The disclosure generally relates to the field of earth or rock drilling (mining), and more particularly to well equipment or well maintenance.
Traditional well construction, such as drilling of an oil or gas well, consists of three phases: drilling, lining with casing, and production with tubing. In the drilling phase, rock is cut away until a deposit is reached. This establishes a wellbore or borehole through a series of formations. Each formation through which the well passes must be sealed so as to avoid an undesirable passage of formation fluids, gases, or materials out of the formation and into the borehole or from the borehole into the formation. In addition, it is often desired to isolate both producing and non-producing formations from each other to avoid contaminating one formation with fluids from another formation.
Lining the wellbore with casing protects the formation layers and stabilizes the wellbore. Packers and liners are often used in lining the wellbore to separate fluid types. Packers are tools used to form an annular seal between two concentric strings of pipe or between the pipe and the wall of the open hole and are usually set just above the producing zone to isolate the producing interval from the casing annulus or from producing zones elsewhere in the wellbore. At times, it is not desired for the casing to extend all the way to the surface of the wellbore, in which case a liner is used. A liner is a casing string that does not extend to the top of the wellbore, but instead is anchored or suspended from inside the bottom of the previous casing string.
Production tubing is run into a drilled well after the casing is run and set in place. Production tubing protects the wellbore casing from wear, tear, and corrosion while providing a continuous bore from the producing zone to the wellhead. When sections of production tubing are run into a wellbore, they often run through a packer or liner top to interconnect them. However, packer bores and liner tops are substantially centered in the wellbore. If the wellbore is deviated, the production tubing will tend to engage the edge of the packer bore or liner top instead of entering it. In order to correct this issue, the production tubing is maneuvered to enter the packer bore or liner top. A guide is attached to the lower end of the production tubing to facilitate entering a packer bore or maneuvering past downhole obstructions. The guide typically includes a muleshoe geometry such that rotation of the muleshoe will allow the end of the guide to bypass the top of a packer or obstruction. This rotation may be accomplished by rotating the entire production tubing from the surface. However, when running the production tubing string into a wellbore, the ability to rotate the production tubing string to enter into packer bores or liner tops may be prevented due to control lines attached to the tubing and/or extreme hole angles. When rotation of the production tubing is not feasible, there are self-aligning muleshoe guides available that will rotate as the weight of the production tubing string applied to the guide increases due to the guide setting down on a packer bore or liner top. A guide with a muleshoe geometry will enter the packer bore or liner top after sufficient rotation. After the guide enters the packer or liner top, the bottom end of the guide will typically rotate back to the original position with the assistance of a spring. In addition, the spring designed for use in the guide is designed for the harsh downhole environment, which incurs a significant cost in material and design.
Embodiments of the disclosure may be better understood by referencing the accompanying drawings.
The description that follows includes example systems that embody embodiments of the disclosure. However, it is understood that this disclosure may be practiced without these specific details. For instance, this disclosure refers to a guide assembly for entering a packer bore or liner top in a wellbore for subsurface drilling operations in illustrative examples. Embodiments of this disclosure can also be applied to subsea drilling operations. In other instances, well-known instruction instances, protocols, structures and techniques have not been shown in detail in order not to obfuscate the description.
Overview
When running production tubing string into a wellbore, a guide is often used on the bottom end of the string to assist maneuvering downhole. Guides are used to keep production tubing centered within the wellbore, thus minimizing problems associated with tubing hitting obstructions (e.g., rock ledges or objects) in the wellbore as the tubing is lowered into the well. A guide has been designed that includes a spring to tilt a guide shoe to guide equipment past obstructions. This tilting (or canting) guide has been designed with a short coil spring and a lug on an upper mandrel in a milled slot on a guide shoe to place a guide shoe in an orientation to enter a packer bore or liner top, for example. The short coil spring is placed between an upper mandrel and an inner mandrel (hereinafter “inner spring mandrel”). The upper mandrel surrounds the outer diameter of the short coil spring. The inner spring mandrel is inside the inner diameter of the short coil spring. The two mandrels protect the short coil spring from outside wear and tear. When the guide shoe encounters an obstruction, forces are applied to both ends of the short coil spring by the upper mandrel and a lower inner mandrel. The lower inner mandrel applies an upward force on the spring due to contact with the obstruction while the upper mandrel applies a force equal to the weight of at least the guide itself. These forces compress the short coil spring.
The guide assembly has a slot or gap between the lower muleshoe guide and the upper mandrel. As the short coil spring is compressed, the gap between the lower muleshoe guide and the upper mandrel closes causing the lug on the upper mandrel to be pushed into the milled slot on the lower muleshoe guide. The milled slot is angled to act as a ramp for the lug to move along. Compression of the short coil spring drives the lug into the milled slot which causes the lower muleshoe guide to tilt. A slot in the upper mandrel allows the lower inner mandrel to move unrestricted as the lower muleshoe guide tilts inward. The lower muleshoe guide tilts until it can pass the obstruction. Once the lower muleshoe guide has passed the obstruction, the forces are removed from the short coil spring allowing it to decompress, and the lower muleshoe guide returns to its original alignment.
This guide assembly features a lower muleshoe guide at the end that tilts instead of rotating. The guide assembly uses a short coil spring to allow the guide shoe longitudinal movement sufficient to tilt to pass an obstruction and to return to longitudinal alignment with the guide when the obstruction has been passed. This allows for the guide to be shorter overall than traditional production tubing string guides, making this a more economical design. In addition, the short coil spring requires a shorter compression distance than a traditional long coil spring and should be more reliable and less prone to fouling from debris than a long coil spring.
Example Illustrations
In the following description of a tilting guide assembly and other apparatus and methods described herein, directional terms, such as “inner”, “outer”, “upper”, “lower”, etc., are used only for convenience in referring to the accompanying drawings. Specifically, upper and lower are used to refer to different regions, parts, portions, or components of an assembly or equipment when vertically oriented. Additionally, it is to be understood that the various embodiments of the inventive subject matter described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the embodiments.
In particular,
Under non-loaded conditions, when no force is applied to the lower muleshoe guide 201, the spring 204 holds the lower muleshoe guide 201 in alignment with the central axis of the guide assembly 200. When the guide encounters an obstruction, such as a packer or liner top in a wellbore, the weight of the upper mandrel 203 and the connected production tubing will apply a downward force on the spring 204. The lower muleshoe guide 201, prevented from downward movement in the wellbore through contact with an obstruction, causes the lower inner mandrel 205 to apply an upward force on the spring 204. Together, the downward force from the upper mandrel 203 and the upward force from the lower inner mandrel 205 compress the spring 204. The gap 206 between the lower muleshoe guide 201 and the upper mandrel 203 allows the lower muleshoe guide 201 to move and tilt as the spring 204 is compressed.
Another embodiment of a tilt guide assembly that does not use a long spring to enter packer bores or liner tops is depicted in
If a packer bore or liner top is encountered, the end of the guide will easily enter the packer bore because of the off-center bias of the muleshoe guide.
While the aspects of the disclosure are described with reference to various implementations and exploitations, it will be understood that these aspects are illustrative and that the scope of the claims is not limited to them. Plural instances may be provided for components, operations or structures described herein as a single instance. Finally, boundaries between various components, operations and data stores are somewhat arbitrary, and particular operations are illustrated in the context of specific illustrative configurations. Other allocations of functionality are envisioned and may fall within the scope of the disclosure. In general, structures and functionality presented as separate components in the example configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements may fall within the scope of the disclosure.
Use of the phrase “at least one of” preceding a list with the conjunction “and” should not be treated as an exclusive list and should not be construed as a list of categories with one item from each category, unless specifically stated otherwise. A clause that recites “at least one of A, B, and C” can be infringed with only one of the listed items, multiple of the listed items, and one or more of the items in the list and another item not listed.
Example embodiments include the following:
A muleshoe guide assembly comprises an upper mandrel having an upper end adapted to couple to well equipment and a lower end. The lower end has a tab extending longitudinally downward. An inner mandrel is inside at least a lower portion of the upper mandrel. A spring is wrapped around the inner mandrel. A muleshoe is concentric to a lower portion of the inner mandrel and coupled to a lower end of the inner mandrel. The muleshoe comprises a milled slot aligned to accept the tab when the spring compresses, allowing the muleshoe to move upwards, and the milled slot slopes downward and outward to tilt the muleshoe as the muleshoe travels upwards, and the spring compresses.
The inner mandrel comprises an inner spring mandrel surrounding the inner diameter of the spring and a lower inner mandrel.
The lower end of the upper mandrel and an upper end of the muleshoe create a gap when the spring is not compressed.
The gap is sufficient to allow the muleshoe to tilt.
The spring comprises a short coil spring.
A muleshoe guide assembly comprises an upper mandrel having an upper end adapted to couple to well equipment and a lower end with a slot along an arc of the lower end. The slot allows a muleshoe to tilt into the slot. The muleshoe guide assembly further comprises an inner mandrel concentrically positioned at least partially within the upper mandrel. A muleshoe is concentric to at least a lower portion of the inner mandrel. A spring is positioned between an inner diameter of the upper mandrel and an outer diameter of the inner mandrel and approximately opposite the slot. The spring tilts the muleshoe towards the slot.
The spring comprises a leaf spring.
The spring is arced to tilt the muleshoe out of longitudinal alignment with the upper mandrel towards the slot.
The spring straightens when compressed and allows the muleshoe to longitudinally align with the upper mandrel.
A muleshoe guide assembly comprises an upper mandrel having an upper end adapted to couple to well equipment and a lower end adapted to allow a muleshoe to tilt out of longitudinal alignment with the upper mandrel. An inner mandrel is concentrically positioned at least partially within the upper mandrel and coupled with the muleshoe. The muleshoe guide assembly further comprises the muleshoe.
A spring is coiled around the inner mandrel. The spring compresses to allow the muleshoe to move upwards. The lower end of the upper mandrel comprises a downward extending tab to tilt the muleshoe out of longitudinal alignment with the upper mandrel as the muleshoe moves upwards.
The muleshoe comprises an external ramp at an upper end of the muleshoe that aligns with the tab of the upper mandrel for the tab to ride as the muleshoe moves upwards.
The spring pushes the muleshoe downward to create a gap between the muleshoe and the upper mandrel.
The lower end is adapted to allow the muleshoe to tilt out of longitudinal alignment with the upper mandrel. The lower end of the upper mandrel has a slot along an arc of the lower end that accepts a portion of an upper end of the muleshoe to allow the muleshoe to tilt into the slot.
A spring is positioned between an inner diameter of the upper mandrel and an outer diameter of the inner mandrel and approximately opposite the slot. The spring tilts the muleshoe towards the slot.
The spring is a leaf spring.
The spring is arced to tilt the muleshoe out of longitudinal alignment with the upper mandrel towards the slot.
The spring straightens when compressed and allows the muleshoe to longitudinally align with the upper mandrel.
Filing Document | Filing Date | Country | Kind |
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PCT/US2018/067971 | 12/28/2018 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2020/139384 | 7/2/2020 | WO | A |
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Entry |
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PCT Application Serial No. PCT/US2018/067971, International Search Report, dated Sep. 24, 2019, 3 pages. |
PCT Application Serial No. PCT/US2018/067971, International Written Opinion, dated Sep. 24, 2019, 6 pages. |
Number | Date | Country | |
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20210355811 A1 | Nov 2021 | US |