Two-stage two-section separate-injection pipe column capable of back-flushing well and protected by insert seal sleeve and separate-injection method of two-stage two-section separate-injection pipe column

Abstract

The invention provides a two-stage two-section separate-injection pipe column capable of back-flushing a well and protected by an insert seal sleeve and a separate-injection method of the separate-injection pipe column. The separate-injection pipe column comprises an insert sealer (2), a sleeve prefabricated sealing cylinder (3), a first-stage water injection layer section (14), and the like; the sleeve prefabricated sealing cylinder (3) is arranged on the upper part of the top boundary of the first-stage water injection layer section (14); a sleeve prefabricated sealing cylinder (6) is arranged between the first-stage water injection layer section (14) and a second-stage water injection layer section (15); the sleeve prefabricated sealing cylinder (6) is simultaneously arranged between a water distributor (4) and a water distributor (7); the insert sealer (2) is arranged in the middle of the sleeve prefabricated sealing cylinder (3); and an insert sealer (5) is arranged in the sleeve prefabricated sealing cylinder (6). With the adoption of the separate-injection pipe column, the channeling phenomenon is effectively avoided, the successful ratio of removing sand blockage is high, and the successful ratio of drop-dipper measuring and dosing is high; and the pipe column has high adaptability to the a high-temperature and high-pressure deep deflecting well with high water injection pressure and obvious difference between layers and is long in period of validity.

Description

technical field [0001] The invention provides a second-stage and second-stage backwashable well insertion sealing sleeve and separate injection pipe string tool for water injection in the petroleum industry and a layered water injection method. Background technique [0002] At present, in the water injection development process of multi-layer reservoirs in various oil fields, separate injection strings are generally used. The split injection string mainly includes packers, water distributors, bidirectional anchors for water wells, double ball seats, screens, plugs, etc. During normal water injection, the injected water enters the formation from the tubing through the water distributor, which can generally meet the split injection requirements. Due to the imperfect structure of the injection string, there are still the following four deficiencies: (1) The well flushing channel of the packer is small, and when the water quality or well condition is poor, the particulate impuri...

AI Technical Summary

Problems solved by technology

Due to the imperfect structure of the injection string, there are still the following four deficiencies: (1) The flushing channel of the packer is small. The well flushing channel is blocked and the well cannot be flushed. On the other hand, the well flushing valve will be stuck or not closed tightly, resulting in channeling up and down the packer and affecting the separate injection effect; (2) For water injection wells that are prone to sand production, The dispensing string is prone to sand burial and sand sticking, and the probability of overhaul is high; (3) The inner diameter of the central pipe of the packer is small, and the throwing and fishing instrument is easy to be blocked and stuck, which reduces the success rate of throwing, measuring and matching; ( 4) The structure of the packer for high-temperature, high-pressure and deep-inclined wells is complex and expensive. Frequent replacement of packers and other tools during inspection and injection operations will result in large investment and high cost

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