Gas storage device for carbon dioxide oil displacement

Abstract

The invention relates to the technical field of oil and gas field development and application, and discloses a gas storage device for carbon dioxide oil displacement. The gas storage device comprises a storage tank, the storage tank comprises a first tank body with a first storage cavity and a second tank body with a second storage cavity, a first valve for controlling the first storage cavity and the second storage cavity to be connected and disconnected is arranged between the first storage cavity and the second storage cavity, the first tank body is provided with a fluid inlet communicating with the first storage cavity, the fluid inlet communicates with a supply device arranged outside the storage tank and used for providing carbon dioxide, the second tank body is provided with a fluid outlet communicating with the second storage cavity, and the fluid outlet communicates with an injection device arranged outside the storage tank; the gas storage device for carbon dioxide oil displacement is further provided with a pressure adjusting device, and by means of the pressure adjusting device, the pressure in the second storage cavity can be closer to the pressure of the inlet end of the injection device compared with the pressure in the first storage cavity. The pressurization action on the carbon dioxide occurs in the storage tank, so that the pressure in the storage tank can be rapidly increased, and the curing phenomenon of the carbon dioxide in the storage tank is prevented.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development and application, in particular to a gas storage device for carbon dioxide flooding. Background technique [0002] Carbon dioxide flooding technology is to inject carbon dioxide into the oil layer through the injection device to improve the oil recovery rate of the oil field. In the prior art, a gas storage device for carbon dioxide flooding is provided before the injection end of the injection device, and the gas storage device for carbon dioxide flooding includes a storage tank, which is used to store low-temperature and high-pressure liquid carbon dioxide, and can be continuously injected into the injection device. Provide carbon dioxide. [0003] When the system is running, it is found that the pressure in the storage tank drops quickly and recovers slowly. When the pressure suddenly drops to a low state and cannot recover quickly, the liquid carbon dioxide will easily co...

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Problems solved by technology

[0003] When the system is running, it is found that the pressure in the storage tank drops quickly and recovers slowly. When the pressure suddenly drops to a low state and cannot recover quickly, the liquid carbon dioxide will easily condense into dry ice in the storage tank. The sudden drop in temperature in the tank will affect the strength of the steel in the storage tank. Even if other methods are used to liquefy the dry ice in the storage tank later, the damage to the strength of the steel in the storage tank will be irreversible, which in turn will affect the service life of the gas storage device; second, Dry ice will occupy the space in the storage tank, reduce the space of the storage tank cavity, reduce the gas storage and gas supply capacity of the gas storage device, and even dry ice may cause blockage of the outlet or inlet, resulting in the inability of the gas storage device to enter and exit carbon dioxide; Third, due to the large difference between the pressure in the storage tank under normal conditions and the pressure at the inlet of the injection device, the injection device needs a large starting power to change the pressure change. If the pressure in the storage tank recovers slowly, the injection device will have to wait for the storage tank Only when the pressure in the tank returns to a normal state can the pump continue to run, resulting in a blank period for feeding carbon dioxide, which affects the work progress, or, the injection device uses a greater starting power to eliminate the above blank period, but such improvement will The startup power consumption of the injection device is increased, the cost is increased, and the actual application is unrealistic

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