CN-121991678-A - Gel breaking activator, fracturing fluid containing gel breaking activator, and preparation method and application of gel breaking activator

Abstract

The invention belongs to the technical field of fracturing fluid gel breaking of oil and gas fields, and relates to a gel breaking activator, a fracturing fluid containing the gel breaking activator, and a preparation method and application of the fracturing fluid. The gel breaking activator comprises, by mass, 3.3% -7.13% of triethanolamine, 6.7% -8.58% of D-sodium erythorbate, 3.3% -7.13% of tea polyphenol, 6.7% -8.58% of sodium dehydroacetate, 8.58% -20% of ethylene glycol and the balance of water. The preparation method of the gel breaking activator is also disclosed, and the preparation method is characterized in that a plurality of raw materials are physically blended, the preparation process is simple, the gel breaking activator can be prepared on site, and the use is convenient. The fracturing fluid containing the gel breaking activator and the application thereof are also disclosed, the dosage of the gel breaking activator is less, only 1% -3% is needed, and the gel breaking performance is good at 20-50 ℃. The problem of difficult gel breaking of the fracturing fluid when the stratum temperature is lower than 50 ℃ can be solved.

Inventors

• LI JIANI
• WU YIGE
• LIU YUCHENG
• LIU YANG
• ZHANG HAO
• ZENG CHANGMIN
• LIANG RUI
• YUAN ZEBO
• ZHANG YAN
• SHI YING
• LIU JIQUAN
• ZHANG LIMING

Assignees

• 中国石油天然气股份有限公司

Dates

Publication Date

20260508

Application Date

20241107

Claims (10)

1. 1. The gel breaking activator is characterized by comprising the following components in percentage by mass: 3.3 to 7.13 percent of triethanolamine, 6.7 to 8.58 percent of D-sodium erythorbate, 3.3 to 7.13 percent of tea polyphenol, 6.7 to 8.58 percent of sodium dehydroacetate, 8.58 to 20 percent of glycol and the balance of water.
2. 2. The method for preparing the gel breaking activator as claimed in claim 1, which comprises the following steps: and mixing and stirring triethanolamine, D-sodium erythorbate, tea polyphenol, sodium dehydroacetate and ethylene glycol uniformly, and adding water for dilution to obtain the gel breaking activator.
3. 3. A fracturing fluid comprising the break activator of claim 1.
4. 4. A fracturing fluid according to claim 3, characterized in that it comprises the following components: super guanidine gum, a cleanup additive, a demulsifier, water and the gel breaking activator of claim 1; the addition amount of the gel breaking activator accounts for 1% -3% of the total mass of the fracturing fluid.
5. 5. The fracturing fluid of claim 4, wherein the cleanup additive is a fluorocarbon surfactant, a complex of a fluorocarbon surfactant and a hydrocarbon surfactant, a complex of a fluorocarbon surfactant and an anionic-containing or nonionic amphoteric surfactant.
6. 6. The fracturing fluid of claim 4, wherein the demulsifier is at least one of an alkyl sulfate, a sulfonate, a carboxyl compound-polyol, or a complex; the compound is a compound of polyalkylene glycol and ether.
7. 7. The application of the fracturing fluid in fracturing fluid gel breaking, which is characterized in that after the fracturing fluid is prepared, a gel breaking main agent and a cross-linking agent are added into the fracturing fluid, wherein the fracturing fluid can break gel of an oil-gas layer at 20-50 ℃; The fracturing fluid full gel breaking time is greater than the fracturing construction time, and the fracturing fluid full gel breaking time is less than the open time.
8. 8. The use of a fracturing fluid according to claim 7 for fracturing fluid breaking, wherein the breaking main agent is a peroxide.
9. 9. The use of the fracturing fluid of claim 8 in fracturing fluid breaking, wherein the peroxide is ammonium persulfate.
10. 10. The use of a fracturing fluid according to claim 7, wherein the cross-linking agent is a borate, a titanium compound or a zirconium compound.

Description

Gel breaking activator, fracturing fluid containing gel breaking activator, and preparation method and application of gel breaking activator Technical Field The invention belongs to the technical field of oil gas development, and particularly relates to a gel breaking activator, a fracturing fluid containing the gel breaking activator, and a preparation method and application of the fracturing fluid. Background The first breaker is enzyme breaker, but must be used under low pH value, generally the enzyme activity is highest at pH6.0, and the enzyme activity is completely lost when the pH is greater than 9.0, and the pH value of the currently used vegetable gum fracturing fluid is between 8 and 10 and is alkaline. Certain specific enzymes can keep the activity of more than 60% within the pH value range of 6.0-10.0, but have high cost, are not easy to operate on site and have limited use conditions. And secondly, adding substances capable of slowly generating acid, reducing the pH value of fracturing fluid in the stratum, and destroying the crosslinked structure and the polymer main chain to achieve the purpose of gel breaking. But still has the defects of high cost, difficult control and compatibility. Thirdly, peroxide (such as ammonium persulfate and potassium persulfate) is used for achieving the purpose of rapid gel breaking. The prior breaker of the oilfield vegetable gum fracturing fluid mainly adopts Ammonium Persulfate (APS), for example, patent document with publication number of CN102352233A discloses a low-damage micromolecular guar gum fracturing fluid, and the breaking process comprises the steps that acid generated by persulfate hydrolysis reaction reduces the pH value of the gel at a certain temperature, and oxygen free radicals generated by self-decomposition reaction act on acetal bonds of the guar gum to oxidize and degrade so as to jointly destroy the gel structure. Thus, the rate of gel breaking depends on the rate of decomposition of the persulfate. Studies show that the decomposition of persulfate is a primary reaction, and the half-life of ammonium persulfate is more than 8 hours at 70 ℃. At a temperature of 50 ℃, the half-life is 152h and the decomposition is slow. At temperatures below 50 ℃, the breaking capacity of the persulfates decreases rapidly. At formation temperatures below 50 ℃, conventional breakers (based on peroxides such as ammonium persulfate, sodium persulfate) do not obtain sufficient activation energy at low temperatures and therefore do not produce sufficient oxygen radicals and acids through self-decomposition reactions, which are the key basis for breaking. In recent years, researchers have begun to study the ability to enhance the breaking of fracturing fluids at low temperatures, focusing mainly on the impact of different breaking aids on breaking performance. The method mainly comprises the steps of adding reducing agents such as RA (inorganic salt) and Fe (II), and the like, wherein the method mainly has the problems that Fe 3+ generated by APS/Fe (II) reaction can generate precipitation when the pH value is more than or equal to 3, and the residue content is larger, so that stratum injury can be caused. 2. The complex activator for inhibiting iron ion sedimentation is added into the ferrous ion salt Fe (II) with a certain concentration to synergistically promote the decomposition of the APS gel breaker, compared with the single ferrous ion salt Fe (II) as an auxiliary agent, the dosage is small, the gel breaking speed of the fracturing fluid is accelerated, and the effect of chelating iron ions accelerates the reaction. In summary, none of the current breakers are suitable for fracturing fluid breaking at low temperatures. Disclosure of Invention The invention aims to provide a gel breaking activator, a fracturing fluid containing the gel breaking activator, and a preparation method and application of the gel breaking activator, and solves the problem that the conventional gel breaking agent is not suitable for breaking gel of the fracturing fluid at low temperature. The invention is realized by the following technical scheme: on the one hand, the invention discloses a gel breaking activator, which comprises the following components in percentage by mass: 3.3 to 7.13 percent of triethanolamine, 6.7 to 8.58 percent of D-sodium erythorbate, 3.3 to 7.13 percent of tea polyphenol, 6.7 to 8.58 percent of sodium dehydroacetate, 8.58 to 20 percent of glycol and the balance of water. On the other hand, the invention discloses a preparation method of the gel breaking activator, which comprises the following steps: and mixing and stirring triethanolamine, D-sodium erythorbate, tea polyphenol, sodium dehydroacetate and ethylene glycol uniformly, and adding water for dilution to obtain the gel breaking activator. In another aspect, the invention discloses a fracturing fluid comprising the gel breaking activator. Further, the fracturing fluid comprises the following compo