Drag reducer for slickwater fracturing fluid and synthesis method for drag reducer

Abstract

The invention discloses a drag reducer for a slickwater fracturing fluid and a synthesis method for the drag reducer. The synthesis method comprises the following steps: adding 5 to 30 weight percent of an acrylamide monomer A, 5 to 30 weight percent of an anionic monomer B, 50 to 75 weight percent of a dispersion medium C and 0.5 to 5.0 weight percent of a dispersion stabilizer D into a reaction kettle to form a mixture according to preset using amounts, performing uniform stirring, controlling reaction temperature within a range of 40 to 60 DEG C under the protection of nitrogen in the reaction kettle, dropwise adding an initiator E into the mixture, and performing polymerization reaction for 6 to 10 hours to obtain a W / W emulsion drag reducer, with a molecular weight of 4 to 6 millions, for the slickwater fracturing fluid. According to the method, the problems of high difficulty in post-treatment of an organic solvent and pollution caused by high probability of the organic solvent in entering the stratum and groundwater during inverse emulsion polymerization synthesis of a drag reducer, and the problems of smaller molecular weight, large addition, poor drag resistance effects, high post-treatment energy consumption and the like of the drag reducer obtained by solution polymerization are effectively solved; the product is high in water solubility and dissolution speed, and the drag reduction rate is higher than or equal to 70 percent.

Description

technical field [0001] The invention relates to the technical field of drag reducer preparation, in particular to a method for synthesizing a drag reducer for slick water fracturing fluid used in oil and gas field fracturing. Background technique [0002] Slippery water fracturing fluid refers to a fracturing fluid in which a certain amount of proppant and a very small amount of drag reducer, surfactant, clay stabilizer and other additives are added to clean water. Slippery water fracturing fluid is generally suitable for low-permeability formations, high-strength rock formations, low closure stress formations, formations with developed natural fractures, and formations with low pressure. Compared with the traditional gel fracturing fluid system, the drag-reducing water fracturing fluid system greatly reduces the damage of the gel to the formation and fractures, and can save 40% to 60% of the construction cost compared with the traditional fracturing method, and can produce ...

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Problems solved by technology

[0004] In order to overcome the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a kind of drag reducer for slick water fracturing fluid and its synthesis method, first acrylamide monomer A, anionic monomer B, dispersion medium C and dispersion medium Stabilizer D is added to the reaction kettle according to the preset dosage percentage to form a mixture, and the mixture is stirred evenly. The reaction temperature inside the reaction kettle is controlled within the range of 40-60°C under the protection of nitrogen, and then the initiator E is added dropwise to the mixture to carry out Polymerization reaction, after 6-10 hours of reaction, a water-in-water (W / W) emulsion drag reducer for slippery water fracturing fluid with a molecular weight between 4 million and 6 million can be obtained. This method can effectively avoid the existence of existing synthetic methods Disadvantages: the synthesis of drag reducers by inverse emulsion polymerization usually requires the use of organic solvents such as benzene, toluene, cyclohexane, naphtha, etc., and there are difficulties in the post-treatment of organic solvents, and the organic solvents are easy to enter the formation and groundwater to cause pollution; the solution The drag reducer obtained by polymerization has the problems of small molecular weight, large addition amount, poor drag reduction effect, and a large amount of energy consumption in post-processing.

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