Well cementing device for controlling shear deformation of casing pipes

Abstract

The invention provides a well cementing device for controlling shear deformation of casing pipes. The well cementing device comprises a concentric pipe column, a first packer, a second packer and a control valve system. The concentric pipe column comprises the inner casing pipe and the outer casing pipe. The first packer is connected to the upper end of the concentric pipe column. First through holes are formed in the side wall of the first packer. The second packer is connected to the lower end of the concentric pipe column. Second through holes are formed in the side wall of the second packer. The control valve system comprises a first control valve and a second control valve. The well cementing device for controlling shear deformation of the casing pipes is provided with a first workingstate of sealing a first liquid inlet by the first control valve, a second working state of opening the first liquid inlet by the first control valve, a third working state of opening the first liquid inlet by the first control valve and sealing a second liquid inlet by the second control valve and a fourth working state of opening the first liquid inlet by the first control valve and opening thesecond liquid inlet by the second control valve. The well cementing device for controlling shear deformation of the casing pipes is capable of reducing the shear deformation of the casing pipes.

Description

technical field [0001] The present application relates to the technical field of oil and gas drilling, in particular to a cementing device for controlling shear deformation of casing. Background technique [0002] The large-scale exploitation of shale gas has gradually achieved high and stable production, and it is possible to make up for the shortage of oil and gas energy as an alternative energy source. However, during the hydraulic fracturing process in the completion stage of shale gas horizontal wells, the problem of casing deformation often occurs. Casing deformation not only reduces the number of fracturing stages and single well production, but also reduces the integrity of the wellbore and shortens the life cycle of the well, seriously restricting the efficient development of shale gas. [0003] The shear deformation of the casing is mainly due to the fact that a large amount of liquid is injected into the formation during the multi-stage fracturing of the shale ga...

AI Technical Summary

Problems solved by technology

However, practice shows that increasing the strength of the casing has little effect on alleviating the casing damage caused by rock formation slippage, and the casing deformation rate is still very high

Conversely, lowering the stiffness of the casing and the cement sheath near the slip surface can relieve the deformation of the casing, but it is difficult to solve the problem of casing shear failure by changing the properties of the cement

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