Abstract: The present invention provides methods of treating subterranean zones penetrated by well bores wherein the static temperatures of the zones are as high as 400° F. and greater. The aqueous treating fluids are basically comprised of an aqueous liquid containing one or more inorganic monovalent salts, multivalent salts or both in an amount no greater than about 5% by weight of said aqueous liquid and one or more synthetic hectorite clay gelling and thixotropy imparting agents selected from the group of a synthetic hectorite clay having the composition by weight on a dry basis of 59.5% SiO2, 27.5% MgO, 0.8% Li2O and 2.8% Na2O, a synthetic hectorite clay having the composition by weight on a dry basis of 54.5% SiO2, 26.0% MgO, 0.8% Li2O, 5.6% Na2O and 4.1% P2O5 and a synthetic hectorite clay having the composition by weight on a dry basis of 54.5% SiO2, 26.0% MgO, 0.8% LiO2, 5.6% Na2O, 4.1% P2O5 and also containing inorganic polyphosphate peptizers.

Abstract: This invention provides a water-free oil based fluid polymer suspension composition for use as a rheology modifier and fluid loss reducer in oil or gas well servicing fluids. It has been found that by using white medicinal oil as a carrier, high solids content and environmental friendly anhydrous fluidized polymer suspensions of xanthan gum, cellulose ethers, guar gum and derivatives thereof can be prepared. More specifically, in one aspect, an oil-based fluid polymer suspension (FPS) composition for use in oil or gas well servicing fluids is preferred containing: a) a hydrophilic polymer, b) an organophilic clay, c) a stabilizer, and d) a white medicinal oil having selected properties.

Abstract: Methods of forming permeable sand screens in long, open hole well bores within fluid producing zones are provided by the present invention. The methods basically comprise the steps of placing a perforated pipe in the open hole well bore, providing a hardenable composition which after being placed in a desired location cures into a hard mass, placing said hardenable composition in said well bore adjacent to said fluid producing zone within the interior of the perforated pipe therein, between the perforated pipe and the walls of the open hole well bore and within voids or fractures in the producing zone, causing the hardenable composition to cure into a hard permeable mass and drilling the hard permeable mass out of the interior of the perforated pipe.

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: The present invention provides oil based compositions and methods of using the compositions for temporarily sealing subterranean zones. The compositions are basically comprised of oil, a hydratable polymer, an organophilic clay, a water-swellable clay, and an acid soluble material such as calcium carbonate. These compositions will form a viscous gel when contacted with water. The gelled mass may then be dissolved with an acidic fluid, such as 15% hydrochloric acid.

Abstract: The present invention relates to methods and compositions for increasing the effective temperature range for viscosified fluids, including particularly fluids that have been viscosified by the addition of a natural or a natural derivative polymer. In one embodiment, the present invention relates to a method for increasing the effective temperature range for a polymer-viscosified fluid used as a well fluid, which includes adding a miscible tertiary, secondary, and/or primary amine compound into a polymer solution. In another embodiment, the present invention relates to a thermally stable well fluid, which includes a polymer, a solvent, and a tertiary, secondary, and/or primaryamine miscible in the solvent.

Abstract: Subterranean formation treating fluid concentrates, treating fluids and methods are provided by the present invention. The treating fluid concentrates are basically comprised of water and a substantially fully hydrated depolymerized polymer. The treating fluids which are formed by adding water to the treating fluid concentrates are basically comprised of water, a substantially fully hydrated depolymerized polymer and a crosslinking agent for crosslinking the hydrated depolymerized polymer.

Abstract: Environmentally acceptable well cement fluid loss control additives, cement compositions including the additives and methods of using the compositions are provided. The environmentally acceptable fluid loss control additives are comprised of ethoxylated hydroxyethylcellulose having a reduced molecular weight.

Abstract: Well drilling and servicing fluids for use in producing formations and methods of removing filter cake therefrom are provided. The methods basically comprise using a drilling or servicing fluid comprised of water, a density increasing water soluble salt, a fluid loss control agent, a hydratable polymer solid suspending agent and a particulate solid bridging agent which is soluble in an aqueous ammonium salt solution. Thereafter, the filter cake deposited by the drilling or servicing fluid is contacted with a clean-up solution comprised of water and an ammonium salt for a period of time such that the bridging agent is dissolved thereby.

Abstract: Clay is stabilized in the drilling of wells for hydrocarbon production by the addition to the drilling fluid of potassium formate together with an amount of guar effective to inhibit clay and shale swelling and sloughing.

Abstract: A new stable liquid suspension containing non-soluble particles dispersed in a non-aqueous liquid medium having a concentration of a suspension aid and a method of making and use thereof.

Abstract: The present invention provides environmentally safe foamed fracturing fluids, additives for foaming and stabilizing foamed fracturing fluids and methods of fracturing subterranean zones. The foamed fracturing fluids of this invention are basically comprised of water, a gelling agent for forming the water into gelled water and increasing the viscosity thereof, sufficient gas to form a foam, and an effective amount of an additive for foaming and stabilizing the gelled water comprised of hydrolyzed keratin.

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 modified cellulose product comprising cellulose ether, such as carboxymethyl cellulose, hydroxyethyl cellullose, carboxymethyl hydroxyethyl cellulose, methyl cellulose, hydroxyethyl methyl cellulose or ethyl hydroxyethyl cellulose, or xanthan gum product, characterized in that it further comprises salts of aluminium-, ferro-, ferri-, zinc-, nickel-, tin(2)- or tin(4)-cations, and nitrilo-tri-acetic acid, 1,2-cyclo-hexan-di-amin-N,N,N′,N′-tetra-acetic acid, di-ethylen-tri-amine-penta-acetic acid, ethylen-di-oxy-bis(ethylen-nitrilo)-tetra-acetic acid, (N-(2-hydroxy-ethyl)-ethylen-diamin-N, N′,N′,tri-acetic acid, tri-ethylen-tetra-amine-hexa-acetic acid or N-(hydroxyethyl) ethylene-di-amine-tri-acetic acid as a ligand. The product can be used especially as a drilling mud additive.

Abstract: The present invention comprises a stable hydrocolloid welan gum in which a hydrocolloid, preferably welan gum, is uniformly dispersed in a superplasticizer such as sulfonated naphthalene, sulfonated melamine, modified lignosulfate, their derivatives and mixtures thereof. This is then dispersed in a rheological control agent which is a microbially-produced cellulose fiber composition. The composition is rapidly hydratable and useful as a stabilizing additive in many cement and drilling fluid applications, insulation fluids and de-icer compositions.

Abstract: The present invention relates to methods of treating subterranean formations with viscosified aqueous well treating compositions which break into thin fluids at static temperatures in the range of from about 150° F. to about 200° F. A breaker system is included in the compositions comprised of an alkali metal or ammonium persulfate breaker and a breaker activity delaying agent comprised of an alkali metal chlorite or hypochlorite.

Abstract: Method to cement a well using low density well cement slurry compositions that are formed by the addition of a free-fluid inhibitor additive to a mixture comprising a hydraulic cement and water. Suitable free-fluid inhibitors are hydroxy ethyl cellulose polymers having a cps value in the range of from about 5000 to about 50,000.

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 equilibum 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: The present invention provides oil based compositions and methods of using the compositions for sealing subterranean zones. The compositions are basically comprised of oil, a hydratable polymer, an organophillic clay and a water-swellable clay.

Abstract: The present invention relates to a process used in a well for controlling the filtration of a drilling, a completion or a workover fluid set in a well. The process comprises adding a predetermined amount of at least one hydrophobically modified cellulose derivative. In a variant of the invention, the cellulose derivative is a hydrophobically modified hydroxyethylcellulose. The invention further relates to a drilling, a completion or a workover fluid including at least one hydrophobically modified cellulose derivative, for example hydrophobically modified hydroxyethylcellulose and notably viscosifiers such as polymers or reactive clay.

Abstract: A process for the thermo-hydraulic control of gas hydrates in subsea production and injection wells as well as pipelines which transport liquid or gaseous hydrocarbons is described, the process making use of a Nitrogen Generating System foamed or in solution. The control may signify the prevention of the formation of the gas hydrates or the dissolution of the gas hydrate plug already formed. Under conditions of use designed for the prevention of the formation of gas hydrates the SGN fluid prevents the thermal conditions leading to the gas hydrate plugs. Under conditions of use designed to dissolve the already formed gas hydrate plugs, the SGN fluid alters the thermo-hydraulic conditions which favor the gas hydrate plugs, so that they are dissolved and return to the water+gas phase.

Abstract: An aqueous foamed fracturing fluid composition and method for using the foamed fracturing fluid for fracturing subterranean formations that have been penetrated by a wellbore wherein the foamed fracturing fluid comprises: (a) a viscosifier which is preferably either hydrophobically modified guar or hydrophobically modified hydroxymethylcellulose; (b) a surfactant which is preferably alpha olefin sulfonate; and (c) the gas phase includes either nitrogen or carbon dioxide.

Abstract: The present invention is directed to an oil-free, water-soluble, liquid, polymer dispersion for use in thickening aqueous mediums, particularly completion and workover fluids used in the oil and gas drilling business. The dispersions of the present invention are comprised of hydroxyethyl cellulose and propylene glycol derivatives, preferably both propylene glycol polyether polyols and an aliphatic propylene glycol ether. Optionally these dispersions include water. Because of their low toxicity, these dispersions are particularly useful for drilling in offshore environments. These compositions rapidly disperse in and viscosity a variety of brines, including sea water and other light brines, with minimum shear and without fisheye formation.

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 composition and a process for treating a subterranean formation are disclosed. The process comprises injecting into the subterranean formation a composition which comprises a polymer, a crosslinking agent, a liquid, optionally a clay, and further optionally a weighting agent wherein the polymer forms a gel in the formation, in the presence of the crosslinking agent.

Abstract: A crosslinked water-based gel, for example a gel plug in an underground rock formation or a pipeline, is broken by an enzyme and a substrate which is capable of being converted by the enzyme into an organic acid which breaks down the gel. The enzyme is allowed to catalyze the conversion of the substrate into the acid to cause the breakdown of the gel.

Abstract: A well completion spacer fluid is provided which is particularly suitable for separating a cement slurry from drilling fluid in primary cementing operations. The well completion spacer fluid is also useful for separating other potentially incompatible fluids in the wellbore, such as, separating drilling fluid from a completion brine. The spacer fluid basically comprises water, a hydrous magnesium silicate clay, silica and organic polymer(s).

Abstract: The present invention provides compositions useful for viscosifying aqueous fluids, methods for making them and methods for using them. In one aspect of the invention, inventive compositions comprise a prehydrating alcohol having at least two hydroxyl groups and having a molecular weight of from about 60 to about 600; an inorganic salt; and a polymer. In a preferred aspect of the invention, the viscosifier composition additionally comprises a solvent having a molecular weight of from about 75 to about 1000. According to another aspect of the invention, inventive compositions comprise a prehydrating alcohol; an inorganic salt; and a polymer; and the composition is essentially free from water. Inventive compositions find advantageous use in viscosifying fluids utilized in subterranean drilling activities such as, for example, drilling, drill-in, completion, hydraulic fracturing, work-over, packer, well treating, testing, spacer, or hole abandonment fluids.

Abstract: Compositions comprising (a) a surfactant and (b) a diluent oil are employed in oil-based drilling fluids and processes for cleaning oil-contaminated substrates (e.g., oil-contaminated animals, drill cuttings) as well as in processes for cementing well casings, enhanced oil recovery, and lifting oil from wellbores.

Abstract: High viscosity well treating fluids having low friction pressure loss when pumped through tubular goods and methods of treating wells using such treating fluids are provided. The treating fluids basically comprise an aqueous fluid, a graft copolymer of hydroxyalkylcellulose and vinyl phosphonic acid, a salt containing a divalent cation and a basic compound for crosslinking the graft copolymer and causing the resulting crosslinked aqueous gel to undergo syneresis.

Abstract: Improved high viscosity well treating fluids for use at temperatures above about 200.degree. F., gel breaking additives for the treating fluids and methods of using the treating fluids are provided by the present invention. The high viscosity well treating fluids are basically comprised of an aqueous liquid, a polysaccharide gelling agent to increase the viscosity of the aqueous liquid and a gel breaker comprised of a bromate ion releasing compound to reduce the viscosity of the aqueous liquid after a desired period of time.

Abstract: The invention involves biopolymer/oil suspension compositions for the oil service industry, most particularly drilling and completion fluids, which provide such fluids a variety of desirable properties. Biopolymers include water soluble polymers and water swellable polymers. Such biopolymer/oil suspension compositions are essentially mixtures of biopolymers such as cellulosics in an oil medium with a specific anti-settling additive. The invention is particularly directed to providing enhanced anti-settling properties to such biopolymer/oil compositions; that is, the ability of the biopolymer/oil composition to retain the biopolymers in suspension prior to the composition being introduced into drilling and completion fluids. The invention in one embodiment is described as a liquid biopolymer-in-oil additive compositions for use in aqueous-based completion fluids, containing an agent comprising: a) one or more polyamides, and b) hydrogenated caster oils including castorwax.

Abstract: An improved method for acidizing an oil bearing formation in the presence of water bearing zones having high permeability is described. An aqueous fluid is pumped into the formation preceding the injection of stimulation material. This fluid contains hydroxyethylcellulose, a fluorescent dye and an organic acid anhydride, which during hydrolysis reduces the pH and the viscosity of the solution making it retrievable without damage to the formation.

Abstract: Polymer enhanced foam fluid is utilized for completion, workover, and kill operations in wells penetrating subterranean formations. The foam is formed by appropriately adding a gas to an aqueous solution of a substantially noncrosslinked water soluble polymer and a surfactant. The solution and the foam are substantially free of crosslinking agents. The foam may be generated at the surface or in a wellbore.

Abstract: The present invention relates to methods and compositions for reducing the production of water from water and oil producing subterranean formations. The methods basically comprise the introduction of an aqueous polymer composition into the water producing zones of the formation which cross-links after being placed therein. The compositions of the invention are comprised of a heavy brine and a graft copolymer of a hydrophilic polymer and a phosphonate.

Abstract: The present invention provides a method of controlling fluid loss to a permeable formation penetrated by a wellbore. A novel fluid loss agent is prepared by forming a crosslinked polymer gel which then is sheared to break the gel into discrete particles of a particular size range. A slurry then is formed of the particles by dispersing the particles in an aqueous fluid having a density similar to that of the gel particles. The slurry then is introduced into contact with the permeable formation and a filter cake of the particles is formed upon contact with the formation and loss of the slurrying fluid to the formation. The filter cake provides further fluid loss control to the permeable formation.

Abstract: The present invention relates to a process used in a well for controlling the filtration of a drilling, a completion or a workover fluid set in a well. The process comprises adding a predetermined amount of at least one hydrophobically modified cellulose derivative. In a variant of the invention, the cellulose derivative is a hydrophobically modified hydroxyethylcellulose. The invention further relates to a drilling, a completion or a workover fluid including at least one hydrophobically modified cellulose derivative, for example hydrophobically modified hydroxyethylcellulose and notably viscosifiers such as polymers or reactive clay.

Abstract: The present invention relates to a method of breaking an aqueous based viscosified fluid containing a breaker comprising an alkali metal chlorite or hypochlorite through use of a breaker activator comprising thioglycolate ion or a compound capable of producing thioglycolate ion in the aqueous fluid. The method is particularly effective in providing a controlled break in a treatment fluid introduced into a subterranean formation having a static temperature in the range of from about 100.degree. F. to about 200.degree. F.

Abstract: The present invention relates to a method of breaking an aqueous based viscosified fluid having potassium ions present therein with a breaker comprising an alkali metal chlorite or hypochlorite through use of a breaker activator comprising a source of ammonium ion in the aqueous fluid. The method is particularly effective in providing a controlled break in a treatment fluid introduced into a subterranean formation having a static temperature in the range of from about 100.degree. F. to about 300.degree. F. In some instances, a second breaker activator comprising a source of thioglycolate ion also may be admixed with the viscosified fluid to further accelerate breaker activation at temperatures below about 200.degree. F.

Abstract: A water-base fluid of optimized composition for solving problems encountered during operations such as drilling, completion or workover operations in a well crossing at least one permeable geologic formation contains (i) a hydrophilic/hydrophobic polymer, (ii) an acrylamide-base polymer of hydrophobic unit, (iii) a hydrophobically modified cellulose derivative, and (iv) a polysaccharide type polymer.The fluid can be used in a process implemented in a well drilled through at least one formation having a given permeability and is for particular application to slim-hole and/or deviated drilling.

Abstract: An aqueous foamed fracturing fluid composition and method for using the foamed fracturing fluid for fracturing subterranean formations that have been penetrated by a wellbore wherein the foamed fracturing fluid comprises: (a) a viscosifier which is preferably either hydrophobically modified guar or hydrophobically modified hydroxymethylcellulose; (b) a surfactant which is preferably alpha olefin sulfonate; and (c) the gas phase includes either nitrogen or carbon dioxide.

Abstract: A method is shown for reducing the viscosity of a cellulose-containing fluid used during workover, fracturing or well completion operations. An enzyme system is used to degrade the polymer, whereby the fluid can be removed from the subterranean formation to the well surface. The enzyme systems are effective over broad pH and temperature ranges.

Abstract: A composition, especially suitable for use as a mud sweep and a spacer. The composition includes a petroleum-based hydrocarbon, a biopolymer, a thickening agent, a surfactant and potassium chloride. Other optional ingredients in embodiments of the present invention include a lower alkanol, sodium salts and aluminum stearate.

Abstract: Oil or water based drilling muds, together with other wellbore contaminants such as pipe thread sealants and lubricants are displaced from the well and the wellbore surfaces are cleaned by a system of four serially pumped fluid pills. The first stage fluid pill is a weighted spacer having an alkyl polyglycoside surfactant, a dispersant, a weighting agent and a viscosifier. The second stage pill is a drive fluid formed by water and a viscous polymer gel such as clarified xanthan gum having a viscosity/shear rate characteristic which minimizes mixing of the drive fluid pill with the displacement fluid pill. A buffer fluid pill comprising completion brine is interposed between the drive fluid pill and a fourth stage comprising a wash fluid pill using an organic solvent or a caustic alkyl polyglycoside as a final cleaning stage. The densities of the pills are controlled to minimize mixing and fingering of one pill into the other.

Abstract: The present invention provides a method of controlling fluid loss to a permeable formation penetrated by a wellbore. A novel fluid loss agent is prepared by forming a crosslinked polymer gel which then is sheared to break the gel into discrete particles. A slurry then is formed of the particles by dispersing the particles in an aqueous fluid having a density similar to that of the gel particles. The slurry then is introduced into contact with the permeable formation and a filter cake of the particles is formed upon contact with the formation and loss of the slurrying fluid to the formation. The filter cake provides further fluid loss control to the permeable formation.