used for this purpose.

Abstract: A composition for sealing porous subterranean formations comprises a mixture of a water-swellable clay and a water insoluble, water absorbent, water-swellable polymer, wherein the mixture is coated with a material that is resistant to penetration by water. The water penetration resistant material helps the delay the onset of swelling of the clay and polymer until it reaches the formations intended for sealing. Mixing the clay with the water-swellable polymer prior to coating assists in coating of the water-swellable polymer with the water penetration resistant material. The coated mixture can be suspended in an aqueous liquid, and then pumped into a subterranean cavity to seal porous formations therein.

Abstract: The invention provides a method and fluid for drilling or servicing a well in a subterranean formation containing lost circulation zones or depleted, low pressure reservoirs. The fluid comprises an aqueous liquid having dispersed therein a viscosifier which increases the low shear rate viscosity of the fluid to at least 10,000 centipoise, an aphron-generating surfactant, and aphrons, wherein the fluid contains less than about 20% by volume of aphrons preferably generated by the turbulence and pressure drop as the fluid exits the drill bit in the vicinity of the formation. The method of drilling a wellbore in a subterranean formation comprises continuously re-circulating, while drilling, such a drilling fluid.

Abstract: Methods of drilling and completing open hole well bores and methods of removing filter cake comprised of a gelling agent and calcium carbonate are provided. A method of the invention for removing filter cake comprised of a gelling agent and calcium carbonate from the walls of an open hole well bore is basically comprised of the steps of contacting the filter cake with a delayed clean-up solution comprised of water and a formate ester and removing the clean-up solution from the well bore.

Abstract: A method for preventing loss of drilling fluid into fractures in the rock formation being drilled includes using coconut coir as a lost circulation material. Additionally, an effective mixture for reducing drilling fluid loss includes drilling fluid and coconut coir. Other lost circulation materials can also be added.

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: Methods of forming chemical casings include drilling a well bore with a drilling fluid having a pH in the range of from about 6 to 10 and comprising water, a water soluble or water dispersible polymer which is capable of being cross-linked by a thermoset resin and causing the resin to be hard and tough when cured, a particulate curable solid thermoset resin, a water soluble or dispersible thermoset resin, and a delayed dispersible acid-catalyst for curing the solid thermoset resin and the water soluble thermoset resin, whereby the drilling fluid forms a filter cake on the walls of the wellbore that cures into a hard and tough cross-linked chemical casing thereon.

Abstract: A method of drilling sub-sea oil and gas production wells in which a liquid hydrocarbon substance, such as a natural gas liquid, is injected into the drilling mud supplied to the well in order to reduce the mud density. The method of the present invention enables reduction and control of the hydraulic pressure of the drilling mud while drilling production wells in deep water, thereby to require fewer casing runs which eventually yields better oil productivity.

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: This invention relates to a low toxicity drilling mud oil. In some embodiments, the fluid loss characteristic of the drilling mud oil as used in a borehole can be reduced to less than 0.2 ml/30 minutes by adding about 0.05% to about 2.0% by weight of a butadiene-styrene-butadiene (BSB) block copolymer having about 20% by weight or more styrene.

Abstract: Methods of consolidating formations include drilling a well bore with a drilling fluid that comprises water, a polymeric cationic catalyst which is adsorbed on minerals and rocks in weak unconsolidated zones or formations and then further contacting the unconsolidated formation with a treating fluid comprising a water soluble or dispersible polymer which is cross-linked by a thermoset resin and causes the resin to be hard and tough when cured, and a water soluble or dispersible thermoset resin which cross-links the polymer, is catalyzed and cured by the catalyst and consolidates the weak zone or formation so that sloughing is prevented.

Abstract: Methods of consolidating unconsolidated weak zones or formations and forming chemical casings include drilling a well bore with a drilling fluid having a pH in the range of from about 6 to 10 and that comprises water, a polymeric cationic catalyst which is adsorbed on the mineral surfaces in the weak zone, a particulate curable solid thermoset resin and a delay acid catalyst for curing the solid resin, and forming a filter cake on the walls of the well bore. The filter cake is then contacted with a treating fluid comprising a water soluble or water dispersible polymer which is capable of being crosslinked by a thermoset resin and causing the resin to be hard and tough when cured, and a water soluble or dispersible thermoset resin, whereby the treating fluid components deposit on the filter cake and the thermoset resin cures into a hard and tough cross-linked chemical casing thereon.

Abstract: The use of polymer latices is described for fluid loss control in water-based drilling fluids. The latices used are water insoluble. The latices are essentially non-swelling in an aqueous solution. The latices are selected from known latices such that they are absorbed within a filter cake building up at the interface between the wellbore and porous formations in essentially the same state as they are in the aqueous drilling fluid during circulation.

Abstract: Improved methods of generating gas in and foaming aqueous well fluids introduced into a subterranean zone are provided. A method of the invention includes the steps of combining with an alkaline aqueous well fluid one or more gas generating chemicals and a mixture of foaming and foaming stabilizing surfactants so that the gas generating chemical or chemicals react with the alkaline aqueous well fluid and gas and foam are formed in the well fluid while it is being pumped, and then pumping the well fluid into the subterranean zone.

Abstract: The invention provides a method and fluid for drilling or servicing a well in a subterranean formation containing lost circulation zones or depleted, low pressure reservoirs. The fluid comprises an aqueous liquid having dispersed therein a polymer which increases the low shear rate viscosity of the fluid to the extent that the thixotropic index of the fluid is at least about 10 and a surfactant, and wherein the fluid contains less than about 15% by volume of aphrons preferably generated by the turbulence and pressure drop as the fluid exits the drill bit in the vicinity of the formation. The method of drilling a wellbore in a subterranean formation comprises continuously circulating, while drilling, such a drilling fluid.

Abstract: Methods of consolidating formations or forming chemical casing or both while drilling are provided. One method of the invention comprises drilling a well bore with a drilling fluid comprised of water, a polymeric cationic catalyst which is adsorbed on weak zones or formations formed of unconsolidated clays, shale, sand stone and the like, a water soluble or dispersible polymer which is cross-linked by a thermoset resin and causes the resin to be hard and tough when cured, a particulate curable solid thermoset resin, a water soluble thermoset resin, and a delayed dispersible acid catalyst for curing the solid and water soluble resins. The drilling fluid forms a filter cake on the walls of the well bore that cures and consolidates the unconsolidated weak zones and formations penetrated by the well bore so that sloughing is prevented and forms a hard and tough cross-linked chemical casing on the walls of the well bore.

Abstract: A method for removing filter cake from a subterranean borehole comprising drilling the borehole with a drilling fluid that includes additives to form a filter cake having an oxidation-degradable component, preferably a polysaccharide. The filter cake is contacted with a clear brine containing a mixture of a persulfate salt in a variable density brine to degrade the polymers within the filter cake. The persulfate mixture breaks down the filter cake in well bores having temperatures ranging from about 65° F. to 165° F. Concentration of the persulfate sets the pace of the reaction.

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: 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: A method is disclosed that affords improved stability to wellbores during drilling in argillaceous formations with water-based drilling fluids. The method comprises adding to the drilling fluid a compound of the invention having the capacity in water to generate a highly efficient membrane on argillaceous materials. The compound is soluble in the drilling fluid at least at the pH at which the compound is added to the drilling fluid or exists in the drilling fluid, but is insoluble in the water in the pores of the argillaceous formations, or at least at the pH of the water in such pores.

Abstract: Methods of consolidating formations or forming chemical casing or both while drilling are provided. One method of the invention comprises drilling a well bore with a drilling fluid comprised of water, a polymeric cationic catalyst which is adsorbed on weak zones or formations formed of unconsolidated clays, shale, sand stone and the like, a water soluble or dispersible polymer which is cross-linked by a thermoset resin and causes the resin to be hard and tough when cured, a particulate curable solid thermoset resin, a water soluble thermoset resin, and a delayed dispersible acid catalyst for curing the solid and water soluble resins. The drilling fluid forms a filter cake on the walls of the well bore that cures and consolidates the unconsolidated weak zones and formations penetrated by the well bore so that sloughing is prevented and forms a hard and tough cross-linked chemical casing on the walls of the well bore.

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: A product, system and method for treating a well bore using a concentrated treatment composition enclosed in a soluble container. The composition-filled container is deposited in the well, preferably through the drill string, followed by a solvent, such as drilling mud or water, to form a circulating solution characterized by the ability to circulate through the well. Most of the circulating solution is recovered at the surface using a mud tank, for example. In a well “sweeping” operation a partially hydrolyzed polyacrylamide powder in a soluble tube is dropped down the drill string. The well bore is then flushed with water or drilling mud to form the liquified polymer down hole. The well is flushed with more water or mud to sweep the cuttings and polymer solution from the well bore.

Abstract: The present invention provides drilling systems for drilling subsea wellbores. The drilling system includes a tubing that passes through a sea bottom wellhead and carries a drill bit. A drilling fluid system continuously supplies drilling fluid into the tubing, which discharges at the drill bit bottom and returns to the wellhead through an annulus between the tubing and the wellbore carrying the drill cuttings. A fluid return line extending from the wellhead equipment to the drilling vessel transports the returning fluid to the surface. In a riserless arrangement, the return fluid line is separate and spaced apart from the tubing. In a system using a riser, the return fluid line may be the riser or a separate line carried by the riser. The tubing may be coiled tubing with a drilling motor in the bottom hole assembly driving the drill bit.

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: Composition of water-based drilling fluids characterized in that they comprise an oil in water emulsion.

Abstract: An environmentally safe lost circulation material and method of use which provides effective drill bit lubrication over a wide temperature range and allows drilling in a variety of porous or fractured subterranean structures. The lost circulation material comprises generally pelletized cottonseed hulls together with between approximately 0.001% and 0.01% by weight of preservative. In another preferred embodiment of the invention, the lost circulation material comprises of between approximately 98% and 99.5% by weight of pelletized cottonseed hulls, between approximately 0.5% and 2.0% by weight of corn starch, between approximately 0.001% and 0.01% by weight of surfactant, and between approximately 0.001% and 0.01% by weight of preservative. In another preferred embodiment, the lost circulation material comprises between approximately 50% and 80% by weight of pelletized cottonseed hulls, between approximately 10% and 40% by weight of pelletized wood, between approximately 0.

Abstract: A water-base fluid for use in drilling wells and other drilling operation includes a shale which swells in the presence of water. The fluid preferably includes: an aqueous based continuous phase, and a shale hydration inhibition agent having the formula: H2N—R—{OR′}x—Y in which R and R′ are alkylene groups having 1 to 6 carbon atoms and x is a value from about 1 to about 25. The Y group should be an amine or alkoxy group, preferably a primary amine or a methoxy group. The shale hydration inhibition agent should be present in sufficient concentration to reduce the swelling of the shale. The fluid may be used for formulating drilling fluids such as invert emulsion drilling muds or clear brine drilling fluids. The fluid may also be used in the slurrification and disposal of drill cuttings that contain water swellable clays or shales.

Abstract: A water-base fluid for use in drilling wells and other drilling operation includes a shale clay which swells in the presence of water.

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: 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: A water-base drilling fluid for use in drilling wells through a formation containing a shale which swells in the presence of water.

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 invention is a novel drilling fluid additive comprising particles of elastomer which are capable of swelling upon contact with a hydrocarbon fluid. The swelling of the elastomer is gradual, allowing the elastomer to reach the lost circulation zone before significant swelling occurs. Once in the lost circulation zone, the polymer expands sealing off the lost circulation zone. A method for preventing drilling fluid loss is also provided.

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: Sulfonated uintaite is prepared by sulfonating a naturally occurring uintaite charge with a sulfonating agent such as sulfur trioxide, fuming sulfuric acid, chlorosulfonic acid, oleum, or concentrated sulfuric acid to produce sulfonic acids of uintaite. The resulting sulfonic acids are neutralized with a caustic neutralizing agent and sulfonated uintaite is the product. The sulfonated uintaite product is dried and packaged. The produced sulfonated uintaite is useful in oil and gas well working fluids (drilling muds). Neutralization of the resulting sulfonic acids with sodium hydroxide or ammonium hydroxide as the caustic neutralizing agent yields water and oil-soluble or dispersible salts of the sulfonated uintaite. Neutralization with Ca(OH)2 (calcium hydroxide) as the caustic neutralizing agent yields a product which is preferable in oil-based muds.

Abstract: A screen assembly and methods for using it, the screen assembly including, in certain aspects, at least two layers of screening material one on top of the other and including at least a first layer over a second layer, each layer having screen mesh with rectangular openings as viewed from above, the first layer having first rectangular openings, and the second layer having second rectangular openings, each of the first rectangular openings having a first width and a first length, and each of the second rectangular openings having a second width and a second length, the ratio of the first length to the first width ranging between 1.55 and 2.00, the ratio of the second length to the second width ranging between 1.55 and 2.00, the ratio of the first length to the second width ranging between 0.95 and 1.05, and the lengths of the first rectangular openings are parallel to lengths of the second rectangular openings.

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: The present invention provides improved compositions and methods of using the compositions for sealing subterranean zones. One composition of the invention is comprised of water, a silane coupling agent, an organophilic clay, an epoxy resin and a hardening agent for said epoxy resin.