Abstract: An acidic viscoelastic surfactant fluid composition is formulated with an acid, for example hydrochloric acid, a cationic surfactant, for example a quaternary amine, and a break-enabling salt, for example NH4Cl. The fluid composition has low viscosity as formulated, undergoes an increase in viscosity as the acid is consumed when it reacts with an acid-reactive material, and returns to approximately the initial viscosity as the last of the acid is consumed. The fluid composition is used as a diverting fluid or as the main treatment fluid in oilfield treatments such as matrix acidizing and acid fracturing.

Abstract: Wellbore treating fluids that include zeolite, an activator, and an organic acid or salt thereof are provided.

Abstract: A well treating composition containing a polysaccharide-based water-superabsorbent material has particularly applicability as a thermal insulating, fracturing or acid stimulation fluid. The water-superabsorbent material is capable of absorbing, at a minimum, its own weight. Particularly effective are biodegradable materials containing guar gum and carrageenan. The composition may further contain a crosslinking agent, brine and/or a viscosifying polymer or a gelling agent. As an oil-based fluid, the crosslinking agent is absorbed onto the water-superabsorbent material and serves to effectively delay crosslinking.

Abstract: A well treating fluid useful in slickwater fracturing processes contains polyacrylamide friction reducer and a viscosity breaker capable of reducing the viscosity of the well treating fluid to about the viscosity of water at ambient temperatures of typical underground formations. The viscosity breaker is selected from the group consisting of hydrogen peroxide, calcium peroxide, magnesium peroxide, and zinc peroxide and is present in an amount above about 0.002% by weight.

Abstract: A method for cleaning oil wells to increase the flow of oil thereof by use of a unique aqueous cleaning emulsion comprising of water, hydrocarbon solvent, detergent and mineral acid. This one step method provides for the simultaneously cleaning/removal of asphaltine and/or paraffin and scale. This method can be used alone or with the assistance of a wash tool which is a combination pressure and surge wash tool having a nipple assembly. A by-pass port is coupled to the nipple assembly and a diverter cup is coupled to the by-pass port. A plurality of pressure wash cups are positioned on the tool. A pressure wash port is located between the plurality of pressure wash cups and a pump shoe assembly is coupled to a bottom pressure wash cup.

Abstract: This Invention relates to methods of treating a subterranean hydrocarbons reservoir comprising contacting the formation with a treating fluid comprising an aqueous solution, an acid, a surfactant acting as gelling agent essentially consisting of erucylamidopropyl betaine (or a protonated/deprotonated homolog or salt thereof). The treating fluid may further comprise a lower n-alcohol for improved temperature stability.

Abstract: Improved casing strings, and methods of using improved casing strings in subterranean operations, are provided. An example of a method is a method of cementing a pipe string in a subterranean formation. Another example of a method is a method of cementing a pipe string in a well bore. An example of an apparatus is an improved pipe string comprising at least one pipe section; and a delivery system of an activator; wherein the delivery system of an activator is disposed adjacent an outer surface of the at least one pipe section.

Abstract: A method for minimizing the amount of metal crosslinked viscosifier necessary for treating a wellbore with proppant or gravel is given. The method includes using fibers to aid in transporting, suspending and placing proppant or gravel in viscous carrier fluids otherwise having insufficient viscosity to prevent particulate settling. Fibers are given that have properties optimized for proppant transport but degrade after the treatment into degradation products that do not precipitate in the presence of ions in the water such as calcium and magnesium. Crosslinked polymer carrier fluids are identified that are not damaged by contaminants present in the fibers or by degradation products released by premature degradation of the fibers.

Abstract: Fluids, such as completion fluids, containing at least one alkali metal tungstate and optionally at least one chelating agent are described. Methods of removing a filter cake from a well bore surface, which may include one or more alkaline earth metal sulfates, is also described, wherein the method includes contacting the filter cake with the completion fluid of the present invention. A drilling fluid or mud is also described wherein the drilling fluid contains at least one alkali metal tungstate. The drilling fluid preferably further contains at least one emulsifier or surfactant and at least one hydrocarbon-based fluid. The various fluids of the present invention can contain other conventional ingredients and optionally at least one alkali metal formate. The present invention permits the fluids to be essentially solids free due to the use of the alkali metal tungstate.

Abstract: Improved methods for treating and for fracturing subterranean formations and the fluid compositions are provided. The viscosity of a treating fluid containing gelling agents is broken, even at temperatures of about 250° F. and lower, utilizing an oxidizing breaker and a reducing sugar to activate the breaker.

Abstract: A method of stimulating and stabilizing an area of a subterranean formation comprising placing an acid fluid into an area of a subterranean formation and allowing the acid to at least partially dissolve a portion of the area of the subterranean formation; placing a consolidation fluid into the area of the subterranean formation; and, placing an afterflush fluid into the area of the subterranean formation. A method of stimulating and stabilizing an area of a subterranean formation comprising placing an acid fluid into an area of a subterranean formation and allowing the acid to at least partially dissolve a portion of the area of the subterranean formation; placing a consolidation fluid into the area of the subterranean formation; and, placing a fracturing fluid into the area of the subterranean formation at a pressure sufficient to create or extend at least one fracture therein.

Abstract: A process for reducing the viscosity of fracturing fluids in downhole oilfield operations is provided. The process comprises contacting a sulfamate stabilized, bromine-based breaker with an aqueous polysaccharide fracturing fluid, with the breaker present in an amount to reduce the viscosity of the fracturing fluid. A composition which comprises a sulfamate stabilized, bromine-based breaker for use in decreasing the viscosity of an aqueous polysaccharide fracturing fluid for use in subterranean oil and gas wells is also provided.

Abstract: Improved methods for treating and for fracturing subterranean formations and the fluid compositions are provided. A method presented herein is a method of reducing the viscosity of a viscosified treatment fluid that comprises providing a viscosified treatment fluid that comprises a basic fluid and a gelling agent, providing a breaker composition comprising an oxidizing breaker and a breaker activator that comprises a reducing sugar; and allowing the breaker composition and the viscosified treatment fluid to interact so as to reduce the viscosity of the viscosified treatment fluid.

Abstract: An aqueous-based composition containing cesium formate and at least one chelating agent is described. Methods of removing scaling deposits, which may include alkaline earth metal sulfates, present on surfaces, including porous media, such as alkaline earth metal sulfate buildup in a well bore, is also described, wherein the method includes contacting the alkaline earth metal sulfate with the compositions of the present invention to remove the scaling deposits. A completion fluid containing at least one alkali metal formate, at least one acid and/or at least one chelating agent, and optionally at least one surfactant or mutual solvent is also described. Methods of removing a filter cake from a well bore surface, which may include weighting agents such as calcium carbonate, is also described, wherein the method includes contacting the filter cake with the completion fluid of the present invention.

Abstract: Methods of reducing the fluid loss from a wellbore servicing fluid include combining a terpolymer with the wellbore servicing fluid to reduce the fluid loss from the fluid, followed by displacing the fluid into a wellbore. In an embodiment, the following monomers are used to make the terpolymer: from about 75 wt. % to about 95 wt. % of 2-acrylamido-2-methylpropanesulfonic acid or an alkali salt thereof; from about 3 wt. % to about 15 wt. % of acrylamide; and from about 3 wt. % to about 15 wt. % of N-vinyl-2-pyrrolidone, all weight percentages being based on a total weight of the monomers. The wellbore servicing fluid may comprise water or an aqueous salt solution such as a formate solution. The wellbore servicing fluid may also comprise clay such as montmorillonite and attapulgite clay.

Abstract: An aqueous oilfield treatment fluid containing a chelating agent and an HF source is described. This fluid is effective at dissolving siliceous materials such as clays and keeping the dissolved materials in solution. In particular it is effective at preventing re-precipitation of initially-dissolved silicon as silica and therefore reduces damage to sandstones with which it is contacted. Methods are given for using this fluid for sandstone matrix stimulation, removal of clay-containing drilling fluid components and filter cakes from wellbores, sandstone acid fracturing, and gravel pack and proppant pack cleaning.

Abstract: Fluid producing wells may be treated with a water-in-oil emulsion for the removal or inhibition of unwanted solid particulates, including pipe dope, asphaltenes and paraffins. Such emulsions are of particular applicability in the displacement of oil base drilling muds and/or residues from such muds from producing wells. The water-in-oil emulsions may optionally contain a dispersing agent as well as a surfactant.

Abstract: In one embodiment, the present invention provides a method of reducing the viscosity of a viscosified treatment fluid comprising contacting the viscosified treatment fluid with an acid generated from an orthoester composition that comprises an orthoester. In another embodiment, the present invention provides a method of reducing the pH of a viscosified treatment fluid comprising providing an orthoester composition that comprises an orthoester; contacting the viscosified treatment fluid with the orthoester composition; allowing the orthoester to generate a generated acid; and allowing the generated acid to at least partially reduce the pH of the viscosified treatment fluid. Embodiments of fracturing and gravel packing methods also are disclosed.

Abstract: The present invention relates to acidic treatment fluids that comprise an acid fluid and an ester-containing quaternary ammonium compound (“esterquat”) and methods of their use. One embodiment of the present invention provides a method of inhibiting metal corrosion during a subterranean treatment operation comprising using an acidic treatment fluid comprising an acidic fluid and an esterquat. Another embodiment of the present invention provides a method of reducing sludge formation during a subterranean treatment operation formation comprising the step of using an acidic treatment fluid comprising an acidic fluid and an esterquat. Another embodiment of the present invention provides a method of inhibiting the formation of emulsions during a subterranean treatment operation comprising using an acidic treatment fluid comprising an acidic fluid and an esterquat. Another embodiment of the present invention provides an acidic subterranean treatment fluid comprising an acidic fluid and an esterquat.

Abstract: Methods of temporarily reducing the permeability of one or more selected sections of a subterranean formation penetrated by a horizontal well bore and the flow of water or water and hydrocarbons or hydrocarbons therefrom are provided. The methods comprise the steps of preparing or providing an aqueous treating fluid comprising water and a water-soluble formation permeability reducing agent, introducing the aqueous treating fluid into one or more selected sections and when required, contacting the one or more selected sections with an aqueous treating fluid comprising water and a formation permeability restoring chemical.

Abstract: Methods and compositions for breaking treatment fluids utilized in the stimulation of a subterranean formation.

Abstract: A low residue well treatment fluid comprises: an aqueous solvent; a gelling agent comprising one or more modified polysaccharides, the modified polysaccharides having hydrophilic groups; and a crosslinking composition. The fluid may optionally further comprise a gel breaker, a buffer and/or a proppant. The fluids generate no or minimal residue upon being broken, and are particularly useful in well fracturing operations.

Abstract: Methods and compositions for wellbore treating fluids, especially settable spotting fluids, that include zeolite and at least one carrier fluid.

Abstract: A method is given for diverting acids in matrix acidizing and acid fracturing. The acids are diverted with a diverting agent that is an energized or foamed acidic viscoelastic surfactant system that contains a viscoelastic surfactant that gels and increases in viscosity when the acid in the foamed acidic viscoelastic surfactant system is spent. The method provides a synergistic combination of the diverting capabilities of foams and the diverting capabilities of viscoelastic gel systems. The resistance to flow of the gelled foamed viscoelastic surfactant system is greater than expected from a foam or a viscoelastic gel system alone.

Abstract: A viscous aqueous high density well treatment fluid composition stable at high temperature containing a surfactant and inorganic salts is described. Methods of preparing the fluid and increasing the stability and viscosity of the fluid are given. The fluid is useful for wellbore cleanout, hydraulic fracturing, gravel packing, completion, acid diversion, lost circulation reduction, well killing, cementing, selective water shutoff, and fracture fluid diversion.

Abstract: A process for enhancing the productivity of a formation consists of introducing into the formation a viscoelastic fluid which contains at least one surfactant, at least one quaternary amine polyelectrolyte, water, and a non-aqueous solvent. The surfactant forms aggregation structures or vesicles. The fluid, which significantly enhances fluid viscosity and thermal stability, is particularly effective as a diverting fluid to divert an acid treatment package from a high permeability or undamaged portion of a formation to a low permeability or damaged portion of a formation as well as a fracturing fluid. In addition, the fluid is useful for sand control completion.

Abstract: The present invention relates to methods and compositions for treating subterranean formations, and more specifically, to improved methods and compositions for generating acids for use downhole, for example, to at least partially degrade the acid-soluble portions of filter cakes deposited in subterranean formations. In one embodiment, the present invention provides a method of degrading an acid-soluble portion of a filter cake comprising contacting the acid-soluble portion of the filter cake with an acid generated from an orthoester.

Abstract: Single phase microemulsions improve the removal of filter cakes formed during drilling with invert emulsions. The single phase microemulsion removes oil and solids from the deposited filter cake. Optionally, an acid capable of solubilizing the filter cake bridging particles may also be used with the microemulsion. In one non-limiting embodiment the acid may be a polyamino carboxylic acid. Skin damage removal from internal and external filter cake deposition can be reduced.

Abstract: A method to synthesize a chlorine dioxide block remover in a well is described. The method includes dissolving a chlorate aqueous solution and some acidic substances in water and to produce a hydrogen ion. The chlorate aqueous solution and acidic substances are quickly injected into the well by an injection pump, so they react with each other and produce chlorine dioxide. The synthesis of the chlorine block remover in the well removes oil layer blocks induced by polymers and microbes, while reducing the risk of explosion caused by leaked chlorine dioxide, and reducing the corrosion of equipment and pipes caused by chlorine dioxide.

Abstract: Foamed completion fluids and methods of completing subterranean zones penetrated by well bores are disclosed. A method of completing a subterranean zone penetrated by a well bore comprises the steps of providing or preparing a foamed completion fluid comprising water, one or more salts, a gas and a capryl/capramidopropylbetaine surfactant foaming agent, introducing the foamed treating fluid into the subterranean zone, and then carrying out a completion operation in the subterranean zone.

Abstract: Methods of using invertible oil external-water internal emulsions in drilling, hydraulic fracturing, gravel packing and completion and then inverting the emulsion to a water external-oil internal emulsion are provided. The methods basically comprise the steps of contacting the oil external-water internal emulsion with an aqueous acid solution containing an anionic sulfonate surfactant for preventing aqueous acid solution-crude oil emulsions and crude oil sludging and a chemical for preventing the anionic sulfonate surfactant from reacting with the emulsifier in the oil external-water internal emulsion.

Abstract: This Invention relates to methods of treating a subterranean hydrocarbons reservoir comprising contacting the formation with a treating fluid comprising an aqueous solution, an acid, a surfactant acting as gelling agent essentially consisting of erucylamidopropyl betaine (or a protonated/deprotonated homolog or salt thereof). The treating fluid may further comprise a lower n-alcohol for improved temperature stability.

Abstract: Propped fractures in formations from which fluids are produced are described that have wormholes extending out into the formations from the faces of the fractures at locations distant from boreholes. Methods are given for creating such propped fractures having wormholes in which either a closed propped fracture is formed and then the wormholes are formed, or the entire fracture and channel system is formed before the closure occurs.

Abstract: A process for stimulating a formation is disclosed wherein a diverting fluid is used to divert an acid treatment package from a high permeability or damaged portion of a formation to a low permeability or undamaged portion of a formation. The fluid, which preferably forms vesicles, comprises at least one surfactant, at least one quaternary amine polyelectrolyte, water, and a non-aqueous solvent.

Abstract: Methods of treating subterranean zones and viscous aqueous fluids containing xanthan biopolymer gelling agent and a combination crosslinker and delayed breaker are provided. A viscous cross-linked aqueous treating fluid of the invention comprises water, a xanthan polymer gelling agent, and a combination cross-linker and delayed breaker for said xanthan biopolymer gelling agent.

Abstract: A method of formulating and the resulting biodegradable wellbore fluid includes a first synthetic internal olefin fraction having from 16 to 18 carbon atoms (C16-18 IO), a second synthetic internal olefin fraction having between 15 to 18 carbon atoms (C15-18 IO), and a third synthetic internal olefin fraction having 15 to 16 carbon atoms (C15-16 IO). The components of the wellbore fluid are blended such that the desired characteristics of polycyclic aromatic hydrocarbon content, toxicity and biodegrability are balance to achieve compliance with environmental requirements for hydrocarbon based drilling fluids.

Abstract: Methods are presented to induce a screenout during a subterranean formation fracturing or combined fracturing and gravel packing treatment having a viscoelastic surfactant-based carrier fluid by laying down a filter cake at least a portion of which is a base-soluble material, injecting proppant slurry, and causing hydrolysis and dissolution of the solid base-soluble material by adding base so that leak-off increases, the concentration of proppant in the fracture increases, and the proppant screens out. A method of gravel packing with a viscoelastic surfactant-based carrier fluid by laying down a filter cake at least a portion of which is a base-soluble material, injecting gravel, and causing hydrolysis and dissolution of the solid base-soluble material by adding base. Methods of slowing or accelerating the hydrolysis and dissolution are given, and addition of bridging-promoting materials is included.

Abstract: Methods of treating subterranean zones and treating fluids are provided. The methods are basically comprised of preparing or providing a subterranean zone treating fluid comprising an aqueous fluid and an additive for preventing the swelling and migration of formation clays in the subterranean zone selected from the group consisting of 1-carboxy-N,N,N-trimethyl methanaminium chloride, 2-hydroxy-N,N,N-trimethyl ethanaminium acetate, and 2-hydroxy-N,N,N-trimethyl 1-propanaminium acetate.

Abstract: A cement slurry comprising a base for reducing the impact of an alkaline solution may be displaced into a wellbore and allowed to set. The base may comprise a metal carbonate that is soluble in water such as potassium carbonate. The cement slurry may further include cement, water, and a salt that is soluble in the water such as potassium chloride. The alkaline solution may be present in a formate-based drilling fluid displaced into the wellbore ahead of the cement slurry. Despite being contacted by such an alkaline solution, the thickening time of the cement slurry is long enough and the set time is short enough to provide for the formation of an impermeable mass in the annulus of the wellbore. The thickening times may range from about 4 hours to about 16 hours, and the set times may be less than about 24 hours.

Abstract: Zeolite compositions having enhanced compressive strength and methods therefor are provided. In particular, methods and compositions for wellbore treating fluids, especially settable spotting fluids having enhanced compressive strength are provided.

Abstract: Methods of diverting treating fluids in subterranean zones penetrated by well bores are provided. The methods basically comprise the following steps. A degradable particulate diverting material is placed in a subterranean zone that contains releasable water. A treating fluid is then introduced into the subterranean zone which is diverted by the degradable particulate diverting material therein. Thereafter, the degradable particulate diverting material is allowed to at least partially degrade in the presence of the released water in the subterranean zone.

Abstract: A solution containing a compound having the general formula XF.nH2O2, wherein X is K+, Na+ or NH4+ and n is an integer from 1 to 3 (e.g., a peroxysolvate of potassium fluoride compound such as potassium fluoride hydroperoxide (KF.H2O2)) is injected into a subterranean formation in order to increase its permeability, especially with respect to hydrocarbon flow. These compounds serve to dissolve a wide variety of subterranean formation minerals (e.g., siliceous materials as well as carbonaceous materials). Potassium hydrofluoride (KHF2), can be employed with these compounds to produce particularly efficacious subterranean formation treatment solutions.

Abstract: A method for retaining a treatment chemical in a subterranean formation containing hydrocarbons is disclosed. The method includes first preparing an emulsion. The emulsion contains an oil continuous phase and first and second aqueous phases. The first aqueous phase includes a treatment chemical, such as a scale inhibitor. The second aqueous phase comprises a retention enhancing chemical which is to be reacted with the treatment chemical in the subterranean formation. Preferably, the first and second aqueous phases remain generally separately dispersed and stable within the oil continuous phase prior to being introduced into the subterranean formation. The emulsion is then placed down a well bore and into the subterranean formation.

Abstract: Improved methods and compositions for consolidating proppant in fractures formed in subterranean zones are provided. An improvement of this invention comprises using proppant particles having a coating of hardenable resin including a gel breaker. The gel breaker facilitates removal of gelled carrier fluid from the surface of the proppant particles.

Abstract: It is proposed a method for completing an unconsolidated interval, including particulates, in a subterranean formation, including a consolidation steps. The consolidation step is performed by injection of an aqueous solution of colloidal particles with a pH modifier and/or an ionic-strength modifier. A hard gel is formed that holds the particulates together. The consolidation is followed by hydraulic fracturing. Diversion towards area of less permeability may be enhanced by the use of micrometric particles.

Abstract: A method for preferentially treating a subterranean formation having at least one primarily oil producing layer and at least one primarily water producing layer. The method involves the steps of providing a water shut-off gel into the formation to preferentially treat the water producing layers. This is followed by providing a viscoelastic fluid into the formation, where the viscoelastic fluid is broken by hydrocarbon, thereby remaining and viscosifying primarily in the water producing layers. Finally, a reactive fluid, such as an acid fluid, is provided. The reactive fluid treats primarily the oil producing layers because the viscoelastic fluid and the water shut-off gel prevent the reactive fluid from substantially entering the water producing layers.

Abstract: The present invention involves methods and compositions for treating subterranean formations, and more specifically, relates to improved methods and compositions for degrading filter cake deposited in a subterranean formation by effecting a uniform distribution of a filter cake breaker. One embodiment of the present invention provides a weighted encapsulated breaker comprising a breaker material; and, a coating material comprising a polymer material and a filler material having a specific gravity of at least about 6.5.

Abstract: The present invention provides improved methods of fracturing subterranean zones penetrated by well bores and improved fracturing fluids. The fracturing fluids are basically comprised of water, a terpolymer of 2-acrylamido-2-methylpropane sulfonic acid, acrylamide and acrylic acid, or its salts, a cross-linking agent for the terpolymer and a delayed viscosity breaker for effecting a controlled reduction in the viscosity of the fracturing fluid.

Abstract: Xanthan gels hydratable in brine, methods of making these xanthan gels, and methods of using these compositions in subterranean formation applications, such as gravel packing, are provided herein.

Abstract: Fracturing fluids and methods of fracturing a subterranean formation using such fluids are provided. A fracturing fluid having a first pH is foamed by introducing a gas to the fluid. The fracturing fluid comprises a surfactant that facilitates formation of the foam at the first pH. The foamed fracturing fluid is subsequently pumped to the subterranean formation to fracture it. The pH of the fracturing fluid is then changed to a second pH at which the surfactant facilitates reduction of the foam. The fracturing fluid releases proppant contained in the fluid to the subterranean formation. The fracturing fluid is then allowed to flow back to the surface. It can be recycled by changing the pH of the fracturing fluid back to the first pH and adding a gas to the fluid, causing it to foam again.