Temperature-resistant composite cleaning fracturing fluid and preparation method thereof

Abstract

The invention discloses a temperature-resistant composite cleaning fracturing fluid and a preparation method thereof, wherein the temperature-resistant composite cleaning fracturing fluid comprises the following components by mass: 2-2% of a surfactant; 1-2% of a countra-ion assistant; 1-2% of nano particles and balance of water. The preparation method comprises the following steps: first esterifying ordinary hydrophilic nano silica with an acid anhydride organic substance to obtain an acid anhydride modified surface carboxylated nano particle, then preparing a nano fluid by using the modifiednano particle, sequentially adding the temperature resistant surfactant and the countra-ion assistant, uniformly mixing, standing at a constant temperature to obtain the temperature-resistant composite cleaning fracturing fluid. The temperature-resistant composite cleaning fracturing fluid has the advantages of simple preparation method and low cost, and the nano silica particles modified by theacid anhydride has a dual mechanism effect in the cleaning fracturing fluid, further strengthens the gelation of the long-chain surfactant so as to improve the viscoelasticity and temperature resistance of the clean fracturing fluid, and broadens the application of the clean fracturing fluid in complex reservoirs.

Description

technical field [0001] The invention belongs to the technical field of functional nanomaterials and oil recovery chemistry in the development of oil and gas fields, and in particular relates to a temperature-resistant composite clean fracturing fluid and a preparation method thereof. Background technique [0002] With the rapid development of the national economy, oil, as an efficient and extensive energy source, is also in increasing demand. With the continuous development of oil and gas exploration and development, the reserves of easy-to-exploit reservoirs are decreasing, so the development of low-permeability oil and gas layers is currently in the technical reserve stage. There are abundant oil and gas reserves in my country's low-permeability oil and gas reservoirs, but due to the low natural production capacity, they cannot achieve effective production by relying on their own energy. Therefore, the recovery rate must be improved by fracturing. The fracturing fluid is t...

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Problems solved by technology

However, the synthesis process of the associative long-chain alkylacrylamide polymer provided by this invention is complicated, the cost of chemicals involved is high, and the polymer monomer is easy to remain in the formation and cannot be degraded

[0004] The use of nanomaterials to further enhance the performance of clean fracturing fluids has become one of the current research hotspots. CN107033868 A discloses a nanomaterial-enhanced clean fracturing fluid and a preparation method thereof. A new type of composite clean fracturing fluid system obtained by compounding silica can further improve the consistency and viscoelasticity of the fracturing fluid. It has been verified that nano-silica has the function of improving the performance of the fracturing fluid. However, the quaternary ammonium used in this invention Salt cationic surfactants have insufficient temperature resistance and are only suitable for medium and low temperature formation environments. In addition, the nano-silica used in this invention is ordinary hydrophilic nano-silica, which is easy to agglomerate in aqueous solution, although it can rely on ultrasound to make it Temporarily dispersed, but still unable to fully exert the strengthening function of nano-silica

Invention patent CN 104927799 A discloses a carbon nanotube composite thickener and its preparation method. The mass fraction of the thickened liquid is as follows: viscoelastic surfactant 1%-5%, modified carbon nanotube particles 0.05- 0.4%, counter ion salt 0-8%, auxiliary agent 0%-3%, the rest is added with water to 100%, and the above components are mixed and stirred according to the proportion to make a carbon nanotube composite thickener. The cost of carbon nanotube materials is too high, and its strengthening mechanism only exists in the physical adsorption strengthening method, which cannot meet higher temperature resistance and cannot meet the needs of field application and promotion

[0005] Although the current research on clean fracturing fluid can improve its current situation and shortcomings, there are still shortcomings such as low application range, high cost, single action mechanism of nanomaterials, insufficient temperature resistance, and inability to be applied on a large scale.

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