CN-121976771-A - Asymmetric sealing element for packer and optimization method thereof

CN121976771ACN 121976771 ACN121976771 ACN 121976771ACN-121976771-A

Abstract

The invention relates to an asymmetric sealing element for a packer and an optimization method thereof, and relates to the field of drilling engineering technology and equipment. The optimization method utilizes a finite element simulation method to simulate the setting process and the stress condition of the asymmetrical sealing element after setting. The method has the advantages that the structure size of the sealing element is optimized by a finite element simulation analysis method, so that the optimal structure parameters can be conveniently found. By changing the element structure, the deformation process is optimized, so that the packer has larger compression resistance. The optimized structure does not change the setting process and the structural shape of the setting mechanism, and the universality is strong.

Inventors

SUN JIA
GUO HUIJUAN
WANG BAODONG
ZHANG QUANLI
XU BINGGUI
LIU YU
LIU ZHITONG
LU JING

Assignees

中国石油天然气集团有限公司
中国石油集团工程技术研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20241031

Claims (10)

1. An asymmetric sealing element for a packer, characterized in that the asymmetric sealing element (4) is cylindrical, the asymmetric sealing element (4) having a wall thickness at one end which is larger than the wall thickness at the other end, the asymmetric sealing element (4) having one end for facing towards a fixed end of a setting mechanism.
2. An asymmetric sealing element for a packer according to claim 1, characterized in that the inner wall of the asymmetric sealing element (4) is a cylindrical bore.
3. An asymmetric sealing element for a packer according to claim 2, characterized in that the generatrix (41) of the outer wall of the asymmetric sealing element (4) is a straight line, a convex curve or a multi-segment fold line.
4. An asymmetric sealing element for a packer according to claim 1, characterized in that the inner wall of the asymmetric sealing element (4) has grooves (42) open in its circumferential direction.
5. An asymmetric sealing element for a packer according to claim 4, characterized in that the groove (42) is located in the axial middle of the asymmetric sealing element (4) and is offset at one end of the asymmetric sealing element (4).
6. An asymmetric sealing element for a packer according to claim 1, characterized in that both end portions of the outer wall of the asymmetric sealing element (4) are provided with rounded lands (43), the diameter of the rounded lands (43) gradually decreasing from the middle of the asymmetric sealing element (4) to the end portions thereof.
7. An asymmetric sealing element for a packer according to any one of claims 1-6, characterized in that the material of the asymmetric sealing element (4) is rubber.
8. A method for optimizing an asymmetric sealing element for a packer, characterized by optimizing a structure of an asymmetric sealing element for a packer according to any one of claims 1-7, comprising the steps of: step 101, obtaining initial geometric parameters and initial material parameters of the asymmetric sealing element (4); Step 102, constructing an initial finite element model of the asymmetric sealing element (4) according to the initial geometric parameters and the initial material parameters; step 103, simulating the deformation process of the initial finite element model in the setting process by a finite element simulation method, and extracting contact force distribution data of the inner wall and the outer wall of the initial finite element model after the setting is completed; Step 104, according to the contact force distribution data, the initial geometric parameters and the initial material parameters are adjusted to obtain new geometric parameters and new material parameters; step 200, manufacturing said asymmetric sealing element (4) according to said new geometrical parameters and said new material parameters.
9. The method of optimizing an asymmetric sealing element for a packer of claim 8, wherein step 104 is followed by a step 105 of repeating said step 102 and said step 104 with said new geometry parameters and said new material parameters as said initial geometry parameters and said initial material parameters in said step 102 until said contact force distribution data meets design requirements.
10. The method of optimizing an asymmetric sealing element for a packer of claim 8, wherein the step 104 comprises, when the contact force profile data indicates that the contact force profile is not uniform: If one end of the initial finite element model is contacted with a force larger than the other end of the initial finite element model, reducing the wall thickness of one end of the initial finite element model, increasing the wall thickness of the other end of the initial finite element model, and moving the position of a groove (42) of the inner wall of the initial finite element model to the other end of the initial finite element model; if the initial finite element model has a smaller contact force at one end than at the other end, increasing the wall thickness at one end of the initial finite element model, decreasing the wall thickness at the other end of the initial finite element model, and moving the position of a groove (42) in the inner wall of the initial finite element model toward one end of the initial finite element model.

Description

Asymmetric sealing element for packer and optimization method thereof Technical Field The invention relates to the field of drilling engineering technology and equipment, in particular to an asymmetric sealing element for a packer and an optimization method thereof. Background The packer is an important tool widely used in well drilling and completion operation, and has the main function of isolating annular spaces above and below the packer, such as gaps between oil pipes and oil and gas well casings or open hole walls, so as to play a role in isolating gas and liquid. The sealing element is a component which directly blocks gas and liquid in the packer and has an isolation effect, and is usually made of rubber materials, and metal materials are also adopted to improve the temperature resistance. In the operation process of the compression type packer, after the packer is put into a designated position, the sealing element is subjected to compression deformation by applying axial pressure through the setting mechanism, and the transverse dimension is enlarged to fill an annular gap, so that the packing effect is achieved. One of the main performance indicators of a packer is the pressure resistance, i.e. the pressure differential that can be tolerated without leakage. Because of the continuous increase of deep oil gas resource development demands in China, the high-pressure environment in the deep well ultra-deep well has higher requirements on the pressure resistance of the packer. The structure of the sealing element directly influences the deformation process of the sealing element in the setting stage, and further influences the sealing state and the pressure resistance after the setting is finished. If the structural design of the sealing element is not reasonable, poor adhesion of the element to the inner/outer wall of the annular space after completion of setting may occur, resulting in leakage when subjected to pressure differentials. Improving the deformation state of the sealing element after completion of setting is therefore an important means of increasing the pressure resistance of the packer. At present, one end of the sealing element of the compression type packer is in a fixed state in the setting process, and the other end of the sealing element is subjected to compression deformation through a setting mechanism to finish setting. Because of the contact friction, the load born by the sealing element in the setting process is asymmetric, so that the deformation state of the sealing element with a traditional symmetrical structure (such as the packing element structure of the patent CN 201720936206.4-compression packer) in the setting process is uneven, the poor contact between the sealing element and the inner wall and the outer wall of an annulus is easily caused after the setting is finished, and the leakage is easily generated in the pressure bearing process. Disclosure of Invention The invention aims to solve the technical problem of how to improve the compression resistance of a packer. The technical scheme of the invention for solving the technical problems is that the asymmetric sealing element for the packer is cylindrical, the wall thickness of one end of the asymmetric sealing element is larger than that of the other end of the asymmetric sealing element, and one end of the asymmetric sealing element is used for facing the fixed end of the setting mechanism. The invention has the beneficial effects that the asymmetric sealing element adopts an asymmetric structure with different thicknesses at two ends, so that the contact state of the asymmetric sealing element and the inner wall and the outer wall can be effectively improved, the contact force at two ends of the asymmetric sealing element is balanced, the setting force in the setting process is reduced, the packer has larger compression resistance, and the performance of the packer is improved. The designed structure is easy to realize, does not affect other structures of the packer, does not change the setting process flow of the packer, has high practicability, and can be widely applied to the packers with different sizes. On the basis of the technical scheme, the invention can be improved as follows. Further, the inner wall of the asymmetric sealing element is a cylindrical bore. The technical proposal has the beneficial effects that the inner wall of the asymmetric sealing element is used for being sleeved outside the cylindrical central tube. Further, the generatrix of the outer wall of the asymmetric sealing element is a straight line, a convex curve or a multi-section fold line. Further, the inner wall of the asymmetric sealing element has a groove opened along the circumferential direction thereof. The beneficial effect of adopting the further scheme is that the middle part of the asymmetric sealing element bulges outwards along the radial direction from the groove position in the axial compression and radial expansion