Abstract: A method is disclosed for drilling a wellbore employing a drilling fluid providing the advantages of easy pumpability of a low viscosity fluid with the drill cuttings suspension capability of a highly viscous fluid. The viscosity of the fluid is also easily and quickly adjustable so that the fluid rheology may be adapted during drilling as the subterranean conditions change. These advantages are obtained by including in said fluid a reversibly crosslinkable polymer and an encapsulated crosslink activator. The crosslink activator causes crosslinking after the fluid is in the wellbore. The crosslinking is reversed at the well surface to reduce the viscosity of the fluid to enable the drill cuttings to be easily removed. Crosslink activator is added back to the fluid and the fluid is returned to the borehole. The amount of crosslink activator and/or crosslinkable polymer may be adjusted in the fluid to change the fluid rheology to conform the fluid to changes in the well conditions as monitored real time.

Abstract: Methods of cementing in subterranean formations, cement compositions, and methods for making the compositions are provided. A cement slurry is passed into a subterranean formation, and a swelling agent is passed into the subterranean formation to reduce an amount of water flowing into the cement slurry. The swelling agent may be combined with a carrier fluid before being displaced into the subterranean formation. Alternatively, the swelling agent may be pre-mixed with the cement slurry to form a new cement composition, followed by displacing the cement composition into the subterranean formation. The swelling agent is present in an amount effective to, upon absorption of water and swelling to form a gel mass, substantially block the flow path of the water into the cement composition or reduce losses to low pore pressure intervals, thereby preventing the integrity of the cement composition from being compromised or lost to voidage, fractures, fissures, etc.

Abstract: A method of treating a well including injecting a thermally stable, substantially water-free well-treating fluid into the well, wherein the well-treating fluid comprises a polymer, a glycol compound, and a salt is disclosed. In another embodiment, a thermally stable, substantially water-free well fluid including a polymer, a diol compound, and a salt is disclosed.

Abstract: A drilling fluid additive is provided wherein the additive is manufactured by a method comprised of admixing colloidal solids such as talc with a combination of oil and glycol or cellulose to create a suspended mixture to thereby allow the colloidal solids to be pre-wet, treated or coated with the oil/glycol combination or the cellulose; and then admixing copolymer beads to the suspended mixture.

Abstract: An annular fluid or packer fluid, and methods of making the same, that includes a water-miscible solvent, a viscosifying additive, a crosslinking agent, a crosslinking inhibitor having the facility to inhibit crosslinking between the viscosifying additive and the crosslinking agent, and an initiating agent having the facility to overcome an action of the crosslinking inhibitor and to initiate crosslinking between the viscosifying additive and the crosslinking agent, is shown and described. The fluid has a thermal conductivity of no more than about 0.25 btu/(hr·ft·° F.) and a potential to substantially increase its viscosity upon sitting for a selected period of time.

Abstract: A drilling fluid additive system is provided wherein the system is manufactured by a method comprised of admixing colloidal solids such as talc with a carrier such as oils and glycols or talc with cellulose to create a suspended mixture to thereby allow the colloidal solids to be pre-wet or coated with the carrier; and then admixing copolymer beads to the suspended mixture to allow the beads to be pre-wet or coated with the carrier; and then adding the suspended mixture with a mixture comprised of hydrophilic clay, a pH controller, a fluid loss controller, and a dispersant.

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: The invention relates to a ligand-modified cellulose product comprising cellulose ether, calcium salt and at least one ligand as a chelating agent. The product can be used e.g. in drilling fluids.

Abstract: Disclosed are drilling fluids suitable for use in connection with oil well drilling. The drilling fluids of the invention include in one embodiment a liquid base, an alkyl glucoside, such as methyl glucoside, and a borehole stability agent that includes a maltodextrin, a carboxyalkyl starch, a hemicellulose-containing material, or a mixture of the foregoing. In another embodiment, the drilling fluid includes a liquid base and desugared molasses solids, preferably in combination with an alkyl glucoside and more preferably in further combination with one of the aforementioned borehole stability agents. The drilling fluids of the invention surprisingly have a reduced tendency to swell shale as compared with known drilling fluids. Also disclosed are a drilling apparatus and process. The drilling apparatus includes a drill string, which may be conventional, that is fluidically coupled to a source of drilling fluid, the source of drilling fluid including the drilling fluid of the invention.

Abstract: Water-based drilling fluid comprising: (a) water, (b) at least one biopolymer of the polysaccharide type, (c) at least one filtrate reducer selected from starches with different cross-linking degrees in presence of cellulose microfibers, (d) optionally a hydrosoluble polymeric surface-active agent having an HLB from 10 to 16, preferably from 11 to 14.

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 relates to a drilling fluid comprising cellulose nanofibrils comprising at least 80% of cells with primary walls and charged with carboxylic acids and with acidic polysaccharides, alone or as a mixture. This additive, alone, gives the drilling fluid shear-thinning properties and is stable up to temperatures of about 180° C.

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: Water based drilling fluid compositions which contain at least one viscosity builder and at least one rheological control agent wherein the rheological control agent is an amphoteric polymer, the cationic groups of the amphoteric polymer being quaternary ammonium groups.

Abstract: A salt water drilling mud comprising a mixture salt water, a solid phase such as pre-hydrated bentonite, attapulgite, sepiolite, and extended bentonite, among others and optionally a synthetic oil, which is mixed with at least one of five different modules. A first module contains caustic, a natural wax and a natural thinner. A second module contains components of the first module and an alkali metal aluminate prepared by reacting the first module with aluminum metal. A third module contains the components of the first module and an alkali metal phosphate and/or alkali metal silicate. A fourth module contains the components of the first module, a saturated or unsaturated carboxylic acid source, a surfactant, and a preservative. The fifth module contains a combination of the first, third and fourth modules.

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 invention relates to the use of oil-soluble oleophilic organic liquid phases—flowable at temperatures of 0 to 10° C.—from the classes of corresponding monocarboxylic and/or polycarboxylic acid esters, carbonic acid esters, fatty alcohols and their oligoalkoxides and/or ethers as the at least predominant part of the liquid phase in storage-stable homogeneous mixtures with guar and/or water-soluble guar derivatives for their use in water-based borehole servicing fluids.

Abstract: The invention concerns a water based foaming composition and the method of making it. The composition is optimized in that it contains a surfactant specifically selected according to the polymer also present in the composition. The surfactant and the polymer are selected so that they are oppositely charged. The invention is very useful in drilling or treating wells.

Abstract: A fluid selected form the group consisting of a drilling, a drill-in, and a completion fluid, said fluid comprising a substantially linear heteropolyglycol in an amount effective to perform a function selected from the group consisting of polymer stabilization, shale stabilization, and a combination thereof. The fluid preferably comprises water as a continuous phase, and the heteropolyglycol preferably consists essentially of monomers selected from the group consisting of ethylene oxide and linear alpha-omega alkylene diols.

Abstract: A dry mix additive, which is used to form a clay-free, i.e., non-argillaceous, inorganic salt-free, i.e., non-brine, biodegradable and chemically degradable aqueous-based wellbore fluid, which is capable of imparting non-Newtonian, pseudoplasticity and fluid loss controlling properties to aqueous systems for use in horizontal directional drilling, finding utility in horizontal environmental well installation for soil and groundwater remediation. The dry mixture comprises (1) from about 80-90 by weight of pre-gelatinized corn starch heteropolysaccharide, and (2) from about 10-20 by weight of a synthetic biopolymer such as Xanthan gum treated with a dispersing agent (glyoxal) for ease of dispersion. Sodium hypochlorite can be added, if desired, to the wellbore fluid to provide resistance to bacterial attack. The dry mixture is added to either fresh water or acidic water in amounts of 12-15 pounds of the dry mixture to a barrel (42 U.S.

Abstract: Rheologically modified compositions, and rheologically modified fluid compositions prepared therefrom, containing reticulated bacterial cellulose in a polyol base fluid, are disclosed. The amount of reticulated bacterial cellulose present in the composition is an amount effective to viscosify the polyol base fluid.

Abstract: This invention relates to drilling fluid additives that suppress clay swelling within a subterranean well and to methods for controlling clay swelling during the drilling of a subterranean well. In one embodiment trihydroxy alkyl amine is reacted with an alkyl halide or a water soluble quaternary amine to form a quaternized trihydroxy alkyl amine. The reaction products can also include condensed reaction products of quaternized trihydroxy alkyl amines. In another embodiment a choline derivative is used. The quaternized reaction products and choline derivatives are characterized by low toxicity and compatibility with anionic drilling fluid components. The products are added to water base drilling fluids which are circulated throughout a well. The drilling fluid additives and the method of controlling clay swelling provide for improved control of the rheological properties of drilling fluids along with increased environmental and drilling fluid compatibility.

Abstract: The invention relates to a gel made of apolar medium including:an apolar medium,a "multichain" liquid surface-active agent in acidic form, soluble or dispersible in the said apolar medium,an agent for neutralizing the said "multichain" surface-active agent,from 0.2 to 5 molecules of water per molecule of "multichain" surface-active agent,optionally at least one emulsifying agent and/or a solid filler which is soluble or insoluble in the apolar medium.This gel may be employed for the formulation of water-based drilling fluids.

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: The present invention relates to water-soluble, particularly ternary, preferably ionic, cellulose mixed ethers, more particularly to anionic water-soluble cellulose mixed ethers, as additives for drilling fluid applications.

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: An drilling fluid additive to reduce loss circulation includes comminuted rice fraction and corn cobs, and includes ground at least one of ground wood fiber, ground nut shells, ground paper and shredded cellophane. A method of treating a drilling fluid includes contacting such drilling fluid additive with the base drilling fluid to form well fluid. A method of operating a well includes circulation of such a well fluid into and out of a borehole.

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: For controlling the dispersion of solids, e.g., cuttings, in water-based fluid used during operations such as drilling, completion or workover operations in a well crossing at least one permeable geologic formation, there is added to the fluid an optimized amount of a water soluble polymer HM PAM based on acrylamide and hydrophobic units. In a variant, a useful amount of hydrophobically modified cellulose derivative, e.g., modified hydroxyethylcellulose, HMHEC, is also added, thus forming a fluid containing HM PAM and HM HEC. The process has particular application to slim-hole and/or strongly deviated drilling.

Abstract: Oil-base drilling fluids containing a non-sulfonated polymer and/or a non-organophilic clay maintain desirable rheological properties at elevated temperatures.

Abstract: An additive to reduce fluid loss from drilling fluids is comprised of comminuted products from the rice plant or blends of other comminuted plant materials with the rice products. Polymers to reduce fluid loss even lower and friction-reducing materials may be added to the plant materials.

Abstract: A composition useful for viscosifying a water-based fluid is provided which comprises a polymer such as guar gum, a metal compound such as an aluminum compound. The composition can also contain a polymer such as guar gum, a magnesium compound such as magnesium oxide, a metal aluminate such as sodium aluminate or a metal compound such as an aluminum compound, and optionally a fatty acid or salts thereof. The water-based fluid can also contain a clay such as bentonite. A process for viscosifying a water-based fluid and for substantially retaining the viscosity of the water-based fluid is also provided which comprises contacting the fluid with the composition described herein. Also disclosed is a process for controlling water loss of a water-based drilling fluid wherein the process comprises contacting the fluid with the composition described herein.

Abstract: A composition for plugging wells that is biodegradable and environmentally safe comprising bentonite particles coated with a water soluble coating of biodegradable natural resin, such as certified three pound Confectioners White Lac Glaze in Specially Denatured Ethyl Alcohol (SDA) Formula 35A, 190 proof. The bentonite may be in the form of chips or compressed pellets. When exposed to water, the soluble coating dissolves at a uniform rate, exposing the bentonite to water whereupon it expands to form a tough but flexible water impermeable seal of a semi-solid, gel-like mass.

Abstract: A water-based fluid for use in the drilling of wells is disclosed. This fluid: is rheologically stable over a wide temperature range, from room temperature to at least about 475.degree. F., thus reducing drilling time in high temperature applications; typically necessitates minimal disposal rates in operation; is resistant to temperature-induced carbonate gellation; creates a thin filter cake; and combines the low toxicity of a water-based fluid with the performance stability of an oil-based fluid.As further disclosed herein, this drilling fluid comprises a water-based colloidal suspension of certain readily available drilling fluid components, including clay, an inorganic salt, and parenchymal cell cellulose ("PCC").

Abstract: A water-based fluid for use in the drilling of wells is disclosed. This fluid: is rheologically stable over a wide temperature range, from room temperature to at least about 475.degree. F., thus reducing drilling time in high temperature applications; typically necessitates minimal disposal rates in operation; is resistant to temperature-induced carbonate gellation; creates a thin filter cake; and combines the low toxicity of a water-based fluid with the performance stability of an oil-based fluid.As further disclosed herein, this drilling fluid comprises a water-based colloidal suspension of certain readily available drilling fluid components, including clay, parenchymal cell cellulose ("PCC") and an inorganic salt.

Abstract: An additive to reduce fluid loss from drilling fluids is comprised of comminuted products from the rice plant or blends of other comminuted plant materials with the rice products. Polymers to reduce fluid loss even lower and friction-reducing materials may be added to the plant materials.