Underground blockage device of casing pressure balanced working method

Abstract

The invention discloses an underground blockage device of a casing pressure balanced working method. The lower end of an upper-stage casing is connected with a blockage casing through a transition conical face. The diameter of the blocking casing is smaller than that of the upper-stage casing. A limiting device is arranged on the inner wall of the blocking casing. The lower end of the blocking casing is connected with a through hole sieve tube. The through hole sieve tube is connected with a correcting tube through a transition conical face. The diameter of the correcting tube is equal to that of the blocking casing. A blocking opening of the lower end of the correcting tube is provided with a vent hole. A blocking blind tube or a blocking device with a closed lower opening is installed in the blocking casing in a matched mode. A disengagement device is arranged on an upper tube opening of the blocking blind tube or the blocking device. A seal ring is installed on the outer wall of the blocking blind tube through a seal ring groove. The blocking blind tube is matched with the blocking casing or the correcting tube through the seal ring, or underground blocking is achieved through the blocking device. The underground blockage device is reasonable in structure and reliable in performance, a pipeline can be blocked underground, pressure inside the casing and pressure outside the casing are separated, and the well repairing work of detaching a sucker rod, an oil tube or a casing under pressure can be achieved.

Description

technical field [0001] The invention relates to the field of downhole operations in oilfields, and belongs to a supporting device for a workover operation method of sucker rods, oil pipes and casings with pressure, in particular to a downhole plugging device for a casing snubbing operation method. Background technique [0002] During the production or workover of various wells in oil fields (such as oil wells, water wells, steam injection wells, etc.), sometimes it is necessary to block the pipeline to isolate the internal and external pressure sources of the pipeline. Such as: [0003] 1. During workover, before pulling out the sucker rod, tubing or casing, it is necessary to block the lower pressure of the casing to avoid the ejection of downhole medium during the construction process, resulting in energy waste, environmental pollution, or safety accidents. [0004] At present, there is no similar product that can meet the above requirements. Generally, well killing fluid...

AI Technical Summary

Problems solved by technology

[0004] At present, there is no similar product that can meet the above requirements. Generally, well killing fluid is used during workover, which is injected from the tubing to limit the downhole pressure.

Long operating cycle and high cost

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