Selective well cementing device

Abstract

The invention discloses a selective well cementing device and belongs to the technical field of well cementing and completion tools in oil field oil-gas well engineering. The selective well cementingdevice comprises a casing inner pipe 3 and a casing outer pipe 4. An upper isolator 2 and an upper diverter valve 1 are mounted at the upper ends of the casing inner pipe 3 and the casing outer pipe 4. A lower isolator 5 and a lower diverter valve 6 are mounted at the lower ends of the casing inner pipe 3 and the casing outer pipe 4. A double-layer casing structure is adopted, well-cementing cement paste can bypass a production layer through the interlayer of a casing, well cementing is not conducted on the production layer and selectively conducted on the upper portion and the lower portion of the production layer, thus the oil drainage area of the production layer is increased, damage of the cement paste to the production layer is avoided, and the yield of an oil-gas well can be increased easily; and the selective well cementing device is simple in process, low in workload and free of construction risks and breaks through the implement bottleneck of an existing selective well cementing technology.

Description

technical field [0001] The invention relates to a selective well cementing device, which belongs to the technical field of well cementing and completion tools in oil and gas well engineering in oil fields. Background technique [0002] In the 1990s, foreign countries promoted the use of the inner pipe method to realize selective cementing, that is, the production zone was completed with a screen, and the upper and lower sides of the production zone were cemented. Compared with the whole well cementing and production zone perforation technology , the sand rate is reduced and the output is increased. Although this technology achieves the technical goal of selective cementing, it is difficult to implement and the process is cumbersome. Each step needs to be calculated accurately, and there are many uncertain factors, such as the need for quantitative displacement, downhole opening and closing of multiple valves, internal pipe The reliability of the coherent action of the tool ...

AI Technical Summary

Problems solved by technology

Although this technology achieves the technical goal of selective cementing, it is difficult to implement and the process is cumbersome. Each step needs to be calculated accurately, and there are many uncertain factors, such as the need for quantitative displacement, downhole opening and closing of multiple valves, internal pipe The reliability of the coherent action of the tool itself increases the construction risk, and the success rate and completion quality cannot be guaranteed

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