Abstract: The invention discloses a method of controlling fluid loss from a subterranean formation of a well bore. In a first aspect, the method is done by providing a treatment fluid made of an aqueous fluid and a hydrophobic polymer; and introducing the treatment fluid into the wellbore. In a second aspect, the method is done by providing a treatment fluid made of water and a water soluble polymer; providing in the treatment fluid a fluid loss additive having a hydrophobic polymer; using the treatment fluid in a well bore of a subterranean formation; allowing the treatment fluid to establish a permeable filter cake with the water soluble polymer in at least a portion of the well bore; and allowing hydrophobic polymer to enter into the filter cake to reduce permeability of the filter cake.

Abstract: The invention discloses a well treatment composition for use in a subterranean formation comprising: a carrier fluid; and a viscoelastic surfactant being present in a concentration of less than about 1.5% by weight. Optionally, the fluid comprises a crosslinked polymer in a thickening amount in the carrier fluid. The invention also discloses a method to increase the viscosity of a fluid, the method comprising: providing a fluid comprising a thickening amount of a crosslinked polymer; adding a viscoelastic surfactant at a given concentration to the fluid; taking the fluid to a given temperature; defining a viscosity profile of the fluid depending of the concentration and the temperature; comparing said viscosity profile to a viscosity profile of the crosslinked polymer fluid alone; and defining an optimum concentration of the viscoelastic surfactant for each temperature.

Abstract: The invention discloses a method of treating a subterranean formation of a well bore: providing a treatment fluid made of: a fluid; a particulate material, and a viscosifier material; wherein the viscosifier material is inactive in a first state and is able to increase viscosity of the treatment fluid when in a second state; introducing the treatment fluid into the wellbore; and providing a trigger able to activate the viscosifier material from first state to second state.

Abstract: Methods and related systems are described for making measurements at multiple locations in an annular region of a cased sequestration well. A first tool module is positionable within the well and adapted to directly or indirectly measure changing pressure at a first location in the annular region of the well. A pressure change is induced at the first location in the annular region. A second tool module is positionable within the well and adapted to directly or indirectly measure changing pressure at a second location in the annular region. The measured pressure changes at the second location are in response to the induced pressure change at the first location.

Abstract: A method of treating a subterranean formation penetrated by a wellbore of a well having iron-containing components is carried out by introducing a treatment fluid into the wellbore of the well. The treatment fluid is formed from an aqueous solution, a mineral acid, a viscoelastic surfactant gelling agent and corrosion inhibitor system containing at least one of an alkyl, alkenyl, alicyclic or aromatic substituted aliphatic ketone and aliphatic or aromatic aldehyde. The treatment fluid is substantially free of any formic acid or precursor formic acid. In certain embodiments, the corrosion inhibitor system comprises a mixture of at least one of an alkenyl phenone or ?,?-unsaturated aldehyde, an unsaturated ketone or unsaturated aldehyde other than the alkenyl phenone and ?,?-unsaturated aldehyde, a dispersing agent, an extender and an alcohol solvent. A corrosion inhibitor intensifier may also be used in certain embodiments, which may include a mixture of cuprous iodide and cuprous chloride.

Abstract: A method for shortening the shear recovery time of cationic, nonionic, anionic, zwitterionic, and amphoteric viscoelastic surfactant fluid systems by adding an effective amount of an amphiphilic polymeric rheology enhancer. The rheology enhancer is a grafted polymer of polydimethylsiloxane, for example polydimethylsiloxanes grafted with ethylene/propylene glycol. The rheology enhancer also increases fluid viscosity and very low rheology enhancer concentration is needed.

Abstract: A well treatment microemulsion for use in a subterranean formation is disclosed, the microemulsion comprises a solvent blend comprising a solvent and a co-solvent; a surfactant blend comprising a surfactant, wherein the surfactant blend is able to give formation intermediate wettability properties; an alcohol; and a carrier fluid; wherein the alcohol, the solvent and surfactant blends are combined with the carrier fluid to produce the well treatment microemulsion. By intermediate wettability it is meant that the water has an advancing contact angle on the surface between 62 and 133 degrees. The associate method of treating a subterranean formation of a well with the microemulsion and the associate method of modifying the wettability of the formation with the microemulsion are also disclosed.

Abstract: Compositions and methods are given for delayed breaking of viscoelastic surfactant gels inside formation pores, particularly for use in hydraulic fracturing. Breaking inside formation pores is accomplished without mechanical intervention or use of a second fluid. Oxidizing agents such as air, oxygen, persulfates, bromates, peroxides, and others are used. The break may be accelerated, for example with a free radical propagating species, or retarded, for example with an oxygen scavenger. In certain brines, for example bromide brines, certain zwitterionic viscoelastic fluid systems that can decarboxylate and that require an anion-containing co-surfactant undergo delayed degradation if oxygen is present, for example from fluid preparation or in a foam.

Abstract: The invention provides a method for perforating a well with a perforating fluid comprising a viscoelastic surfactant that essentially stops fluid leak-off after perforation in an overbalanced condition. Another aspect of the invention provides the perforating fluid in itself. The well has a wellbore defined by a generally cylindrical casing in at least a portion of the wellbore (i.e., the wellbore is cased, although it is not necessary cased in its entire length). The wellbore passes through a subterranean formation that comprises hydrocarbon formation fluids (such as oil and/or gas), at least in certain strata. The method comprises placing a perforating device in a wellbore which includes at least one explosive perforating charge that can be detonated in order to perforate the casing and allow the formation fluids to enter the wellbore. The casing is located between the subterranean formation and the perforating device.

Abstract: A method includes hydraulically fracturing a subterranean formation with a first treatment fluid and allowing the hydraulic fracture to close. The method includes preparing a second treatment fluid having a damage removal agent including carbon dioxide. The second treatment fluid further includes a proppant pack damage removal agent including an oxidizer, a radical initiator, an acid, a solvent, and/or other damage removal agents. The method further includes injecting the second treatment fluid into the subterranean formation at a downhole pressure below a fracturing pressure for the subterranean formation. The method includes holding pressure on the formation while the second treatment fluid enhances formation and proppant pack permeability, and flowing the second treatment fluid back to the surface.

Abstract: A composition and method for improving the fluid efficiency of many oilfield treatments is given. The composition is a solid additive, in a viscosified fluid, in a size range small enough that it enters formation pores; it optionally bridges there to form an internal filter cake, and then decomposes to provide a breaker for the viscosifying system for the fluid. Examples of suitable additives include waxes, polyesters, polycarbonates, polyacetals, polymelamines, polyvinyl chlorides, and polyvinyl acetates. Degradation of the additive may be accelerated or delayed.

Abstract: The current disclosure describes a multifunctional fluid that addresses a new concept in the removal of filter cake. A composition is disclosed comprising: a carrier fluid, a surfactant, a fluorine source and an organic stabilizer able to minimize precipitation of fluorine The associated method to remove the filter cake is also described.

Abstract: An adaptive cementitious composite composition, comprising: a coarse particulate material such as sand or proppant; a series of other particulate or fibrous materials; and a carrier fluid; the sand and other particulate materials being present as a series of coarse, medium and fine particle sizes in ratios selected to provide an optimized packing volume fraction; wherein the sand or proppant is coated with a resin and at least one of the other particulate or fibrous materials is a material that can be modified when placed at a downhole location.

Abstract: The invention provides geopolymeric compositions intended for use in carbon dioxide injection or production wells or storage reservoirs and preferably in a supercritical carbon dioxide conditions. The geopolymeric composition is formed from a suspension comprising an aluminosilicate source, a metal silicate, an alkali activator, a retarder and/or an accelerator and a carrier fluid wherein the oxide molar ratio M2O/SiO2 is greater than 0.20 with M an alkali metal.

Abstract: A method of treating a subterranean formation penetrated by a wellbore is carried out by forming a treatment fluid comprising an aqueous carrier fluid and a solid-form polyimide homopolymer or copolymer capable of hydrolyzing to form polycarboxylates and/or polycarboxylic acids. The treatment fluid is introduced into the formation through the wellbore. In another method, a treatment fluid comprising an aqueous carrier fluid, a solid-form polysuccinimide homopolymer or copolymer and at least one of a viscosifying agent, proppant and an acid capable of dissolving materials of the formation is formed. This is introduced into the formation through the wellbore. A method of treating a sandstone-containing formation penetrated by a wellbore may also be carried out by forming a treatment fluid comprising an aqueous solution containing a hydrogen fluoride source, ammonium hydroxide and at least one of a polyimide and a polycarboxylate, which is introduced into the formation through the wellbore.

Abstract: An aqueous viscoelastic surfactant (VES) fluid foamed or energized with carbon dioxide, in which the VES is more compatible with the carbon dioxide, is made by the addition of one or more than one synergistic co-surfactant. The synergist co-surfactant includes quaternary amines and ethoxylated carboxylates having a hydrophobic chain shorter than the hydrophobic chain of the VES. Improved compatibility is evidenced for a given surfactant concentration either by formation and maintenance of a foam under conditions at which the foam could not otherwise have been formed or maintained, or by either higher viscosity of the foamed fluid at a given temperature or longer foam life at a given temperature or a higher temperature at which useful fluid viscosity can be generated or maintained for a useful time. The aqueous carbon dioxide foamed fluids may be used in acidizing, acid fracturing, gravel packing, diversion, and well cleanout.

Abstract: A method for use within a subterranean formation penetrated by a wellbore includes introducing a thixotropic agent into the well and introducing a cement slurry into the well. The method includes forming a thixotropic cement slurry downhole, including mixing the cement slurry and the thixotropic agent downhole.

Abstract: Methods of improving shear recovery time of viscoelastic surfactant fluid systems are described, one method involving providing a viscoelastic surfactant fluid system comprising a major portion of a surfactant and a rheology enhancer in a concentration sufficient to shorten shear recovery time of the fluid system compared to shear recovery time of the fluid system absent the rheology enhancer, the rheology enhancer selected from aromatic sulfonates having a molecular weight of at least 500; and injecting the fluid system down a well. The rheology enhancer may be a lignosulfonate derived from wood pulping. Viscoelastic surfactant systems including the rheology enhancer are also described.

Abstract: An oilfield treatment method is given that uses fluids that contain surfactants used as foamers and/or viscosifiers such that the fluids pass the Alberta Energy and Utilities Board Directive 27 requirements for low toxicity to certain bioluminescent bacteria. Such fluids may be used in oilfield treatments, for example drilling and stimulation, near fresh water aquifers. The surfactants are certain non-ionic surfactants that are not aromatic, or certain amphoteric surfactants (that can be neutral), or certain zwitterionic surfactants, (in which both positive and negative charges are present in a single molecule so that the whole molecule is neutral).

Abstract: A method of treating a shale-containing subterranean formation penetrated by a wellbore is accomplished by forming a carbon dioxide treatment fluid having a viscosity of less than about 10 mPa-s at a shear rate of about 100 s?1. The carbon dioxide treatment fluid is introduced into the formation through the wellbore at a pressure above the fracture pressure of the formation. In certain embodiments, the treatment fluid may be comprised of from about 90% to 100% by weight carbon dioxide and may contain a proppant. A method of treating hydrocarbon-bearing, shale-containing subterranean formation penetrated by a wellbore may also be carried out by forming a carbon dioxide treatment fluid and introducing the carbon dioxide treatment fluid into the formation through the wellbore at a pressure above the fracture pressure of the formation. The formation being treated may have a permeability of less than 1 mD.