Liquid CO2/N2 two-phase system dry fracturing fluid sand adding system and method

Abstract

The invention relates to a liquid CO2 / N2 two-phase system dry fracturing fluid sand adding system under a high-pressure condition and an implementation method thereof, and belongs to the technical field of liquid CO2 / N2 two-phase system dry fracturing fluid performance testing. The sand adding system comprises a gas pressurizing system, a sand adding pump, a sand adding control system, a conveyingpipe, a conveying pump and a flow control valve; the gas pressurization system comprises a CO2 storage tank, a CO2 pump, a liquid nitrogen storage tank and a liquid nitrogen pump; the CO2 storage tank is connected with the CO2 pump, and the liquid nitrogen storage tank is connected with the liquid nitrogen pump; and the CO2 pump is sequentially connected with the bottom end of the sand adding pump, the liquid nitrogen pump, the flow control valve and the conveying pump through the conveying pipe, the CO2 pump is connected with the upper end of the sand adding pump through a branch conveying pipe, and the sand adding pump is connected with the sand adding control system. By means of the system, sand is evenly added into fracturing of a liquid CO2 / N2 two-phase system, the sand ratio is adjusted in real time, sand blocking is prevented, the fracturing construction effect is improved, and then the recovery efficiency and the development effect are improved.

Description

technical field [0001] The invention relates to a liquid CO 2 / N 2 Two-phase system dry fracturing fluid sand adding system and its implementation method, belonging to liquid CO 2 / N 2 The technical field of performance testing of two-phase system dry fracturing fluid. Background technique [0002] With the increasing demand for oil and natural gas energy, more and more unconventional low-permeability oil and gas reservoirs, including shale oil, shale gas, and tight oil, have been developed and utilized. The most effective way to develop these unconventional oil and gas reservoirs is to conduct Fracturing to improve oil and gas production. Compared with conventional fracturing, dry fracturing has unique advantages: since there is no water in the system, it has good compatibility with the formation and wider applicability; rapid flowback after fracturing, no residue, avoiding pollution to the formation, etc. . [0003] Liquid CO 2 / N 2 Two-phase system dry fracturing ...

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Problems solved by technology

[0006] Aiming at the difficulty of adding sand to high-pressure fracturing fluid and the deficiencies of the prior art, the present invention provides a liquid CO 2 / N 2 Two-phase system dry fracturing fluid sand adding system, the system ensures the normal fall of the sand body by setting a pressure branch, and achieves the uniform fall of the sand body through the rotation of the sand pump, so as to achieve the liquid CO 2 / N 2 Add sand evenly in the fracturing of the two-phase system, and adjust the sand ratio in real time to prevent sand plugging, improve the effect of fracturing, and then improve the recovery rate and development effect

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