Double-anchoring and double-packing tie-back system for staged fracturing string

Abstract

The invention discloses a double-anchoring and double-packing tie-back system for staged fracturing string. The double-anchoring and double-packing tie-back system comprises a first tie-back plug, a tie-back barrel and a second tie-back plug, a first anchoring device is arranged on the first tie-back plug and comprises a locking slip. A plurality of locking grooves are formed in one end of the locking slip, one end of each locking groove is open, and a simply supported beam structure is formed; a self-locking male buckle is further arranged on the locking slip; a self-locking female buckle is arranged on the inner wall of the tie-back barrel, the tie-back barrel is detachably connected with the locking slip through a locking groove of the locking slip and is locked with the self-locking male buckle through the self-locking female buckle, the lower end of the tie-back barrel is connected with a lower end pipe column, and an anti-retreating slip and a packer are sequentially arranged on the lower end pipe column from top to bottom. The upper end of the second tie-back plug is connected with the lower end of the lower-end pipe column, and the lower end of the second tie-back plug is further connected with another tie-back barrel in an anchoring mode. The double-anchoring design is adopted, the standby releasing function and the standby packing function are achieved, the use reliability of the tool is improved, and the construction risk is reduced.

Description

technical field [0001] The invention relates to the technical field of cementing and completion of oil and gas wells, in particular to a double-anchor and double-package tie-back system for segmental fracturing strings. Background technique [0002] Many tight oil and gas reservoirs in China are low-porosity, low-permeability gas reservoirs, strong heterogeneity and developed micro-fractures. Complexity, thin barrier layer of the reservoir, etc., lead to artificial fractures easily penetrate the bottom cover layer and communicate with the bottom water during fracturing construction, resulting in severe water discharge during production, which may easily cause the entire wellbore of the horizontal well to be flooded. Affect single well productivity. In addition, there are also problems that the horizontal well has been drilled, but the wellbore conditions do not meet the open hole completion string entry, or the reservoir properties do not meet the technical requirements for...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a double-anchor double-package tie-back system for staged fracturing strings in view of the defects existing in the prior art. The double-anchor design is adopted to realize backup drop-off and backup containment It can improve the reliability of tools and reduce construction risks; it can solve technical problems such as complex structure, poor sealing and reliability of the tie-back string after liner cementing; the tie-back string can be recycled and reused after fracturing to improve resource utilization , saving cost; the structure of the return pipe string is simple, which can ensure the full diameter of the return pipe string and the tail pipe string, and meet the large-diameter requirements of subsequent production

Images