Abstract: Methods for drilling, running casing in, and/or cementing a borehole in a subterranean formation without significant loss of drilling fluid are disclosed, as well as compositions for use in such methods. The methods employ drilling fluids comprising fragile gels or having fragile gel behavior and providing superior oil mud rheology and overall performance. The fluids are especially advantageous for use in offshore wells because the fluids exhibit minimal differences between downhole equivalent circulating densities and surface densities notwithstanding differences in drilling or penetration rates. When an ester and isomerized olefin blend is used for the base of the fluids, the fluids make environmentally acceptable and regulatory compliant invert emulsion drilling fluids.

Abstract: Water based drilling, drill-in, and completion fluids comprising surfactant-polymer blends that are effective to generate effective rheology comprising low shear rate viscosity and effective fluid loss control properties. The water based fluids preferably are substantially solid free.

Abstract: Drilling, completing or workover of a well, particularly an oil and/or gas well, is carried out using a fluid which includes a continuous phase including an ester of the formula (I): (R2)p-Ph-(CH2)m—COO-(AO)n—R1 where R1, AO, n, m, Ph, R2 and p have defined meanings and particularly where the esters are alkyl or alkenyl benzoate esters. These esters are beneficial by having a range of viscosities, especially extending to low viscosities, and attractive toxicological and environmental profiles for use in drilling, completion and/or workover of wells.

Abstract: This invention relates to a wellbore treatment fluid and a method of enhancing wellbore treatment fluids to increase efficiency and productivity of wells. More specifically this invention provides methods for enhancing the thermal stability of wellbore treatment fluids such as drill-in, completion, workover, packer, well treating, testing, spacer or hole abandonment fluids. The methods include providing a wellbore treatment fluid that comprises polyol, polysaccharide, weighting agent, and water, wherein the fluid is solids free.

Abstract: An additive which increases the density of wellbore fluids used during the construction or repair of oil, gas, injection, water or geothermal wells comprises solid colloidal particles of weight average particle diameter (D50) of less than 2 microns, the particles being deflocculated by the action of a dispersant, preferably incorporated during the process of grinding or communication of the particles to the specified particle size. The additives may be used in any wellbore fluid such as drilling, cementing, completion, packing, work-over (repairing), stimulation, well killing and spacer fluids as well as in a dense media separating fluid or in a ship's ballast fluid.

Abstract: Blends of synthetic olefins for use as the continuous phase of fluids selected from the group consisting of drilling, drill-in, and completion fluids. The blends meet EPA discharge requirements while also permitting investigators to clearly discern the presence and quantity of biological markers in reservoir fluid samples—particularly pristane and phytane.

Abstract: It has been discovered that biodegradable and non-toxic chelant compositions can perform multiple beneficial functions in an aqueous fracturing fluid through the chelation of ions. Some of the multiple functions include various combinations of the following: demulsifier, demulsifier enhancer, scale inhibitor, crosslink delay agent, crosslinked gel stabilizer, enzyme breaker stabilizer, and the like. Some of the chelants used in the compositions include, but are not necessarily limited to, sodium polyaspartate; sodium iminodisuccinate; disodium hydroxyethyleneiminodiacetate (Na2HEIDA); sodium gluconate; sodium glucoheptonate; sugar alcohols; monosaccharides; disaccharides; and mixtures thereof.

Abstract: A wellbore fluid including a peroxide degradable polymer and an encapsulated peroxide source. The peroxide degradable polymer may be a polysaccharide. The peroxide source may include an inorganic peroxide, including zinc and alkaline earth metal peroxides, such as magnesium peroxide. The encapsulating material may be a polymer, including enteric polymers. The release of peroxide, from peroxide sources generally, can be controlled by means of pH such that peroxide source can be activated, and peroxide released, by a change in pH. In a wellbore, this pH change can be effected by using produced fluids to lower the pH of a more basic wellbore fluid.

Abstract: Disclosed is a copolymer useful for preparing acid gels comprising a copolymer having a copolymer backbone, the copolymer having a general formula: 1

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: A method for treating a relatively permeable formation containing heavy hydrocarbons in situ may include providing heat from one or more heat sources to a portion of the formation. The heat may be allowed to transfer from the heat sources to a selected section of the formation. The transferred heat may pyrolyze at least some hydrocarbons within the selected section. A temperature proximate a selected portion of a heater well may be selectively limited to inhibit coke formation at or near the selected portion. A mixture of at least some hydrocarbons may be produced through the selected portion of the heater well.

Abstract: A method and composition is provided for sealing a subterranean zone penetrated by a well bore and restoring lost circulation, wherein the composition basically comprises a mixture of latex, melamine-formaldehyde resin, and a catalyst.

Abstract: An invert emulsion, in which the aqueous phase includes a low concentration of potassium formate, is used in well drilling. The low concentration of potassium formate may be maintained by monitoring the potassium level in the circulating drilling fluid and/or by intermittently measuring the water activity of the drilling fluid. As an emulsifier, a reaction product of tall oil and a fatty alkanolamide may be used, optionally with an additional reaction product of tall oil with an aminoethylpiperazine.

Abstract: The drilling mud with a lowered coefficient of friction comprising a silicate-based mud and a lubricant selected from the group comprising glycosides, alkylpolyalkoxyalcohols, alcohol ester polymers, amine phosphates, starch and combinations thereof.

Abstract: It has been discovered that certain fracturing fluid compositions can be used to fracture a subterranean formation and be permitted to stay within the formation for a relatively extended period of time, for example 28 days or more, before being flowed back or produced. At least two embodiments are envisioned, a bacteria-containing formulation and an anti-bacterial formulation. Both systems would be expected to prevent the potential of the fluid to oil wet the formulation (water block condition) by keeping the formation water wet through the use of water wetting surfactants or solvents. Additionally, both formulations would control reservoir crude souring (H2S generation by in situ sulfate-reducing bacteria), reservoir plugging (via slime biopolymers generated by in situ microbes, inorganic scale deposition like calcium carbonate or barium sulfate, and clay fines migration).

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 drilling fluid homogenizer and method of homogenizing drilling fluid which produce a non-clogging homogenized drilling fluid at a high throughput, in an open-loop process. The non-clogging homogenized drilling fluid is capable of being created at high rate so that the non-clogging homogenized drilling fluid is available on demand to eliminate halting of drilling operations. The drilling fluid homogenizer is coupled in series with the closed-loop designed drilling fluid system and is adapted to homogenize water-based drilling fluid and other drilling fluid types, such as, synthetic drilling fluid during drilling operations on demand.

Abstract: A foamable drilling fluid is provided which includes an aqueous solvent; a surfactant; and a polysaccharide preferably derived from a galactomannan gum. The foamed drilling fluid includes a liquid phase consisting of the aqueous solvent, polysaccharide and surfactant, and a gas phase of air, nitrogen, natural gas, CO2 and mixtures thereof. The drilling fluid is stable in the presence of crude oil and salt and environmentally friendly.

Abstract: A method for drilling, running casing in, and/or cementing a borehole in a subterranean formation without significant loss of drilling fluid is disclosed, as well as compositions for use in such method. The method employs a drilling fluid comprising a fragile gel or having fragile gel behavior and providing superior oil mud rheology and overall performance. The fluid is especially advantageous for use in deep water wells because the fluid exhibits minimal difference between downhole equivalent circulating density and surface density notwithstanding differences in drilling or penetration rates. When an ester and isomerized olefin blend is used for the base of the fluid, the fluid makes an environmentally acceptable and regulatory compliant invert emulsion drilling fluid. The fluid preferably contains no organophilic clays.

Abstract: Methods of drilling well bores using an invertible oil external-water internal emulsion drilling fluid and then inverting the drilling fluid to a water external-oil internal emulsion are provided. The methods basically comprise the steps of contacting the oil external-water internal emulsion with an aqueous acid solution containing an anionic sulfonate surfactant for preventing aqueous acid solution-crude oil emulsions and crude oil sludging and a chemical for preventing the anionic sulfonate surfactant from reacting with the emulsifier in the oil external-water internal emulsion.

Abstract: Permeable subterranean underground formations and fractures can be sealed using lost circulating material fluids having borate and metallic crosslinked polysaccharide gels that are crosslink in the well bore. Compositions and methods are illustrated whereby lost circulation material solids can be mixed in a mixing tank on the surface with a crosslinkable polysaccharide and a crosslinking agent under conditions whereby the lost circulating material fluid can be pumped into the well bore before undergoing gelation. Once the lost circulation material fluid equilibrates to the reservoir temperature the polysaccharide component of the lost circulation material fluid will crosslink.

Abstract: A composition for oil and gas drilling fluids containing organic contaminants comprising: a solidification agent; cell transport agent; a cellulosic additive; and wherein said composition comprises enough solidification agent to enable the solidification agent to electrolytically attract the organic contaminates to the surface of the solidification agent when hydrated.

Abstract: A composition and method for treating oil and gas drilling fluids containing organic contaminants comprising: a solidification agent, and a cell transport agent; wherein the composition comprises enough solidification agent to enable the solidification agent to electrolytically attract the organic contaminates to the surface of the solidification agent when hydrated.

Abstract: A composition and method for treating oil and gas drilling fluids containing organic contaminants comprising: a solidification agent and a cellulosic additive; and wherein the composition comprises enough solidification agent to enable the solidification agent to electrolytically attract the organic contaminates to the surface of the solidification agent when hydrated.

Abstract: A method to significantly reduce mounding on the seafloor near oil drilling operations comprising the steps of: mixing drilling fluids with organic contaminates in a high shear mixer; adding a solidification agent which expands when hydrated and electrolytically attracts said organic contaminates to its surface; adding a cellulosic additive in an amount between 1 and 50 wt % based on the amount of said organic contaminate in the drilling fluid forming a mixture; adding a cell transport agent in an amount between 0.5 wt % and 10 wt % based on the amount of said organic contaminate in the drilling fluid, wherein said cell transport agent is capable of transporting large organic molecules through cell walls and neutralizing said mixture to a pH of between 7 and 8 to said mixture; and mixing at a high shear rate until said mixture forms a fine powder, dispersing said fine powder into the sea.

Abstract: A nutrient source for marine organisms comprising: drilling fluids containing organic contaminants; a solidification agent; a cell transport agent; and a cellulosic additive.

Abstract: A water-based drilling fluid having a polymer latex capable of providing a deformable latex film on at least a portion of a subterranean formation has been discovered to provide reduced drilling fluid pressure invasion when used to drill in shale formations for hydrocarbon recovery operations. A precipitating agent such as a silicate or an aluminum complex (e.g. sodium aluminate) is preferably used in conjunction with the polymer. Typically, the water present contains a salt to form a brine, often to saturation, although the invention may be practiced with fresh water. If a salt is employed, it is often helpful to additionally employ a surfactant, such as a betaine, for example.

Abstract: The present invention comprises the use of hexamethylene diamine (HMDA) and its salts formed with organic or inorganic acids as an inhibitor for shales and clay found in drilling and producing petroleum oil and gas wells. When HMDA is added to the aqueous base of a drilling fluid, the resultant mixture inhibits shale and clays to impart and/or increase permanent permeability stability in reservoirs. Thus, with the use of the present invention, a more environmentally acceptable, chloride free, water base drilling fluid may be used in place of an oil base drilling fluid, or fluid with the heretofor more commonly used potassium additives. The present invention may be used as a completion fluid, and as a drill-in fluid.

Abstract: Conventional organophilic clays, when used as rheological additives in oil based invert muds, display marked viscosity loses in the mud when these muds are heated much above 350° F., whereas muds prepared according to the present invention are dramatically more viscosity stable at temperatures through 500° F. The present invention relates to the discovery of oil based invert emulsion drilling fluids that provides more stable drilling fluid viscosity and anti-settling performance over varying temperatures when compared to conventional fluids containing organoclays. As a result, the inventive fluids of this invention are ideal candidates for high temperature applications. This invention in another aspect of this invention is a process for improving the rheological properties of oil well drilling fluids particularly useful for oil-based invert emulsion types of drilling fluids.

Abstract: Coatings for well screens that protect the screens from damage as they are inserted into the wellbore and once in the well, release reactive materials to react with and degrade potentially plugging materials such as drill solids, fluid filtercakes, fluid loss additives, and drilling fluids. The coatings can be specifically designed for individual well conditions and are comprised of a binder that either melts or dissolves within the wellbore and one or more reactive materials such as acids, enzymes, surfactants, chelants, oxidizers or free radical generators and the like which are released into the screen and the near wellbore area and which are effective in degrading or dissolving materials which could potentially plug the screen.

Abstract: A method for treating a drilling fluid is provided, which method includes the steps of providing a drilling fluid, providing a drilling fluid additive in the form of superparamagnetic nanoparticles, mixing the drilling fluid additive with the drilling fluid so as to provide a treated drilling fluid, and exposing the treated drilling fluid to a magnetic field so as to recover the superparamagnetic nanoparticles.

Abstract: Disclosed are drilling fluids suitable for use in connection with oil well drilling. The drilling fluids of the invention include in one embodiment a liquid base, an alkyl glucoside, such as methyl glucoside, and a borehole stability agent that includes a maltodextrin, a carboxyalkyl starch, a hemicellulose-containing material, or a mixture of the foregoing. In another embodiment, the drilling fluid includes a liquid base and desugared molasses solids, preferably in combination with an alkyl glucoside and more preferably in further combination with one of the aforementioned borehole stability agents. The drilling fluids of the invention surprisingly have a reduced tendency to swell shale as compared with known drilling fluids. Also disclosed are a drilling apparatus and process. The drilling apparatus includes a drill string, which may be conventional, that is fluidically coupled to a source of drilling fluid, the source of drilling fluid including the drilling fluid of the invention.

Abstract: Pumpable and flowable bentonite clay slurries having a bentonite solids content of about 50% or greater have been prepared for the first time through the use of a non-aqueous fluidizing agent, characterized by being a highly-saturated hydrocarbon oil with low affinity for reactivity with bentonite or other hydrophilic swelling agents such as starches, guars and xanthans. The slurries are useful in the economical transport of bentonite without impairing its swellability in aqueous media in applications such as mining, papermaking and oil drilling.

Abstract: An oil-based demulsifying formulation which can be used in the treatment of drains bored in oil-based mud, non ecotoxic and optimally compatible with formation fluids, comprises at least one wetting agent selected from the group consisting of anionic surfactants and at least one demulsifier (or “emulsion breaker”) selected from the group consisting of copolymers of ethylene oxide and propylene oxide, alcohol or phenol derivatives with alkoxylated or polyalkoxylated chain formations, polyalkyleneglycols, polyamines, alkoxylated or polyalkoxylated derivatives of amines, quaternary ammonium salts, quaternized alkanolamine esters, alkyl esters of fatty acids or natural oils, possibly alkoxylated or polyalkoxylated, and silicated derivatives such as polysiloxanes.

Abstract: An improved method and fracturing fluid for hydraulic fracturing of a subterranean formation, the fracturing fluid comprising a surfactant, a water soluble or dispersible anionic organic salt, an acid and a low molecular weight organic solvent.

Abstract: Present invention relates to high brine carrier fluid, said carrier fluid selected from the group consisting of organic acids, organic acid salts, inorganic salts and combination of one or more organic acids or organic acid salts, a co-surfactant and an amount of a zwitterionic surfactant. The invention also relates to methods of treating a subterranean wellbore, including drilling, hydraulic fracturing, gravel placement, scale removing, mud cake removing, using said high brine carrier fluid.

Abstract: A borehole retention assembly for anchoring a well tool within a wellbore including a gripping assembly and an actuation assembly. The gripping assembly includes expandable members such that upon expanding the expandable members, the gripping assembly engages the wall of the borehole. The gripping assembly includes a pair of expandable members and a medial member, the members having cooperating tapered surfaces therebetween such that upon the actuation assembly contracting the gripping assembly, the expandable members are cammed outwardly against the borehole wall. The gripping assembly is mounted on a mandrel enabling them to resist rotational and axial forces on the well tool. When engaged, space is provided on each side of the borehole retention assembly such that annular flow is permitted therearound.

Abstract: Disclosed is a method of increasing the low shear rate viscosity and the shear thinning index of aqueous fluids containing a divalent cation salt, a crosslinked amylopectin starch which functions as both a viscosifier/suspending agent and as a fluid loss control additive, and a bridging agent, the fluids resulting from the method, and the use of the fluids in drilling a well, wherein the bridging agent is a sized particulate magnesium carbonate or a mixture of sized magnesium carbonate and sized calcium carbonate. The median (D50) particle size of the magnesium carbonate is from about 2 &mgr;m to about 10 &mgr;m. The weight ratio of calcium carbonate to magnesium carbonate is from about 70/30 to about 0/100.

Abstract: Non-aqueous base wellbore fluids characterized by enhanced electrical conductivity due to formulation with specified ionic liquids are disclosed. Drilling, completion, and workover methods utilizing the wellbore fluids are also disclosed.

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: A drilling fluid homogenizer and method of homogenizing drilling fluid which produce a non-clogging homogenized drilling fluid at a high throughput, in an open-loop process. The non-clogging homogenized drilling fluid is capable of being created at high rate so that the non-clogging homogenized drilling fluid is available on demand to eliminate halting of drilling operations. The drilling fluid homogenizer is coupled in series with the closed-loop designed drilling fluid system and is adapted to homogenize water-based drilling fluid and other drilling fluid types, such as, synthetic drilling fluid during drilling operations on demand.

Abstract: Pumpable multiple phase compositions for carrying agents and components downhole and controllably releasing them by breaking the suspensions are described. The multiple phase composition may have an external or third phase, which in turn has a first pumpable emulsion internally. The first pumpable emulsion has a second phase containing a first phase which bears the agent to be controllably released. The entire pumpable multiple phase composition may thus be an oil phase-in-aqueous phase-in-oil phase emulsion, or an aqueous phase-in-oil phase-in-aqueous phase emulsion. The agent may be released by one or more of a variety of mechanisms. For example, a water-soluble shale stabilizer could be delivered downhole in an aqueous phase-in-oil phase-in-aqueous phase multiple phase emulsion by injecting the multiple phase composition into a water-based drilling fluid, and then the suspension broken by rotary bit nozzles under high shear stress to release the shale stabilizer at the drilling zone.

Abstract: Pumpable multiple phase compositions for carrying agents and components downhole and controllably releasing them by breaking the suspensions are described. The multiple phase composition may have an external or third phase, which in turn has a first pumpable emulsion internally. The first pumpable emulsion has a second phase containing a first phase which bears the agent to be controllably released. The entire pumpable multiple phase composition may thus be an oil phase-in-aqueous phase-in-oil phase emulsion, or an aqueous phase-in-oil phase-in-aqueous phase emulsion. For example, a water-soluble shale stabilizer could be delivered downhole in an aqueous phase-in-oil phase-in-aqueous phase multiple phase emulsion by injecting the multiple phase composition into a water-based drilling fluid, and then the suspension broken by rotary bit nozzles under high shear stress to release the shale stabilizer at the drilling zone.

Abstract: The method for releasing the stuck pipe of the present invention uses a combination of components which oxidize the mud cake and generated gas bubbles to create an upward buoyancy for the oxidized mud cake. The spotting method of the present invention comprises adding to the borehole in the region of the stuck pipe: 1) an oxidizer which oxidizes the mud cake; and 2) at least one component which reacts in the borehole to generate a gas. Optionally, but preferably, the spotting method further uses a lubricant which is added to the borehole in the region of the stuck pipe. The lubricant acts to lubricate the oxidized parts of the mud cake. Also disclosed is a spotting fluid system comprising 1) an oxidizer which oxidizes the mud cake, 2) at least one component which reacts in the borehole to generate a gas, and, optionally a lubricant which acts to lubricate the oxidized parts of the mud cake.

Abstract: The materials include non-polyampholite crosslinked polymers and gels based on a polymer which in uncrosslinked form is substantially soluble in ionic fluids and substantially insoluble in water. The materials change their state of hydration in response to an environmental trigger. The disclosed materials are useful as drilling, completion or workover fluids in wells such as hydrocarbon producing wells. According to the disclosed method, crosslinked polymers or gels are introduced into a stratum, blocking or bridging the pores of the stratum. Thereafter, an environmental condition is changed to cause the hydrated material to become less hydrated to unblock the pores allowing production from the well.

Abstract: An oil base environmentally benign drilling fluid composition having a stable high viscosity and high gel strength at use temperatures of up to at least 450.degree. F. The drilling fluid includes a low toxicity biodegradable oil vehicle, and as a viscosifying agent an organoclay which is the reaction product of a mineral clay mixture and an alkyl quaternary ammonium salt. The mineral clay mixture comprises at least 50% by weight of a mineral clay selected from the group consisting of sepiolite, palygorskite and mixtures of sepiolite and palygorskite; and substantially the balance of the mixture is a smectite. Conventional additives such as emulsifiers and fillers may also be present in the drilling fluid.

Abstract: A lubricant which is prepared from at least one synthetic ester composition exhibiting thermal and oxidative stability which comprises the reaction product of 3,5,5-trimethyl-1-hexanol and an acid or anhydride; and a lubricant additive package; whereby the incorporation of an antioxidant in the lubricant additive package for the purpose of maintaining oxidative and thermal stability of the crankcase lubricating oil formulation to at least 20 minutes as measured by HPDSC at 220.degree. C., 3.445 MPa air and 0.5 wt. % dioctyl diphenyl amine can be either reduced or eliminated. The synthetic ester composition preferably exhibits the following additional properties: a metals content of 10 ppm or less metals based on the total synthetic ester composition, an ash content of 15 ppm or less ash based on the total synthetic ester composition, a total acid number of 0.05 mg KOH/g or less, and a volume resistivity of at least about 1.times.10.sup.11 ohm cm.

Abstract: The present invention provides compositions useful for viscosifying aqueous fluids, methods for making them and methods for using them. In one aspect of the invention, inventive compositions comprise a prehydrating alcohol having at least two hydroxyl groups and having a molecular weight of from about 60 to about 600; an inorganic salt; and a polymer. In a preferred aspect of the invention, the viscosifier composition additionally comprises a solvent having a molecular weight of from about 75 to about 1000. According to another aspect of the invention, inventive compositions comprise a prehydrating alcohol; an inorganic salt; and a polymer; and the composition is essentially free from water. Inventive compositions find advantageous use in viscosifying fluids utilized in subterranean drilling activities such as, for example, drilling, drill-in, completion, hydraulic fracturing, work-over, packer, well treating, testing, spacer, or hole abandonment fluids.

Abstract: Emulsifiable oil, suitable for use as oil phase in oil-based drilling fluids, having one or more ketones with a flashpoint of at least 55.degree. C., in particular oligoketones obtainable by co-oligomerization of carbon monoxide and olefins.

Abstract: An additive for a water-based fluid which is to be used when the likelihood of differential sticking is high and which reduces the sticking tendency of the fluid and mud cake. An additive according to the invention comprises a well dispersed-particulate phase such as an emulsion, a fine emulsion, a microemulsion, a micellar phase or a polymeric phase having a particle size comparable with the pore throat size of a mud cake and comprising a material which forms easily deformable particles and which reduces the sticking propensity of the mud. One embodiment of the invention comprises a microemulsion of an oil which is well dispersed, substantially stable and has a substantial portion of the particle size distribution in the range 5-500 nm. An alternative embodiment comprises a micellar phase comprising one or more surfactants. The additive is typically used at a level of about 5% by volume in the drilling fluid.