Wells – Processes – Parallel string or multiple completion well
Reexamination Certificate
1999-08-10
2001-04-03
Suchfield, George (Department: 3672)
Wells
Processes
Parallel string or multiple completion well
C166S117600, C166S237000, C166S378000
Reexamination Certificate
active
06209649
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to subsurface well equipment in wellbores having a plurality of production tubing strings and, more particularly, to an apparatus for selection of and entry into a particular tubing string by a re-entry device and a related method.
2. Description of the Related Art
Wells having a central bore and lateral branches extending therefrom, and extending into the hydrocarbon producing subterranean formations are well known as “multilateral wells.” Also well known in the art are “dual completions,” i.e., wells having a plurality of production tubing strings to carry hydrocarbons from subterranean producing zones via discrete and corresponding tubing strings to the surface of the earth. During the life of a well, remediation of one or more producing zones may be required by a technique commonly known as “wireline or coiled tubing intervention,” whereby a well known intervention tool is lowered into the well on a small diameter wire or coiled tubing, and a service operation is performed that improves production, collects data, or performs operations critical to the well's performance.
Well known to those of ordinary skill in the art are two basic types of “wireline” tools: electric line (commonly called “e-line”) and slickline. E-line tools require a multi-functional wire, whereby in addition to suspending and conveying the tool to a specific location in a well, the e-line is also used to transmit power from the surface to the intervention tool and/or transmit data between the surface and the intervention tool. Conversely, slickline tools use a simple wire to suspend and convey the tool to its selected location, and are designed to require no electrical power from the surface to perform their designed function. One of ordinary skill in the art will immediately appreciate the difficulty of both types of wireline tools in selecting a particular branch lateral wellbore extending from a central wellbore, where at least one lateral branch is present. As noted above, coiled tubing, as opposed to wireline, is also commonly used to run intervention tools into wells.
Well known in the art of completion techniques are methods and associated completion equipment for “tieing-back” or connecting two production tubing strings, attached to a permanent downhole tubing hanger, to a subsea christmas tree. The ability to manipulate a tie-back string so that it reliably and accurately aligns with one of a plurality of production strings located a distance in the well below the christmas tree illustrates the importance of downhole orientation. It is essential to well operations to be able to select and interconnect the production tubing strings to a respective location and orientation of flow lines in the tree. The tie-back string is essentially a spool connecting the tubing hanger to the christmas tree, and enables discrimination between tubing fixed in the downhole tubing hanger, and flow ports in the christmas tree.
In most dual completions, a first length of production tubing extends from a first producing zone to the tree and a second length of production tubing extends from a second producing zone to the tree. Therefore, a selection of the desired tubing string for intervention is often as simple as inserting the intervention tool directly or indirectly into the tubing via a device known as a “lubricator.” The lubricator sealably connects to the tree, and allows insertion of the intervention tool in the wellbore while simultaneously preventing the flow of pressurized wellbore fluids into the surrounding environment. In the case of multiple tubing strings and flow lines, the lubricator must be connected separately to each flow line if intervention techniques are to be employed.
When remediation or service is required in multilateral and dual completion wells, the operator must select and enter the proper branch of the well, or completion string, and simply and reliably enable a service tool to be conveyed therein. An object of the present invention is to enable the operator to simply and easily make a configurational modification to the intervention tool at the surface prior to deployment. This modification enables the invention to enter a selected branch of a multilateral wellbore or a dual completion. Another object of the invention is to simplify the configuration of the completion. By eliminating expensive components, initial costs can be minimized, thereby making the well more cost effective to deploy and operate.
There is a need for a selective re-entry tool for use in wells having a plurality of tubing strings and which has the ability to discriminate between the strings and to reliably orient a service tool string for entry into a desired lateral branch. This need may exist, for example, where the tubing entry point is at a depth below the wellhead, possibly very deep in the well. There is also a need to accomplish discrimination and selection functions with a simple surface modification to the intervention tool that will result in cost savings in the design, operation, and implementation of the well. Further, it is desirable to eliminate the need for a “tie-back” tubing string for intervention operations and the high costs associated with building and deploying it.
SUMMARY OF THE INVENTION
The present invention has been contemplated to meet the above described needs. In a broad aspect, the invention may be a selective re-entry tool for use in a tubing string having a plurality of branch tubings, comprising: a carrier body having a navigation port extending longitudinally therethrough; and an orienting key movably connected to the carrier body and releasably engageable with a discriminator groove in the tubing string to align the navigation port with a predetermined one of the plurality of branch tubings. Another feature of this aspect of the present invention may be that the orienting key is adapted to be removably disposed within one of a plurality of key recesses in the carrier body, the identity of the predetermined one of the plurality of branch tubings alignable with the navigation port depending on which of the plurality of key recesses the orienting key is disposed in. Another feature of this aspect of the present invention may be that the orienting key is hingedly connected to the carrier body. Another feature of this aspect of the present invention may be that the orienting key is outwardly biased by a spring. Another feature of this aspect of the present invention may be that the tool may further include a locking dog movably connected to the carrier body and releasably engageable with a locking recess in the tubing string to prevent rotation of the carrier body after the navigation port has been aligned with the predetermined one of the plurality of branch tubings. Another feature of this aspect of the present invention may be that the locking dog is adapted to be removably disposed within one of a plurality of dog recesses in the carrier body. Another feature of this aspect of the present invention may be that the locking dog is outwardly biased by a spring. Another feature of this aspect of the present invention may be that the engagement of the locking dog and the locking recess prohibits further rotation of the carrier body relative to the tubing string and permits limited longitudinal movement of the carrier body relative to the tubing string. Another feature of this aspect of the present invention may be that the tool may further include a guide bar extending from the carrier body in alignment with the navigation port. Another feature of this aspect of the present invention may be that the carrier body further includes a no-go process cooperably engageable with a no-go shoulder in the tubing string.
In another aspect, the invention may be a method for inserting a well tool in a selected one of a plurality of branch tubings in a tubing string, comprising: connecting an orienting key to a carrier body, the carrier body having at least one navigation port extending longitudinally therethroug
Leismer Dwayne D.
Milligan, Jr. Clay W.
Pringle Ronald E.
Camco International, Inc
Goldstein & Healey LLP
Suchfield George
LandOfFree
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