Foam drainage gas recovery method for natural gas horizontal well

Abstract

The invention relates to a foam drainage gas recovery method used for a natural gas horizontal well. The method is capable of injecting a foam scrubbing agent into the bottommost end of a gas well shaft, so that the whole shaft is filled with foam fluid and optimal drainage gas recovery effect is achieved. The technical scheme of the method comprises the following steps: firstly, manufacturing a dynamical underground foam scrubbing bar which consists of a gas nozzle, a tail wing, a boosting agent, a shell and a protection head sleeve, wherein the material for manufacturing the tail wing, the shell and the protection head sleeve is the solid foam scrubbing agent which consists of polyoxyethylene alkyl ethers, polyethylene glycol, urea, imidazoline, sodium dodecyl benzene sulfonate and saturated alcohol sulfate; and the boosting agent is one of dry ice, sodium hydride or potassium oxide; and secondly, throwing the dynamical underground foam scrubbing bar to the bottom of the well, wherein the boosting agent is in contact with water to generate a large amount of gas, so that the foam scrubbing bar is pushed to the bottommost end; and as the foam scrubbing agent is dissolved, a large amount of foam is formed to achieve the optimal effect of drainage gas recovery. The method disclosed by the invention has a wide application range without any wellhead equipment and energy, is simpleand safe in operation, low in cost and has no pollution to the environment.

Description

technical field [0001] The invention relates to a method for recovering gas by foam drainage in horizontal gas wells of natural gas, belonging to the field of oil and gas exploitation. Background technique [0002] During the production process of the gas well, the liquid is produced in different degrees. At the initial stage of the gas well's production, it can rely on its own energy to bring the accumulated liquid out of the wellbore. With the production of the gas well, the energy of the gas well decreases, and the wellbore will form liquid accumulation, which affects the production of the gas well. . Through the foam drainage gas recovery process, that is, inject foam drainage agent into the gas well to reduce the density of the wellbore fluid accumulation, reduce the critical liquid carrying capacity of the gas well, and bring the fluid accumulation out of the wellbore to achieve the purpose of maintaining the normal production of the gas well. [0003] In the commonly...

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Problems solved by technology

[0005] According to literature research, there is no report on the idea, product, process design method and theoretical basis of a foam drainage gas recovery method for natural gas horizontal gas wells in terms of foam drainage gas recovery technology.

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