Patent Grant
9458702
NONE
1. Field of the Invention
The present invention pertains to a method and apparatus for preventing unwanted objects from entering 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 rig and a wellhead, such as in a marine riser assembly, in order to prevent unwanted ferrous objects from entering a wellbore below said wellhead.
2. Brief Description of the Prior Art
Objects can sometimes accidentally fall into the uppermost opening of a well from above including, without limitation, from the rig floor surrounding said opening. 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. In oil and gas operations there is usually significant expense associated with having to use fishing tools.
By contrast, relatively small objects dropped in a wellbore—and particularly ferrous 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 blind 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.
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 marine riser. The magnetic field is used to catch falling metal and/or magnetic objects and keep them from passing beyond the slip joint in a marine riser assembly 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 as part of a riser assembly. Typically, the magnet assembly of the present invention can be installed within a riser assembly situated between a subsea wellhead and a floating drilling vessel—that is, in the portion of the riser assembly below the floating drilling vessel but above a subsea wellhead.
The magnets of the present invention are 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 body member defining an internal chamber, as well as an inlet and outlet in communication with said internal chamber. A single hinged and recessed stripper door allows selective access into said internal chamber. Hinged magnet members, which can be partially received within recesses formed in the sides of said central body member (including said stripper door), are mounted in proximity to said hinged stripper door. Further, said hinged magnet members and stripper door can be selectively positioned relative to one another.
Importantly, the magnet assembly of the present invention is capable of maintaining a fluid pressure seal within said central body member when said stripper door is closed and secured. As a result, the magnet assembly of the present invention can withstand and contain fluid pressures normally observed within a marine drilling or completion riser assembly. Put another way, the magnet assembly of the present invention can be included within a marine drilling or completion riser assembly without compromising or limiting the fluid pressure integrity of said riser assembly.
The apparatus of the present invention 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 a preferred embodiment, said apparatus can be conveniently and effectively located as part of a marine drilling or completion riser assembly on a floating drilling rig and still permit access to remove objects that have been captured above the water line (that is, the upper water surface). This access above the water line is less expensive, safer, limits environmental impact, and faster than a subsea retrieval process.
Alternative embodiments of magnet assemblies (for use primarily in connection with a bell nipple of a non-floating drilling vessel) are disclosed in U.S. Non-Provisional patent application Ser. No. 13/553,915, filed Jul. 20, 2012 and entitled “Method and Apparatus for Catching and Retrieving Objects in a Well”, as well as U.S. Non-Provisional patent application Ser. No. 13/873,718, filed Apr. 30, 2013 entitled “Method and Apparatus for Catching and Retrieving Objects in a Well”, both of which are incorporated herein by reference for all purposes.
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,
Still referring to
Upper connection member 12 having flange 13 extends from the upper surface of central body member 11. Flange 13 further comprises a plurality of holes or apertures 14 for receiving threaded bolts or other similar fasteners, as well as to provide openings for control line conduits. Lower connection member 15 having flange 16 extends from the bottom surface of said central body member 11. Flange 16 further comprises a plurality of holes or apertures 17 for receiving threaded bolts or other similar fasteners, as well as to provide openings for control line conduits. Said upper connection member 12 and lower connection member 15 are axially aligned with one another, and both open into and are in communication with the inner chamber of central body member 11 as described in more detail below.
In the preferred embodiment depicted in
Although said riser magnet assembly 10 can be installed within a wellbore in many different configurations, in the preferred embodiment said riser magnet assembly 10 can be installed as part of a well's riser assembly above a subsea wellhead and BOP assembly. In this manner, said riser magnet assembly 10 can be installed “in-line” such as, for example, with upper flange member 13 and lower flange member 16 being operationally attached to flange connections of riser members as part of a riser assembly.
Referring to
Referring to
On the opposite lateral side of riser magnet assembly 10, a hinge assembly comprises magnet hinge body members 81 of second magnet member 80 pivotally connected to stripper door hinge body member members 51 using a hinge pin disposed through said aligned magnet hinge body members 81 and stripper door hinge body member members 51. Said hinge assembly permits stripper door member 50 to open or swing outward relative to body member 11 about an axis passing through said hinge assembly. Further, it is to be observed that said stripper door 50 and second magnet member 80 can hingeably swing independently from one another other.
When said stripper door 50 is closed and secured as depicted in
Still referring to
Referring to
In a preferred embodiment of the present invention, said magnet members 70 and 80 comprise rare earth or ceramic magnets exhibiting desired magnetic characteristics (that is, creating their own persistent magnetic fields). Further, in the preferred embodiment, each of said magnet members 70 and 80 forms a substantially U-shaped configuration. Accordingly, referring to
As depicted in
Referring to
When stripper door 50 is in a closed position (as depicted in
Referring back to
Referring to
Although specific equipment configurations can vary, a drilling riser generally comprises a conduit that connects a floating drilling vessel (floating on the surface of a body of water) to the upper opening of a well (typically via a subsea blowout preventer assembly and subsea wellhead assembly which are disposed on the sea floor). Many such risers comprise a plurality of flanged tubular sections that are bolted together or otherwise joined to make a continuous string having a desired length. The riser acts as a “funnel” to guide drilling tools into and out of the upper opening of a wellbore.
Unfortunately, not all objects that a riser guides into a wellbore are beneficial. If unwanted falling objects are not stopped before entering the subsea assemblies and/or 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.
Referring to
As noted above, in certain circumstances, it may be beneficial to selectively position said magnets members 70 and 80 temporarily away from central through bore 90 of riser magnet assembly 10 in order to prevent magnetic interference with logging tools or other equipment that may be run into a well equipped with riser magnet assembly 10. Similarly, it may also be beneficial to selectively position said magnets members 70 and 80 temporarily away from central through bore 90 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 riser magnet assembly 10. Notwithstanding the foregoing, in other circumstances, it is highly beneficial to remove metallic particles or debris from wellbore fluids at a riser using riser magnet assembly 10. If metal from the wellbore travels through the surface system it gets grounded up by the surface mud treating and pumping equipment and will be very difficult to remove in the future circulations.
Referring to
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 mud or other fluids.
Thus, although riser magnet assembly 10 of the present invention can be used to catch falling objects, said riser 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 stripper door 50. Moreover, any such metallic material can be recovered and measured, which can frequently provide valuable insight into ongoing operations within a well.
Any drilling mud or other fluid can be drained from inside riser magnet assembly 10 via a drain port. Stripper door 50 can be opened completely to provide access into the inner chamber of a central body member 11 (including, without limitation, inner surface 20 thereof); as seen from the embodiment depicted herein, said stripper door 50 can be unbolted in order to be opened. In most instances, stripper door 50 and magnet members 70 and 80 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 riser magnet assembly 10. Once the caught object is removed, said stripper door 50 can be closed and bolted in place. Thereafter, drilling or other operations can be resumed.
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 claims priority of U.S. Provisional patent application Ser. No. 62/015,069, filed Jun. 20, 2014, incorporated herein by reference.
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| Number | Date | Country | |
|---|---|---|---|
| 62015069 | Jun 2014 | US |
