A cement isolation and segmented water control and sand prevention completion string and method for open hole horizontal wells

The double-tube structure of the open-hole horizontal well cement isolation segmented water control and sand prevention completion string solves the problem of easy damage of the packer in the existing technology, realizes the effective isolation of the oil layer and the reliable injection of cement slurry, and prolongs the high and stable production period of the oil well.

CN115992652BActive Publication Date: 2025-09-19CHINA PETROLEUM & CHEMICAL CORP +1
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Patent Information

Application Number
CN202111218161.4
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2021-10-19
Publication Date
2025-09-19
Estimated Expiration
2041-10-19

AI Technical Summary

Technical Problem

Existing technologies are unable to effectively isolate open-hole horizontal wells, resulting in a sharp increase in water content in the oil wells. Especially under thermal recovery conditions, the packers are easily damaged and cannot effectively delay the coning of bottom water or edge water, affecting the high and stable production of the oil wells.

Method used

The double-tube structure of the open hole horizontal well cement isolation segmented water control and sand prevention completion string is adopted. Through the combination of the outer string and the inner string, cement isolation is achieved, ensuring the reliability of cement slurry circulation injection and the packer, adapting to the conditions of thermal recovery steam injection, and delaying water coning.

Benefits of technology

It achieves effective isolation of oil layers under thermal recovery conditions, prolongs the high-yield and stable production period of oil wells, improves cementing quality and construction safety, avoids water channeling, and is suitable for horizontal wells in loose sandstone reservoirs.

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Abstract

The present invention discloses a segmented water control and sand prevention completion string and method for cementing and isolating open-hole horizontal wells, comprising an outer string and an inner string. The outer string is provided with casing, a cementing device, a sand filter, an external packer, a blind pipe, an external packer, a sand filter, and a well flushing valve in order from top to bottom, and the inner string is provided with a first packer, a cementing external blind pipe, a second packer, a cementing external blind pipe, an upper switch, a first protective packer, a lower switch, a second protective packer, and a plug in order from top to bottom. The invention adopts a double-tube structure, with the string provided with a cement injection port and a cement return port, to achieve cyclic injection of cement slurry and improve the quality of cementing. After cementing is completed, the inner injection port and the cement return channel are provided with an automatic closing mechanism, which automatically closes after the cementing pump is stopped to prevent the injected cement slurry from being spitted back.
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