Abstract: Disclosed herein are new graft copolymers of dextran and polyacrylamide. The graft copolymers can include dextran, where the dextran is a backbone polymer including about 15 wt % to about 50 wt % of the graft copolymer; and polyacrylamide, where the polyacrylamide is a side chain polymer including about 50 wt % to about 85 wt % of the graft copolymer, based on the total weight of the graft copolymer, where the graft copolymer has a weight-average molecular weight from about 1,000,000 g/mol to about 1,500,000 g/mol. The graft copolymers of dextran and polyacrylamide can be used as friction reducers for well treatment fluids.

Abstract: Oil-soluble well treatment agents may be slowly released into a well or a subterranean formation by use of an aqueous fluid of (i) an oil-in-water dispersion having the oil-soluble well treatment agent as a dispersed phase and (ii) a second component having an oil-soluble or water-soluble primer coated onto a portion of its surface. The amount of the oil-soluble well treatment agent in the oil-in-water dispersion is from 20 to 50 weight percent and the average particle size of the oil-soluble well treatment agent in the dispersion may be from 0.005 to 2 micrometers. The oil-in-water dispersion may further contain a water-soluble well treatment agent.

Abstract: Disclosed herein are new graft copolymers of dextran and polyacrylamide. The graft copolymers can include dextran, where the dextran is a backbone polymer including about 15 wt % to about 50 wt % of the graft copolymer; and polyacrylamide, where the polyacrylamide is a side chain polymer including about 50 wt % to about 85 wt % of the graft copolymer, based on the total weight of the graft copolymer, where the graft copolymer has a weight-average molecular weight from about 1,000,000 g/mol to about 1,500,000 g/mol. The graft copolymers of dextran and polyacrylamide can be used as friction reducers for well treatment fluids.

Abstract: Disclosed herein are new graft copolymers of dextran and polyacrylamide. The graft copolymers can include dextran, where the dextran is a backbone polymer including about 15 wt % to about 50 wt % of the graft copolymer; and polyacrylamide, where the polyacrylamide is a side chain polymer including about 50 wt % to about 85 wt % of the graft copolymer, based on the total weight of the graft copolymer, where the graft copolymer has a weight-average molecular weight from about 1,000,000 g/mol to about 1,500,000 g/mol. The graft copolymers of dextran and polyacrylamide can be used as friction reducers for well treatment fluids.

Abstract: A fluid for use in hydraulic fracturing contains underivatized guar or a guar gum derivative as viscosifying or gelling polymer, a crosslinking agent, carbon dioxide as foaming agent and urea and, optionally, a bifunctional organic compound containing at least one hydroxyl group and at least one quaternary group and, optionally, a non-gaseous foaming agent. The fluid may be characterized by a low pH such as a pH than or equal to 3.0 and less than or equal to 5.0.

Abstract: The flow of well treatment fluids may be diverted from a high permeability zone to a low permeability zone within a fracture network within a subterranean formation by use of a mixture comprising a dissolvable diverter and a proppant. At least a portion of the high permeability zone is propped open with the proppant of the mixture and at least a portion of the high permeability zone is blocked with the diverter. A fluid is then pumped into the subterranean formation and into a lower permeability zone of the formation farther from the wellbore. The diverter in the high permeability zones may then be dissolved at in-situ reservoir conditions and hydrocarbons produced from the high permeability propped zones of the fracture network. The mixture has particular applicability in the enhancement of production or hydrocarbons from high permeability zones in a fracture network located near the wellbore.

Abstract: A method of reducing water saturation onto surfaces exposed to hydrocarbons during the production of hydrocarbons from subterranean formations by altering the wettability of the surface of the formation with surface modified nanoparticles.

Abstract: Oil-soluble well treatment agents may be slowly released into a well or a subterranean formation by use of an aqueous fluid of (i) an oil-in-water dispersion having the oil-soluble well treatment agent as a dispersed phase and (ii) a second component having an oil-soluble or water-soluble primer coated onto a portion of its surface. The amount of the oil-soluble well treatment agent in the oil-in-water dispersion is from 20 to 50 weight percent and the average particle size of the oil-soluble well treatment agent in the dispersion may be from 0.005 to 2 micrometers. The oil-in-water dispersion may further contain a water-soluble well treatment agent.

Abstract: A method of treating a well or a subterranean formation with an aqueous treatment fluid containing one or more oil-soluble, water-insoluble well treatment agents. The fluid includes an aqueous dispersion containing the well treatment agent in an amount from 25 to 60 weight percent. The volume average particle diameter of the oil-soluble well treatment agent in the fluid may be less than or equal to 2.5 microns. The fluid may further contain a water-soluble well treatment agent.

Abstract: A system for slowly releasing an oil-soluble well treatment agent into a well or a subterranean formation includes a composite of the oil-soluble well treatment agent associated with a second component. The amount of the oil-soluble well treatment agent in the composite is from 20 to 35 weight percent and the average particle size of the oil-soluble well treatment agent in the composite is less than or equal to 1 micrometer. The composite may further contain a water-soluble well treatment agent.

Abstract: Sandstone formations of oil and gas and geothermal wells may be successfully stimulated with a fluid containing GLDA or salt and HF or a HF-generating component and an organophosphonate component. The organophosphonate acts as a sequestering agent and reduces the amount of metal fluoride precipitates produced.

Abstract: The strength of a proppant or sand control particulate may be improved by coating the proppant to form a composite. The composite has enhanced compressive strength between about 34 to about 130 MPa and minimizes the spelling of fines at closure stresses in excess of 5,000 psi. Conductivity of fractures is further enhanced by forming a pack of the composites in the fracture.

Abstract: A composite for controlling the release of a well treatment agent or for inhibiting or preventing the formation of contaminants into a fluid or a surface within a reservoir contains a well treatment agent adsorbed onto a water-insoluble or oil-insoluble adsorbent, the adsorbent having a surface area between from about 110 m2/g to about 700 m2/g. The composite may be also used to monitor the production of fluids from the reservoir or the flow of fluids in the reservoir.

Abstract: The complexity of a fracture network may be enhanced during a hydraulic fracturing operation by monitoring operational parameters of the fracturing job and altering stress conditions in the well in response to the monitoring of the operational parameters. The operational parameters monitored may include the injection rate of the pumped fluid, the density of the pumped fluid or the bottomhole pressure of the well after the fluid is pumped. The method provides an increase to the stimulated reservoir volume (SRV).

Abstract: A method of reducing water saturation onto surfaces exposed to hydrocarbons during the production of hydrocarbons from subterranean formations by altering the wettability of the surface of the formation with surface modified nanoparticles.

Abstract: A fluid for use in hydraulic fracturing contains underivatized guar or a guar gum derivative as viscosifying or gelling polymer, a crosslinking agent, carbon dioxide as foaming agent and urea and, optionally, a bifunctional organic compound containing at least one hydroxyl group and at least one quaternary group and, optionally, a non-gaseous foaming agent. The fluid may be characterized by a low pH such as a pH than or equal to 3.0 and less than or equal to 5.0.

Abstract: The flow of a fluid may be diverted from a high permeability zone to a low permeability portion of a subterranean formation by use of particulates comprising dicarboxylic acid, ester or an anhydride of the formula: or an anhydride thereof, wherein R1 is —COO—(R5O)y—R4 or —H; R2 and R3 are selected from the group consisting of —H and —COO—(R5O)y—R4, provided both R2 and R3 are —COO—(R5O)y—R4 when R1 is —H and further provided only one of R2 or R3 is —COO—(R5O)y—R4 when R1 is —COO—(R5O)y—R4, R4 is —H or a C1-C6 alkyl group, R5 is a C1-C6 alkylene group, and each y is 0 to 5. The dicarboxylic acid, ester or anhydride may further be admixed with an aliphatic polyester having the general formula of repeating units: where n is an integer between 75 and 10,000 and R is selected from the group consisting of hydrogen, alkyl, aryl, alkylaryl, acetyl, heteroatoms, and mixtures; thereof.

Abstract: Fluids produced from a fractured subterranean formation may be monitored by pumping into the well a fracturing fluid which contains a tracer. The method may be used to monitor produced hydrocarbons as well as produced water. The tracer may also be used in a sand control, frac pack or acid fracturing operation. The tracer is a component of a composite where it may be immobilized within a matrix (such as an emulsion) or porous particulate, onto a support or compressed with a binder into a solid particulate. The tracer may be slowly released from the composite.

Abstract: A well treatment fluid containing borated galactomannan may be used to isolate a pre-determined productive zone in an oil or gas well. The fluid is pumped into the well in a substantially non-hydrated form and forms a temporary seal. The fluid may be used as a chemical packer in place of a mechanical packer. After the pre-determined productive zone is isolated, a well intervention operation may be performed within the isolated pre-determined zone.

Abstract: A fines-fixing agent that has improved compatibility with organic complexed borate fracturing fluids is disclosed. Existing fines fixing agents have a high concentration of unreacted caustic that results in a product pH of approximately 12. This high pH affects the crosslinker and the overall fracturing fluid system stability, promoting precipitation of the organic crosslinker. These effects can be mitigated by neutralizing the fines fixing agents with an acid such as hydrochloric or acetic acid to a pH of 6 or lower.