Abstract: Methods of treating a subterranean formation including providing a spacer fluid including acrylamide/2-acrylamido-2-methylpropane sulfonic acid grafted copolymer (acrylamide copolymer), polyethylene glycol alkyl ether sulfate (PEGAES), and ethoxylated nonylphenol (ENP), and introducing the spacer fluid into a wellbore of the subterranean formation to displace at least a portion of a first fluid from the wellbore. The spacer fluid maintains its yield point for at least half an hour when subjected to a temperature of greater than 300° F.

Abstract: The invention provides an oilfield suspending friction reducer treatment composition fluid comprising from about 0.001 weight percent to about 0.5 weight percent of a drag reducing surfactant; at least one drag reducing enhancer selected from the group consisting of polymeric drag reduction enhancers, monomeric drag reduction enhancers, and mixtures thereof.

Abstract: Spacer fluids that are stable at temperatures up to at least 300° C. comprise water, polystyrene sulfonate and a mixture of particulate materials. The particulate materials may be chosen such that the mixture has at least a trimodal particle-size distribution. The fluids may further comprise inorganic clays, mutual solvents and surfactants.

Abstract: The disclosure is directed to polyelectrolyte complex nanoparticles that can be used to deliver agents deep into hydrocarbon reservoirs. Methods of making and using said polyelectrolyte complex nanoparticles are also provided.

Abstract: A method, system, and composition for producing oil from a formation utilizing an oil recovery formulation comprising a surfactant, an ammonia liquid, an alkali metal carbonate or bicarbonate, a polymer, and water are provided.

Abstract: A particulate suspending agent may be useful for mitigating particulate settling in wellbore applications with high-temperature and/or at near-neutral and higher pH values. Methods of treating a wellbore may include providing a treatment fluid comprising an aqueous liquid, a plurality of particulates, and a particulate suspending agent, wherein the particulate suspending agent comprises a crosslinked polymer particulate formed by a reaction comprising a first monofunctional monomer and an orthoester crosslinker, the orthoester crosslinker comprising an orthoester linkage and at least two crosslinking moieties; and placing the treatment fluid in a wellbore penetrating a subterranean formation.

Abstract: An enhanced oil recovery formulation composition containing a sacrificial agent and a surfactant dispersed in a fluid is provided. The sacrificial agent reduces the amount of surfactant required to enhance oil recovery from a petroleum-bearing formation. The sacrificial agent is selected from the group consisting of a compound comprising a single carboxylic acid, a single carboxylic acid derivative, or a single carboxylate salt, or a compound lacking a carboxylic acid group, a carboxylate group, a sulfonic acid group, or a sulfonate group that is a pheol, a sulphonamide, or a thiol, or a compound having a molecular weight of 1000 or less that comprises one or more hydroxyl groups.

Abstract: A copolymer and preparation method and application thereof are disclosed. The copolymer is random copolymer obtained from monomers consisting of acrylamide, acrylic acid, alkenyl sulfonate, 2-acrylamido-dodecyl sulfonate, p-styrene sulfonate or isoprene sulfonate and so on. The copolymer of present invention can be used as fluid loss additive and has good fluid loss properties, which would not make the drilling fluid thicken at high temperature of 200° C. and high salt conditions of saturated brine. It has a medium-pressure fluid loss after aging and rolling for 16 h at high temperature of 200° C., as measured in accordance with the American Petroleum Institute Standard Test at room temperature, and has good properties of high temperature-resisting and salt-resisting.

Abstract: Well treatment agents containing a particulate substrate are coated with a polyelectrolyte bilayer to provide a well treatment composite for use in well treatment operations. Each layer of the polyelectrolyte bilayer is composed of oppositely charged polyionic material. The well treatment composite may further contain a succession of polyelectrolyte bilayers, each polyelectrolyte bilayer containing layers of oppositely charged polyionic materials.

Abstract: A method of treating a subterranean formation comprises providing a treatment fluid comprising: an aqueous fluid; a gelling agent, and a multifunctional boronic crosslinker comprising two or more boronic functional groups; and introducing the viscosified fluid into a subterranean formation.

Abstract: Methods of using relative permeability modifiers for the diversion of aqueous fluids during subterranean operations are provided. An embodiment of the present invention provides a method of diverting fluids in a subterranean formation that may comprise providing a treatment fluid comprising an aqueous fluid and a relative permeability modifier that comprises water-soluble polymer with hydrophobic or hydrophilic modification; introducing the treatment fluid into a well bore that penetrates the subterranean formation; and at least a first portion of the treatment fluid to penetrate into a portion of the subterranean formation so as to substantially divert a second portion of the treatment fluid or another aqueous treatment fluid to another portion of the subterranean.

Abstract: Methods and compositions are provided that include a water-in-oil composition comprising an oil-based continuous phase and a discontinuous phase that comprises at least a plurality of hydrogel droplets and a method comprising providing a water-in-oil emulsion comprising an oil-based continuous phase and a discontinuous phase that comprises at least a plurality of hydrogel droplets; and placing the water-in-oil emulsion in a well bore penetrating a subterranean formation. Additional methods are also provided.

Abstract: A spacer for use in an oil well cementing operation comprises an aqueous solution of a visco-elastic surfactant. A method of treating a well in a cementing operation, comprises pumping the spacer into a well ahead of a cement slurry for cementing the well.

Abstract: A method of reducing fluid loss from a wellbore that includes emplacing a fluid loss pill in the wellbore, the fluid loss pill comprising: a base fluid; a hydratable or solvatable synthetic copolymer having at least one crosslinkable comonomer; and a crosslinking agent is disclosed.

Abstract: A method of controlling the pressure of a casing annulus in a subterranean well that includes injecting into the casing annulus a composition including a base fluid and a polymer coated colloidal solid material. The polymer coated colloidal solid material includes: a solid particle having an weight average particle diameter (d50) of less than two microns, and a polymeric dispersing agent coated onto the surface of the solid particle during the cominution (i.e. grinding) process utilized to make the colloidal particles. The polymeric dispersing agent may be a water soluble polymer having a molecular weight of at least 2000 Daltons. The solid particulate material may be selected from materials having of specific gravity of at least 2.

Abstract: Methods and compositions are provided that include a water-in-oil composition comprising an oil-based continuous phase and a discontinuous phase that comprises at least a plurality of hydrogel droplets and a method comprising providing a water-in-oil emulsion comprising an oil-based continuous phase and a discontinuous phase that comprises at least a plurality of hydrogel droplets; and placing the water-in-oil emulsion in a well bore penetrating a subterranean formation. Additional methods are also provided.

Abstract: A method of controlling the pressure of a casing annulus in a subterranean well that includes injecting into the casing annulus a composition including a base fluid and a polymer coated colloidal solid material. The polymer coated colloidal solid material includes: a solid particle having an weight average particle diameter (d50) of less than two microns, and a polymeric dispersing agent coated onto the surface of the solid particle during the cominution (i.e. grinding) process utilized to make the colloidal particles. The polymeric dispersing agent may be a water soluble polymer having a molecular weight of at least 2000 Daltons. The solid particulate material may be selected from materials having of specific gravity of at least 2.

Abstract: An aqueous fluid composition useful for the recovery of hydrocarbons from a subterranean formation, including a mixture of water, a water soluble polymer, an inorganic salt and at least one zwitterionic surfactant and methods of using same.

Abstract: It was found that the addition of polymers to viscoelastic surfactant base system allows to adjust the rheological properties of the base fluid. Depending in particular on one side of the ratio of the concentration of added polymer and the concentration of viscoelastic surfactant and on the other side of the molecular weight of the added polymer, the same polymer—or the same type of polymer—may perform different functions such as viscosity enhancer, viscosity breaker or viscosity-recovery enhancer.

Abstract: Water soluble associative polymers and compositions comprising them together with alkali metal salts of carboxylic acid are disclosed. Methods comprise introducing into a wellbore a fluid comprising such associative polymers and alkali metal salts of carboxylic acid, e.g., cesium formate. Disclosed water soluble associative polymers have functionality including at least sulfonate groups, carboxylate groups and hydrophobes associative with one another in a saturated aqueous solution of an alkali metal salt of a carboxylic acid.

Abstract: Methods and compositions are disclosed for controlled addition of components that decrease the viscosity of the viscoelastic surfactant fluids or for controlled changes in the electrolyte concentration or composition of the viscoelastic surfactant fluids. One aspect of the invention relates to the use of internal breakers with a delayed activation. Another aspect of the invention relates to the use of precursors that release a breaking system such as alcohol by a process such as melting, slow dissolution, reaction with a compound present in the fluid or added to the fluid during or after the step of injecting, rupture of an encapsulating coating and de-adsorption of a breaking agent absorbed into solid particles. In another aspect of the invention, alcohols are included in a pad to reduce the low-shear viscosity and reduce the resistance to flow of the treatment fluids during a desired phase of the treatment.

Abstract: Well completion foamed spacer fluids and methods of using the foamed spacer fluids are provided. A method of the invention for displacing a first fluid from a well bore with an incompatible second fluid comprises the following steps. A foamed spacer fluid is placed between the first and second fluids to separate the first and second fluids and to remove the first fluid from the walls of the well bore. Thereafter, the first fluid and the foamed spacer fluid are displaced from the well bore with the second fluid.

Abstract: It has been found that a large variety of solid chemicals available in a bulk powder form could be added to subterranean treatment fluids with delayed release when said chemicals are delivered as capsules consisting of encapsulated granulates obtained by aggregating the bulk powder under pressure to form a densified material and optionally, dry comminuting said densified material to produce granulates at the desired size. The invention is particularly useful for delivering new types of breaking agents for stimulation fluids or additives for wellbore cementing.

Abstract: The present invention provides methods of preventing the flow of water or gas or both through a subterranean zone having a high temperature and a depth such that a long pumping time is required to place a sealing composition therein. The methods basically comprise the steps of preparing a polymeric sealing composition comprised of water, a cross-linking agent and a selected water-soluble polymer which reacts with the cross-linking agent and forms a sealing gel which is stable for a desired period of time at the temperature of the zone and has a pumping time before gelation in the presence of the cross-linking agent whereby the composition can be pumped to the depth of the zone and placed therein. Thereafter, the sealing composition is pumped into the zone and allowed to form a sealing gel therein.

Abstract: The present invention provides a water-based fluid, in particular for drilling, completion or for any other intervention in a well such as a hydrocarbon well, in which the viscosity is controlled by a system constituted by precipitated silica nanoparticles (A) associated with a water-soluble copolymer (B) comprising one or more water-soluble co-monomers (I) having little or no affinity for silica and one or more co-monomers (II) which absorb onto the silica. The invention is of particular application to the secondary recovery of hydrocarbons.

Abstract: The invention concerns a water-based additive for well fluid, comprising an acrylamide and branched styrene sulphonate copolymer. It also concerns a water-based fluid comprising an acrylamide and branched styrene sulphonate copolymer. The additive is useful for controlling the filtering of a well fluid through the wall. The invention is advantageously applicable to drilling and/or completion of oil wells having a temperature higher than 120° C.

Abstract: Oil degradable encapsulated breaker particles are used in fracturing operations to break hydro-carbon liquid gelled with salts of alkyl phosphate esters. The preferred breaker chemical is particulate urea coated with sulfonated EPDM.

Abstract: A method and a drilling fluid/cement slurry composition for cementing a wellbore. The drilling fluid/cement slurry composition comprises A cement slurry composition comprising:a) a cementitious material;b) a drilling fluid; andc) a dispersant selected from the group consisting of water soluble polymers comprising allyloxybenzene sulfonate or allyloxybenzene phosphonate polymerized with at least one of acrylic acid, acrylamides, alkyl acrylamides, maleic anhydride, itaconic acid, sulfonated or phosphonated styrene sulfonated or phosphonated vinyl toluene, sulfonated or phosphonated isobutylene, acrylamidopropane sulfonate, acrylamidopropanephosphonate, vinyl alcohol, sulfonated or phosphonated propene and alkali, alkaline earth and ammonium salts thereof.

Abstract: Spacer fluids comprising a dispersant selected from the group consisting of water soluble polymers comprising allyloxybenzene sulfonate or allyloxybenzene phosphonate polymerized with at least one of acrylic acid, acrylamides, alkyl acrylamides, maleic anhydride, itaconic acid, sulfonated or phosphonated styrene, sulfonated or phosphonated vinyl toluene, sulfonated or phosphonated isobutylene, acrylamidopropane sulfonate or acrylamidopropanephosphonate, vinyl alcohol, sulfonated or phosphonated propene and alkali metal, alkaline earth metal and ammonium salts thereof and water with optional additional components such as surfactants, viscosifiers and wetting materials to form a rheologically compatible spacer fluid for use between a drilling fluid and a cement slurry and a method for using such spacer fluids to displace drilling fluids from a wellbore space with a cement slurry.

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 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: A method and use for a dry composition comprising a mixture of water-soluble polymer and an aluminum citrate preparation is disclosed. The polymer is capable of cross-linking in the presence of water and aluminum ions. Any water-soluble polymer known to the art is suitable. Cross-linked polymer forms a gel in highly permeable, watered-out regions of oil-containing rock, allowing for increased oil recovery and decreased water use and recycling.

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: This invention relates to a method for preparing and earth stabilization fluid, a method for using such an earth stabilization fluid and to the earth stabilization fluid itself. This invention uses a continuous phase that has been added to a borehole and a polymer material that forms gel masses having desired functional properties when added to the continuous phase.

Abstract: A gelable composition and process are disclosed that delay the gelation and increase the gel strength of gelled water soluble acrylamide-containing polymers contains: (1) a water dispersible first crosslinking compound selected from the group consisting of p-aminosalicylic acid, furfuryl alcohol, RArOC(O)R' and HOArC(O)OR" wherein Ar represents a phenyl group which can be substituted or non-substituted; R is a hydrogen or a carboxylic group; R' is a C.sub.1 -C.sub.6 alkyl; R" is a hydrogen, a phenyl group, or a C.sub.1 -C.sub.6 alkyl; and when R is a carboxylic group, R and C(O)OR" can be at ortho, meta, or para position with respect to the OC(O)R' group and the OH group, respectively; (2) a water dispersible second crosslinking compound selected from the group consisting of aldehydes and aldehyde-generating compounds; (3) a water soluble acrylamide-containing polymer; and (4) water.

Abstract: Oil and gas wells and injection wells are cleaned of oil-based drilling muds, pipe thread compounds, other oil contaminants, cement and contaminants in injection water by a composition comprising fresh water or seawater, one-half to ten percent concentration of an alkyl polyglycoside surfactant and one to ten percent of a caustic agent such as sodium hydroxide, potassium hydroxide or ammonium hydroxide.