A self-suspending proppant that resists the adverse effects of calcium and other cations on swelling comprises a proppant substrate particle and a gelatinized cationic starch coating on the proppant substrate particle.

A synthetic acid composition for use in oil industry activities, said composition comprising: urea and hydrogen chloride in a molar ratio of not less than 0.1:1; and an alcohol or derivative thereof optionally, it may further comprise a phosphonic acid derivative.

Discrete, individualized carbon nanotubes having targeted, or selective, oxidation levels and/or content on the interior and exterior of the tube walls can be used for nanotube-mediated controlled delivery of degradative molecules, such as oxidizers and enzymes, for oil-field drilling applications. A manufacturing process using minimal acid oxidation for carbon nanotubes may also be used which provides higher levels of oxidation compared to other known manufacturing processes.

A wellbore treatment fluid comprising: a base fluid; and a water-soluble salt, the salt comprising: a cation; and an anion, wherein the anion is selected from phosphotungstate, silicotungstate, phosphomolybdate, and silicomolybdate. The treatment fluid can have a density greater than or equal to 13 pounds per gallon. A method of treating a portion of a subterranean formation penetrated by a well comprising: introducing the treatment fluid into the well.

Treatment fluids for use in subterranean formations, particularly sandstone and other siliceous formations, may contain a source of fluoride ions to aid in mineral dissolution. In some cases, it may be desirable to generate the fluoride ions from a fluoride ion precursor, particularly a hydrofluoric acid precursor, such as a boron trifluoride complex. Methods described herein can comprise providing a treatment fluid that comprises an aqueous base fluid, a boron trifluoride complex, and a chelating agent composition, and introducing the treatment fluid into a subterranean formation.

A drilling mud composition including Aloe vera particles with a largest dimension of 75-600 μm, an aqueous base fluid, and a viscosifier, where the Aloe vera particles are present in the drilling mud composition at a concentration of less than 150 ppm, relative to the total weight of the drilling mud composition. A process for fracking a geological formation, whereby the drilling mud composition is injected into the geological formation through a well bore at a pressure of at least 5,000 psi to fracture the geological formation.

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.

The present invention relates to a method for increasing oil recovery from an oil-bearing formation including the following successive stages of treating the formation: injecting an invert emulsion in a volume of 3-5 m.sup.3/m of perforated interval thickness followed by squeezing down an acidic composition or a composition containing a nonionic surfactant in a volume of 2-3 m.sup.3/m of perforated interval thickness to the formation, injecting a highly stable direct emulsion containing a colloidal solution of silicon dioxide nanoparticles in a volume of 3-7 m.sup.3/m of perforated interval thickness followed by squeezing down a liquid from a reservoir pressure maintenance system to the formation.

A system and method of decreasing contaminant concentration in an oilfield brine fluid, such as a high density completions fluid, that includes mixing the oilfield brine fluid with chlorine dioxide (ClO.sub.2). The oilfield brine fluid includes dissolved contaminant, such as iron, and one or more dissolved salts, such as selected from the group consisting of NaCl, NaBr, CaCl.sub.2, CaBr.sub.2, and ZnBr.sub.2. The mixing is for a time sufficient for the ClO.sub.2 to react with at least one component of the oilfield brine fluid to form precipitated contaminant without reacting to the one or more salts.

A gel composition for use in subterranean formations is disclosed. The composition can comprise a base fluid, a cross-linkable polymer that is soluble in the base fluid, a nonionic surfactant and a cross-linking agent. The gel composition has improved crosslinked stability. The gel composition can be injected into the subterranean formation as a fracturing fluid and allowed to penetrate the formation. Preferably, the gel composition effectively blocks the water-bearing regions while the oil or gas producing regions are left unblocked so that the oil or gas can be recovered.