Abstract: The disclosure relates to a method of delaying viscosification of a well treatment fluid within a well or within a subterranean formation penetrated by a well by introducing into the well a hydratable viscosifying agent of particulates having a minimum of 40% retention on a 60 mesh screen and a minimum of 1% retention on a 20 mesh screen.

Abstract: The disclosure relates to a method of delaying viscosification of a well treatment fluid within a well or within a subterranean formation penetrated by a well by introducing into the well a hydratable viscosifying agent of particulates having a minimum of 40% retention on a 60 mesh screen and a minimum of 1% retention on a 20 mesh screen.

Abstract: The disclosure relates to a method of delaying viscosification of a well treatment fluid within a well or within a subterranean formation penetrated by a well by introducing into the well a hydratable viscosifying agent of particulates having a minimum of 40% retention on a 60 mesh screen and a minimum of 1% retention on a 20 mesh screen.

Abstract: Loss of wellbore fluids (such as drilling fluids, completion fluids and workover fluids) into the flow passages of a subterranean formation may be reduced or eliminated by introducing into the wellbore in communication with the formation a composition containing a composite of a deformable core having a hardened coating which contains a viscosifying agent and, optionally, a crosslinking agent. The viscosity of the composition increases in-situ as the viscosifying agent, and optional crosslinking agent, disassociate from the deformable core and react. A fluid-impermeable barrier is thereby formed. The composites may also be used in spacers, well cements, workover and completion fluids as their need arises.

Abstract: Set retarders of copolymers of at least one polymerizable ethylenically unsaturated monomer and at least one alkoxylated monomer are capable of delaying the hardening of a cementitious slurry when introduced into a subterranean formation until a downhole temperature greater than or equal to 500° F. is obtained, even in the absence of an intensifier.

Abstract: The disclosure relates to a method of delaying viscosification of a well treatment fluid within a well or within a subterranean formation penetrated by a well by introducing into the well a hydratable viscosifying agent of particulates having a minimum of 40% retention on a 60 mesh screen and a minimum of 1% retention on a 20 mesh screen.

Abstract: Methylhydroxyethyl cellulose may be used as an additive in cement slurries in the treatment of wells to prevent or reduce the occurrence of gas channeling. In addition to acting as a gas control additive, methylhydroxyethyl cellulose controls fluid loss, minimizes free fluid and stabilizes foam during cementing of the well.

Abstract: Loss of wellbore fluids (such as drilling fluids, completion fluids and workover fluids) into the flow passages of a subterranean formation may be reduced or eliminated by introducing into the wellbore in communication with the formation a composition containing a composite of a deformable core having a hardened coating which contains a viscosifying agent and, optionally, a crosslinking agent. The viscosity of the composition increases in-situ as the viscosifying agent, and optional crosslinking agent, disassociate from the deformable core and react. A fluid-impermeable barrier is thereby formed. The composites may also be used in spacers, well cements, workover and completion fluids as their need arises.

Abstract: Methylhydroxyethyl cellulose may be used as an additive in cement slurries in the treatment of wells to prevent or reduce the occurrence of gas channeling. In addition to acting as a gas control additive, methylhydroxyethyl cellulose controls fluid loss, minimizes free fluid and stabilizes foam during cementing of the well.

Abstract: Set retarders of copolymers of at least one polymerizable ethylenically unsaturated monomer and at least one alkoxylated monomer are capable of delaying the hardening of a cementitious slurry when introduced into a subterranean formation until a downhole temperature greater than or equal to 500° F. is obtained, even in the absence of an intensifier.

Abstract: Loss of wellbore fluids (such as drilling fluids, completion fluids and workover fluids) into the flow passages of a subterranean formation during well drilling, cementing, completion and workover operations may be reduced or eliminated by introducing into the wellbore in communication with the formation a suspension of a polysaccharide in a aqueous fluid. The aqueous fluid contains water and a delayed viscosification material or agent. Hydration of the polysaccharide may be delayed until after introduction of the composition into the formation. A fluid-impermeable barrier is thereby formed.

Abstract: Loss of wellbore fluids (such as drilling fluids, completion fluids and workover fluids) in a wellbore or into the flow passages of a subterranean formation during well drilling, cementing, completion and workover operations may be reduced or eliminated by introducing into the wellbore a fluid of a hydratable polyvinyl alcohol in an aqueous fluid. The amount of polyvinyl alcohol in the well treatment composition is between from about 50 pounds to about 1,200 pounds per 1,000 gallons of aqueous fluid. The aqueous fluid may contain a delayed viscosification agent and/or crosslinking agent. Alternatively, the polyvinyl alcohol may be greater than or equal to 95 percent hydrolyzed. When introduced into the well, a fluid impermeable barrier is formed within the formation or wellbore.