Abstract: Emulsified acids have been used to increase production rates of oil and gas in carbonate reservoirs through acid fracturing and matrix acidizing operations. An emulsifier is used to emulsify the aqueous acid with an oil, usually diesel. Very small particles, such as colloidal clay particles and/or nanoparticles increase the stability of the emulsified acids over an elevated temperature range.

Abstract: Nano-particles that possess either selective fluid phase blocks or modify the relative permeability of an earth formation to different fluids are used to inhibit the invasion of borehole mud into the formation. This makes it possible to make formation evaluation measurements using sensors with a shallow depth of investigation.

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 phyllosilicate mineral viscosity enhancers associate, link, connect, or relate the VES elongated micelles into associations thereby increasing the viscosity of the fluid, possibly by mechanisms involving chemisorption or surface charge attractions. The nano-sized phyllosilicate mineral particles, also called clay mineral nanoparticles, 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: Alkaline earth metal compounds may be fluid loss control (FLC) agents for viscoelastic surfactant (VES) fluids used for fluid loss control pills, lost circulation material pills and kill pills in hydrocarbon recovery operations. The FLC 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 FLC agent may alternatively be transition metal oxides and/or transition metal hydroxides. The FLC agent appears to associate with the VES micelles and together form a novel pseudo-filter cake quasi-crosslinked viscous fluid layer that limits further VES fluid flow into the porous media. The FLC agent solid particles may be added along with VES fluids. The pills may also contain internal breakers to reduce the viscosity thereof so that the components of the pill may be recovered.

Abstract: Nanoparticle-treated particle packs, such as sand beds, may effectively filter and purify liquids such as waste water. Proppant beds treated with nanoparticles may fixate or reduce fines migration therethrough. When tiny contaminant particles or fines in these fluids flow through the nanoparticle-treated bed or pack, the nanoparticles will capture and hold the tiny contaminant or fines particles within the pack due to the nanoparticles' surface forces, including, but not necessarily limited to van der Waals and electrostatic forces. Nanoparticle-treated beds or packs may be recharged by contacting the bed with an inorganic acid (but not hydrofluoric acid) or an organic acid, and optionally followed by subsequent treatment with hydrofluoric acid. This treating substantially removes the nanoparticles and the fine particulates that have been removed from a fluid (e.g. wastewater being treated, produced fluids in a formation, etc.). The particle pack may then be re-treated or recharged with nanoparticles.

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: A disposable downhole tool is disclosed. The tool is suitable for use as a frac tool. The tool includes a housing having an inner wall surface defining a bore. The tool also includes a valve structure disposed within the bore, the valve structure comprising a disposable plug seat, the disposable plug seat comprising a first natural material. The disposable tool may also include a disposable plug in fluid sealing engagement with the seat, the plug comprising a second natural material, the plug and the plug seat comprising a plug valve. The first and second natural materials may include sedimentary rock, such as various forms of limestone, including Carrara marble or Indiana limestone.

Abstract: In hydrocarbon recovery applications, viscoelastic surfactant (VES) gelled fluids may be preheated to a temperature that will increase viscosity of the VES gelled fluid. The preheated VES gelled fluid retains at least a portion of its preheated viscosity when cooled such as by introduction into a low temperature condition. In an embodiment, the VES gelled fluid may be a drilling fluid, completion fluid, or fracturing fluid, and the low temperature condition may be an offshore operation, an operation in a locality having a cold climate, and/or a shallow oil, gas, or both land-based operation where the formation temperature is 120° F. or less. The surfactant in the VES gelled fluid may be one or more of an amine, amine salt, quaternary ammonium salt, betaine, amidoamine oxide, amine oxide, and combinations thereof.

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, and the like. The methods are practiced in the absence of acids typically used in acidizing operations, such as hydrochloric acid and hydrofluoric acid.

Abstract: A downhole sealing element includes, a malleable member having at least one closed wall cavity therein positionable downhole in a gap defined between downhole members, and a chemical disposed within the at least one closed wall cavity. The malleable member is deformable to fill variations in a dimension of the gap and the chemical is reactive to form a nonflowable element.

Abstract: Non-aqueous carrier fluids containing nano-sized particles in high concentration are effective for zone isolation and flow control in water shutoff applications for subterranean formations. The nanoparticles interact with water and solidify it to inhibit its flow, but do not have the same effect on hydrocarbons and thus selectively assist the production of hydrocarbons while suppressing water. Suitable nanoparticles include alkaline earth metal oxides, alkaline earth metal hydroxides, alkali metal oxides, alkali metal hydroxides, transition metal oxides, transition metal hydroxides, post-transition metal oxides, post-transition metal hydroxides, piezoelectric crystals, and/or pyroelectric crystals.

Abstract: Viscoelastic surfactant (VES) gelled aqueous fluids containing water, a VES in an amount effective to increase the viscosity of the water, and an internal breaker may be useful in removing a residual polymer from a hydraulic fracture. Optionally, a pseudo-crosslinker may be present to further improve the properties related to treatment fluid placement and polymer clean-up. A plurality of aliquots of VES gelled fluid may be injected into a subterranean formation. A stop-start interval may exist between the injection of each aliquot. The VES gelled fluid may contact at least some of the residual polymer in the hydraulic fracture, and a broken fluid is formed once the viscosity of the VES gelled fluid is reduced with the internal breaker. At least a portion of the residual polymer and a majority of the broken fluid may be removed.

Abstract: Porous objects, such as porous balls, may be employed within telescoping devices to control proppant flowback through a completed well during production. The telescoping devices may connect a reservoir face to a production liner without perforating. Acid-soluble plugs initially disposed within the telescoping devices may provide enough resistance to enable the telescoping devices to extend out from the production liner under hydraulic pressure. The plugs may then be dissolved in an acidic solution, which may also be used as the hydraulic extension fluid. After the plugs are substantially removed from the telescoping devices, the reservoir may be hydraulically fractured using standard fracturing processes. The porous balls may then be inserted into the telescoping devices to block proppant used in the fracturing process from flowing out of the reservoir with the production fluids.

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: Acid-soluble plugs may be employed within telescoping devices to connect a reservoir face to a production liner without perforating. Such technology eliminates formation damage and debris removal associated with perforating, as well as reducing risk and time. The plugs may provide enough resistance to enable the telescoping devices to extend out from the production liner under hydraulic pressure. The plugs may then be dissolved in an acidic solution, which may also be used as the hydraulic extension fluid. After the plugs are substantially removed from the telescoping devices, the reservoir may be hydraulically fractured using standard fracturing processes.

Abstract: An aqueous fluid system that contains an aqueous dicarboxylic acid solution, a viscoelastic surfactant as a gelling agent to increase the viscosity of the fluid, and an internal breaker such as mineral oil and/or fish oil to controllably break the viscosity of the fluid provides a self-diverting acid treatment of subterranean formations. The internal breaker may be at least one mineral oil, a polyalphaolefin oil, a saturated fatty acid, and/or is an unsaturated fatty acid. The VES gelling agent does not yield viscosity until the organic acid starts to spend. Full viscosity yield of the VES gelling agent typically occurs at about 6.0 pH. The internal breaker allows the VES gelling agent to fully viscosify the spent organic acid at 6.0 pH and higher, but as the spent-acid VES gelled fluid reaching reservoir temperature, controllable break of the VES fluid viscosity over time can be achieved.

Abstract: Nanoparticle-treated substrates, such as screens, sand beds or proppant beds, may effectively filter and purify fluids such as waste water or fluids produced from a formation, as well as other liquids. When tiny contaminant particles in a fluid such as waste water flow contact the nanoparticle-treated substrate, the nanoparticles will capture and hold the tiny contaminant particles on the substrate due to the nanoparticles' surface forces, including, but not necessarily limited to van der Waals and electrostatic forces or other associative forces. Coating agents such as alcohols, glycols, polyols, vegetable oil, and mineral oils may help apply the nanoparticles to the surfaces of structures in the filter beds or packs.

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: 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: Compositions including relatively low reactivity acids, mixed with viscoelastic surfactants (VESs) and internal breakers may serve as drilling fluids to open underground hydrocarbon reservoirs with carbonate contents of 10 wt % or above. The drilling fluids have low viscosities in the drilling pipe. After the fluid flows out of the drill bit, the acids react with carbonates in the formation thereby increasing the pH of the drilling fluids causing the VES to gel the fluid at the bottom of the hole and the downhole annulus between the drilling pipe and the formation rock. The viscosified drilling fluid will reduce fluid loss and will carry no dissolved drilling debris to the surface. After drilling through the targeted formation, the internal breakers in the viscosified drilling fluids will break down the fluids to permit their removal, and the well is ready to produce with very little or no near well bore damage.