Roller standoff assemblies

Roller standoff assemblies and devices facilitate disposal of an interior tubular member within an exterior tubular member. Roller standoff devices include a roller cage and at least one roller supported by the roller cage to contact and roll upon the exterior tubular member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to roller devices that are used to aid in disposing an inner tubular member within an outer tubular member.

2. Description of the Related Art

During development of a wellbore for production, it is often necessary to run a smaller interior tubular member or string into a larger, exterior tubular member or string. For example, a production liner string might be run into a surrounding casing string. In another example, a logging tool might be run into a production tubing string on wireline. In such cases, one or more centralizers or other roller standoff devices might be attached to the interior tubular member or string to facilitate insertion of the interior tubing members or strings.

SUMMARY OF THE INVENTION

The present invention provides improved roller standoff assemblies and devices which can be readily attached and removed from an interior tubular member or string and used to facilitate disposal of the interior tubular member or string into a larger, exterior tubular member or string. In particular embodiments, roller standoff devices include a roller cage which carries a number of individual rollers that are designed to contact the exterior tubular member/string and roll along it. In embodiments, the rollers are provided with indentations on their contact surface which aids in the rollers gaining traction. In further embodiments, the indentations are oriented at an angle to the longitudinal axis of the roller they are formed in, thereby reducing any vibration that might be induced into the exterior tubular member/string during operation.

In certain embodiments, the roller cage of the roller standoff device is formed of cage halves that are pivotably secured at a hinge and moveable between an open configuration and a closed configuration. In described embodiments, the roller cage is secured in the closed position by a latch assembly that is preferably spring-loaded and capable of being secured and released rapidly and easily. When secured in the closed position, the roller cage preferably rotates readily about the axis of the interior tubular.

In particular embodiments, a roller standoff assembly is provided with a clamshell adaptor that permits a roller standoff device to be secured onto a joint coupling between two interior tubular members which has a number of wrench flats. An exemplary clamshell adaptor is described which includes a pair of mating halves having interior radial surfaces which are complimentary in shape to that of the joint coupling. Each of the halves also presents a radially outer surface that is shaped to provide a track within which the roller cage can reside. The track permits the roller cage to rotate freely about the hex joint. In a further embodiment, an exemplary clamshell adaptor provides a pair of shoulders that retain the roller cage within the track.

Assemblies constructed in accordance with the present invention are of particular value in deviated bores wherein portions of the inner tubular member tend to frictionally engage the lower portion of the outer tubular member. Roller standoff assemblies in accordance with the present invention may attach to the exterior of a new or existing tubular product to improve deployment of the tubular product in an open hole wellbore, tubular, casing, pipe, etc., by reducing friction through the use of rollers and axial rotation of the standoff device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-4depict an exemplary roller standoff device10which is constructed in accordance with the present invention. In a current embodiment, the standoff device10includes an annular roller cage12which is made up of two, generally semi-circular cage halves12a,12b. The cage halves12a,12bare both pivotably secured to a hinge pin14. As a result, the cage halves12a,12bof the roller cage12can be moved between an open configuration (FIG. 1) wherein the roller cage12can be placed around an interior tubular member and a closed configuration (FIG. 2) wherein the roller cage12forms a closed annular ring.

In a current embodiment, the roller cage12is provided with a spring-loaded latch assembly16which can be rapidly and easily secured and released. The latch assembly16, which is shown in greater detail inFIGS. 1A and 1B, includes a pin-retaining housing18which encloses a chamber20. AsFIG. 1illustrates, the pin-retaining housing18is formed on the cage half12b. A generally cylindrical latching pin22is disposed partially within the chamber20and is moveable therewithin. The latching pin22defines an interior spring recess24. The outer radial surface of the latching pin22presents an outwardly radially-projecting flange26which ensures that the latching pin22is retained within the chamber20. The outer radial surface of the pin22also preferably includes an annular groove28that is shaped to be engageable by a tool or finger so as to move the pin22axially within the chamber20. A compressible spring member30is located within the chamber20and the spring recess24. A retaining nut32is secured within a threaded portion34of the chamber20and retains the spring member30within the recess24. The spring member30biases the latching pin22downwardly until the flange26engages inwardly projecting lip36on the pin-retaining housing18. InFIGS. 1A,3and4, the latching assembly16is shown in a latched condition such that the latching pin22is disposed within a latching retainer38that is formed on the roller cage half12a. This is the closed position for the roller cage12. Thus, the latching pin22is moveable to be selectively latched within the latching retainer38.

In order to move the roller cage12to its open position, an operator must engage the groove28and move the latching pin22to the position shown inFIG. 1Bso as to compress the spring member30. When this is done, the cage halves12a,12b, may be pivoted about the hinge pin14from their closed position to the open position shown inFIG. 1. In order to move the roller cage12from the open position to the closed position, an operator would similarly move the latching pin22to compress the spring30. The cage halves12a,12bare pivoted to their closed position, and the pin22is released. The spring member30biases the latching pin22into seating engagement within the latching retainer38. It will be understood by those of skill in the art that the construction and operation of the roller cage12and latch assembly16advantageously permits the roller standoff device10to be attached to and detached from an interior tubular member without loose hardware or the need for tools.

In the depicted embodiment, each of the cage halves12a,12bincludes a central semicircular radially inner portion40and a plurality of roller lobes42which project radially outwardly from the radially inner portion40. In the depicted embodiment, there are three lobes42provided on each cage half12aand12b. As a result, there are six total lobes42. Gaps44separate each of the lobes42from each other and permit fluid flow past the roller standoff device10during operation. A roller recess46is formed within each roller lobe42. The roller recesses46preferably are formed by openings which pass entirely through the body of the roller cage12.

A generally cylindrical roller48is disposed within each roller recess46and is rotatable about a roller shaft50which passes through the lobe42and secures the roller48within the roller recess46. The rollers48are supported by the roller cage12to contact and roll against an exterior tubular member. A retaining pin52is preferably disposed through the lobe42and roller shaft50to retain the roller shaft50in place. An alternative construction is depicted in the cross-sectional view ofFIG. 13which shows a plurality of ball bearings53disposed between the roller48and the shaft50in order to facilitate rotation of the roller48upon the shaft50.

In one embodiment, the rollers48each present a radially outer rolling contact surface54having a plurality of indentations56which assists the rollers48in gaining traction upon a surrounding tubular member. As a result, the rollers48will more readily rotate and translate the interior tubular member or string within the outer tubular member or string. In the depicted embodiment, the indentations56are elongated and extend from a point proximate one axial end of the roller48to a point proximate the other axial end of the roller48. In addition, each indentation56is oriented at an acute angle with respect to the axis58(seeFIG. 2) of the roller shaft50. The inventors have determined that this orientation of the indentation56reduces undesirable vibration of the surrounding outer tubular during operation and ensures that the roller48remains in constant contact with the outer tubular member throughout rotation of the roller48. A currently preferred range of acute angles between the indentation56and the axis58is from about 30 degrees to about 50 degrees. An angle that is from about 40 degrees to about 45 degrees is particularly preferred.

In a further embodiment, thrust bearings60(seeFIG. 2) are provided upon each roller shaft50at the axial ends of each roller48. The thrust bearings60may comprise annular washers formed of a material that is substantially softer than the material used to form the rollers48and/or the roller cage12. This permits the thrust bearings60to absorb torsional forces imposed by the rollers48during operation.

FIG. 5depicts an alternative embodiment for a roller standoff device10′ which is constructed similarly to the standoff device10in most respects. However, the roller standoff device10′ has four roller lobes42′ instead of six lobes. InFIG. 5, the roller standoff device10′ is depicted within the outlines of a 6-inch diameter deviated surrounding tubular62and an 8-inch diameter deviated wellbore64. These tubulars62,64are deviated in the sense that they depart from a vertical orientation and may be oriented substantially horizontally. Each deviated tubular62,64provides a lower wellbore portion66. It is noted that, in the instance of roller standoff device10′, at least two rollers48are in contact with the lower tubular portions66, thereby permitting greater stability than devices which provide single point contact between the standoff device and the lower tubular portion66. In addition, it is noted that the amount of clearance or standoff between the lower tubular portion66and the roller cage12is increased due to the use of the reduced-diameter gaps44between adjacent lobes42,42′ or42″. In the instance of the roller standoff device10′ illustrated inFIG. 5, an increased amount of clearance for gaps44is provided by the use of planar surfaces45. In the instance of roller standoff device10″ inFIG. 6, curved, reduced diameter outer surfaces47are employed.

FIG. 6illustrates a further alternative roller standoff device10″ which is similar to the standoff device10′ in construction with the exception of the rollers that are used used. In roller standoff device10″, the rollers are spherical roller balls48′ which reside within ball recesses66. Each roller ball48′ is retained within its respective recess66by a retaining plate68which is secured to the roller cage12″ by screws70.

In operation, the roller standoff device10,10′ or10″ is secured about an interior tubular member or string, such as the tubular member72depicted inFIGS. 4 and 5. In particular embodiments, the roller standoff device10,10′ or10″ is affixed around a reduced diameter portion of a connection between two tubular members such that the roller cage12,12′ of the standoff device can rotate about the axis of the interior tubular member or string. Then the interior tubular member72and roller standoff device10,10′ or10″ is disposed into a surrounding exterior, larger diameter tubular member or string62or64(see, e.g.,FIG. 5). The rollers48,48′ of the roller standoff device10,10′ or10″ will rollingly contact the interior surface of the exterior tubular member or string62and thereby facilitate the disposal of the interior tubular member or string into the exterior tubular member or string.

FIGS. 7-11illustrate an exemplary clamshell adaptor74which can be used with the roller standoff devices10,10′ or10″ to permit the roller standoff devices10,10′ or10″ to be used with a portion of the inner tubular member or string having flat portions for the engagement of an assembly tool. One example is a hex wrench connection point, which has a collar with six wrench flats for engagement by a wrench. An exemplary hex wrench connection point75is shown inFIGS. 9,12and13with six wrench flats77and corners79.FIGS. 12 and 13illustrate an exemplary roller standoff assembly100which includes a roller standoff device10and a clamshell adaptor74.

The depicted clamshell adaptor74is made up of two mating, generally semi-circular adaptor halves74aand74bwhich can be assembled about the connection collar75. The adaptor74presents a radially interior surface, generally indicated at76, which is shaped and sized to be complimentary to the surfaces of the wrench flats77and corners79of the connection collar75about which the adaptor74is placed. When the clamshell adaptor74is disposed upon the connection collar75, it will be unable to rotate about the collar75. In the particular embodiment shown inFIGS. 7-13, the adaptor74presents six inwardly-facing engagement flats78which will matingly contact the wrench flats77. In particular embodiments, openings80are provided between the engagement flats78which accommodate the corners79of the hex wrench connection collar75. The inventors have determined that the presence of the openings80permits the overall thickness of the adaptor74to be minimized.

The exemplary clamshell adaptor74also presents an outer radial surface, generally indicated at82, which is shaped to provide an annular track84within which the roller cage12,12′ of a roller standoff device10,10′ or10″ can reside and rotate upon. In addition, the outer radial surface82of the adaptor74includes a pair of shoulders86,88adjacent the track84which are shaped and sized to abut each axial side of the roller standoff device10,10′ or10″ and maintain it upon the track84. A further advantage of the shoulders86,88is that they prevent the hinge pin14and retaining nut32from inadvertently backing out and releasing the roller cage12.

The exemplary roller standoff devices10,10′ and10″ and roller standoff assemblies100of the present invention allow methods to facilitate disposing or conveying a tool or other interior tubular member within an open hole wellbore, a casing, pipe or other outer tubular string or member by reducing frictional engagement between the tool or other interior tubular member and the outer tubular string or member. Frictional engagement is reduced by the rollers48,48′, which permit ease of translational motion between the interior and exterior tubular members. Frictional engagement is also reduced by axial rotation between the roller standoff device10,10′ or10″ and the interior tubular member (i.e.,72). Exemplary methods in accordance with the present invention include the step of securing a roller standoff device to an interior tubular member by surrounding the interior tubular member with the roller standoff device and then moving the roller standoff device to a closed configuration so that it radially surrounds the interior tubular member. A latching device is then moved from an unlatched to a latched position to secure the roller standoff device is its closed configuration, the roller standoff device being axially rotatable with respect to the interior tubular member when in the closed configuration. In particular embodiments, the latch assembly is actuated to a latched position by a spring member biasing the latching pin into seating engagement within a latching retainer38. Thereafter, the interior tubular member and roller standoff device are disposed within an outer tubular member.

FIG. 14depicts a roller standoff device10which has been affixed around interior tubular member72and which is constrained from axial movement with respect to the interior tubular member72by two collars102,104. The collars102,104can be secured around the interior tubular member72either before or after the roller standoff device10has been secured around the tubular member72, thereby permitting the roller standoff device10to be installed at essentially any location upon the interior tubular member72.

Those of skill in the art will understand that the present invention also provides methods wherein a roller standoff assembly is secured about an interior tubular member and, thereafter, the interior tubular member an roller standoff assembly are disposed into an outer tubular member. A roller standoff assembly is made up of a roller standoff device and a clamshell adaptor. According to exemplary methods, a roller standoff assembly is assembled around an interior tubular member by first disposing a clamshell adaptor around a portion of the interior tubular member and, in particular embodiments, the portion of the interior tubular member is provide with flat portions, such as the wrench flats of a hex wrench connection point. In preferred embodiments, the clamshell adaptor will not rotate axially with respect to the interior tubular member when so assembled. A roller standoff device is then disposed within a track formed on an outer radial surface of the clamshell adaptor so that the roller standoff device is axially rotatable with respect to the interior tubular member.

Within the following claims, the term “interior tubular member” is used to refer generally to a reduced diameter member or string or interconnected members to be disposed within a surrounding tubular member or string. The term “interior tubular member” also includes tools that are to be inserted into a surrounding tubular member or string, including wireline run tools, such as logging tools. The term “exterior tubular member,” as used within the claims, refers generally to surrounding tubular members and strings of members, including open hole wellbores, casings, linings, pipes and so forth, into which the interior tubular member is to be disposed.

Those of skill in the art will recognize that numerous modifications and changes may be made to the exemplary designs and embodiments described herein and that the invention is limited only by the claims that follow and any equivalents thereof.