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1. Field of the Invention
The present invention pertains to a method and apparatus for preventing unwanted objects from entering subterranean portions of a wellbore. More particularly, the present invention pertains to the use of magnetic field(s) to catch unwanted objects within a wellbore. More particularly still, the present invention pertains to an apparatus for generating magnetic field(s) between a rig floor of a drilling or completion rig and a wellhead, such as in or near a bell nipple or riser assembly, in order to prevent unwanted objects from entering a wellbore below said wellhead.
2. Brief Description of the Prior Art
A bell nipple is a large diameter length of pipe utilized on most drilling and completion rigs. In most cases, a bell nipple is installed at or near the top of a rig's blowout preventers and extends to a well's uppermost opening at the rig floor; the bell nipple typically serves as a “funnel” to guide drilling tools and/or other equipment into and out of the upper opening of a well. Most conventional bell nipples also serve as conduits for drilling muds and/or other fluids present within a well. As such, most conventional bell nipples are typically configured with a side outlet to permit fluid to flow from a well to a rig's surface fluid equipment such as shale shakers and mud tanks.
Unfortunately, not all objects that a bell nipple guides into a wellbore are beneficial. Objects can sometimes accidentally fall into the uppermost opening of a well from the rig floor. In other instances, objects can be purposely thrown or dropped into a well as an intentional act of sabotage. If such objects are not stopped before entering the subterranean portion of the wellbore, the objects can prevent downhole equipment from functioning properly and can often impede the drilling and/or completion process.
Relatively large objects can generally be retrieved from a wellbore using specially designed “fishing tools.” Such fishing tools are lowered into a wellbore and connect to a dropped object within the wellbore. Thereafter, the fishing tools and the connected object can both be safely retrieved from the wellbore. In many instances, the retrieval process for such large objects can be relatively simple because the size of the objects enables such objects to be grasped and lifted out of the wellbore.
By contrast, relatively small objects dropped in a wellbore—and particularly metal objects—can often cause the most disruption to downhole equipment and related operations. For example, during completion operations, small pieces of metal present in a wellbore can prevent packers and other completion tools from sealing against a casing wall. During open hole drilling operations, such small metal objects can destroy very expensive downhole equipment such as Polycrystalline Diamond Compact (PDC) bits.
Such small objects can also be very difficult to retrieve from a wellbore, as they are often too small to be grasped using conventional fishing tools. This is especially true for small metal objects and, in particular, small metal objects that have an irregular shape or small pieces that can be broken up during the retrieval process. Unfortunately, drilling rigs typically have many small metal objects (such as, for example, wrenches, chain, bolts, tong dies and nuts) at or near the rig floor. Such objects, which are in relatively close proximity to the upper opening of a well, are at risk of falling into a wellbore.
As noted above, such relatively small metal objects can cause significant disruptions to downhole operations. Further, fishing operations for small metal objects can be very time consuming and, as a result, very costly. Accordingly, the best way to prevent such disruptions and to avoid long and expensive fishing operations for such small objects is to keep such objects from entering a wellbore in the first place.
Rig operating procedures frequently dictate that when no pipe is present in a wellbore that blind rams in a blowout preventer (“BOP”) assembly be closed in order to block access to subterranean portion of said wellbore and keep any unwanted falling objects from entering said wellbore from above the BOP assembly. If an object is dropped into a well at the rig floor, with such BOP blind rams closed, the object will not fall all the way into the subterranean portion of a wellbore. However, this solution is less than optimal, because the object must still be retrieved from the top of the rams before operations can resume. Such retrieval process typically requires draining such BOP assembly of fluids to locate the object, opening the bonnet in the BOP assembly, finding and retrieving the object, and then closing and retesting the BOP assembly to the required test pressures. This retrieval process—while frequently quicker and less expensive than fishing the item from the bottom of the well—is nonetheless still relatively expensive, time consuming and dangerous for personnel.
Thus, there is a need for an apparatus and method for catching dropped objects, and particularly metallic objects, before such objects enter the subterranean portion of a well. Such apparatus and method should prevent dropped objects from falling further into a wellbore, and should hold such objects for ultimate retrieval and removal from a wellbore. As an added benefit, such apparatus should also allow for the removal of metallic debris from well fluids. Such apparatus can be disposed at virtually any location(s) between a rig floor of a drilling or completion rig, and a wellhead assembly of a well. In many cases, said apparatus can be conveniently and effectively situated at or in proximity with a bell nipple assembly, or as part of a riser assembly on a floating drilling rig.
The present invention comprises an apparatus for generating a magnetic field that can be attached to, placed in the vicinity of, or made a part of a wellbore. The magnetic field is used to catch falling metal and/or magnetic objects from passing beyond a wellhead and entering the subterranean portions of a wellbore. Said magnetic field can also catch ferrous metallic and/or other magnetic objects and debris present in well fluids, and permit easy and efficient removal thereof.
A magnet assembly of the present invention comprises at least one magnet and is disposed on, around, or as an integral part of a wellbore. The magnet(s) of the magnet assembly of the present invention can be sized based on the internal diameter of a wellbore, as well as the ability to catch certain representative objects that have been dropped into or fished out of wellbores.
In the preferred embodiment, the magnet assembly of the present invention can be mounted at or near the bell nipple. Typically, the magnet assembly of the present invention can be installed between the upper surface of a BOP assembly and the lower portion of a bell nipple assembly. However, it is to be observed that such magnet assembly can be placed in other areas such as, for example, within a riser assembly situated between a subsea wellhead and a floating drilling vessel.
The magnets of the present invention are removably mounted and can be selectively moved away from a wellbore when desired. For example, it may be beneficial to selectively move said magnets away from said wellbore to prevent magnetic interference with logging tools or other equipment that may be sensitive to magnetic fields, or when circulating large concentrations of metallic debris in a rig fluid system (such as, for example, when milling up stuck metal objects in a well). Movement of said magnets can be manually performed, or remotely actuated using pneumatic or hydraulic powered assemblies.
In the preferred embodiment, the magnet assembly of the present invention comprises a central housing member defining an internal chamber, as well as an inlet and outlet in communication with said internal chamber. Hinged and recessed hatch doors allow selective access into said internal chamber. Hinged magnet members, which can be partially received within recesses formed in said hatch doors, are mounted in proximity to said hinged hatch doors. Further, said hinged magnet members and hatch doors can be selectively positioned relative to one another.
The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, the drawings show certain preferred embodiments. It is understood, however, that the invention is not limited to the specific methods and devices disclosed. Further, dimensions, materials and part names are provided for illustration purposes only and not limitation.
Referring to the drawings,
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Upper tubular extension 12 extends from the upper surface of central housing member 11, while lower tubular extension 14 extends from the bottom surface of said central housing member 11. Said upper tubular extension 12 and lower tubular extension 14 are axially aligned with one another, and both open into and are in communication with the inner chamber of central housing member 11.
In the preferred embodiment depicted in
Although said magnet assembly 10 can be installed within a wellbore in many different configurations, in the preferred embodiment said magnet assembly 10 can be installed immediately above a BOP assembly with said base connection flange 16 mating with the upper connection flange of said BOP assembly (typically the uppermost connection flange of an annular blowout preventer). A bell nipple can connect to upper extension member 12. In this manner, said magnet assembly 10 can be installed “in-line” between said BOP assembly and said bell nipple assembly.
It is to be observed that an unobstructed bore and flow path is formed through magnet assembly 10. Specifically, said bore and flow path extends through upper tubular extension 12, central housing member 11 and lower tubular extension 14 (not shown in
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In the preferred embodiment of the present invention, said magnet members 70 comprise rare earth or ceramic magnet segments 73 exhibiting desired magnetic characteristics (that is, creating their own persistent magnetic fields). Further, in the preferred embodiment, each of said magnet members 70 has magnet segments 73 oriented in a V-shaped configuration, which helps to focus the magnetic field(s) generated by said magnet members 70.
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Bell nipple assembly 120 acts as a “funnel” to guide drilling tools into and out of the upper opening of a wellbore. Unfortunately, not all objects that a bell nipple guides into a wellbore are beneficial, such as chain segment 150 that is depicted falling in central through-bore 124 of bell nipple assembly 120. If falling objects such as chain segment 150 are not stopped before entering the subterranean portion of a wellbore, such objects can prevent downhole equipment from functioning properly and can often negatively impede the drilling process as detailed herein.
It is to be observed that the magnet assembly 10 of the present invention can be disposed at virtually any position along the distance that exists between: (1) a rig floor of a drilling or completion rig; and (2) a wellhead of a well being serviced by said drilling or completion rig. For example, it is possible that said magnet assembly of the present invention and related method could be incorporated directly within a BOP assembly or wellhead assembly. Additionally, when installed in connection with a floating drilling vessel, it is to be observed that magnet assembly 10 of the present invention can be installed as part of the riser that extends from a rig to a subsea BOP assembly. However, without limiting the scope of the present invention in any manner, the simplest and most effective manner of implementing the present invention will frequently involve installing the magnet assembly of the present invention between a BOP assembly and a bell nipple assembly as described herein.
Said magnet assembly 10 can be beneficially situated above or below the side outlet of said bell nipple; however, as depicted herein, when said magnet assembly 10 is installed between a bell nipple assembly and BOP assembly, said magnet assembly 10 will be situated below said fluid outlet part. Because any liquid in central through-bore 124 of bell nipple assembly 120 drains through said side outlet port 121, the liquid level within said through-bore 124 does not extend above said outlet port 121. Accordingly, magnet assembly 10 can be positioned below said outlet port 121 of bell nipple assembly 120. In such an installation, the magnetic field generated by magnet assembly 10 extends into a “wet” portion of bell nipple assembly 120 (that is, a portion of bell nipple central through-bore 124 that contains drilling mud or other liquid).
As noted above, in certain circumstances, it may be beneficial to selectively position said magnets members 70 temporarily away from central housing 11 of magnet assembly 10 in order to prevent magnetic interference with logging tools or other equipment that may be run into a well equipped with magnet assembly 10. Similarly, it may also be beneficial to selectively position said magnets members 70 temporarily away from central housing 11 when circulating large concentrations of metallic debris in a rig mud system (such as, for example, when milling up stuck metal objects in a well) in order to prevent clogging of magnet assembly 10. Notwithstanding the foregoing, in other circumstances, it may be beneficial to remove metallic particles or debris from wellbore fluids using magnet assembly 10.
In operation, magnet assembly 10 of the present invention can be used to quickly and efficiently capture certain objects dropped in a well. When such an object is dropped into a well, the BOP assembly can be closed as a “fail-safe” to prevent access into a wellhead and the upper portion of a wellbore. Thereafter, any drilling mud or other fluid can be drained from inside said magnet assembly 10 via drain port 15. One hatch door 50, with an applicable magnet member 70 (or, more particularly, magnet segments 73 thereof) still partially received within said hatch door, can be opened completely to provide access into the inner chamber of central housing 11. (In most instances, both hatch doors 50 are not opened simultaneously in order to prevent possible loss of magnetic forces on a caught object, particularly if such object spans substantially across the width of magnet assembly 10). Once the object is removed, hatch door(s) 50 can be closed and locked in place. Thereafter, the BOP assembly can be opened, and drilling or other operations can be resumed.
In many cases, milling of downhole equipment or other wellbore operations can generate metallic shavings, particles or other debris supported in drilling mud or other fluid within a wellbore. Although efforts are made on virtually all rigs to remove debris and contaminants from drilling mud or other fluids, over time such metallic shavings, particles and/or debris can reach significant concentrations in such drilling mud or other fluids. Such metallic content can adversely affect fluid properties, equipment performance and/or operational effectiveness. Thus, it is generally beneficial to remove such metallic materials from such drilling muds or other fluids.
Although magnet assembly 10 of the present invention can be used to catch falling objects, said magnet assembly 10 can also serve the function of catching undesirable metallic materials from drilling mud or other fluid. Such metallic material materials can often attach to the internal surface of hatch doors 50. Moreover, any such metallic material can be recovered and measured, which can frequently provide valuable insight into ongoing operations within a well.
The above-described invention has a number of particular features that should preferably be employed in combination, although each is useful separately without departure from the scope of the invention. While the preferred embodiment of the present invention is shown and described herein, it will be understood that the invention may be embodied otherwise than herein specifically illustrated or described, and that certain changes in form and arrangement of parts and the specific manner of practicing the invention may be made within the underlying idea or principles of the invention.
This Application is a Continuation-in-Part of U.S. Non-Provisional patent application Ser. No. 13/553,915, filed Jul. 20, 2012, which claims priority of U.S. Provisional Patent Application Ser. No. 61/510,229, filed Jul. 21, 2011, and U.S. Provisional Patent Application Ser. No. 61/610,757, filed Mar. 14, 2012, all incorporated herein by reference.
Number | Name | Date | Kind |
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2699871 | Stem | Jan 1955 | A |
2781128 | Stem | Feb 1957 | A |
3187238 | Wilson et al. | Jun 1965 | A |
5052491 | Harms et al. | Oct 1991 | A |
5944100 | Hipp | Aug 1999 | A |
Entry |
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PCT International Search Report dated Oct. 1, 2012. |
Number | Date | Country | |
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61510229 | Jul 2011 | US | |
61610757 | Mar 2012 | US |
Number | Date | Country | |
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Parent | 13553915 | Jul 2012 | US |
Child | 13873718 | US |