Abstract: An aqueous, viscoelastic treating fluid gelled with a crosslinked guar or guar derivative is stabilized and improved with an effective amount of a glycol, such as ethylene glycol. These fluids are more stable in that viscosity is maintained, particularly at elevated temperatures. The additives may also increase viscosity to the point where less of a crosslinked guar or guar derivative gelling agent is required to maintain a given viscosity. These stabilized, enhanced, aqueous, viscoelastic fluids may be used as treatment fluids for subterranean hydrocarbon formations, such as in hydraulic fracturing.

Abstract: An aqueous, viscoelastic fluid gelled with a viscoelastic surfactant (VES) is inhibited against hydrate formation with an effective amount of an additive that could be one or more halide salts of alkali metals and alkali earth metals, formate salts, alcohols, glycols, glycol amines, sugars, sugar alcohols, amidoamine oxides, polymers such as polyamines, polyvinylpyrrolidones and derivatives thereof, polyvinyl alcohols and derivatives thereof, polycaprolactams and derivatives thereof, hydroxyethylcellulose, and mixtures thereof. These fluids are inhibited against hydrate formation and may have increased viscosity as well. The additives may increase viscosity to the point where less VES is required to maintain a given viscosity. These inhibited, aqueous, viscoelastic fluids may be used as treatment fluids for subterranean hydrocarbon formations, such as in stimulation treatments, e.g. hydraulic fracturing fluids.

Abstract: An aqueous, viscoelastic fluid gelled with a viscoelastic surfactant (VES) is stabilized and improved with an effective amount of an alkali earth metal oxide and/or alkali earth metal hydroxide. These fluids are more stable and have reduced or no tendency to precipitate, particularly at elevated temperatures. The additives may also increase viscosity to the point where less VES is required to maintain a given viscosity. These stabilized, enhanced, aqueous viscoelastic fluids may be used as treatment fluids for subterranean hydrocarbon formations, such as in hydraulic fracturing.

Abstract: A silicate drilling fluid having effective rheology and filtration control properties comprising water as a continuous phase wherein hematite is used as a weighting agent and manganese oxide is used as a bridging agent. The drilling fluids uses a minimal number of components, which includes a salt, preferably sodium chloride, water-soluble polymers for viscosification and filtration control, and a glycol for shale stabilization and filtration control.

Abstract: New compositions have been discovered which are useful as slurry concentrates to carry solid particles along in a fluid. A non-limiting example would be to carry proppants in a concentrate to a completion fluid being pumped downhole in a hydrocarbon recovery operation. The composition employs both a trivalent salt, such as aluminum chlorohydrate, as a viscosifying agent, and a surfactant. Surprisingly, it has been discovered that a synergistic effect is present between the aluminum chlorohydrate and the surfactant in that less of each component is required when both are used together to suspend the same amount of solids, than if one or the other is used separately. The viscoelasticity of the concentrate may be easily broken by dilution; other mechanisms are also anticipated.

Abstract: A drilling fluid having a brine base fluid, aluminum chlorohydrate as a viscosifying agent, an alkoxylated surfactant, and an amphoteric polymer encapsulant has been found to have excellent viscoelasticity and suspension characteristics. Surprisingly, it has been discovered that a synergistic effect is present between the aluminum chlorohydrate and the surfactant such that less of each component is required when both are used together to suspend the same amount of solids, than if one or the other is used separately.

Abstract: An oil-based fluid system has been discovered using a distribution of salt particle sizes, an oil or water/oil emulsion, a suspending agent for suspending the salt particles in the oil and a filtration control agent. It is important that the salt particles be distributed across a wide size range to effectively prevent filtration or fluid loss into the formation. Since the filter cake particles do not invade the well bore, no high pressure spike occurs during the removal of the filter cake. This high pressure spike indicates damage to the formation and well bore surface, which damage typically reduces overall permeability of the formation. The rheological properties of the fluid allow it to be used in a number of applications where protection of the original permeable formation is desirable. The applications include, but are not limited to, drilling fracturing and controlling fluid losses during completion operations, such as gravel packing or well bore workovers.