Method for a fracturing fluid system at high temperatures

Patent metadata

Field	Value
Publication number	US-2018223174-A1
Application number	US-201815948766-A
Country	US
Kind code	A1
Filing date	Apr 9, 2018
Priority date	Nov 18, 2015
Publication date	Aug 9, 2018
Grant date	—

Abstract

The method for well-stimulation through a wellbore in a rock formation is hydraulic fracturing under high temperature conditions. The method includes injecting a fracturing fluid system to the rock formation; fracturing the rock formation at a temperature between 150-260 degrees Celsius; and recovering fluid components of the fracturing fluid system from the wellbore and setting the proppant in the fractures. The fracturing fluid system includes proppant and a plurality of fluid components. The fluid components can include water, a gelling agent, and a stabilizer made of ascorbic acid. The ascorbic acid stabilizes viscosity of the gelling agent, adjusts pH, and delays cross linking. Amount of components and additional components, such as a cross-linking agent, a breaker, another adjusting agent and an inverting surfactant adjust the fracturing fluid system for well conditions and a type of treatment to be completed.

First claim

1 . A method for well-stimulation through a wellbore in a rock formation, comprising the steps of:
injecting a fracturing fluid system to said rock formation, said fracturing fluid system comprising:
a proppant; and a plurality of fluid components, said fluid components being comprised of:
water;
a gelling agent;
a cross linking agent; and
a stabilizer comprising ascorbic acid;

fracturing said rock formation at a temperature between 150-260 degrees Celsius; cross linking said gelling agent with said cross linking agent so as to increase viscosity of said fracturing fluid system; delaying said cross linking of said gelling agent with said ascorbic acid; and recovering said fluid components of said fracturing fluid system from said wellbore.

2 . The method for well-stimulation, according to claim 1 , wherein said proppant is comprised of a granular material to prevent fractures from closing.

3 . The method for well-stimulation, according to claim 1 , wherein said gelling agent is comprised of a high molecular weight synthetic polymer resistant to hydrolysis.

4 . The method for well-stimulation, according to claim 3 , wherein said fracturing fluid system further comprises an inverting surfactant to hydrate the polymer in said water, the polymer being an emulsion polymer.

5 . The method for well-stimulation, according to claim 1 , wherein said gelling agent is comprised of a copolymer derived from acrylamide, acrylamidomethylpropanesulfonic acid, and vinyl phosphonate.

6 . The method for well-stimulation, according to claim 1 , wherein said fracturing fluid system cross linking said gelling agent with said cross linking agent so as to increase viscosity of said fracturing fluid system comprises increasing apparent viscosity without a spike in apparent viscosity.

7 . The method for well-stimulation, according to claim 1 , wherein said cross linking agent is selected from at least one of a group consisting of boron based compounds, zirconium based compounds, and titanium based compounds.

8 . The method for well-stimulation, according to claim 1 , wherein said fracturing fluid system further comprises a breaker, and wherein the step of recovering said fluid components comprises loading said breaker into said fracturing fluid system, after the step of fracturing.

9 . The method for well-stimulation, according to claim 1 , wherein the step of injecting said fracturing fluid system comprises: forming said ascorbic acid in said fracturing fluid system by loading an ascorbate salt and an acid into said fracturing fluid system.

10 . The method for well-stimulation, according to claim 1 , wherein said fracturing fluid system further comprises a cross linking agent, the method further comprising the steps of: adjusting pH of said fracturing fluid system with said ascorbic acid, said fracturing fluid system having a pH ranging from about 3.5 to 6.9 as a linear gel before adding said cross linking agent to said fracturing fluid system.

11 . The method for well-stimulation, according to claim 1 , wherein the ascorbic acid is present as a fluid component of the fracturing fluid in a range of from about 1 ppt to about 50 ppt so as to adjust pH and delay cross linking of said gelling agent.

12 . The method for well-stimulation, according to claim 12 , wherein said ascorbic acid ranges from about 3 ppt to about 25 ppt so as to adjust pH and delay said cross linking agent.

13 . The method for well-stimulation, according to claim 12 , wherein said pH adjusting agent maintains said fracturing fluid system in a range of about 3.5 to about 6.9 as a linear gel.

14 . A method for well-stimulation through a wellbore in a rock formation, comprising the steps of:
injecting a fracturing fluid system to said rock formation, said fracturing fluid system comprising:
a proppant; and a plurality of fluid components, said fluid components being comprised of:
water;
a gelling agent;
a cross linking agent; and
a stabilizer comprising ascorbic acid;

adjusting pH of said fracturing fluid system with ascorbic acid, said fracturing fluid system having a pH in a range of from about 3.5 to about 6.9 as a linear gel before adding said cross linking agent to said fracturing fluid system; fracturing said rock formation at a temperature between 150-260 degrees Celsius; cross linking said gelling agent with said cross linking agent so as to increase viscosity of said fracturing fluid system without a spike in apparent viscosity; delaying said cross linking of said gelling agent with said ascorbic acid; and recovering said fluid components of said fracturing fluid system from said wellbore.

15 . The method for well-stimulation, according to claim 14 , wherein the ascorbic acid is present as a fluid component of the fracturing fluid in a range of from about 1 ppt to about 50 ppt so as to adjust pH and delay cross linking of said gelling agent.

16 . A method of delaying an increase in viscosity in a fracturing fluid, the method comprising:
increasing viscosity in a fracturing fluid by cross linking a gelling agent in the fracturing fluid with a cross linking agent in the fracturing fluid; and controlling the cross linking of the gelling agent by the addition of a sufficient amount of ascorbic acid to delay the cross linking of the gelling agent a sufficient amount of time such that the increase in viscosity occurs at a preselected depth.

17 . The method according to claim 16 , wherein the addition of a sufficient amount of ascorbic acid to delay the cross linking of the gelling agent a sufficient amount of time such that the increase in viscosity occurs at a preselected depth comprises adjusting pH of the fracturing fluid with ascorbic acid, where the fracturing fluid has a pH in a range of from about 3.5 to about 6.9 as a linear gel before adding the cross linking agent to the fracturing fluid.

18 . The method according to claim 16 , wherein the addition of a sufficient amount of ascorbic acid to delay the cross linking of the gelling agent a sufficient amount of time such that the increase in viscosity occurs at a preselected depth comprises adding ascorbic acid in an amount to comprise a fluid component of the fracturing fluid in a range of from about 1 ppt to about 50 ppt.

19 . The method according to claim 16 , wherein the addition of a sufficient amount of ascorbic acid to delay the cross linking of the gelling agent a sufficient amount of time such that the increase in viscosity occurs at a preselected depth comprises forming the ascorbic acid in the fracturing fluid by loading an ascorbate salt and an acid into the fracturing fluid.

20 . The method according to claim 16 , wherein the preselected depth is in a rock formation having a temperature range of from about 150 degrees Celsius to about 260 degrees Celsius.

Assignees

• Cnpc Usa Corp

Inventors

• Song Lulu
• Yang Zhenzhou

Classifications

• C09K8/685 Primary

  containing cross-linking agents · CPC title

• C09K2208/26

  Gel breakers other than bacteria or enzymes · CPC title

• C09K8/887

  containing cross-linking agents · CPC title

• C09K8/885

  obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• E21B43/267

  reinforcing fractures by propping · CPC title