Low-pressure gas well two-fluid supersonic atomization drainage gas recovery system and process thereof

Abstract

The invention belongs to the technical field of drainage gas recovery process, and specifically provides a low-pressure gas well two-fluid supersonic atomization drainage gas recovery system and a process thereof, wherein a wellbore is taken as a good gas-liquid separator, and gas in a casing pipe is introduced to a Laval nozzle to form supersonic gas flow; by utilizing the characteristic that the air pressure of the casing pipe is higher than that of an oil pipe, accumulated liquid in a well is introduced to a supersonic area of the Laval nozzle through the oil pipe, so as to form a two-fluid supersonic atomization technology. Moreover, through a control method of digitized gas recovery, the ratio of pressure at an inlet to pressure at an outlet, entering an atomizer reaches an atomization condition, through a constant pressure valve switching technology and a diameter extra-long pipe restriction decompression technology, the maximum flow of accumulated liquid entering the atomizer is controlled, the vapor liquid ratio of atomization liquid drainage is reached, and the critical technical problem that the atomizer is liable to block is solved. The system and the process thereof, provided by the invention can effectively utilize energy in the well to perform atomization liquid drainage, solve the problem of accumulated liquid in the well, improve the gas recovery speed and reduce gas recovery cost.

Description

technical field [0001] The invention belongs to the technical field of drainage gas recovery technology, and specifically provides a low-pressure gas well dual-fluid supersonic atomization drainage gas recovery system and its technology. Background technique [0002] Changqing gas field is a typical "three low" gas reservoir. With the increase of domestic demand for natural gas, the development scale is getting bigger and bigger, the formation pressure is getting lower and lower, and the fluid accumulation in the well is getting more and more serious. Even at the stage of intermittent gas production, drainage gas production has become a constraint on the production capacity of gas wells. The biggest constraint factor of production speed, PetroChina has to spend a lot of money and scientific research to develop drainage and gas recovery technology. Since the gas field was exploited, the problem of removing fluid accumulation in the well has been perplexing the relevant gas p...

AI Technical Summary

Problems solved by technology

Since the gas field was exploited, the problem of eliminating fluid accumulation in the well has been plaguing the relevant gas production departments. So far, the following methods of drainage and gas production have been carried out, but none of them can be effectively solved

[0003] 1. Methanol injection for drainage and gas recovery has high operating cost and poor effect, and cannot meet the requirements of removing effusion

[0004] 2. Foam drainage for gas recovery has poor effect, high operating costs, and cannot fully remove fluid accumulation in the well

[0005] 3. The plunger drainage and gas recovery also seriously restrict the production of the gas well due to the long time of opening and closing the well, so it is not suitable

[0006] 4. The atomization and drainage in the well adopts swirling atomization and supersonic atomization respectively, both of which cannot be popularized and applied in gas fields because of their technical performance.

[0009] 1. When the atomizer is at the top of the liquid surface, because the gas extraction pressure of the oil pipe at the wellhead is as high as 3MPa, the production of the gas well is 5000 cubic meters per day, and the gas flow rate in the oil pipe is too small, 0.6 m / s, which is equivalent to the wind speed of the second to third grade , the gas in the well cannot bring the liquid into the Laval atomizer, and the atomization cannot be carried out, and the effusion still stays in the well

[0010] 2. When the atomizer is lowered below the liquid level, the gas-liquid ratio entering the atomizer is too small to achieve atomization. Even if a small amount of atomized liquid does not follow up in time due to lack of gas, the atomized liquid will fall back to the fog The upper part of the atomizer, can no longer atomize

[0011] Therefore, the current supersonic atomization does not have the atomization function and atomization conditions, and it needs to be researched and tested again

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