Patent Application
20070044970
The present invention generally relates to equipment used for removing stuck downhole tools from an oil or gas well. In particular, the present invention relates to an improved cable hanger for use as part of a cable-guided fishing assembly used to remove downhole tools that have become stuck in a well.
There are various methods of completion of and production from an oil or gas well. Typically, an oil or gas well is completed by cementing casing strings in place along substantially the entire depth of the well. Once the well is completed, production can commence. To facilitate the production of hydrocarbons or other fluids from the well, production tubing is typically installed within the cased wellbore. Production tubing is set in a portion of the well generally concentric with the casing. The production tubing allows communication of the producing zone of the well with the surface.
After the casing and production tubing are installed in the borehole, there is often need for various procedures to be performed on the well, such as perforating the well, well logging operations, and the like. These procedures are performed with tools that are typically attached to what is known as a wireline. The wireline is a metallic, braided cable with a plurality of electrical conductors contained therein, or is often just a metallic braided cable. The tools to be used for a given operation are lowered into the well on the end of the wireline and then activated or monitored at the surface by an operator. When operations with the tools are completed, the wireline and attached tool are pulled to the surface and removed from the well so that production can commence or resume, or so that further operations can be conducted in the well.
Occasionally, downhole tools become stuck in the well during the retrieval process. Downhole tools can become stuck in a well for various reasons, such as encountering a restriction that has formed in the inner diameter of the wellbore. Additionally, downhole tools sometimes become bridged over, or the line on which the tools are run becomes key-seated in the walls of the well bore, thereby hindering or preventing removal of the tools from the well. Often, these downhole tools are very expensive pieces of electronic instrumentation and/or have radioactive sources contained therein and, thus, they must be retrieved from the well. Moreover, these tools often present a hindrance to further operations in or production from the well and, thus, must be retrieved from the well. The procedure of retrieving a stuck tool is known as “fishing.”
For situations in which the stuck tool is still attached to an intact wireline, either the cable-guided fishing method (also known as the “cut and strip” method) or the side-door overshot method is typically used to retrieve the tool. The cable-guided fishing method is typically used for deep, open-hole situations or when a radioactive instrument is stuck in the hole. For these situations, the cable-guided fishing method is a safe method that offers a high probability of success. In particular, the cable-guided fishing method allows retrieval of the stuck tool while the tool remains attached to the cable, thereby minimizing or removing the possibility that the tool will fall down the well during the fishing operation and allowing for the well bore to be cleared with a minimum of downtime. Further, in some instances, through use of the cable-guided fishing method, expensive multi-conductor cable can be salvaged.
The cable-guided fishing method is performed with a special set of tools (hereinafter referred to as the “fishing assembly”). The fishing assembly typically comprises a cable hanger with a T-bar, a spearhead rope socket, a rope socket, one or more sinker bars, a spearhead overshot, and a “C” plate. The fishing assembly may also comprise a swivel joint and a knuckle joint. To use the fishing assembly, the individual components of the assembly are assembled together in a series of steps. Specifically, a typical procedure for assembling the individual components of the fishing assembly is as follows (refer to
(1) a light pulling force is exerted on the wireline to remove any slack;
(2) a cable hanger (A) is attached to the wireline at the well head;
(3) the wireline is lowered until the cable hanger (A) rests on the well head or rotary table;
(4) the wireline is cut a short distance above the cable hanger (A);
(5) a spear head rope socket (B) is then “made up” to the end of the lower half of the severed wireline above the cable hanger (A);
(6) a rope socket (C) (“the upper rope socket”) is made up to the end of the upper severed half of the wireline;
(7) one or more sinker bars (D) are connected to the upper rope socket (C);
(8) a spear head overshot (E) is connected to the lowermost sinker bar (D);
(9) the spear head overshot (E) is then engaged with the spear head rope socket (B), and a “test strain” is exerted on the assembly by “pulling” on the wireline to ensure that the components are properly connected;
(10) with the spear head overshot (E) engaged with the spear head rope socket (B), the wireline is then “pulled” to exert a force sufficient to raise the cable hanger (A) so that it can be removed from the assembly;
(11) after removing the cable hanger (A) from the assembly, a “C” plate (F) is placed under a specially-shaped section of the spear head rope socket (B);
(12) with the specially-shaped section of the spear head rope socket (B) resting on the “C” plate (F), the entire assembly can be lowered such that the “C” plate (F) rests on the well head or rotary table.
After assembling the individual components of the fishing assembly in this (or a similar) manner, the assembly can be used to “fish” the stuck tool out of the well.
In operation, the fishing assembly fishes the stuck tool out of the well in a series of steps. Specifically, the following steps are typical of the operation of the fishing assembly (refer to
(1) the spear head overshot (E) is disconnected from the spear head rope socket (B) and raised up to the derrick man;
(2) the derrick man will then thread the spear head overshot (E) and sinker bar (D) through the first stand of pipe (G) to be run into the well as part of the fishing operation;
(3) the driller will then pick up the first stand of pipe (G) and suspend it over the well head;
(4) the spear head overshot (E) should then be connected to the spear head rope socket (B), a light strain taken on the cable, and the “C” Plate (F in
(5) the first stand of pipe (G) is then run in the well bore and slips (H) are set;
(6) the “C” Plate is then replaced, and the assembly is allowed to rest on the tool joint;
(7) the spear head overshot (E) is then disconnected and raised back up to the derrick man;
(8) the derrick man threads the spear head overshot (E) and sinker bar (D) through the next stand of pipe (I), which in turn is picked up by the driller and suspended over the well head through use of the rig's elevator (J);
(9) the spear head overshot (E) is connected to the spear head rope socket (B), the “C” Plate is removed, and the second stand of pipe (I) is stabbed into and made up to the first stand of pipe (G) and run into the well bore;
(10) the “C” Plate is replaced, the spear head overshot (E) is again disconnected and raised up to the derrick man, and the procedure is repeated until enough pipe has been run into the well to contact and free the stuck tool;
(11) after the fish has been contacted and pulled free, the cable hanger (A in
(12) the elevator (J) is then latched around the “T” bar on the cable hanger, and a strain sufficient to pull the cable out of the tool is taken;
(13) the cable hanger is then removed, and the free cable is spooled on to a service truck reel;
(14) the fishing string along with the fish may then be pulled from the hole in the conventional manner.
While the fishing assembly and method of use described in the preceding paragraphs has proven to be quite successful, shortcomings with some of the components of the fishing assembly have been identified. For example, prior art cable hangers (such as is shown in
Additionally, prior art cable hangers (
Further, prior art cable hangers typically include a “liner” (of a type shown in
Finally, the prior art cable hangers typically included eight bolts—four bolts on each side of the center-line of the cable hanger body—to “clamp” the upper plate and lower plate of the hanger body around the cable. In such prior art cable hangers, it was important to ensure that the cable was centered between the sets of bolts on either side of the center-line so that the distance between the cable and each set of bolts was the same (or substantially the same). If the cable was not centered in the hanger body, the moment arm of one set of bolts (i.e., the distance between the bolts and the cable) would be shorter than the moment arm of the other set of bolts. In such a situation, if an equal torque is exerted on both sets of bolts, one set of bolts has “leverage” over the other set of bolts such that the force exerted on one set of bolts could exceed the yield strength of the bolts. As such, a lower torque may be applied to the bolts to guard against such a problem arising, which ultimately leads to a reduced clamping force that could be placed on the cable. Additionally, the need to tighten and adjust the torque on eight individual bolts is tedious and time consuming.
Accordingly, what is needed is a cable hanger that is designed to ensure a straight pull on the cable. Additionally, an improved liner is needed that is less susceptible to being damaged or to becoming “stuck” in the cable hanger when a pulling force is exerted on the cable hanger. Further, a cable hanger that can be “clamped” about the cable in less time and with greater force is needed. Finally, a cable hanger that allows for changes in the “throat” length of the hanger without replacing substantially the entire cable hanger body is needed. It is, therefore, an object of the present invention to provide a cable hanger that meets these needs and eliminates the problems with prior art cable hangers identified above. The ability of the improved cable hanger disclosed and claimed herein to meet these objectives will become apparent to those of skill in the art from a review of the specification below.
An improved cable hanger used in a cable-guided fishing assembly is disclosed. The disclosed invention is a unique cable hanger in which a specially-shaped hanger body is connected to a handle having a cable groove running through it. The cable groove allows for the centerline of the cable to run through the centerline of the handle, thereby allowing for a straight-line pull to be exerted on the cable through the cable hanger.
The specially-shaped hanger body is operatively connected to a specially-shaped body cover by a plurality of links. In this way, the hanger body and cover form a “clamshell” arrangement in which the cover can rotate from an open position to a closed position around a cable. When in the closed position, the cover and body are bolted together along the side of the cover and body opposite the links.
The use of links to connect one side of the cover to the hanger body eliminates one set of bolts that would normally be required to clamp the cover and hanger body together around a cable. By eliminating a set of bolts, the cable hanger of the present invention can be more quickly clamped around a cable, as only one set of bolts must be torqued and adjusted during the clamping operation.
Further, in the preferred embodiment of the present invention, the hanger body and cover are designed such that the cable rests closer to the links rather than in the center of the hanger body when the hanger body and cover are clamped around the cable. In this way, the moment arm between the bolts and the cable is increased, and the amount of clamping force that the bolts can provide is thereby increased. Thus, the unique “clamshell” design of the disclosed invention allows for a higher clamping force to be exerted on the cable.
The hanger body is connected to the handle by one or more connector rods that are inserted through the handle and threaded into the hanger body. The use of one or more separate connector rods to connect the handle to the hanger body allows for easy modification of the throat length of the cable hanger by simply replacing the existing connector rods with either longer or shorter connecting rods.
The cable hanger of the present invention also utilizes a specially designed liner having a plurality of “notches” along the outside edges of the liner such that the liner is held in place within the hanger body and cover by the heads of large head diameter machine screws, such as for example pan-head screws, resting in the notches. In this way, the screws do not pass through the liner, and the liner is less likely to “pinch” or shear the screws in the event the liner moves in response to a pulling force exerted on the cable hanger.
The following figures form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these figures in combination with the detailed description of specific embodiments presented herein.
The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventors to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.
Referring to
The components of cable hanger 10 include hanger body 60, body cover 40, connector rods 30 and handle 20. As shown in
While the preferred embodiment of cable hanger 10 shown in
Hanger body 60 and body cover 40 are designed to be operatively connected together by a plurality of links 70. As shown in
The use of links 70 to connect one side of the hanger body 60 and the body cover 40 eliminates one set of mechanical fasteners, such as nuts and bolts, that would normally be required to clamp the body cover 40 and hanger body 60 together around a cable. By eliminating a set of nuts and bolts, the cable hanger 10 of the present invention can be more quickly clamped around a cable, as only one set of nuts and bolts must be torqued and adjusted during the clamping operation.
When in the closed position, the hanger body 60 and the body cover 40 are mechanically fastened together along the side of the hanger body 60 and body cover 40 opposite the links 70 by a plurality of specially-shaped bolts 80 and nuts 82. As shown in
While the preferred embodiment of the present invention utilizes nuts 82 and connecting bolt 80 to secure the body cover 40 to the hanger body 60 in the closed position as shown in the figures, one of skill in the art will appreciate that other means can be employed to secure the cable hanger 10 in the closed position. By way of example, the orientation of the connecting bolts 80 and nuts 82 can be turned upside down such that the nuts 82 are secured to the connecting bolts 80 on the underside of the hanger body 60. Similarly, instead of using nuts 82, hanger body 60 or body cover 40 could include threaded holes threaded to receive the threaded ends of connector bolts 80, thereby eliminating the need for separate nuts 82.
Referring to
Rod 90 can also be seen in
Further,
As shown in
Referring to
In the preferred embodiment, liner 100 is made of brass and is thicker than typical prior art liners. One of skill in the art will appreciate, however, that liner 100 can be made of any suitable metal, and can be made of any suitable thickness, that can withstand the forces acting on the liner 100 during use of the cable hanger 10. Similarly, although four notches 106 are shown in the preferred embodiment of the present invention, one of skill in the art will appreciate that the number of notches 106 formed along the edges of liner 100 can vary depending on the length of liner 100.
Referring to
Referring to
Referring to
In operation, cable hanger 10 is placed around a cable such that the cable rests within the liner 100 in hanger body 60. Although not shown in
With the cable properly seated in liner 100 of the hanger body 60, body cover 40 will be rotated about rods 90 and 92 passing through the plurality of links 70 until liner 100 of the body cover 40 rests on top of the cable. In this position, the body cover 40 is in the closed position and is ready to be secured in this position so that a clamping force will be applied to the cable.
With body cover 40 in the closed position, the plurality of connecting bolts 80 are rotated about rod 94 to a vertical (or substantially vertical) clamping position in which the posts 86 of the connecting bolts 80 reside within the notches 45 of the body cover 40. Rotation of connecting bolts 80 to the clamping position is aided by the washer plate 85 through which the posts 86 of each connecting bolt 80 pass. Washer plate 85 allows each of the connecting bolts 80 to be moved in a single action rather than one-by-one. Further, washer plate 85 ensures that each of the plurality of connecting bolts 80 will reside at the same depth within notches 45 in the body cover 40.
When the connecting bolts 80 have been rotated to the clamping position, nuts 82 are then tightened onto the threaded portions of posts 86 of the connecting bolts 80 until the appropriate amount of torque has been applied. With the nuts 82 appropriately torqued, the body cover 40 is tightly secured in engagement with hanger body 60, and the cable hanger 10 is “clamped” in place about the cable. The cable hanger 10 is now ready for use as part of a cable guided fishing operation.
While the cable hanger 10 of the present invention is designed for use as part of a cable-guided fishing assembly, one of skill in the art will appreciate that the cable hanger 10 can be used on its own, i.e., without the remaining components of a typical cable-guided fishing assembly. If it is desired to use the cable hanger 10 on its own, a pull force can be exerted on the cable hanger 10 to attempt to remove the stuck tool. In such use, the pulling force places only the cable below the cable hanger 10 in tension, while the cable above the cable hanger 10 is not in tension. In this way, if the cable breaks during the fishing operation, the cable above the cable hanger 10 will not “snap” or “recoil” like a rubber band breaking, and a potential safety hazard is eliminated.
Additionally, while the cable hanger 10 of the present invention can be used as part of a fishing operation in cased hole applications, one of skill in the art will appreciate that the cable hanger 10 of the present invention can also be used in open hole fishing operations.
While the apparatus, compositions and methods of this invention have been described in terms of preferred or illustrative embodiments, it will be apparent to those of skill in the art that variations may be applied to the process described herein without departing from the concept and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope and concept of the invention as it is set out in the following claims.
