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: This invention relates to a method for use in coiled tubing operations wherein fatigue of the coiled tubing owing to short trips is reduced by reducing the number of bending and straightening events that coiled tubing undergoes to accomplish a particular wellbore objective. The invention relates to a method that allows the coiled tubing reel and tubing reeled thereon to remain stationary while making small movements of coiled tubing using the injector. The invention also relates to a method that permits synchronized movement of coiled tubing between the coiled tubing reel and injector.

Abstract: Herein is described a method of consolidating a subterranean formation or repairing a gravel pack, comprising (i) providing a consolidating fluid, wherein the consolidating fluid comprises a gel component and a gel-forming agent; and (ii) injecting the consolidating fluid into the formation or gravel pack, under conditions wherein the gel component forms a flexible gel, thereby consolidating the formation.

Abstract: The improved recovery of hydrocarbons from subterranean formations by hydraulically fracturing a subterranean formation is accomplished. Fracturing fluids using a viscosifying surfactant fluid containing viscosifying micelles, for example, wormlike micelles, are useful to improve recovery of hydrocarbons and limit the loss of fracturing fluid into the formation fracture face. The invention further relates to novel fracturing and acidizing methods useful for increasing hydrocarbon production, limiting water production, resisting fracturing fluid loss into the subterranean formation, and reducing the equipment requirements in mixing and pumping fracturing fluid. The action of viscosifying micelles of surfactant in aqueous zones of the subterranean formation diverts fracturing fluid or acid from the aqueous zones to the hydrocarbon-bearing zones and also facilitates the flowback of increased amounts of hydrocarbons once a fractured well is placed back on production.

Abstract: An acidic fluid that is useful in stimulation and workover operations, and in particular, for the control of iron in acidizing operations, the removal of alkaline earth carbonate scale in scale removal operations, and matrix or fracture acidizing operations, comprises an acid, such as hydrochloric acid; water; and a hydroxyethylaminocarboxylic acid. Preferred hydroxyethylaminocarboxylic acids are hydroxyethylethylenediaminetriacetic acid (HEDTA) and hydroxyethyliminodiacetic acid (HEIDA). Also disclosed herein are methods of controlling iron, removing alkaline earth carbonate scale, or matrix or fracture acidizing, involving the use of the acidic fluid.

Abstract: An improved method for transport of particulate matter in a wellbore fluid, and particularly the transport of particulate matter in subterranean wells, such as hydrocarbon wells, is disclosed, the method being characterized by utilization of specified fibers to aid in transport of the particulate matter. Additional embodiments include the removal of particulate matter (particles) and particle deposits, such as from drill cuttings, during the drilling of wells, and the removal of particulate matter deposits in cleanout operations.

Abstract: An acidic fluid that is useful in stimulation and workover operations, and in particular, in matrix acidizing treatments, comprises an acid, such as hydrochloric acid; water; an aliphatic aldehyde having 1-10 carbon atoms; and an aromatic aldehyde having 7-20 carbon atoms. The aliphatic aldehyde preferably has 1-6 carbon atoms. Glyoxylic acid and glyoxal are especially preferred aliphatic aldehydes. The aromatic aldehyde preferably has 7-10 carbon atoms. Cinnamaldehyde is especially preferred.

Abstract: The invention provides a method of isolating an open hole fitted with a slotted liner, the method consisting in pumping a cement or a resin to the level of the slotted liner by means of injection apparatus provided with lips for scrapping the slotted liner downstream from the injection point so that the cement or resin fills the entire borehole upstream from the injection apparatus and also fills the space behind the slotted liner while the apparatus is being raised towards the surface. The invention also provides injection apparatus particularly adapted to implement the method, which apparatus can advantageously be displaced by means of coiled tubing.

Abstract: An emulsion with flow-initiated gelling properties is described, comprising at least two discontinuous phases with a polymer and cross-linking agent separated by two phase boundaries. The novel emulsion is preferably used for remedial operations in a subterranean formation or wellbore.

Abstract: Liquids comprised solely of anions and cations (“ionic liquids”) are disclosed as novel components of fluids (and techniques relying upon those fluids) for stimulation of hydrocarbon wells. In particular, the fluids disclosed are useful in matrix acidizing. Formation of the ionic liquids of the present Invention is highly exothermic, hence the heat generated can be used, for instance, to melt de-watered drilling fluid in the near-wellbore region of the formation. Further, reaction of the ionic liquids with water results in acid generation; this acid can be used to, for instance, to stimulate a formation, either by conventional matrix acidizing or fracture acidizing. In addition, certain preferred species of the ionic liquids of the present Invention are highly stable solvents, hence they can be used as carrier fluids for highly reactive super acids (e.g., SbF5+HF) in connection with matrix acidizing.

Abstract: A chemical system and method to stop or minimize fluid loss during completion of wells penetrating hydrocarbon formations are provided. The inventions relates to formulating a highly stable crosslinked hydroxyethyl cellulose (HEC), control released viscosity reduction additives, and user friendly packaging. The chemical system contains a linear HEC polymer solution, a low solubility compound which slowly raises the fluid pH, a chelating agent which further increases the pH level beyond the equilibrium achievable by the low solubility compound, a metal crosslinker which crosslinks HEC at elevated pH, a crosslink delaying agent which allows fluid viscosity to remain low until the fluid reaches the subterranean formation, and optionally an internal breaker. The chemical additives are packaged as an integrated pallet and transported to a field location which allows operators to conveniently mix them before pumping.

Abstract: A method for actuating or installing downhole equipment in a wellbore employs non-acoustic signals (e.g., radio frequency signals) to locate, inventory, install, or actuate one downhole structure in relation to another downhole structure. The method comprises the steps of: (a) providing a first downhole structure that comprises a non-acoustic (e.g.

Abstract: The invention concerns cementing compositions, particularly for squeeze cementing, comprising a liquid phase and a solid phase constituted by particulate materials which are insoluble in said liquid phase, in particular a microcement. The compositions of the invention comprise additives of a nature and composition such that variations in viscosity of the composition due to fluid loss are minimized. Preferably, the compositions comprise at least one “very fine” additive formed from particles which are smaller than the cement, with a ratio of the average grain sizes of the particles of said additive and those of the cement in the range 5 to 100, preferably about 10, the respective proportions of the solid particles corresponding to a packing volume fraction close to the maximum, and the porosity of the solid mixture being such that the mixture is in a state of hindered settling.

Abstract: The invention relates to iron control in an acid medium for forestalling the formation of precipitates known as “sludges” (asphaltic products) in contact with certain crude oils. Use is made of compounds comprising a mercaptan function, and, in combination, a selection of catalysts. Application to acid treatments for oil, gas, water, geothermal and analogous wells, as well as to industrial cleaning.

Abstract: A method of maintaining the integrity of a sheath, in particular a cementing sheath in a well consists in calculating or estimating variations in well pressure and/or in well temperature and/or in the variations in in-situ stresses, which may occur during the lifetime of the well, evaluating the stresses in the sheath as a function of the above variations, determining the nature of the stress likely to be first in causing deterioration of the sheath, and the risk thereof, and evaluating the influence of the elastic properties of the sheath, of the rock and/or of the casing on this stress, in order to select a sheath which is capable of attenuating this deterioration. The method is of particular application to oil, water, gas, and geothermal wells.

Abstract: The present Invention relates to hydrocarbon well stimulation, and more particularly to methods and compositions to remove (or more generally to transfer) fluid introduced into the subsurface. For instance, preferred methods involve creating then exploiting a capillary pressure gradient at the fracture face to induce fluid flow from the fracture into the formation thereby increasing effective fracture length, and then improving fracture conductivity.

Abstract: A settable thixotropic material comprises a thixotrope and a settable substance, the material being capable of gelling reversibly in a gelling time of less than 60 seconds. The thixotrope conveniently comprises a fine grained clay, especially smectite clays, e.g. hectorites. It is preferred to use synthetic smectite type clay colloids, and goods results have been obtained with the synthetic clay known as Laponite RDS. The settable material conveniently comprises cement, particularly Portland cement. The thixotropic material finds use generally in oilwell applications, e.g. to plug lost circulation zones, to repair damaged or corroded casing, as grouts, and to limit annular gas migration. The material also finds particular application in techniques for completion of horizontal wells completed with slotted or pre-drilled liners.

Abstract: A trailer (10) has a dropped center section (12) defining a well (16) for a coiled tubing reel (22). A mast (30) has a pair of posts (34) on which a carriage (32) is mounted for movement along posts (34). An injector head (36) is supported on carriage (32) for pivotal movement in a vertical plane relative to mast (30) and for horizontal movement along a tubular support member (38) of carriage (32) relative to mast (30). Mast (30) is pivotally mounted on the rear end of trailer (10) for movement away from trailer (10) for positioning over a wellhead. In a stored position, mast posts (34) fit alongside the ends of reel (22) so that to the total height of the stored coiled tubing rig is no more than 13½ feet for over the road travel.

Abstract: In one embodiment, the invention relates to a method or process, useful in cementing a well, especially a hydrocarbon well, which is characterized by the use of increased external and internal diameter liners, the method being characterized by provision and use of a novel liner and liner-tool assembly. Novel liner apparatus, a liner-tool assembly, and a fluid circulating tool are also disclosed.

Abstract: A CO2-foamable gelling composition and use of said composition for conformance control operations are described The gelling fluid comprises a decomposing agent to counteract the detrimental effect of CO2 on the gelling process.