Preparation method and fracturing construction method of locally and continuously mixed clean fracturing fluid additive

Abstract

The invention discloses a preparation method and a fracturing construction method of a locally and continuously mixed clean fracturing fluid additive. The invention is characterized in that the preparation of the locally and continuously mixed clean fracturing fluid additive comprises four steps, and the purposes of local and continuous mixing and continuous construction of the prepared clean fracturing fluid additive can be realized without preparation in a fluid preparation station or a well filed in advance. Thus, both the preparation method and the fracturing construction method of the locally and continuously mixed clean fracturing fluid additive are very simple and convenient.

Description

technical field [0001] The invention relates to a fracturing fluid used in an oil and gas field and a fracturing construction method, in particular to a preparation method for continuously mixing clean fracturing fluid additives on site and a fracturing construction method. Background technique [0002] Viscoelastic surfactant fracturing fluids (also known as clean fracturing fluids) are widely used. [0003] Chinese patent 200310116815.8 introduces a method for preparing clean fracturing fluid by mixing unsaturated fatty acid salt with 18 carbon atoms and brine or mixing fatty acid with 18 carbon atoms, inorganic base and brine. The clean fracturing fluid is an anionic surfactant fracturing fluid system, which is composed of more than two kinds of additives. The inorganic salts such as KCl account for more than 4.0% in the clean fracturing fluid, and the addition of inorganic bases such as KOH is more than 2.0%. Rely on formation crude oil to break the gel. The content of...

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Problems solved by technology

[0008] (1) The raw materials of clean fracturing fluid main agent are not easy to obtain and the cost is high;

[0009] (2) When cleaning the fracturing fluid on site, in order to improve the performance, additional inorganic salts such as KCl need to be added. Time-consuming

In addition, in order to ensure a smooth construction, it is generally necessary to prepare 15-20% of the remaining fracturing fluid. After the construction is completed, a part of the fracturing fluid is often left, which is difficult to recover and also increases the difficulty of subsequent treatment, which not only increases the cost, but also There is a certain degree of pollution to water resources and the environment;

[0010] (3) The environment temperature required for the preparation and construction of clean fracturing fluid is relatively high. Generally, the temperature of clean fracturing fluid requires water for preparation to be above 15°C. Ensure the viscosity and sand-carrying capacity of clean fracturing fluid, which makes the construction of clean fracturing fluid more difficult in winter in the north;

[0011] (4) During the fracturing operation, the clean fracturing fluid depends on formation crude oil or formation water to dilute and break the gel. For oil layers with reservoir temperature between 20-80℃ Or low-yield oil wells, natural gas layers, coal seams (gas), (oil, gas) shale all have the problem that the gel cannot be broken or the gel is not broken completely, which leads to the problem that it cannot be applied

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