摘要:
In the presence of certain polyols, a guar gum or similar polysaccharide thickener solution is boron crosslinked before achievement of complete hydration of the thickener, without compromising the viscosity level achieved in a fracturing fluid by the time it is pumped into the wellbore and fractures the subterranean formation adjacent the wellbore. Methods continuously involve hydrating a polysaccharide thickener to an extent of 10% to 75%, but less than full hydration. Before 75% hydration is exceeded, a boron crosslinker is added. Upon addition of the boron crosslinker, the fluid is injected into the wellbore to stimulate hydrocarbon production. Because less time is needed for hydration, well site mixing equipment is down-sized smaller to achieve better efficiency and cost savings.
摘要:
Methods comprising preparing an aqueous mixture of an anionic polymer, a charge screening surfactant, and a borate crosslinker, wherein the mixture has a conductivity less than 10 mS/cm, injecting the mixture down a wellbore, and gelling the mixture. An embodiment of the aqueous mixture can also include tetramethylammonium chloride as a clay stabilizer and a metal crosslinker such as a complex of zirconium and an amino acid ligand system. An embodiment can effectively provide borate crosslinking of an anionic polymer in a low-ionic-strength fluid system, without sacrificing ultimate gel strength or thermal persistence of the metal crosslinked polymer.
摘要:
Suspensions are provided of water-soluble materials in non-aqueous carrier fluids using suspension agents that include organophilic clays. Methods of forming such suspensions are provided. Methods are also provided for using such suspensions to prepare aqueous solutions, in particular thickened aqueous solutions, in particular for use in oilfield treatments.
摘要:
Subterranean formation treatment methods incorporating a rheology model which enables prediction of fluid rheology properties during a treatment operation, where the foundation of the model is a description of the reaction chemistry which describes how the number of crosslinks and broken polymer linkages develops in time under the influence of crosslinkers, breakers, and/or thermally induced effects and pressure effects. In one aspect, when used as a tool for simulating the fluid viscosity, the model can help optimizing the fluid design and optional breaker schedule for a hydraulic fracturing treatment.
摘要:
A fluid that is useful in stimulation operations, and in particular, in hydraulic fracturing treatments, comprises a carrier fluid; a solvatable, crosslinkable polymer; a cross-linking agent that does not cause substantial cross-linking of the polymer at temperatures less than about 105° F. and a pH of about 10 or greater; and an organic amine stabilizing agent that has a first pKa or a pH in water of at least about 9.5. One group of such amines has the formula H2N—(R1NH)n—H where R1 is C1-C4 alkyl and n is from 1-6. In one embodiment, the cross-linking agent is an organic zirconate, such as bis(hydroxyethyl)glycine zirconate. The organic zirconate is effective to cross-link the polymer when the composition is at a temperature of at least about 105° F., and a pH of about 10 or higher, preferably a pH in the range of about 10.5-12.
摘要:
A method for treating a subterranean formation is made of steps of providing a composition comprising a carrier fluid, a polymer viscosifying agent, carbon dioxide and a formate salt or formic acid; injecting into a wellbore, the composition; contacting the composition with the subterranean formation, wherein the temperature is above 100 degrees Celsius at this contact; and allowing the composition to treat the subterranean formation.
摘要:
A delayed crosslinker system useful in downhole treatment fluids is disclosed. The crosslinker system comprises water-reactive solids, a non-aqueous, non-oily, hygroscopic liquid, a suspension aid, and an optional polyol. The crosslinker system may be prepared at a remote location and transported to the site of its intended use. There it may be pumped into a formation and activated when a gel fluid is introduced into the wellbore, only then forming a high viscosity treatment fluid. Thus, the amount of energy required for pumping is reduced. The optional polyol component increases crosslink delay and enhances the rate of viscosity after high shear (shear recovery).
摘要:
Methods comprising preparing an aqueous mixture of an anionic polymer, a charge screening surfactant, and a borate crosslinker, wherein the mixture has a conductivity less than 10 mS/cm, injecting the mixture down a wellbore, and gelling the mixture. An embodiment of the aqueous mixture can also include tetramethylammonium chloride as a clay stabilizer and a metal crosslinker such as a complex of zirconium and an amino acid ligand system. An embodiment can effectively provide borate crosslinking of an anionic polymer in a low-ionic-strength fluid system, without sacrificing ultimate gel strength or thermal persistence of the metal crosslinked polymer.
摘要:
The invention discloses a method of treating a wellbore by providing an aqueous mixture of a hydrated polysaccharide with a salt; adding to the mixture a cross-linking agent for cross-linking the hydrated polysaccharide, wherein the cross-linking agent comprises a zirconium compound, glutamic acid, and a polyol; pumping the aqueous mixture of the hydrated polysaccharide and the cross-linking agent into the wellbore; and cross-linking the hydrated polysaccharide.
摘要:
A well treatment fluid and method uses an organic peroxide. An activator embodiment can lower an effective concentration of the peroxide to break the fluid. A weight ratio of activator:organic peroxide can be at least about 1:20 in one well treatment fluid embodiment. A peroxyester breaker embodiment can be used in a well treatment fluid and method. A breaker delay agent embodiment can control the polymer break window in a well treatment fluid and method using an organic peroxide. A breaker package embodiment used in a well treatment fluid and method can include an organic peroxide and an amine breaker delay agent having the formula RR1NR2 wherein R, R1 and R2 are independently selected from hydrogen, alkyl, hydroxyalkyl, and combinations thereof.