Air foam flooding shaft bottom foaming process pipe column

Abstract

The invention discloses an air foam flooding shaft bottom foaming process pipe column, which at least comprises an inner pipe and an outer pipe arranged outside the inner pipe. The air foam flooding shaft bottom foaming process pipe column also adopts a ground-matched check valve to simplify ground valve switching operation and reduce the risk of damaging a topping-up pump and an air compressor; because double-pipe injection is adopted, the air and liquid pass through an independent passage respectively to reduce the risk of pipe column corrosion; and a foam generator is arranged at the bottom of a well to generate foams near the well bottom so that the performance of injected foams is guaranteed and the foams better play a role in the displacement of reservoir oil and profile control.

Description

technical field [0001] The invention relates to the field of oil production machinery, and relates to an air foam driving well bottom foaming process string. Background technique [0002] Air foam flooding is to use injection wells to inject air foam into oil layers. It not only has the dual functions of profile control and oil displacement, but also uses the flue gas drive effect of oxidation products and the heat generation effect of oxidation to recover oil. [0003] At present, there are two types of process strings used in oilfields for foam injection: (1) The structure of the permanent packer gas-filled sealing tubing, the injection method mostly adopts the alternate injection of gas and liquid to mix and form foam in the formation. The disadvantages of the injection method are: ① When the gas-liquid exchange needs to reverse the wellhead valve, it is easy to cause the liquid injected into the wellbore to flow back into the compressor, causing fatal damage to the compr...

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Problems solved by technology

[0003] At present, there are two types of process strings used in oilfields for foam injection: (1) The structure of the permanent packer gas-filled sealing tubing, the injection method mostly adopts the alternate injection of gas and liquid to mix and form foam in the formation. The disadvantages of the injection method are: ① When the gas-liquid exchange needs to reverse the wellhead valve, it is easy to cause the liquid injected into the wellbore to flow back into the compressor, causing fatal damage to the compressor; it may also cause the gas to flow back into the injection pump to reduce pump efficiency; ② Due to the heterogeneity in the formation, it is easy to cause the inhomogeneity of the foam formation, and the experiment shows that the mixed injection of air and foam agent has a stronger plugging ability than the foam under the alternate injection method.

The disadvantage of this injection method is: due to the formation of bubbles on the ground, the stability of the foam is limited, and the foam is more likely to form under the long-term shear and gravity differentiation in the wellbore, and the performance of the bubbles will deteriorate when they reach the bottom of the well and inject into the formation

[0004] In addition, regardless of the above-mentioned injection methods, ① air and liquid go through the same channel, and the air will seriously corrode the pipe string in the presence of water; Risk of leakage, gas leakage into the annulus of the oil casing, which may easily cause the risk of casing pressure and casing inner wall corrosion; ③Gas-sealed tubing is expensive

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