Low-temperature guar gum breaker for oil and gas well fracturing as well as preparation method and application of low-temperature guar gum breaker

Abstract

The invention belongs to the technical field of fracturing fluid chemicals in the oil and gas field exploitation process, and discloses a low-temperature guar gum breaker for oil and gas well fracturing, a preparation method and application. The low-temperature guar gum breaker for oil and gas well fracturing is prepared from the following components in percentage by mass: 58% of beta-D-mannanase, 0.1%-1.0% of a composite initiator, 12%-23% of hydroxyalkyl chitosan, 5%-12% of tetramethyl ammonium polyhedral oligomeric silsesquioxane, 10%-15% of polyethylene glycol and 5%-8% of water. The preparation method comprises the following steps: adding the beta-D-mannanase liquid, the hydroxyalkyl chitosan and the water into a reaction kettle, and mixing; adding a composite initiator, stirring, and adding tetramethyl ammonium polyhedral oligomeric silsesquioxane; and adding polyethylene glycol, stirring, and cooling to room temperature to obtain the low-temperature guar gum breaker for oil-gas well fracturing. The method has the advantages of wide application range, small damage to strata, high flowback rate and realization of rapid gel breaking.

Description

technical field [0001] The invention belongs to the technical field of fracturing fluid chemicals in the process of oil and gas field exploitation, and in particular relates to a low-temperature guar gel breaker for oil and gas well fracturing, a preparation method and application. Background technique [0002] Fracturing is currently the most effective means to increase the production and injection of oil and water wells during the development of oil and gas fields. Among them, the performance of fracturing fluid will directly affect the success or failure of fracturing. Traditional fracturing fluids usually use potassium persulfate, ammonium persulfate, capsule breakers, acid breakers, etc., which have the following disadvantages: the breaker system reacts with the fracturing string during fracturing construction, corroding the pipe At the same time, it is easy for iron ions to form insoluble precipitates in the formation to block the matrix pores. In addition, some gel b...

AI Technical Summary

Problems solved by technology

Traditional fracturing fluids usually use potassium persulfate, ammonium persulfate, capsule breakers, acid breakers, etc., which have the following disadvantages: the breaker system reacts with the fracturing string during fracturing construction, corroding the pipe At the same time, it is easy for iron ions to form insoluble precipitates in the formation to block the matrix pores. In addition, some gel breaker systems are also likely to react with clay minerals in the formation matrix and formation crude oil to form extremely difficult-to-handle emulsions. The liquid system is difficult to handle after flowback, which greatly increases the processing cost of the fracturing fluid; while the oxidative gel breaking system has a certain randomness in the gel breaking, and the polymer macromolecules cannot be completely degraded. According to statistics, the polymerization The molecular weight of the substance is greater than 2.0×10 6 About 20% of the fracturing fluid is not degraded after being broken with an oxidative breaker; at the same time, the addition of a conventional breaker will increase the salinity of the fracturing fluid, which will cause corrosion of the pipe string during the fracturing process , the flowback fluid entering the system after fracturing will cause the electric field of the crude oil electric dehydrator to fail, and the dehydration will fail

[0005] The difficulties in solving the above problems and defects are as follows: it is difficult to break the guar gum fracturing fluid system below 30°C through the existing normal temperature gel breaking system, which will cause adsorption and retention damage to the reformed formation. Preservation and transportation is the key technology that urgently needs a breakthrough

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