Abstract: Alkaline earth metal compounds may be fluid loss control agents for viscoelastic surfactant (VES) fluids used for well completion or stimulation in hydrocarbon recovery operations. The VES fluid may further include proppant or gravel, if it is intended for use as a fracturing fluid or a gravel packing fluid, although such uses do not require that the fluid contain proppant or gravel. The fluid loss control agents may include, but not be limited to, oxides and hydroxides of alkaline earth metal, and in one case magnesium oxide where the particle size of the magnesium oxide is between 1 nanometer to 0.4 millimeter. The fluid loss agent appears to associate with the VES micelles and together form a novel pseudo-filter cake crosslinked-like viscous fluid layer that limits further VES fluid flow into the porous media. The fluid loss control agent solid particles may be added along with VES fluids.

Abstract: The handling, transport and delivery of particulate materials, particularly fine particles, may be difficult. Alkaline earth metal oxide particles such as magnesium oxide (MgO) may be suspended in glycerin and/or alkylene glycols such as propylene glycol up to loadings of 51 wt %. Such suspensions or slurries make it easier to deliver MgO and similar agents into fluids, such as aqueous fluids gelled with viscoelastic surfactants (VES). The MgO serves as stabilizers and/or fluid loss control agents for VES-gelled fluids used to treat subterranean formations, e.g. for well completion or stimulation in hydrocarbon recovery operations. The particle size of the magnesium oxide or other agent may be between 1 nanometer to 0.4 millimeter.

Abstract: The handling, transport and delivery of particulate materials, particularly fine particles, may be difficult. Alkaline earth metal oxide particles such as magnesium oxide (MgO) may be suspended in glycerin and/or alkylene glycols such as propylene glycol up to loadings of 51 wt %. Such suspensions or slurries make it easier to deliver MgO and similar agents into fluids, such as aqueous fluids gelled with viscoelastic surfactants (VES). These concentrated suspensions or slurries may be improved in their stability by the inclusion of minor amounts of a vegetable oil and/or a fish oil. The MgO serves as stabilizers and/or fluid loss control agents for VES-gelled fluids used to treat subterranean formations, e.g. for well completion or stimulation in hydrocarbon recovery operations. The particle size of the magnesium oxide or other agent may be between 1 nanometer to 0.4 millimeter.

Abstract: Piezoelectric crystal particles (which include pyroelectric crystal particles) enhance the viscosity of aqueous fluids that have increased viscosity due to the presence of viscoelastic surfactants (VESs). In one non-limiting theory, when the fluid containing the viscosity enhancers is heated and/or placed under pressure, the particles develop surface charges that associate, link, connect, or relate the VES micelles thereby increasing the viscosity of the fluid. The higher fluid viscosity is beneficial to crack the formation rock during a fracturing operation, reduce fluid leakoff, and carry high loading proppants to maintain the high conductivity of fractures.

Abstract: Viscoelastic surfactant (VES) gelled aqueous fluids containing a VES, an internal breaker, and optionally a viscosity enhancer are useful as diverting fluid for directing placement of an acid into a subterranean formation, where the acid is injected subsequent to introducing the VES gelled fluid. These VES-based diverting fluids have faster and more complete clean-up than polymer-based diverting fluids. The viscosity enhancers may include pyroelectric particles and/or piezoelectric particles. The VES gelled fluid may optionally contain a fluid loss agent which increases the viscosity of the fluid and/or facilitates development of an external viscous VES fluid layer (e.g. a pseudo-filter cake) on the formation face. The VES gelled fluid may also optionally contain an agent that stabilizes the viscosity of the fluid, for instance at high temperatures, such as MgO, Mg(OH)2, CaO, Ca(OH)2, NaOH, and the like.

Abstract: A flow conduit having at least one orifice is placed in the vicinity of a flow source, which in one non-limiting embodiment may be a hydrocarbon reservoir. The flow pathway between the orifice and the source is temporarily blocked with a degradable barrier. Once the flow pathway is physically placed, the degradable barrier is removed under the influence of an acid, a solvent, time and/or temperature. The flow source and the flow pathways are at least partially covered (and flow blocked by) a temporary coating such as a pseudo-filter cake formed by a viscoelastic surfactant-gelled aqueous drill-in fluid, and the flow conduit is extended to the flow source. The pseudo-filter cake is removed when viscosity is reduced by an internal breaker, and flow is then allowed. The method is useful in one context of recovering hydrocarbons where the flow conduit is a telescoping sleeve or tube that contacts the borehole wall.

Abstract: A fracturing fluid, gravel pack fluid and/or frac pack fluid containing particles such as proppants, gravel and/or sand, may contain an effective amount of a nano-sized particulate additive to fixate or reduce fines migration, where the particulate additive is an alkaline earth metal oxide, alkaline earth metal hydroxide, alkali metal oxides, alkali metal hydroxides, transition metal oxides, transition metal hydroxides, post-transition metal oxides, post-transition metal hydroxides piezoelectric crystals and pyroelectric crystals. The nano-sized particulate additive is bound to the particles with a coating agent such as an oil. The particle size of the magnesium oxide or other agent may be nanometer scale, which scale may provide unique particle charges that help fixate the formation fines. The carrier fluid used in the treating fluid may be aqueous, brine, alcoholic or hydrocarbon-based.

Abstract: An apparatus for controlling fluid flow into a tubular includes an in-flow control device having a plurality of flow paths; and a reactive media disposed in each of the flow paths. The reactive media may change permeability by interacting with a selected fluid such as water. Two or more of the flow paths may be hydraulically parallel. The reactive media may include a Relative Permeability Modifier. An associated method may include conveying the fluid via a plurality of flow paths; and controlling a resistance to flow in plurality of flow paths using a reactive media disposed in each of the flow paths. An associated system may include a wellbore tubular; an in-flow control device; a hydraulic circuit formed in the in-flow control device; and a reactive media disposed in the hydraulic circuit, the reactive media may change permeability by interacting with a selected fluid.

Abstract: An aqueous, viscoelastic fluid gelled with a viscoelastic surfactant (VES) is stabilized and improved with an effective amount of an alkaline earth metal oxide alkaline earth metal hydroxide, alkali metal oxides, alkali metal hydroxides transition metal oxides, transition metal hydroxides, post-transition metal oxides, and post-transition metal hydroxides. These fluids are more stable and have a reduced or no tendency to precipitate, particularly at elevated temperatures, and may also help control fluid loss. When the particle size of the magnesium oxide or other particulate agent is a nanometer scale, for instance having a mean particle size of 100 nm or less, that scale may provide unique particle charges that use chemisorption, “crosslinking” and/or other chemistries to associate and stabilize the VES fluids, and also help trap or fixate formation fines when deposited into a proppant pack in a fracture.

Abstract: Nano-sized clay minerals enhance the viscosity of aqueous fluids that have increased viscosity due to the presence of viscoelastic surfactants (VESs). In one non-limiting theory, the nano-sized clay mineral viscosity enhancers associate, link, connect, or relate the VES micelles thereby increasing the viscosity of the fluid, possibly by mechanisms involving chemisorption or surface charge attractions. The nano-sized clay particles may have irregular surface charges. The higher fluid viscosity is beneficial to crack the formation rock during a fracturing operation, to reduce fluid leakoff, and to carry high loading proppants to maintain the high conductivity of fractures.

Abstract: A flow conduit having at least one orifice is placed in the vicinity of a flow source, which in one non-limiting embodiment may be a hydrocarbon reservoir. The flow pathway between the orifice and the source is temporarily blocked with a degradable barrier. Once the flow pathway is physically placed, the degradable barrier is removed under the influence of an acid, a solvent, time and/or temperature. The flow source and the flow pathways are at least partially covered (and flow blocked by) a temporary coating such as a pseudo-filter cake formed by a viscoelastic surfactant-gelled aqueous drill-in fluid, and the flow conduit is extended to the flow source. The pseudo-filter cake is removed when viscosity is reduced by an internal breaker, and flow is then allowed. The method is useful in one context of recovering hydrocarbons where the flow conduit is a telescoping sleeve or tube that contacts the borehole wall.

Abstract: Viscoelastic surfactant (VES) based fluid systems are effective to pre-saturate high permeability subterranean formations prior to a treatment operation that would undesirably suffer from high fluid leakoff. The fluid systems may include brine, a viscosity enhancer, as well as the VES, and a high temperature stabilizer. The stabilizer may be an alkaline earth metal oxide, alkaline earth metal hydroxide, alkali metal oxide, alkali metal hydroxide, Al2O3, and mixtures thereof. The viscosity enhancer may include pyroelectric particles, piezoelectric particles, and mixtures thereof. The fluid system is easy to pump into the formation, and after initial pumping, the fluid system will soak into and occupy or “pre-saturate” the pores of the formation prior to pumping of a second treating fluid for fracturing, gravel packing, frac-packing, matrix acidizing, and the like.

Abstract: Viscoelastic surfactant (VES) based fluid systems for zone isolation and flow control are effective in water and/or gas shutoff applications. The fluid systems may include brine, a viscosity enhancer, as well as the VES, and optionally a stabilizer for high temperature applications. The stabilizer may be an alkali earth metal oxide, alkali earth metal hydroxide, alkali metal oxide, alkali metal hydroxide, Al2O3, and mixtures thereof. The viscosity enhancer may include pyroelectric particles, piezoelectric particles, and mixtures thereof. The fluid system is easy to pump into the formation, and after pumping, the fluid system will generate very high viscosities to prevent the VES fluid from flowing back to stop undesirable water and/or gas production.

Abstract: Fluids viscosified with viscoelastic surfactants (VESs) may have their viscosities reduced (gels broken) by the direct or indirect action of a synergistic internal breaker composition that contains at least one first internal breaker that may be a mineral oil and a second breaker that may be an unsaturated fatty acid. The internal breakers may initially be dispersed oil droplets in an internal, discontinuous phase of the fluid. This combination of different types of internal breakers break the VES-gelled aqueous fluid faster than if one of the breaker types is used alone in an equivalent total amount.

Abstract: The handling, transport and delivery of particulate materials, particularly fine particles, may be difficult. Alkaline earth metal oxide particles such as magnesium oxide (MgO) may be suspended in glycerin and/or alkylene glycols such as propylene glycol up to loadings of 51 wt %. Such suspensions or slurries make it easier to deliver MgO and similar agents into fluids, such as aqueous fluids gelled with viscoelastic surfactants (VES). These concentrated suspensions or slurries may be improved in their stability by the inclusion of minor amounts of a vegetable oil and/or a fish oil. The MgO serves as stabilizers and/or fluid loss control agents for VES-gelled fluids used to treat subterranean formations, e.g. for well completion or stimulation in hydrocarbon recovery operations. The particle size of the magnesium oxide or other agent may be between 1 nanometer to 0.4 millimeter.

Abstract: Viscoelastic surfactant (VES) gelled aqueous fluids containing water, a VES, an internal breaker, a VES stabilizer, a fluid loss control agent and a viscosity enhancer are useful as treating fluids and particularly as fracturing fluids for subterranean formations. These VES-based fluids have faster and more complete clean-up than polymer-based fracturing fluids. The use of an internal breaker permits ready removal of the unique VES micelle based pseudo-filter cake with several advantages including reducing the typical VES loading and total fluid volume since more VES fluid stays within the fracture, generating a more optimum fracture geometry for enhanced reservoir productivity, and treating reservoirs with permeability above the present VES limit of approximately 400 md to at least 2000 md.

Abstract: An aqueous, viscoelastic fluid gelled with a viscoelastic surfactant (VES) may suspend solids such as proppants, gravel, drilling debris, waste solids and the like with an effective amount of a nano-sized additive including, but not necessarily limited to alkali earth metal oxides, alkali earth metal hydroxides, alkali metal oxides, alkali metal hydroxides, transition metal oxides, transition metal hydroxides, post-transition metal oxides, and post-transition metal hydroxides. The additives may also reduce the amount of VES required to maintain a given viscosity. These viscoelastic surfactant gelled aqueous fluids may be used as treatment fluids for subterranean hydrocarbon formations, such as in hydraulic fracturing, gravel packing and the like. The magnesium oxide, zinc oxide or other nanometer scale-sized additives are at a scale that may provide unique particle charges that use chemisorption, crosslinking and/or other chemistries to associate the micelles and suspend the solids.

Abstract: Fluids viscosified with viscoelastic surfactants (VESs) may have their fluid loss properties improved with the presence of at least one mineral oil in combination with at least one particulate fluid loss control agent that may be an alkaline earth metal oxides, alkaline earth metal hydroxides, transition metal oxides, transition metal hydroxides, and mixtures thereof. The mineral oil may initially be dispersed oil droplets in an internal, discontinuous phase of the fluid. In one non-limiting embodiment, the mineral oil is added to the fluid after it has been substantially gelled. The particulate fluid loss control agent may be added in any order relative to the VES and the mineral oil fluid loss control agent. The mineral oil may enhance the ability of a particulate fluid loss control agent to reduce fluid loss. The presence of the mineral oil may also eventually reduce the viscosity of the VES-gelled aqueous fluid.

Abstract: Piezoelectric crystal particles (which include pyroelectric crystal particles) enhance the viscosity of aqueous fluids that have increased viscosity due to the presence of viscoelastic surfactants (VESs). In one non-limiting theory, when the fluid containing the viscosity enhancers is heated and/or placed under pressure, the particles develop surface charges that associate, link, connect, or relate the VES micelles thereby increasing the viscosity of the fluid. The higher fluid viscosity is beneficial to crack the formation rock during a fracturing operation, reduce fluid leakoff, and carry high loading proppants to maintain the high conductivity of fractures.

Abstract: Fluids viscosified with viscoelastic surfactants (VESs) may have their fluid loss properties improved with at least one mineral oil which has a viscosity greater than 20 cps at ambient temperature. The mineral oil may initially be dispersed oil droplets in an internal, discontinuous phase of the fluid. In one non-limiting embodiment, the mineral oil is added to the fluid after it has been substantially gelled in an amount between about 0.2 to about 10% by volume.