Abstract: A method and a device for solvent injection in a subsurface well (1) where the solvent flows towards the formation wall (4) of the subsurface well (19) via a releasable duct (8).

Abstract: An assembly and methods for constructing a MONOWELL include a monodiameter casing disposed in a monodiameter wellbore having diametric efficiency with a monobore production delivery system disposed within the monodiameter casing. An assembly for constructing a monodiameter wellbore includes a bottomhole assembly having a overgauge hole drilling member, a directional steering assembly, a measurement while drilling tool, and a logging while drilling tool; a work string attached to the bottomhole assembly and extending to the surface; drilling fluids flowing through the work string and bottomhole assembly; chemical casing casing the borehole; expandable casing disposed in the wellbore; and a sealing composition disposed between the expandable casing and the wellbore.

Abstract: In one aspect, the invention relates to a method for “tagging” proppants so that they can be tracked and monitored in a downhole environment, based on the use of composite proppant compositions containing dispersed fillers whose electromagnetic properties change at a detectable level under a mechanical stress such as the closure stress of a fracture. In another aspect, the invention relates to composite proppant compositions containing dispersed fillers whose electromagnetic properties change under a mechanical stress such as the closure stress of a fracture. The currently preferred embodiments use substantially spherical thermoset nanocomposite particles where the matrix comprises a terpolymer of styrene, ethylvinylbenzene and divinylbenzene, a PZT alloy manifesting a strong piezoelectric effect or Terfenol-D manifesting giant magnetostrictive behavior is incorporated to provide the ability to track in a downhole environment, and carbon black particles possessing a length that is less than 0.

Abstract: A method of preventing or treating lost circulation during the drilling of a well comprises the addition, at concentration ranging between about 0.5 and 6 pounds per barrel, of water-dispersible fibers having a length between about 10 and 25 mm, for instance glass or polymer fibers, to a pumped aqueous base-fluid including solid particles having an equivalent diameter of less than 300 ?m. The base-fluid with the solid particles can be the drilling fluid or a small-volume pill specially pumped for curing lost circulation.

Abstract: Among many things, in some embodiments, improved viscoelastic surfactant gels that comprise non-aqueous tackifying agents, and their associated methods of use, are provided. In one embodiment, the methods comprise: providing a treatment fluid that comprises an aqueous base fluid, a non-aqueous tackifying agent, and a viscoelastic surfactant; and introducing the treatment fluid into a subterranean formation.

Abstract: A subterranean location accessed via a wellbore is treated with an oilfield fluid containing a viscosifying agent which is a polymer and a cross-linking agent which can undergo the Diels-Alder reaction to form a gel. Conditions at the subterranean location alter fluid viscosity by bringing about the Diels-Alder reaction to increase viscosity or the retro Diels-Alder reaction to decrease the viscosity of the gel.

Abstract: A sand consolidation system and a method for use of the system is provided. The consolidation system includes an emulsion having an oil phase and an aqueous phase, wherein the emulsion contains a source of insoluble silica particles and a source of calcium hydroxide, wherein the calcium hydroxide particles are present in the oil phase, and the insoluble silica particles are contained in the aqueous phase. Both types of particles must have average particle sizes which will fit into the pores of the formations.

Abstract: The invention generally relates to a spacer system for cleaning a section of a subterranean well borehole and casing prior to cementing. The spacer system of the invention comprises a at least one alkyl ether citrate and, optionally, at least one alcohol ethoxylate.

Abstract: A clayish subterranean formation, such as may be encountered in rock surrounding a well bore during hydrocarbon recovery operations may be stabilized with a polyamine salt of an imide of polymaleic anhydride. The salt may be unneutralized or partially neutralized. The invention is particularly relevant to hydraulic fracturing fluids used in enhanced oil recovery. The compositions of this invention are more environmentally friendly than some current technology.

Abstract: The invention concerns an aqueous delayed-gelation solution and a method of selectively placing a delayed-gelation solution in a hydrocarbon well. According to the invention, the aqueous delayed-gelation solution a dissolved metal salt which, in use, hydrolyses to form a gel, wherein the solution contains suspended inorganic particles and the method comprises the steps of—providing the aqueous delayed-gelation solution, and—injecting the solution into the hydrocarbon well, whereby the suspended inorganic particles reduce or block the flow of the delayed-gelation solution to relatively low permeability formation zones thereby selectively placing the solution in a relatively high permeability formation zone. Applications of the invention relate to the treatment of hydrocarbon wells.

Abstract: Provided herein are defoaming agents that comprise lecithin and a solvent. Optionally, they may comprise hydrophobic particles. One embodiment provides a method comprising: providing a well fluid that comprises foam; providing a defoaming agent that comprises lecithin and a solvent; and contacting the well fluid with the defoaming agent so that the amount of foam present in the well fluid is reduced.

Abstract: The problem of fiber or particle settling in well cement slurries is addressed by providing a fluid containing two fiber components of differing properties. Such a well treatment fluid, comprising a base fluid; a first fiber component that it substantially more dense than the base fluid; and a second fiber component that has a density close to that of the base fluid and is relatively flexible.

Abstract: A method of servicing a wellbore, comprising providing a wellbore fluid comprising a carrier fluid and a resilient material, and introducing the wellbore fluid to an annulus, wherein at least a portion of the resilient material reduces in volume to affect the annular pressure.

Abstract: A method is provided for in-situ gasification of coal wherein a network of fractures is formed by providing a substantially vertically disposed borehole and a plurality of substantially horizontally disposed boreholes in fluid communication with the substantially vertically disposed borehole, at least one substantially horizontally disposed boreholes being a fracturing borehole, at least one substantially horizontally disposed boreholes being an injection borehole and at least one substantially horizontally disposed boreholes being an injection borehole. An initial quantity of liquified gas is introduced into the at least one substantially horizontally disposed fracturing borehole whereby the liquified gas vaporizes forms fractures in the formation.

Abstract: Viscoelastic surfactant fluids, and methods of using such fluids and controlling the viscosity thereof. In one embodiment, the methods of the present invention comprise: providing a viscoelastic surfactant fluid that comprises an aqueous-base fluid, and a surfactant; providing a metal ion having at least two oxidation states wherein at least one of the oxidation states interferes with the ability of the surfactant to form a viscosifying micelle, wherein at least a portion of the metal ion is present in an oxidation state that interferes with the ability of the surfactant to form a viscosifying micelle; allowing the metal ion to interact with viscoelastic surfactant fluid so as to decrease the ability of the surfactant to form a viscosifying micelle; and introducing the viscoelastic surfactant fluid into at least a portion of a subterranean formation.

Abstract: Exemplary embodiments relate to cementing operations and, more particularly, to foamed cement compositions, foaming and stabilizing additives, and associated methods. A foaming and stabilizing additive, that comprises a mixture of an alkali salt of an alkyl ether sulfate surfactant, wherein the alkali salt of the alkyl ether sulfate surfactant comprises a mixture of an alkali salt of a C6-10 alkyl ether sulfate surfactant, and an alkali salt of a C2-4 alkyl ether sulfate surfactant, an alkyl or alkene amidopropyl betaine surfactant, an alkyl or alkene amidopropyl dimethylamine oxide surfactant, sodium chloride, and water, is provided. Also provided are foamed cement compositions that comprise the foaming and stabilizing additive, and associated methods.

Abstract: A method for selectively reducing the permeability of one or more relatively permeable geological layers of an oil-bearing formation, to inhibit breakthrough of driving fluid from a driving fluid injection well via at least one of said layers into an oil production well, which method comprises the steps of injecting a driving fluid comprising a first compound into the formation via the injection well; detecting the first compound in well fluid of the oil production well; upon detection, injecting a second compound into the formation via the oil production well, to react with the first compound in order to provide a flow restriction generated by a third compound which comprises a reaction product of the first and second compounds in at least one relatively permeable geological layer through which breakthrough of the driving fluid into the oil production well has occurred.

Abstract: Methods and compositions for reducing the viscosity of subterranean treatment fluids that comprise a gelling agent utilizing breakers that comprise hydroquinone and/or a derivative thereof. In one embodiment, the present invention provides a method comprising: providing a treatment fluid that comprises an aqueous base fluid and a gelling agent; providing a breaker that comprises a hydroquinone component; allowing the breaker to interact with the treatment fluid; and allowing the breaker to at least partially reduce the viscosity of the treatment fluid.

Abstract: A valve assembly connects into a drill string for opening and closing a passage within the drill string. The valve assembly has an inner valve member for opening and closing an inner passage of the drill string. The valve member moves between the open and closed positions in response to axial movement of the drill string. Lifting the drill string causes the upper portion to move upward relative to the lower portion, bringing along with it the valve member, while the valve sleeve remains stationary with the lower portion, opening the valve. The valve assembly can include an annular valve assembly for opening and closing an annular passage located around the inner passage. The annular valve assembly is opened and closed by increasing the pressure in the annular passage above the annular valve assembly.