Abstract: A treatment of a subterranean formation which contains a hydrocarbon-bearing zone, is carried out using a hydrocarbon-responsive fluid thickened with an oligomeric surfactant consisting of from 2 to 8_linked surfactant monomer subunits. The process of treatment comprises (i) mixing a thickening amount of oligomeric surfactant with an aqueous liquid to make a viscoelastic treatment fluid, (ii) pumping said viscoelastic treatment fluid through a wellbore and into the subterranean formation, where (iii) contact with hydrocarbons within the formation dissipates the viscosity of the treatment fluid.

Abstract: A powder composition comprising viscoelastic surfactant forms, in aqueous solution, a viscoelastic wellbore treatment fluid.

Abstract: A method of providing a viscous emulsion at a subterranean location accessible via a wellbore, begins by providing an aqueous/aqueous emulsion comprising two aqueous solutions which, at surface temperature and pressure, are able to co-exist as separate aqueous phases in contact with each other. The two phases contain respective solutes which are sufficiently incompatible that they cause phase separation. The dispersed phase is rich in one solute, which may be a thickening polymer, while continuous phase is rich in a second solute, which may comprise surfactant. A hydrophobic liquid is dispersed in this emulsion to become the dispersed phase of a viscous emulsion whose continuous phase is provided by the aqueous/aqueous emulsion. The hydrophobic liquid and the aqueous/aqueous emulsion may be pumped separately down the wellbore to the subterranean location, and allowed to mix there so as to form the viscous emulsion at the subterranean location.

Abstract: Embodiments of this invention relate to compositions and methods of treating a subterranean formation penetrated by a well bore including introducing a Theological polymer into a subterranean formation, introducing a partitioning agent into a subterranean formation and forming a heterogeneous mixture comprising a dispersed Theological polymer-rich phase and a partitioning agent-rich phase, wherein the viscosity of the mixture is lower than the viscosity of the mixture when no partitioning agent is present.

Abstract: Methods and apparatus for forming a fluid for use within in a subterranean formation comprising combining a partitioning agent, crosslinkable polymer, and crosslinker into a fluid, wherein more than 50 percent of the crosslinkable polymer crosslinks and less than 10 percent of the partitioning agent crosslinks, and introducing the fluid into the subterranean formation. Methods and apparatus of forming a fluid for use within in a subterranean formation comprising combining a partitioning agent, crosslinkable polymer, and crosslinker into a fluid, wherein a critical polymer concentration for crosslinking the crosslinkable polymer is lower than if the partitioning agent were not in the fluid, and introducing the fluid into the subterranean formation.

Abstract: Methods and apparatus for forming a fluid for use within in a subterranean formation including combining a partitioning agent and viscosifying polymer into a fluid, introducing the fluid into the subterranean formation, and recovering at least a portion of the fluid at a uppermost surface of the subterranean formation. Methods and apparatus of forming a fluid for use within in a subterranean formation including combining a partitioning agent and viscosifying polymer into a fluid, introducing the fluid into the subterranean formation at a temperature of about 45° C. or higher, and recovering at least a portion of the fluid at a uppermost surface of the subterranean formation at a temperature of about 45° C. or lower.

Abstract: A method of plugging a fracture in a subterranean formation which includes placing into the fracture a composition comprising microspheres or microbeads, wherein the microspheres are created by surface crosslinking of droplets in a water-in-water emulsion. Such microspheres may form a filter cake in the formation. The microspheres may include a chemical agent to be released when the microspheres dissolve.

Abstract: A treatment of a subterranean formation which contains a hydrocarbon-bearing zone, is carried out using a hydrocarbon-responsive fluid thickened with an oligomeric surfactant consisting of from 2 to 8_linked surfactant monomer subunits. The process of treatment comprises (i) mixing a thickening amount of oligomeric surfactant with an aqueous liquid to make a viscoelastic treatment fluid, (ii) pumping said viscoelastic treatment fluid through a wellbore and into the subterranean formation, where (iii) contact with hydrocarbons within the formation dissipates the viscosity of the treatment fluid.

Abstract: A water-based wellbore treatment fluid contains: one or more viscoelastic-gelling carboxylic acids and/or alkali metal salts thereof; and one or more solubilising alkylolamines. The carboxylic acids and/or alkali metal salts and the alkylolamines are present in the fluid in respective amounts such that, at 25° C., the alkylolamines solubilise a sufficient portion of the carboxylic acids and/or alkali metal salts to render the fluid viscoelastic. A remaining portion of the carboxylic acids and/or alkali metal salts forms a suspension of solid particulates in the fluid.

Abstract: A fluid loss control method uses a fluid loss control pill in a well in advance of a completion operation. An embodiment of the fluid loss control pill comprises polyester solids that are hydrolysable and can exhibit plastic deformation at formation conditions. An embodiment of the method comprises spotting the fluid loss control pill in the well adjacent to a formation to form a filtercake to inhibit fluid entry from the well into the formation, performing a completion operation comprising contacting the filtercake with overbalanced wellbore fluid, and degrading the filtercake wherein the polyester particles are hydrolyzed to remove formation damage.

Abstract: Methods and apparatus for forming a fluid for use within in a subterranean formation including crosslinking a polymer along the surface of microspheres in a water-in-water emulsion and introducing the microspheres into the subterranean formation. Methods and apparatus for forming a fluid for use within in a subterranean formation including crosslinking a polymer along the surface of microspheres in a water in water emulsion, isolating the microspheres from the emulsion, and introducing the microspheres into the subterranean formation. Methods and apparatus for forming a fluid to treat a subterranean formation including introducing a crosslinkable polymer, partitioning agent, and crosslinker into a solvent, crosslinking the crosslinkable polymer, isolating beads of the crosslinkable polymer from the partitioning agent, introducing the beads into a fluid for treating a subterranean formation.

Abstract: A low viscosity wellbore polymer fluid gelling system comprising an aqueous medium and a water-in-water emulsion comprising a plurality of polymers or oligomers, including at least one removable polymer or oligomer, and at least one gelling polymer or oligomer, wherein said fluid has a low viscosity when injected, and the gelling polymer forms a gel downhole which has a storage modulus of at least about 60 Pa after the removable polymer is removed from the fluid. A method of isolating at least one zone of a subterranean formation penetrated by a wellbore includes the steps of preparing a water-in-water emulsion comprising a plurality of polymers or oligomers including at least one removable polymer or oligomer, and at least one gellable polymer or oligomer; and combining the water-in-water emulsion with an aqueous medium to prepare a low viscosity polymer fluid.

Abstract: The invention relates to the use of one or more water-soluble reactive liquid component capable of subsequent polymerization or cross-linking to form a solid to improve the zonal isolation and alleviate the impacts of cracks and fissures in the cement sheath around a completed subterranean well. It includes the steps of injecting a wellbore fluid carrying the reactive component or additive into the wellbore, injecting a cementitious composition as slurry into the wellbore and letting said reactive liquid component pass through at least one of the interfaces between cement and formation, cement and filter cake, and filter cake and formation before forming a solid of said reactive liquid component that traverses said at least one of the interfaces.

Abstract: A viscoelastic wellbore treatment fluid comprises an effective amount of an oligomeric surfactant for controlling the viscoelasticity of the fluid.

Abstract: A seismic data acquisition assembly includes a cable; seismic sensors that are disposed along the cable; and a filler material inside the cable. The filler includes a hydrocarbon-based liquid and an agent to cause the filler material to have a rheological property that is substantially different than a corresponding rheological property of the hydrocarbon-based liquid.

Abstract: A reservoir sampling apparatus (20) is described having at least one probe (26) adapted to provide a fluid flow path between a formation and the inner of the apparatus with the flow path being sealed from direct flow of fluids from the borehole annulus with a heating projector (251) adapted to project heat into the formation surrounding the probe and a controller (253) to maintain the temperature in the formation below a threshold value.

Abstract: The present invention provides aqueous viscoelastic compositions comprising a cleavable anionic surfactant which is a sulphonate and possibly also an electrolyte. The cleavable surfactants useful in the present invention comprise a chemical bond, which is capable of being broken under appropriate conditions, to produce oil soluble and water soluble products typically having no interfacial properties and surface activity compared with the original surfactant molecule. Further, the rheological properties of the aqueous viscoelastic composition are usually altered upon cleavage of the cleavable surfactant generally resulting in the elimination of the viscosifying, viscoelastic and surfactant properties of the composition. Aqueous viscoelastic compositions in accordance with the present invention are suitable for use in oil-field applications, particularly for hydraulic fracturing of subterranean formations.

Abstract: Methods and apparatus for forming a fluid for use within in a subterranean formation including crosslinking a polymer along the surface of microspheres in a water-in-water emulsion and introducing the microspheres into the subterranean formation. Methods and apparatus for forming a fluid for use within in a subterranean formation including crosslinking a polymer along the surface of microspheres in a water in water emulsion, isolating the microspheres from the emulsion, and introducing the microspheres into the subterranean formation. Methods and apparatus for forming a fluid to treat a subterranean formation including introducing a crosslinkable polymer, partitioning agent, and crosslinker into a solvent, crosslinking the crosslinkable polymer, isolating beads of the crosslinkable polymer from the partitioning agent, introducing the beads into a fluid for treating a subterranean formation.

Abstract: A method of plugging a fracture in a subterranean formation which includes placing into the fracture a composition comprising microspheres or microbeads, wherein the microspheres are created by surface crosslinking of droplets in a water-in-water emulsion. Such microspheres may form a filter cake in the formation. The microspheres may include a chemical agent to be released when the microspheres dissolve.

Abstract: A wellbore fluid comprising a surfactant, the surfactant having the formula (R1—X)nZ, wherein R1 is an aliphatic group—comprising a C18-C22 principal straight chain bonded at a terminal carbon atom thereof to X, and comprising at least one C1-C2 side chain—X is a charged head group, Z is a counterion, and n is an integer which ensures that the surfactant is charge neutral, and wherein the charged head group X is selected to provide that the surfactant is soluble in oil and at least one part of the charged head group is anionic.