A variable stiffness hydraulic vibration damper for drilling

Abstract

This invention belongs to the field of oil drilling equipment technology, specifically relating to a variable stiffness hydraulic vibration damper for drilling. It includes a mandrel, a centralizer, a splined sleeve, an upper sealing assembly, a hydraulic cylinder, a punch pipe, a check valve, a check valve fixing device, a clamping nut, a lower sealing assembly, and a lower connector. The centralizer is mounted on the mandrel, and the splined sleeve is splinedly connected to the mandrel. The centralizer, splined sleeve, upper sealing assembly, hydraulic cylinder, lower sealing assembly, and lower connector are sequentially threaded together. The mandrel is threadedly connected to the punch pipe. The check valve is mounted on the isolation sealing ring of the punch pipe via the check valve fixing device and is locked in place by the clamping nut. The hydraulic cylinder has a guide hole. Compared with traditional vibration dampers, this device can change the stiffness of the vibration damper by adjusting the drilling pressure during drilling, thereby protecting the integrity of the drill bit, drill string, and downhole measurement electronic components. It is suitable for formations prone to drill string vibration or even drill skipping, such as dense conglomerate, igneous rocks, and dense shale.

Description

Technical Field

[0001] This invention belongs to the field of oil drilling equipment technology, specifically relating to a variable stiffness hydraulic vibration damper for drilling. Background Technology

[0002] In modern oil and gas well drilling, the drill string generates strong three-dimensional vibrations in the longitudinal, torsional, and lateral directions. These vibrations typically have two consequences: firstly, they can generate regular impact loads on the bottom-hole rock, improving the rock-breaking efficiency of the drill bit; secondly, and more frequently, they can damage the drill string, even causing sudden accidents such as drill bit chipping or drill string breakage. Furthermore, the vibrations have a more severe impact on electronic components such as logging-while-drilling (LoWW) and measurement-while-drilling (MSWW) systems, significantly reducing their lifespan.

[0003] Installing vibration dampers on the drill string can effectively prevent large-scale drill string vibrations, protect the integrity of the drill bit, drill string tools, and downhole measurement electronics, and extend their service life. As oil and gas drilling projects continue to advance into deeper water and deeper ground, the number of complex rock formations encountered will inevitably increase. For formations such as conglomerate, dense shale, and igneous rocks, which are prone to drill string vibration or even drill skipping, it is essential to use drill string vibration damping tools to prevent downhole accidents. Existing vibration dampers generally have a constant stiffness; however, the impact on drill string vibration varies depending on different lithologies, formation dip angles, bottom hole tool combinations, wellbore sizes, and well depths. Therefore, improvements are necessary to address these issues. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a variable stiffness hydraulic vibration damper for drilling, which can effectively reduce the vibration of the drill string under different conditions and reduce production costs.

[0005] The technical solution adopted in this invention is as follows: a variable stiffness hydraulic vibration damper for drilling, comprising a mandrel, a centralizer, a splined sleeve, an upper sealing assembly, a hydraulic cylinder, a punch pipe, a one-way valve, a one-way valve fixing device, a clamping nut, a lower sealing assembly, and a lower connector; the centralizer is fitted onto the mandrel to ensure that the mandrel can move up and down; the splined sleeve is splinedly connected to the mandrel to achieve circumferential fixation; the centralizer, splined sleeve, upper sealing assembly, hydraulic cylinder, lower sealing assembly, and lower connector are sequentially threaded together; the mandrel is threadedly connected to the punch pipe; the one-way valve is mounted on the isolation sealing ring of the punch pipe through the one-way valve fixing device and locked in place by the clamping nut; the hydraulic cylinder has a guide hole.

[0006] Furthermore, the isolation sealing ring divides the hydraulic cylinder cavity into two cavities.

[0007] Furthermore, the flushing pipe, check valve, check valve fixing device, and clamping nut constitute the flushing pipe assembly. Drilling fluid flows in from the mandrel, passes through the flushing pipe, and flows out from the lower connector to the next stage drill string or drill bit. The centralizer ensures that the mandrel does not become eccentric during operation. The mandrel is equipped with splines that cooperate with the spline sleeve to circumferentially position the vibration damper.

[0008] The beneficial effects of this invention are as follows: This invention provides a variable stiffness hydraulic vibration damper for drilling, which can effectively reduce drill string vibration under different conditions, thereby reducing production costs. Its main advantages compared to the prior art are as follows:

[0009] (1) The hydraulic vibration reduction method effectively solves the problem of strong longitudinal, torsional and transverse three-dimensional vibration of the drill string during operation, and protects the drill string, drill bit and drilling electronic device;

[0010] (2) The stiffness of the shock absorber is adjustable and can adapt to various working conditions, thus reducing production costs;

[0011] (3) By combining the guide hole on the hydraulic cylinder and the isolation sealing ring and check valve on the punch pipe, the stiffness of the damper can be controlled while drilling. The stiffness can be adjusted in time when the working conditions change during the operation, thus improving drilling efficiency. Attached Figure Description

[0012] Figure 1 This is a structural schematic diagram of Embodiment 1;

[0013] Figure 2 This is a magnified view of a portion of Example A in Example 1;

[0014] Figure 3 This is a magnified view of part B in Example 1;

[0015] Figure 4 This is a magnified view of part C in Example 1;

[0016] Figure 5 This is a magnified view of part of D in Example 1. Implementation Example

[0017] Referring to the figures, a variable stiffness hydraulic vibration damper for drilling includes a mandrel 1, a centralizer 2, a splined sleeve 3, an upper sealing assembly 4, a hydraulic cylinder 5, a punch pipe 6, a one-way valve 7, a one-way valve fixing device 8, a clamping nut 9, a lower sealing assembly 11, and a lower connector 12. The centralizer is mounted on the mandrel to ensure that the mandrel can move up and down. The splined sleeve is connected to the mandrel by a spline for circumferential fixation. The centralizer, splined sleeve, upper sealing assembly, hydraulic cylinder, lower sealing assembly, and lower connector are sequentially threaded together. The mandrel is threadedly connected to the punch pipe. The one-way valve is mounted on the isolation sealing ring of the punch pipe by the one-way valve fixing device and locked by the clamping nut. The isolation sealing ring divides the hydraulic cylinder cavity into two cavities. The hydraulic cylinder has a guide hole 10.

[0018] The isolation sealing ring on the punch pipe and the guide hole on the hydraulic cylinder are spaced axially. During normal drilling, the guide hole is completely located in the lower half of the fluid chamber, and the one-way ball valve on the isolation sealing ring is closed. At this time, only the lower half of the damper's cavity provides damping. Since the volume of the damping fluid is at its minimum, the damper's stiffness is also at its maximum. When the damper's stiffness needs to be reduced, the drilling pressure can be increased, causing the outer cylinder of the damper to rise. At this time, the volume of the damping fluid in the lower half of the hydraulic cylinder decreases due to pressure. When the upper opening of the guide hole rises above the upper end of the isolation sealing ring along with the outer cylinder, the upper and lower cavities of the hydraulic cylinder are connected. High-pressure fluid flows from the lower half of the cavity to the upper half through the guide hole. At this time, all the fluid in the damper's cylinder participates in the damping effect, thereby reducing the damper's stiffness. When the damper stiffness needs to be adjusted to increase again, the drilling pressure is reduced to allow the outer cylinder of the damper to reset. The high-pressure liquid medium is then redistributed to the two chambers through the guide hole and the single-flow ball valve on the isolation sealing ring, thus achieving drilling-while-drilling control of the downhole drilling damper stiffness. When the downhole vibration load is too large, it will also cause intense longitudinal vibration of the lower drill string. The dynamic load will also push the outer cylinder of the damper upward. When the amplitude is large enough, it will also cause the guide hole in the hydraulic cylinder to connect the upper and lower hydraulic chambers, ultimately reducing the stiffness of the damper. This is the active adjustment of the downhole damper stiffness in the complex vibration environment of the well.

[0019] The connection between the punch pipe and the hydraulic cylinder is well-sealed. During normal operation, the check valve is closed, and the lower half of the hydraulic cylinder chamber works independently, providing vibration damping. Increasing the drilling pressure allows the check valve to open, causing both parts of the hydraulic cylinder chamber to work together, further reducing vibration and altering stiffness. Compared to traditional vibration dampers, this device can change its stiffness during drilling by adjusting the drilling pressure, thereby protecting the integrity of the drill bit, drill string, and downhole measurement electronics. It is suitable for formations prone to drill string vibration or even drill skipping, such as dense conglomerate, igneous rocks, and dense shale.

[0020] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A variable stiffness hydraulic vibration damper for drilling, characterized in that: The variable stiffness hydraulic vibration damper for drilling includes a mandrel, a centralizer, a splined sleeve, an upper sealing assembly, a hydraulic cylinder, a punch pipe, a check valve, a check valve fixing device, a clamping nut, a lower sealing assembly, and a lower connector. The centralizer is mounted on the mandrel, and the splined sleeve is splined to the mandrel. The centralizer, splined sleeve, upper sealing assembly, hydraulic cylinder, lower sealing assembly, and lower connector are sequentially threaded together. The mandrel is threaded to the punch pipe. The check valve is mounted on the isolation sealing ring of the punch pipe by the check valve fixing device and locked in place by the clamping nut. The hydraulic cylinder has a guide hole.

2. The variable stiffness hydraulic vibration damper for drilling as described in claim 1, characterized in that: The isolation sealing ring divides the hydraulic cylinder cavity into two chambers.

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