Packer staged unsealing device

Abstract

The present invention relates to a packer graded unsealing device, comprising an unsealing outer cylinder, the inner side of which is provided with a cone and N anchoring slips, the unsealing outer cylinder is provided with N graded release grooves of different lengths, one end of the anchoring slips of the N anchoring slips is respectively installed in the N graded release grooves; when the packer is unsealed, the unsealing tension is transmitted to the unsealing outer cylinder by lifting the completion string, and the unsealing outer cylinder moves upward to drive the N graded release grooves to move upward successively, and different anchoring slips are released in stages. Compared with the existing packer unsealing device, the present invention can achieve graded unsealing, effectively reduce the packer unsealing force, and has the characteristics of simple structure, low cost, reliable unsealing effect, simple operation, etc.

Description

Technical Field

[0001] The present invention relates to the field of well testing and completion engineering, and more specifically, to a packer staged releasing device. Background Art

[0002] With the in-depth exploration and development of the northwest oilfield, the completion depth of oil and gas wells is gradually developing towards deep wells and ultra-deep wells. To meet the requirements of deep and ultra-deep "three-high" oil and gas wells in the northwest oilfield, high-performance retrievable completion packers can effectively achieve completion operations for deep and ultra-deep "three-high" oil and gas wells. Currently, the mainly used retrievable completion packers all adopt an uphole string releasing mechanism. Although this mechanism has advantages such as good releasing effect and simple operation, its disadvantage of relatively high releasing tension has become a major potential downhole risk for deep and ultra-deep "three-high" oil and gas wells. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a packer staged releasing device, which can reduce the packer releasing force and reduce the risk of completion string fracture caused by excessive releasing force during the packer releasing process.

[0004] The technical solution adopted by the present invention to solve its technical problems is: to construct a packer staged releasing device, including a releasing outer cylinder, a cone and N anchor slips are arranged inside the releasing outer cylinder, the releasing outer cylinder is provided with N staged release grooves with different lengths, and one ends of the N anchor slips are respectively installed in the N staged release grooves;

[0005] When the packer is released, the releasing tension is transmitted to the releasing outer cylinder through the uphole completion string, and the upward movement of the releasing outer cylinder drives the N staged release grooves to move upward successively, releasing different anchor slips in stages.

[0006] In the above solution, a slip spring piece is arranged between the anchor slip and the releasing outer cylinder.

[0007] In the above solution, the releasing outer cylinder and the cone are connected by shear pins. [[ID=2,7]]

[0008] In the above solution, an inverted hanging step is arranged inside the releasing outer cylinder.

[0009] In the above solution, the cone is provided with an inverted hanging step and shear pin holes.

[0010] In the above solution, the slip spring piece is a V-shaped thin-walled structure.

[0011] Implementing the packer staged releasing device of the present invention has the following beneficial effects:

[0012] 1. The present invention unseals the outer cylinder in stages to achieve the effect that the anchor slips of the packer are released one by one during the packer unsealing process, prepares for the smooth implementation of the secondary construction of deep and ultra-deep "three-high" oil and gas wells, and reduces the possibility of the completion string fracture caused by excessive unsealing force during the packer unsealing process.

[0013] 2. Compared with the existing packer unsealing devices, the present invention has the characteristics of simple structure, low cost, reliable unsealing effect, reduced packer unsealing force, and simple operation.

[0014] 3. By developing a packer staged unsealing device, the present invention can effectively reduce the unsealing pulling force of the packer while assisting the smooth unsealing of the completion packer, greatly reduce the overall force on the completion string, and effectively reduce the potential well control risk of the completion string fracture caused by excessive unsealing force during the packer unsealing process, providing effective safety guarantee for the secondary construction of deep and ultra-deep "three-high" oil and gas wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0016] Figure 1 is the structural schematic diagram of the packer staged unsealing device of the present invention;

[0017] Figure 2 is Figure 1 the exploded view of

[0018] Figure 3 is the front view of the unsealing outer cylinder;

[0019] Figure 4 is the front view of the anchor slip;

[0020] Figure 5 is the front view of the cone;

[0021] Figure 6 is the top view of the slip spring. DETAILED DESCRIPTION OF THE INVENTION

[0022] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the drawings.

[0023] As Figures 1-6 shown, the packer staged unsealing device of the present invention includes an unsealing outer cylinder 1. An anchor slip 2 and a cone 3 are arranged inside the unsealing outer cylinder. A slip spring 8 is arranged between the anchor slip 2 and the unsealing outer cylinder 1. The unsealing outer cylinder 1 and the cone 3 are connected by a shear pin, and the shear pin can break when subjected to a certain external force.

[0024] In this embodiment, four identical anchoring slips 2 are provided, and the unsealing outer cylinder 1 is provided with four graded release grooves of different sizes, namely the first graded release groove 4, the second graded release groove 5, the third graded release groove 6, and the fourth graded release groove 7. The anchoring slips 2 are used to anchor the well wall, and the graded release grooves mainly use different groove lengths to release the anchoring slips 2 one-to-one. Ordinary packer unsealing devices release all anchoring slips 2 at the same time. This unsealing method can easily cause excessive unsealing force to break the slips or the upper tubing string. The graded unsealing device releases the anchoring slips 2 one-to-one, which can reduce the risk of unsealing. The number of anchoring slips 2 in this embodiment is N = 4, but this is only one embodiment. N can be other natural numbers and can be set as needed.

[0025] When the packer is unsealed, the unsealing tension is transmitted to the unsealing outer cylinder 1 by lifting the completion string. The unsealing outer cylinder 1 moves upward, driving the first graded release groove 4 to move upward, releasing the anchoring force of its corresponding anchoring slip 2. The unsealing outer cylinder 1 continues to move upward under the unsealing tension, driving the second graded release groove 5 to move upward, releasing the anchoring force of its corresponding anchoring slip 2. Then the unsealing outer cylinder 1 continues to move upward, driving the third graded release groove 6 to move upward, thereby releasing the anchoring force of its corresponding anchoring slip 2. Finally, the unsealing outer cylinder 1 drives the fourth graded release groove 7 to move upward under the action of the maximum unsealing force, releasing the anchoring force of its corresponding anchoring slip 2, and driving the cone 3 to move upward, thereby completing the graded unsealing of the packer.

[0026] The length law of the graded release groove is y=ax in the Cartesian coordinate system. 2 +bx+c, where y is greater than 0, a, b, and c are design coefficients, x is the shortest slot length in mm, and a, b, and c are safety design coefficients, which can be adjusted into a linear relationship according to the unsealing force. Under ideal conditions, the value range is (0, +∞).

[0027] The slip spring piece 8 is a V-shaped thin-walled structure. When the packer is lowered, the fluid has an upward thrust on the anchoring slip 2, and the V-shaped thin-walled structure can limit the anchoring slip 2. At the same time, it has the elasticity to help the slip reset when the anchoring slip is unanchored. The slip spring piece 8 is made of high-strength, pressure-resistant and corrosion-resistant metal.

[0028] An inverted hanging step is provided on the inner side of the unsealing outer cylinder 1, and an inverted hanging step is also provided on the cone 3, which hook and cooperate with each other to play a role of limiting.

[0029] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative rather than restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit of the present invention and the scope protected by the claims. All of these fall within the protection scope of the present invention.

Claims

1. A packer staged unsealing device, comprising an unsealing outer cylinder, the inner side of which is provided with a cone and N anchoring slips, characterized in that: The unsealing outer cylinder is provided with N grading release grooves with different lengths, and one ends of the N anchoring slips are respectively installed in the N grading release grooves; a slip spring piece is arranged between the anchoring slip and the unsealing outer cylinder, the unsealing outer cylinder and the cone are connected by a shear pin, an inverted hanging step is arranged on the inner side of the unsealing outer cylinder, and an inverted hanging step and a shear pin hole are arranged on the cone; When the packer is unsealed, the unsealing pulling force is transmitted to the unsealing outer cylinder by lifting the completion string, and the upward movement of the unsealing outer cylinder drives the N grading release grooves to move upward successively, and different anchoring slips are released in a graded manner.

2. The packer staged unsealing device according to claim 1, characterized in that: The slip spring piece is of a V-shaped thin-wall structure.

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