Abstract: The current application discloses methods and systems to analyze on-site and in real-time or quasi real-time the composition of the well fluid before or during use or disposition. The method is based on capillary electrophoresis (CE) and does not require the addition of tracers into the well fluid or additive. Based on the significance of each additive on the well fluid properties, it can be decided to determine the concentration of all additives or only one or a limited number of the additives present in the fluid, and the concentrations can be adjusted as needed to reach the desired target concentration(s).

Abstract: Hydroxyethylcellulose (HEG) may be used to provide fluid-loss control in well-cement slurries HECs that have a molecular weight above 600,000, a degree of substitution higher than 1.9 and a molar substitution above 2.0 are particularly useful in that they not only provide fluid-loss control, but also may be used as a cement extender. Furthermore, the retardation effect may be reduced.

Abstract: The current application discloses methods and systems to analyze on-site and in real-time or quasi real-time the composition of the well fluid before or during use or disposition. The method is based on capillary electrophoresis (CE) and does not require the addition of tracers into the well fluid or additive. Based on the significance of each additive on the well fluid properties, it can be decided to determine the concentration of all additives or only one or a limited number of the additives present in the fluid, and the concentrations can be adjusted as needed to reach the desired target concentration(s).

Abstract: A thermoviscoelastic system (TVE) fluid useful in a well treatment method can include a hydrophobically-modified polymer and a viscoelastic surfactant (VES) in an aqueous medium, wherein the polymer has a lower critical solution temperature (LCST). The polymer can have water solubility for preparation below the LCST, and the TVE has a low viscosity for pumping down a well bore in communication with a subterranean formation. When the TVE is heated above the LCST, interaction between the hydrophobic groups of the polymer and the VES form a cross-linked network to increase the viscosity to transport proppant into a fracture. The thickened TVE can have a low leak-off rate, optionally including colloidal particles or other fluid loss control agent, and can be broken by contact with hydrocarbons as during flowback from the reservoir.

Abstract: A cement slurry composition is described as having cement, water, and organic polymer particles. The composition also includes non-ionic surfactants, which may contain ethoxylate groups or contain both ethoxylate groups and propoxylate groups in the hydrophilic part. The non-ionic surfactant acts to disperse the hydrophobic polymeric particles in the slurry, thereby reducing mixing time. The cement slurry composition is prepared and then pumped into the subterranean well and placed in a zone of the subterranean well. Time is then allowed for the cement slurry composition to set and form a solid mass in the zone.

Abstract: A method of treating a sandstone-containing formation penetrated by a wellbore is carried out by forming a treatment fluid comprising an aqueous fluid containing a hydrogen fluoride source and an amorphous silica precipitation inhibitor. The treatment fluid is introduced into the formation through the wellbore at a pressure below the fracture pressure of the formation to facilitate dissolution of formation materials, optionally as a single stage. The amorphous silica inhibitor may be a polycarboxylate and/or polycarboxylic acid, an organosilane or a phosphonate compound. The amorphous silica inhibitor may be capable of inhibiting precipitation of amorphous silica so that the treatment fluid contains at least about 500 ppm of silicon after at least about 100 minutes subsequent to the treatment fluid being introduced into the formation.

Abstract: A method for treating a subterranean formation penetrated by a wellbore comprising combining a carrier fluid, a first amount of particulates, and a second amount of particulates into a slurry, wherein the first amount of particulates have a first average size distribution and the second amount of particulates have a second average size distribution, wherein at least one of the first amount of particulates and the second amount of particulates comprise an expanding material, placing the slurry in the wellbore, and lowering a screen into the slurry.

Abstract: The invention concerns an aqueous viscoelastic fracturing fluid for use in the recovery of hydrocarbons. According to the invention, the fluid comprises a cleavable viscoelastic surfactant and a hydrophobically-modified polymer, wherein the cleavable surfactant comprises a head group and a hydrophobic tail of at least 18 carbon atoms connected through a degradable acetal, amide, ether or ester bond and wherein the concentration of the hydrophobically-modified polymer is comprised between its overlap concentration c* and its entanglement concentration ce.

Abstract: An apparatus and a method for treating a subterranean formation penetrated by a wellbore comprising combining a carrier fluid, a first amount of particulates, and a second amount of particulates into a slurry, wherein the first amount of particulates have a first average size distribution and the second amount of particulates have a second average size distribution, wherein the first amount of particulates comprise an expanding material, placing the slurry in the wellbore, and lowering a screen into the slurry.

Abstract: The invention discloses a method of treating a subterranean formation of a well bore, comprising: providing a treatment fluid comprising a carrier fluid, proppant, a viscosifying agent 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, allowing the treatment fluid to interact with a trigger able to activate the viscosifier material from first state to second state.

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 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: 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: 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 provides a method for treating tight gas sand and shale subterranean formations, the method comprising: forming a solvent-surfactant blend by combining a solvent, a surfactant and a co-surfactant; adding a diluent to the solvent-surfactant blend to form a micro emulsion; wherein the wettability of the formation altered from water-wet to gas-wet, and the amount of water imbibed into the formation is reduced.

Abstract: A method of treating a sandstone-containing formation penetrated by a wellbore is carried out by forming a treatment fluid comprising an aqueous fluid containing a hydrogen fluoride source and an amorphous silica precipitation inhibitor. The treatment fluid is introduced into the formation through the wellbore at a pressure below the fracture pressure of the formation to facilitate dissolution of formation materials, optionally as a single stage. The amorphous silica inhibitor may be a polycarboxylate and/or polycarboxylic acid, an organosilane or a phosphonate compound. The amorphous silica inhibitor may be capable of inhibiting precipitation of amorphous silica so that the treatment fluid contains at least about 500 ppm of silicon after at least about 100 minutes subsequent to the treatment fluid being introduced into the formation.

Abstract: The invention concerns an aqueous viscoelastic fracturing fluid for use in the recovery of hydrocarbons. According to the invention, the fluid comprises a cleavable viscoelastic surfactant and a hydrophobically-modified polymer, wherein the cleavable surfactant comprises a head group and a hydrophobic tail of at least 18 carbon atoms connected through a degradable acetal, amide, ether or ester bond and wherein the concentration of the hydrophobically-modified polymer is comprised between its overlap concentration c* and its entanglement concentration ce.

Abstract: The invention provides a method of treating a sandstone-containing subterranean formation penetrated by a wellbore. The method is carried out by forming a slurry of a carrier fluid containing a viscosifying agent and encapsulated particles of a hydrogen fluoride source without settling of the particles. The carrier fluid may be an acid-based carrier fluid. The encapsulated hydrogen fluoride source may be encapsulated with a solid polymer acid precursor. The hydrogen fluoride source is present within the slurry in an amount of about 10% or more by weight of the slurry. The slurry is introduced into the wellbore at a pressure above the fracture pressure of the formation under conditions wherein the hydrogen fluoride source is released.

Abstract: In a method of treating a sandstone-containing subterranean formation penetrated by a wellbore, a slurry of a carrier fluid containing a surface modification agent of at least one of a hydrolyzable organosilicon compound, a phosphonate compound or a combination of these is formed. The slurry is introduced into the wellbore at or above the fracture pressure of the formation. A sandstone-dissolving material is introduced into the wellbore with or subsequent to introduction of the slurry. The surface modification agent may be encapsulated within an encapsulating material. A composition for use in treating sandstone-containing subterranean formations is also provided. The composition includes an aqueous carrier fluid containing an encapsulated surface modification agent of at least one of a hydrolysable organosilicon compound and a phosphonate compound that is encapsulated within an encapsulating material.

Abstract: The invention concerns an aqueous viscoelastic fracturing fluid for use in the recovery of hydrocarbons. According to the invention, the fluid comprises a viscoelastic surfactant and a hydrophobically-modified polymer wherein the concentration of the hydrophobically-modified polymer is comprised between its overlap concentration c* and its entanglement concentration ce.