Downhole Gas Production String and Gas Production Method

Abstract

The invention relates to an underground gas production pipe string and a gas production method, comprising a velocity pipe string and a double-channel jet pump connected by a first straight joint, and a power gas inlet and an underground fluid inlet corresponding to the double-channel jet pump. The other end of the channel jet pump is connected with a suction pipe through a second straight connector, and the outer diameters of the velocity column, the double channel jet pump and the suction tube are consistent. The downhole gas production string and gas production method of the present invention can effectively perform drainage and gas recovery for gas wells with low pressure, low production and large water production, especially for multi-layer combined production, lower water flooded wells and horizontal wells. Increasing the degree of production of the production zone has significantly slowed down the rate of gas well production and pressure decline, effectively prolonging the stable production period of the gas well.

Description

technical field [0001] The invention relates to a device and method for drainage and gas recovery of a natural gas well, in particular to an underground gas recovery pipe string and a gas recovery method. Background technique [0002] In the engineering operation of natural gas well drainage and gas recovery, when the gas wells in the middle and shallow gas reservoirs enter the low-pressure and low-yield development period, their productivity is generally low and the stable production period is short. Improving the stable production in the low-pressure stage is the key to improving the recovery, especially for gas wells. Gas wells with low water ratio and high water production put forward higher requirements for liquid drainage; for gas wells with high pressure, low production and large water production in deep gas reservoirs, the production capacity of the bottom section at the initial stage of production cannot reach the capacity of lifting the liquid in the well. requirem...

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Problems solved by technology

For gas wells with low production and large water production, the effect of bubble drainage is not obvious. For horizontal wells, it can only alleviate the degree of liquid accumulation, but cannot completely discharge liquid; the velocity string is easy to form large slugs due to the small diameter of the pipe, whether the start-up fluid exists Risk, for horizontal wells, it is impossible to discharge fluid in the horizontal section, and the drainage effect in the later stage of drainage becomes worse

Gas lift drainage can only realize the lifting of fluid accumulation above the circulating sliding sleeve, and cannot realize fluid drainage in the horizontal section; for low-pressure and low-production gas wells, hydraulic jet pumps and gas acceleration pumps use external energy drainage methods, and supporting The equipment pumps high-pressure medium to carry liquid to the ground. Once the pump is stopped on the ground, the hydraulic jet pump does not have the self-excitation function due to the lack of power water source in the well, and the bottom of the well will accumulate liquid again; the self-excitation function of the gas acceleration pump is limited, and the gas Once the pumping of high-pressure gas is stopped after lifting, there is a risk of liquid accumulation at the bottom of the well. This is because the inner diameter of the tubing is much higher than the inner diameter of the velocity string, and the required critical liquid-carrying flow rate is high, and the powerful atomization effect of the pump has Therefore, the gas acceleration pump can only prolong the self-spraying period of gas wells with high gas-water ratio and low water production

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