Controlled-valve placed well-cementing staged-fracturing well-completion string and hydraulically-controlled switch string

Abstract

The invention discloses a controlled-valve placed well-cementing staged-fracturing well-completion string and a hydraulically-controlled switch string, which are suitable to be applied to a well-completion process for horizontal wells and vertical wells, and through tripping in the hydraulically-controlled switch string to start and close the controlled-valve placed well-cementing staged-fracturing well-completion string, multi-layer-and-section fracturing well-completion construction is realized, thereby meeting the needs of development on low-permeability oil reservoirs and unconventional oil/gas resources. The controlled-valve placed well-cementing staged-fracturing well-completion string, from top to bottom, is sequentially connected with a hydraulically-controlled switch tool detention cylinder, a switchable control valve and hydraulic casing centralizers connected with the two ends of the switchable control valve, a pressed settling valve and a bottom circulating valve by using a casing; and at least a set of switchable control valve and hydraulic casing centralizers connected with the two ends of the switchable control valve are equipped in the string. The hydraulically-controlled switch string comprises hydraulically-controlled switch tools and a continuous oil pipe, and a set of hydraulically-controlled switch tool is connected to the bottom of the continuous oil pipe. The switchable control valves are same in inner drift diameter (same in size), and can carry out well completion on stratums through the sand fracturing of the casing, thereby satisfying the needs of large-displacement and large-scale fracturing reformation.

Description

technical field [0001] The invention relates to a well completion device in the petroleum industry, in particular to a cementing segmental fracturing completion pipe string and a hydraulic control switch pipe string with controllable valves, which are suitable for the completion process of horizontal wells and vertical wells. The staged fracturing and completion strings for cementing and fracturing with controllable valves are installed to control the opening and closing of the strings, so as to realize the fracturing and completion construction in multiple stages, and meet the development needs of low-permeability reservoirs and unconventional oil and gas resources. Background technique [0002] At present, the use of horizontal well staged fracturing technology to improve the development and application scale of unconventional resources such as low permeability reservoirs and shale oil and gas is gradually increasing. However, the currently commonly used horizontal well op...

AI Technical Summary

Problems solved by technology

However, the currently commonly used horizontal well open hole packer staged completion technology, such as: the application number 200920248979.9 of the horizontal well completion and fracturing integrated pipe string, the sliding sleeve staged fracturing technology is opened step by step by throwing balls, in order to allow input The inner diameter of the ball seat at the bottom must be smaller than the inner diameter of the ball seat at the upper level. Affected by the hierarchical arrangement of ball seat sizes, the number of stages and the scale of fracturing are different. It is greatly restricted, which affects the transformation effect; and the sliding sleeve is a ball-pitching sliding sleeve, the sliding sleeve is opened after the ball is thrown in, and it cannot be closed in later production

If selective production or repeated fracturing is to be carried out in the later stage, the sliding sleeve needs to be closed, and the integrated pipe string will not be used as a whole

The tubing fracturing string can only be rerun into the tubing string for small-scale in-pipe segmental fracturing, so it cannot meet the use requirements in the follow-up construction after the completion of the well

At the same time, the structure of the utility model integrated well completion and fracturing string is relatively complex, and it is prone to operational failures.

In the development of low-permeability reservoirs and unconventional oil and gas resources, for vertical wells with multi-stage fracturing, especially horizontal wells with complex string structures and high technical requirements, there is no casing fracturing completion method that can solve the above problems. Restricting the development of low permeability reservoirs and unconventional oil and gas resources

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