Abstract: A method of separating from a mixture of oil-based drilling fluid and sample of formation hydrocarbon, the liquid component of the drilling fluid, which method comprises treating, e.g. chemically, the mixture in a way that selectively substantially affects the liquid component of the drilling fluid, producing one or more treatment products, while leaving the formation hydrocarbon substantially unaffected; and separating the treatment products from the formation hydrocarbon, by solvent extraction. The liquid component of the drilling fluid conveniently comprises one or more esters (which do not occur in significant quantities in naturally occuring formation hydrocarbons) and which can be hydrolysed to give water-soluble products readily removable from the formation hydrocarbon. The invention is applicable to sampling of formation hydrocarbon using wireline formation testers or sampling tools.

Abstract: The invention is of oil-based drilling fluids including invert emulsion fluids that are able to maintain a relatively consistent rheological profile over a wide temperature range. The invention also includes new additives that enable the preparation of drilling fluids with viscosities that are less affected by temperature over a temperature range from less than about 40° F. to more than about 250° F. compared to conventional fluids. These additives are based on reaction products of polyamines and carboxylic acids with two or more carboxylic moieties combined with alkoxylated amines and fatty acid amides. In addition, this invention permits the use of reduced amounts of organoclay rheological additives in drilling fluids.

Abstract: The present invention provides aqueous viscoelastic compositions comprising a cleavable surfactant and possibly also an electrolyte. The cleavable surfactants useful in the present invention comprise at least one weak chemical bond, which is capable of being broken under appropriate conditions, to produce oil soluble and water soluble products typically having no interfacial properties and surface activity compared with the original surfactant molecule. Further, the rheological properties of the aqueous viscolelastic composition are usually altered upon cleavage of the cleavable surfactant generally resulting in the elimination of the viscofying, viscoelastic and surfactant properties of the composition. Aqueous viscoelastic compositions in accordance with the present invention are suitable for use in oil-field applications, particularly for hydraulic fracturing of subterranean formations. Thus, the present invention also relates to a wellbore service fluid and a method of fracturing a subterranean formation.

Abstract: A method for preferentially treating a subterranean formation having at least one primarily oil producing layer and at least one primarily water producing layer. The method involves the steps of providing a water shut-off gel into the formation to preferentially treat the water producing layers. This is followed by providing a viscoelastic fluid into the formation, where the viscoelastic fluid is broken by hydrocarbon, thereby remaining and viscosifying primarily in the water producing layers. Finally, a reactive fluid, such as an acid fluid, is provided. The reactive fluid treats primarily the oil producing layers because the viscoelastic fluid and the water shut-off gel prevent the reactive fluid from substantially entering the water producing layers.

Abstract: The current invention provides a novel downhole maleic acid solution suitable for restoring fluid permeability to subterranean formations that were previously treated with chemical fluid loss control agents based on hydroxyethyl cellulose polymer. The current invention also provides methods for restoring fluid permeability to subterranean formations that have been treated with chemical fluid loss control agents based on hydroxyethyl cellulose polymer. The methods of the current invention contact the subterranean formation with downhole maleic acid solutions for a period of time sufficient to restore fluid permeability to the formation.

Abstract: Invert emulsion drilling system fluids comprising an oleaginous continuous phase and a non-oleaginous dispersed phase, the dispersed phase comprising organofunctional compound(s) effective to provide shale inhibition. The organofunctional compound(s) may be used either as a supplement to or as a substitute for metallic salts.

Abstract: An apparatus for creating a cemented lateral junction including a sleeve with a premachined opening and a cover disposed at the sleeve. A release material is disposed at the cover.

Abstract: A packer fluid is provided for use with a wellbore fluid in an annulus or casing bore, having an aqueous portion which contains additives for preventing corrosion, microbiological activity, salt and scale deposition, and an environmentally-acceptable capping fluid which resides at a top of the wellbore to act as freeze protection and as thermal insulation in a the frost penetration layer. The additives in the packer fluid are particularly selected to exist in the aqueous additive fluid and in the wellbore fluid and to be substantially immiscible with the capping fluid and thereby prevent significant migration of the additives into the capping fluid which would compromise its environmental acceptability.

Abstract: Viscoelastic surfactant based aqueous fluid systems useful as thickening agents in various applications, e.g. to suspend particles produced during the excavation of geologic formations. The surfactants are zwitterionic/amphoteric surfactants such as dihydroxyl alkyl glycinate, alkyl ampho acetate or propionate, alkyl betaine, alkyl amidopropyl betaine and alkylimino mono- or di-propionates derived from certain waxes, fats and oils. The thickening agent is used in conjunction with an inorganic water-soluble salt or organic additive such as phthalic acid, salicylic acid or their salts.

Abstract: A method of reducing the viscosity of invert emulsions and oil-based drilling fluids and well service fluids comprising such emulsions over a broad temperature range is disclosed. The method comprises adding to said invert emulsions of the invention a non-ionic surfactant alone or in combination with a co-thinner having the formula: R″″—(C2H4O)n(C3H6O)m(C4H8O)k—H where R″″ is a saturated or unsaturated, linear or branched, alkyl radical having about 8 to about 24 carbon atoms, n is a number ranging from about 1 to about 10, m is a number ranging from about 0 to about 10, and k is a number ranging from about 0 to about 10. The non-ionic surfactant is a reaction product of ethylene oxide, propylene oxide and/or butylene oxide with C10-22 carboxylic acids or (C10-22 carboxylic acid derivatives containing at least in position 9/10 and/or 13/14 structural units of general formula (I) where R1 is a hydrogen atom or an OH group or a group OR2.

Abstract: A drilling fluid system comprising a brine and a quantity of cationic copolymers comprising a ratio of acrylamide monomers to cationic derivatives of acrylamide monomers, wherein the quantity and the ratio are effective to maintain effective rheology and fluid loss control in said drilling fluid system at temperatures of at least about 250° C. for at least about 16 hours.

Abstract: A new composition for a spotting fluid and a method of using such spotting fluid for freeing differential stuck pipe in a subterranean well drilling operation is disclosed. The composition comprises an invert water-in-oil emulsion comprising iso-butyl oleate as its external phase and glycerin as the internal phase. In an altemative embodiment, calcium chloride and water may be substituted for glycerin.

Abstract: An invert emulsion suitable for drilling subterranean wells, in particular oil and gas wells is disclosed which has negative alkalinity and includes an oleaginous phase, and a non-oleaginous phase and an emulsifying agent which stabilizes the invert emulsion under conditions of negative alkalinity. The practice of the present invention permits the formulation of drilling fluids which are absent an alkaline reserve and yet are suitable for drilling oil and gas wells.

Abstract: Compositions for increasing the thermal and pressure stability of well fluids viscosified using viscoelastic surfactants, the compositions including an effective amount of an oligomeric or polymeric compound that has a thermally stable backbone structure and at least one pendent viscoelastic surfactant functional group. Preferred compositions for increasing the stability of well fluids viscosified using monomeric viscoelastic surfactants include an effective amount of an oligomeric or polymeric compound that has a thermally stable backbone structure and a multiplicity of pendent viscoelastic surfactant functional groups attached to said backbone structure through relatively long hydrocarbon chains, 1 to 18 carbons in length.

Abstract: A drilling fluid additive system is provided wherein the system comprises: a drilling fluid additive comprising talc, graphite and at least one carrier such as a glycol; and hydrophilic clay, a pH controller, a fluid loss controller, and at least one dispersant.

Abstract: A drilling fluid additive is provided wherein the additive is manufactured by a method comprised of admixing graphite with at least one carrier such as a polypropylene glycol or oil to create a suspended mixture, and allowing the surface of the graphite to be pre-wet with the carrier prior to adding the mixture to a drilling fluid.

Abstract: An invert drilling fluid composition containing: (a) an oil phase; (b) a water phase; (c) at least one emulsifier; (d) at least one weighting agent; (e) at least one fluid loss additive; (e) at least one electrolyte component containing a mixture of calcium acetate and magnesium acetate; and (g) at least one thickening agent.

Abstract: A surfactant has the formula (R1—X)nZ, where R1 is an aliphatic group comprising a C10-C25 principal straight chain bonded at a terminal carbon atom thereof to X, and comprising at least one C1-C6 side chain. X is a charbed head group, Z is a counterion, and n is an integer which ensures that the surfactant is charge neutral.

Abstract: Methods are provided for fracturing subterranean formations using fluids having substantially reduced polymer loadings that have performance equivalent to conventional fluids. Reduced polymer loadings provide significant advantages such as reduced treatment costs and less damage to the fracture sand pack and surrounding subterranean formations.

Abstract: An efficient oil based drilling fluid is provided that includes a polymer additive effective at imparting suspension characteristics without the presence of organophilic clays, while also providing filtration control. The fluid is shear thinning and has good fluid rheology over a broad temperature range. A preferred polymer for the additive is substantially linear and comprises mostly hydrophobic monomers and some hydrophilic monomers such as, for example, an emulsion copolymer of 2-ethylhexyl acrylate and acrylic acid.

Abstract: A method and composition is provided for a suspending agent for supporting components in drilling fluids, particularly oil-based drilling fluids, the suspending agent comprising the condensation product of a dimer or trimer fatty acid and diethanolamine.

Abstract: The invention relates to drilling fluids used in methods for drilling wells into subterranean formations containing oil, gas or other minerals for the purpose of extraction and production of said minerals and the use of starch in such fluids. The invention provides a method for drilling such a well using a drilling fluid comprising a high-amylose starch or starch-blend.

Abstract: The present invention provides a drilling fluid composition and a method of drilling comprising a drilling fluid, which may be oil- or water-based, and a composite microsphere component. The invention drilling fluid composition advantageously reduces the density of a conventional fluid, reduces costs associated with pumping and overcomes problems associated with conventional gas-injection processes. The invention uses conventional drilling and pumping equipment, requires no sea-floor based pumps and may be easily pressure-controlled to maintain the pressure of the fluid.

Abstract: The invention relates to a coin (1) which has a metallic surface (2, 3) and comprises macroscopic reliefs (5) that serve to visually indicate the value of the coin and as a legitimacy feature. Microscopically fine relief structures (8) that cause diffraction are placed directly inside at least one of the surfaces (2, 3). The relief structures (8) are preferably recessed and covered with a lacquer (9). In addition, it is advantageous when at least one portion of the relief structures (8) has an asymmetrical profile shape and/or the lattice vectors are radially aligned. The relief structures (8) can also contain a machine-readable coding which is recognized by cost-effective optical reading devices to be installed in coin examiners. The microscopic relief structure (8) can be provided on a hard material surface (2, 3) by removing material effected by exposing the material surface (2, 3) to a laser beam.

Abstract: The invention relates to a method of fracturing a subterranean formation including injecting into a wellbore a fracturing fluid based on a liquid medium having a density higher than 1.3 g/cm3, thereby allowing the use of a surface pressure at least 10% smaller than the surface pressure required with a fracturing fluid based on a liquid medium having a density of about 1 g/cm3.

Abstract: The present invention relates to methods and compositions for treating subterranean well formations, and more specifically, to improved subterranean formation treating fluid concentrates, treating fluids and methods of using such treating fluids in subterranean formations. The treating fluid concentrates generally comprise water and a substantially fully hydrated depolymerized polymer. The treating fluids which are formed by adding water to the treating fluid concentrates generally comprise water, a substantially fully hydrated depolymerized polymer and a crosslinking agent for crosslinking the hydrated depolymerized polymer.

Abstract: This invention proposes a method for completing an interval of an open-hole injection wellbore penetrating a subterranean formation, said wellbore being communicating with the formation by way of an interface that comprises at least a filter cake invaded zone comprising bridging materials and other embedded solid materials, said method comprising the steps of injecting a clean-up fluid and contacting it with the filtercake for a period of time sufficient to loose some of the other solids embedded in the filter cake; removing the loosened solids by a high-rate displacement fluid comprising suspending additives; and then injecting a dissolving fluid comprising a diverter and an effective amount of a salt or acid capable of dissolving the bridging material.

Abstract: A method is disclosed for reducing sag in drilling and completion fluids and in workover fluids. The method employs a drilling fluid comprising a low molecular weight polyalkyl methacrylate with an average molecular weight ranging from about 40,000 to about 90,000. This additive does not result in increased viscosity of the fluid.

Abstract: Compositions of oil-based biodegradable drilling fluids are described, the compositions comprising an oil phase composed by methyl esters of soybean oil fatty acids, an aqueous phase finely dispersed in the oil phase by specific emulsifiers and several other additives having specific functions for providing suitable performance to the finished drilling fluid composition. The process to manufacture the inverted emulsion and the drilling process that employs the compositions of the invention are described too.

Abstract: A method is disclosed for reducing sag in drilling and completion fluids and in workover fluids. The method employs a drilling fluid comprising a low molecular weight polyalkyl methacrylate with an average molecular weight ranging from about 40,000 to about 90,000. This additive does not result in significantly increased viscosity of the fluid.

Abstract: A method is disclosed for drilling a wellbore employing a drilling fluid providing the advantages of easy pumpability of a low viscosity fluid with the drill cuttings suspension capability of a highly viscous fluid. The viscosity of the fluid is also easily and quickly adjustable so that the fluid rheology may be adapted during drilling as the subterranean conditions change. These advantages are obtained by including in said fluid a reversibly crosslinkable polymer and an encapsulated crosslink activator. The crosslink activator causes crosslinking after the fluid is in the wellbore. The crosslinking is reversed at the well surface to reduce the viscosity of the fluid to enable the drill cuttings to be easily removed. Crosslink activator is added back to the fluid and the fluid is returned to the borehole. The amount of crosslink activator and/or crosslinkable polymer may be adjusted in the fluid to change the fluid rheology to conform the fluid to changes in the well conditions as monitored real time.

Abstract: A rheology modified aqueous fluid composition comprising clay, water, magnesium oxide, aluminum oxide hydroxide, sodium carbonate or potassium carbonate, and calcium oxide or calcium hydroxide. The magnesium oxide and aluminum oxide hydroxide are prepared by a specific thermal treatment protocol involving heating of appropriate precursors within a specified temperature range. The pH of the composition is at least about 10. The composition is prepared by admixing the components and, optionally, sodium oxide or sodium hydroxide for pH adjustment as necessary. A substantially dry rheology modification agent comprising the enumerated components, not including the water, is also included. The resulting composition preferably exhibits shear-thinning capability including very rapid thinning upon application of shear forces and also rapid viscosification upon removal of such forces.

Abstract: A lubricant for use in silicic acid muds and other drilling fluids comprising silicate or silica species is disclosed. The lubricant significantly improves the lubricity of the fluid. A method of drilling a wellbore in a subterranean formation employing the lubricant is also disclosed. A preferred lubricant of the invention comprises about 80 volume percent 2-octyldodecanol and about 20 volume percent alkylglucoside. The alkylglucoside is preferably comprised of 2-ethylhexylglucoside or a mixture of alkylglucosides having more than about 10 carbon atoms in the alkyl chain.

Abstract: A process is provided for a method a preparing a novel non-aqueous suspension which can be used as additives in a water-based fluids. Water-based fluids such as, for example, drilling fluids and mining fluids, are useful in a variety of industrial applications. Thus, because of the particular properties of the inventive non-aqueous suspension described, it can suitably be used as an additive to oil and gas well treatment fluids by admixing with a water-based fluid in such manner as to form an admixture. A method is disclosed for the introducing the admixture into a wellbore.

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: Methods of improving the pressure containment integrity of subterranean well bores are provided. The methods include pumping a fracture sealing composition into the well bore that rapidly converts into a high friction pressure sealing composition which is impermeable, deformable, extremely viscous and does not bond to the faces of fractures. Thereafter, the fracture sealing composition is squeezed into one or more natural fractures or into one or more new fractures formed in the well bore to thereby increase the pressure containment integrity of the well bore. The methods also include the prediction of the expected increase in pressure containment integrity.

Abstract: A drilling fluid additive is provided wherein the additive is manufactured by a method comprised of admixing colloidal solids such as talc with a combination of oil and glycol or cellulose to create a suspended mixture to thereby allow the colloidal solids to be pre-wet, treated or coated with the oil/glycol combination or the cellulose; and then admixing copolymer beads to the suspended mixture.

Abstract: The reaction product of thiourea (alternatively, a primary amine), formaldehyde, and an aromatic ketone (e.g. acetophenone) in the presence of an organic acid (e.g. acetic acid) and a mineral acid has been found effective as a corrosion inhibitor base for metals in acid media, particularly fluids containing halogen acids. The corrosion inhibitor base can be prepared in nearly 100% yield, and is a more effective base, as contrasted with bases prepared with fatty acids as contrasted with lower molecular weight organic acids such acetic acid.

Abstract: A drilling fluid additive is provided wherein the additive is manufactured by a method comprised of admixing colloidal solids such as talc with at least one carrier such as an oil or glycol to create a suspended mixture to thereby allow the colloidal solids to be pre-wet with the carrier; and then admixing copolymer beads to the suspended mixture.

Abstract: A drilling fluid additive system is provided wherein the system is manufactured by a method comprised of admixing colloidal solids such as talc with a carrier such as oils and glycols or talc with cellulose to create a suspended mixture to thereby allow the colloidal solids to be pre-wet or coated with the carrier; and then admixing copolymer beads to the suspended mixture to allow the beads to be pre-wet or coated with the carrier; and then adding the suspended mixture with a mixture comprised of hydrophilic clay, a pH controller, a fluid loss controller, and a dispersant.

Abstract: A drilling fluid additive system is provided wherein the system is manufactured by a method comprised of admixing colloidal solids such as talc with a carrier such as oils or glycols to create a suspended mixture to thereby allow the colloidal solids to be pre-wet or coated with the carrier; and then admixing copolymer beads to the suspended mixture to allow the beads to be pre-wet or coated with the carrier; and then adding the suspended mixture with a mixture comprised of hydrophilic clay, a pH controller, a fluid loss controller, and a dispersant.

Abstract: Magnetorheological fluids, which solidify in response to a magnetic field, offer the ability to simplify many of the valves and control systems used downhole in the search for and production of oil and gas. They lessen the need for moving parts, provide solid-state valves, and can provide a differential movement of fluid through the valves by varying the strength of the magnetic field. Combinations of permanent and electro-magnets can improve safety by providing valves that fail, when power is lost, in either an open or closed position, depending on design. A number of examples are given.

Abstract: The effect of various chemical or biological agents in well treatment fluids can be delayed by sequestering the agents in the discontinuous phase of an emulsion for a period of time, before the emulsion is destabilized by exposure to at least one of: (1) a change in temperature, (2) a change in pH, (3) a change in salinity, (4) a change in alcohol concentration, (5) a change in stabilizing surfactant concentration, (6) a change in organic ion concentration, (7) a change in destabilizing surfactant concentration, (8) a change in surfactant adsorbent material concentration, (9) an ultrasonic pulse, and (10) an electrical field. Upon exposure to the emulsion destabilizing condition, the agent sequestered in the discontinuous phase of the emulsion is released into the continuous phase of the fluid composition, where it can have its intended effect.

Abstract: A method and product is disclosed which provides emulsion stability and filtration control to invert emulsion drilling fluids. The product comprises a blend of a carboxylic acid terminated polyamide and a mixture produced by the Diels-Alder reaction of dienophiles, preferably carboxylic acids, polycarboxylic acids, acid anhydrides, or combinations or mixes thereof, with a mixture of fatty acids and resin acids. The product is extremely effective, decreasing by about two-thirds the amount of emulsifier generally required to formulate an effective drilling fluid. The product also greatly reduces and in many cases eliminates the need for conventional fluid loss additives, and additionally provides electrical stability. Moreover, the product has a pour point as low as about 20 degrees Fahrenheit with minimal solvents, thereby eliminating the need to ship large amounts of inert material for use, and may be transported in a highly active state.

Abstract: In accordance with a method of this invention, formation integrity problems are discovered, diagnosed and corrected in successively drilled subterranean well bore intervals. If one or more of well bore fluid outflows, formation fluid inflows or inadequate well bore pressure containment integrity are discovered in a drilled well bore interval, well logs are run and other relevant well bore data is collected in the drilled well bore interval and analyzed to provide a specific treatment using a specific pumpable sealing composition for sealing and increasing the pressure containment integrity of the well bore. Thereafter, the sealing composition is pumped into the drilled well bore interval whereby the well bore interval is sealed or the pressure containment integrity is increased, or both.

Abstract: A drilling fluid or mud is described wherein the drilling fluid contains at least one alkali metal formate or monovalent carboxylic acid salt. The drilling fluid preferably further contains at least one emulsifier or surfactant and at least one hydrocarbon-based fluid. The drilling fluids of the present invention can contain other conventional ingredients. The present invention permits drilling fluids to be essentially solids free due to the use of the alkali metal formate.

Abstract: Lost circulation materials and methods for maintaining emulsion stability in emulsion type drilling, drill-in, and completion fluids, particularly invert emulsions.

Abstract: The invention provides an organic diacid anhydride-modified chitosan and a method of preparing the same under high shear conditions which eliminates the use of solvents and excessive amounts of aqueous liquids. Also provided are organic diacid anhydride-modified chitosans containing an inorganic basic material which enhances the aging stability thereof. The invention also provides fluids useful in various well drilling and servicing operations comprising an alkaline aqueous liquid containing an organic diacid anhydride-modified chitosan, as well as a method of drilling wells therewith.

Abstract: A power supply assembly, which is placed subsea and is connected to an umbilical from a platform, supplies electrical power to subsea equipment. The power supply assembly supplies power during drilling operations to a pump for pumping drilling fluid from the sea floor to the sea surface. During production operations, the power supply assembly provides power to a booster pump to pump the well fluid away from the subsea well for collection. The subsea power supply assembly optionally also provides power to electrically charged portions of subsea separators that remove water from the oil in the well fluid. The booster pump the pumps the oil from the separator away from the subsea wellhead for collection.

Abstract: Drilling fluid additives that act to control clay swelling in drilled formations without adversely effecting the properties of the drilling fluid. The drilling fluid additives preferably comprise a polyether amine, a polyether amine derivative, or mixtures thereof Drilling fluids that comprise such drilling fluid additives and a method of reducing clay swelling in drilled formations are also disclosed.