Sealed sand mixing device and method for continuous operation under pressure

Abstract

The invention provides a sealed sand mixing device and method for continuous operation under pressure. A skid seat of the closed sand mixing device is separately provided with a first sealed sand mixing tank, a second sealed sand mixing tank, a first spiral sand feeder, a first solid-liquid mixer, a second spiral sand feeder, a second solid-liquid mixer, a liquid inlet manifold, a liquid outlet manifold and a pressurizing and cooling mechanism. The liquid inlet manifold separately communicates with a first base liquid introduction valve and a second base liquid introduction valve, the liquid outlet manifold separately communicates with a first solid-liquid introduction valve and a second solid-liquid introduction valve, and the pressurizing and cooling mechanism separately communicates with first sealed sand mixing tank and the second sealed sand mixing tank through a first pressurizing and cooling valve and a second pressurizing and cooling valve. By controlling the alternating circulation operation of the first sealed sand mixing tank and the second sealed sand mixing tank, long-time continuous sand mixing under pressure is achieved, the requirements of dry method CO2 sand addingfracturing operation with large displacement and large sand amount in unconventional oil and gas exploitation are met, and good sealing performance, simple and convenient operation and easy popularization are achieved.

Description

technical field [0001] The invention relates to the technical field of petroleum and oil gas equipment, in particular to a closed sand mixing device and method for continuous operation under pressure. Background technique [0002] my country's unconventional oil and gas resources have huge potential and will become important replacement resources. Unconventional oil and gas production conditions are complex. Hydraulic fracturing is the most commonly used method for reservoir stimulation at home and abroad, that is, water-based fracturing fluid is used to fracturing reservoirs. However, water-based fracturing fluid systems have waste of water resources, return Issues such as drainage pollution. In order to avoid the above problems, the liquid CO 2 Alternative to conventional water-based fracturing fluids, using liquid CO 2 As a fracturing medium, the proppant is mixed with CO 2 Liquid CO after pressurization by booster 2 Mixed, then pumped into the reservoir by a high-pr...

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Problems solved by technology

[0003] Chinese patent documents CN 201310164852 and CN 201310165040 disclose a fracturing sand mixing device capable of keeping CO 2 The liquid state, and then mixed with solid particles to form fracturing fluid, realized the preparation of liquid CO 2 The purpose of the fracturing fluid as the base fluid is that the fracturing sand mixing device can only realize the dry process CO with a fixed amount of sand due to the influence of the closed sand storage tank. 2 The sand fracturing operation cannot meet the requirements of dry CO2 with large displacement and large sand volume. 2 sand fracturing

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