Abstract:
Compositions and methods are given for delayed breaking of viscoelastic surfactant gels inside formation pores, particularly for use in hydraulic fracturing. Breaking inside formation pores is accomplished without mechanical intervention or use of a second fluid. Bromate oxidizing agents are used along with selected breaking activators for the bromate breaking compounds. Useful bromate breaking activators include acid-generating breaking activators, oxidizing sulfur containing breaking activators, and reducing agent breaking activators.
Abstract:
A method for treating a wellbore or a subterranean formation penetrated by a wellbore includes preparing a gelled oil at the surface, introducing the gelled oil into the wellbore, recovering the gelled oil at the surface, adding a base to the gelled oil to reduce the viscosity, allowing entrained solids to settle out, adding an acid to increase the viscosity, and re-injecting the gelled oil.
Abstract:
Compositions and methods of treating a subterranean formation including forming a fluid comprising polyacrylamide and calcium carbonate and introducing the fluid to the formation, wherein the viscosity of the fluid is higher than if no calcium carbonate is present. Compositions and methods of treating a subterranean formation penetrated by a well bore including forming a fluid comprising polyacrylamide, calcium carbonate, and crosslinker, and introducing the fluid to the formation, wherein the fluid viscosity at 100 s-1 is increased from 300 cP to 600 cP at a temperature of 93 degC. Compositions and methods of treating a subterranean formation penetrated by a well bore including forming a fluid comprising polyacrylamide and barium carbonate and introducing the fluid to the formation, wherein the viscosity of the fluid is higher than if no barium carbonate is present.
Abstract:
The invention provides a method made of steps of injecting into a wellbore, a composition comprising a solvent, a crosslinkable polymer, a crosslinking agent capable of crosslinking the polymer or forming a polymer, and a gelling accelerator selected from the group consisting of carbon dioxide, polylactic acid, encapsulated acid and latent acid; and allowing viscosity of the composition to increase and form a gel more quickly with the gelling accelerator than without.
Abstract:
A method of treating a subterranean formation penetrated by a wellbore utilizes a treating fluid formed from an aqueous solution of a water-soluble polymer. The treating fluid further contains a crosslinking agent and an optional delayed release alkaline additive. The delayed release alkaline additive may be at least one of urea, a urea derivative, a solid alkaline earth metal carbonate, a solid alkaline earth metal oxide and combinations of these. The treating fluid further includes an acidic pH adjusting agent used in an amount to provide the treating fluid with a pH of less than about 5. The treating fluid is then introduced into the formation.
Abstract:
A method and apparatus for treating a subterranean formation traversed by a wellbore including forming an emulsion comprising oil, acid, and particulate, wherein the forming the emulsion is prepared on the fly, and introducing the emulsion into a wellbore.
Abstract:
A well treatment microemulsion for use in a subterranean formation is disclosed, the microemulsion comprises a solvent blend comprising a solvent and a co-solvent; a surfactant blend comprising a surfactant, wherein the surfactant blend is able to give formation intermediate wettability properties; an alcohol; and a carrier fluid; wherein the alcohol, the solvent and surfactant blends are combined with the carrier fluid to produce the well treatment microemulsion. By intermediate wettability it is meant that the water has an advancing contact angle on the surface between 62 and 133 degrees. The associate method of treating a subterranean formation of a well with the microemulsion and the associate method of modifying the wettability of the formation with the microemulsion are also disclosed.
Abstract:
The invention provides a well treatment composition comprising: a viscoelastic surfactant or a cementing composition and an environmentally friendly component made of cellulosic matrix with organic acid trapped within. A method is disclosed comprising introducing into a wellbore penetrating a subterranean formation an environmentally friendly component made of cellulosic matrix with organic acid trapped within.Also, the invention provides a method for rheology modification optimization of a viscoelastic surfactant, comprising: (a) defining a rheology profile of the viscoelastic surfactant; (b) defining a comparative rheology profile of a composition of the viscoelastic surfactant and a first environmentally friendly naturally occurring component made of cellulosic matrix with organic acid derivative trapped within; (c) repeating step (b) with a second environmentally friendly component made of cellulosic matrix with organic acid derivative trapped within; (d) defining between the first and second environmentally friendly components, environmentally friendly component showing optimum modification of the rheology based on analysis of the rheology profile and comparative rheology profile.
Abstract:
The invention discloses method of treating a subterranean formation of a well bore, the method comprising: providing a treatment fluid comprising: an aqueous base fluid; a viscosity enhancer; and a viscoelastic surfactant, wherein the enhancer is acid in the aqueous base fluid and co-operates with the viscoelastic surfactant to enhance viscosity compared to viscoelastic surfactant alone in the aqueous base fluid; and introducing the treatment fluid into the well bore.
Abstract:
A treatment fluid for treating a subterranean formation is formed from an aqueous solution of a polysaccharide, a polyacrylamide, a crosslinking agent, which may be a Group 4 transition metal crosslinking agent, and less than 0.1% by weight of any clay component. In certain embodiments, the polyacrylamide may have an average molecular weight of from greater than 0.5 million to about 20 million and may be present in the fluid in an amount of from about 0.01% to 1% by weight of the fluid. A method of treating a subterranean formation penetrated by a wellbore may be carried out by introducing the treatment fluid into the formation through the wellbore. In certain embodiments, the treatment fluid may be introduced into a portion of the formation having a temperature of 120° C. or higher.