Abstract: A method of stabilizing a clayey geological formation surrounding a hydrocarbon well is described. It comprises the step of treating the formation with a first reactant and a second reactant, characterized in that a reaction of said first and said second reactant is essentially initiated in the presence of clayey material. The reaction can be characterized by substrate intercalation or condensation stabilization with no pH adjustment or stabilization through reaction of glycol with a carbonyl group containing second reactant or a reaction involving an epoxide ring opening under neutral or acidic conditions.

Abstract: This invention relates generally to the art of hydraulic fracturing in subterranean formations and more particularly to a method and means for optimizing fracture conductivity. According to the present invention, the well productivity is increased by sequentially injecting into the wellbore alternate stages of fracturing fluids having a contrast in their ability to transport propping agents to improve proppant placement, or having a contrast in the amount of transported propping agents.

Abstract: Present invention relates to high brine carrier fluid, said carrier fluid selected from the group consisting of organic acids, organic acid salts, inorganic salts and combination of one or more organic acids or organic acid salts, a co-surfactant and an amount of a zwitterionic surfactant. The invention also relates to methods of treating a subterranean wellbore, including drilling, hydraulic fracturing, gravel placement, scale removing, mud cake removing, using said high brine carrier fluid.

Abstract: A new process of fracture stimulating a carbonate reservoir in a subterranean formation to stimulate the production of hydrocarbon fluids from the formation is described. During the process, the composition and reactivity of the fracture stimulation fluid that is injected into the formation surrounding a wellbore is varied from a lower reactive fluid to a higher reactive fluid. The process is designed to stimulate the fracture starting from the tip of the fracture and progressing along the fracture back to the wellbore. The reactivity of the fracture stimulation fluid is increased to maintain optimum stimulation conditions for the formation of conductive flow channels along the faces of the fracture. An optimum fracture stimulation efficiency number, Ff, is used (generally integrated into a fracture simulator computer program) to regulate the fluid composition by reactivity and flow rate, based on formation and fluid parameters.

Abstract: The present invention provides cementing compositions for an oil well or the like, comprising an hydraulic binder, dense particles with a density higher than the density of the hydraulic binder, and reinforcing particles with a density of less than 1.5 g/cm3, preferably less than 1.2 g/cm3, constituted by a flexible material or rubber, of low compressibility and with an average grain size of less than 600 &mgr;m. The compositions of the invention are of particular advantage when preventing zones which are subjected to extreme stresses, such as perforation zones and the junctions of a multi-branch lateral well. They are also highly suitable for producing plugs.

Abstract: Improved aqueous fracturing fluids are disclosed that are particularly useful as well stimulation fluids to fracture tight (i.e., low permeability) subterranean formations. Gas wells treated with these fracturing fluids have rapid cleanup and enhanced well production. The fluids contain small but sufficient amounts of certain amine oxides to aid in the removal of the fracturing fluid from the formation. By facilitating the removal of fluid from the invaded zones, the amount of damage to the fracture faces in the formation is thereby minimized. The amine oxides correspond to the formula I, wherein R1 is an aliphatic group of from 6 to about 20 carbon atoms, and wherein R2 and R3 are each independently alkyl of from 1 to about 4 carbon atoms.

Abstract: A method for hydraulic fracturing subterranean formation whereby at least part of the fracture is propped with proppant material essentially in the form of elongated particles having a shape with a length-basis aspect ratio greater than 5, preferably such as metallic wire segment. The remaining part of the fracture may be propped with conventional non-metallic proppant. Fracture conductivity is optimized.

Abstract: A well treatment fluid composition that comprises a carrier fluid and an amphoteric surfactant, and optionally a viscosifying agent and proppant, is well suited for use in fracturing coal beds to stimulate methane production. The composition preferably is a foam that comprises a gas such as nitrogen or air. Preferably, the surfactant has the formula R—NH2—(CH2)n—C(O)OX wherein R is a saturated or unsaturated alkyl group having from 6-20 carbon atoms, n is from 2-6, and X is hydrogen or a salt forming cation.

Abstract: A method for assessing the fracture pressure closure is proposed. This method includes first injecting a fluid into the formation at a first generally constant rate Q to create a fracture, and then, dropping the pumping rate to significantly smaller feed rate q so that the volume of the fracture becomes constant, in other words. As the fracture volume becomes constant at equilibrium, the well is shut-in. The wellbore pressure is monitored and the closure pressure is determined from the analysis of the wellbore pressure using a time-function of the dimensionless “shut-in” time, defined as the ratio of time since shutting to pumping time. This method provides a way of estimating the friction component of the monitored wellbore pressure due to the fracture tortuosity and friction. It is applicable to the art of fracturing subterranean formations and more particularly to the process of designing and analyzing stimulation treatments.

Abstract: Viscoelastic surfactant based aqueous fluid systems useful as thickening agents in various applications, e.g. to suspend particles produced during the excavation of geologic formations. The surfactants are zwitterionic/amphoteric surfactants such as dihydroxyl alkyl glycinate, alkyl ampho acetate or propionate, alkyl betaine, alkyl amidopropyl betaine and alkylimino mono- or di-propionates derived from certain waxes, fats and oils. The thickening agent is used in conjunction with an inorganic water-soluble salt or organic additive such as phthalic acid, salicylic acid or their salts.

Abstract: A valve apparatus that has a longitudinal axis therethrough comprises a valve seat member, a valve closure member, a fluid flow path, and a screening member. The valve seat member comprises a hollow bore and a first frustoconical contact surface. The valve closure member comprises a body and a second frustoconical contact surface that is adapted to seal against the first frustoconical contact surface. The valve closure member is movable along the longitudinal axis of the valve apparatus. The fluid flow path extends through the bore of the valve seat member and between the valve seat member and the valve closure member. This fluid flow path is closed when the second frustoconical contact surface is sealed against the first frustoconical contact surface. The screening member is attached to at least one of the valve closure member or the valve seat member, and screens particles from fluid passing through the fluid flow path when the valve closure member approaches the valve seat member.

Abstract: A surfactant composition for use in well treatment, particularly for removing oil-based mud deposits from a well prior to cementing, comprises an alkylpolyglucoside in a solution of a mutual solvent for water and hydrocarbon. The composition can be used to formulate a chemical wash by dissolving the composition at a concentration of about 1%-10% (e.g. 5%) by weight in water or brine.

Abstract: This Invention relates to a novel reversible thickener, i.e., a fluid whose viscosity can be carefully modulated—from very low viscosity to sufficient viscosity to act as a barrier to further flow; particularly preferred embodiments are directed to fluids and methods for stimulating hydrocarbon low viscosity to sufficient viscosity to act as a barrier to further flow; particularly preferred—bearing formations—i.e., to increase the production of oil/gas from the formation. In particular, the Present Invention is directed to a family of fluids (and methods incorporating those fluids) intended to be pumped through a wellbore and into the hydrocarbon-bearing formation.

Abstract: Methods are provided for increasing the production of hydrocarbons from shaly formations that contain adsorbed condensed hydrocarbon gases by treating such formations with dewatering compositions comprising surfactants that cause the surfaces of the formation to be or to remain oil-wet. The methods may be used in stimulation (acidizing or acid fracturing or hydraulic fracturing), remediation or workover, and in enhancing flow from natural fractures or from unstimulated formations.

Abstract: The present invention provides a cementing composition for an oil well or the like with porosity of less than 50%, and with a solid phase constituted by 35% to 65% (by volume) hollow microspheres, 20% to 45% Class G Portland cement, and 5% to 25% of Class G Portland micro-cement. The invention is used to cement conductor pipes in arctic zones or in deep water holes.

Abstract: A cementing composition comprising a hydraulic cement powder dispersed in a solvent that is miscible both with water and hydrocarbons to make a slurry. The cement powder can be made up simply of hydraulic cement materials or can be a mixture of such materials with particles that are inert or reactive with cement. The composition can also include surfactants or retarders. The composition is used to plug water production in a well while leaving hydrocarbon production unaffected.

Abstract: Non-aqueous base wellbore fluids characterized by enhanced electrical conductivity due to formulation with specified ionic liquids are disclosed. Drilling, completion, and workover methods utilizing the wellbore fluids are also disclosed.

Abstract: Herein is disclosed a well completion or stimulation fluid, comprising (i) a carrier fluid; (ii) a viscoelastic surfactant; and (iii) a fluid loss control additive (FLA) comprising at least one polymer and at least one crosslinker. The fluid may further comprise 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 comprise proppant or gravel. Also disclosed herein are methods of fracturing a subterranean formation, comprising (i) providing a fracturing fluid discussed above and (ii) injecting the fracturing fluid into the formation at a pressure sufficiently high to fracture the formation. In addition, disclosed herein are methods of gravel packing a wellbore, comprising (i) providing a gravel packing fluid discussed above and (ii) injecting the gravel packing fluid into the wellbore.

Abstract: A water-based drilling fluid (WBM) comprises as additive a reaction product of a polyhydroxyalkane and alkylene oxide. The polyhydroxyalkane is desirably based on a monosacchoride, and is preferably sorbitol. The alkylene oxide may comprise ethylene oxide (EO), propylene oxide (PO) and/or butylene oxide (BO). Good results have been obtained with additives including Sorbitol+18EO, Sorbitol+9PO, Sorbitol+4EO+6BO, Sorbitol+6EO+6BO, or Sorbitol+6BO. Drilling fluids in accordance with the invention have been found in laboratory tests to exhibit improved shale inhibition properties as compared with known polyol containing WBM, particularly in the absence of added potassium ions. This is environmentally advantageous.

Abstract: Systems for retarding setting in an oilfield well cement slurry comprise a solution of a phosphonate selected from methylene phosphonic acid derivatives and a phosphate, in particular selected from the following salts or the corresponding acids: mono-phosphates (ortho-phosphates PO42; meta-phosphates PO3), acyclic poly-phosphates (pyrophosphates P2O74, tripolyphosphates P3O105) or cyclic poly-phosphates. The system preferably may also comprise a retarder booster and is more particularly applicable to cementing at low or medium temperatures.