Patent Grant
6994165
The present invention relates generally to operations performed in conjunction with subterranean wells and, in an embodiment described herein, more particularly provides a method of gravel packing a multilateral well.
Wells which have intersecting wellbores (“multilateral wells”) generally require the wellbore intersections to be sealed. Many proposals have been made for accomplishing this difficult task of sealing wellbore intersections. Some of these have been quite successful and enjoy widespread acceptance in the industry.
However, special problems are encountered when a branch wellbore and a parent wellbore intersect at or relatively near a horizontal inclination and a gravel packing operation is to be performed in the branch wellbore. In the past, this was accomplished by setting a gravel pack packer in the parent wellbore with a well screen positioned in the branch wellbore. A gravel slurry was pumped outwardly through a crossover or other discharge device in the parent wellbore below the packer, and flowed into the branch wellbore.
Unfortunately, this procedure typically results in gravel being deposited on the low sides of the parent and branch wellbores at the intersection. This gravel at the intersection is hard to remove, and it interferes with achieving a seal between the parent and branch wellbores. Of course, this situation is most troublesome when the branch wellbore is completed open hole and, thus, there is no liner available in the branch wellbore to seal against at the wellbore intersection.
Therefore, it may be seen that it would be desirable to provide improved methods of gravel packing a branch wellbore.
In carrying out the principles of the present invention, in accordance with an embodiment thereof, a method is provided which solves the above problem in the art. The method aids in the formation of a sealed wellbore junction and is particularly useful when a branch wellbore is to be completed open hole and gravel packed.
In one aspect of the invention, a method of gravel packing a branch wellbore extending outwardly from a parent wellbore is provided. The method includes the step of conveying a gravel packing assembly into the parent wellbore, the gravel packing assembly including a packer, a well screen, a tubular string interconnected between the packer and the well screen, and a discharge device for discharging a gravel slurry from the tubular string. The well screen and discharge device are positioned in the branch wellbore and the packer is set in the parent wellbore. The gravel slurry is flowed out of the discharge device and into the branch wellbore about the well screen.
In another aspect of the invention, cement is flowed into the branch wellbore, so that the cement extends in the branch wellbore at least into a window at the intersection between the branch and parent wellbores. The cement seals the wellbore intersection.
In yet another aspect of the invention, after the cementing process, a portion of the tubular string with cement thereabout extends from the branch wellbore into the parent wellbore. The portion of the tubular string extending into the parent wellbore is then cut off, along with the cement extending into the parent wellbore.
These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of a representative embodiment of the invention hereinbelow and the accompanying drawings.
Illustrated in
The discharge device 20 is typically of the type known to those skilled in the art as a crossover. A gravel slurry pumped through the packer 18 using another tubing string (not shown) is directed laterally outward into the parent wellbore 14 through ports in the device 20. A fluid portion of the slurry is returned to the parent wellbore 14 above the packer 18 via longitudinal passages (not shown) in the device 20. The ports in the device 20 may be closed after the gravel packing procedure is completed.
The gravel slurry is pumped into the parent wellbore 14 prior to flowing the slurry into the branch wellbore 12. The slurry does not flow through the tubular string 24 into the branch wellbore 12. Gravel 26 from the slurry accumulates about the screen 22 in the branch wellbore 12. The fluid portion of the slurry passes inwardly through the screen 22 and flows through the inside of the tubing string 24, crossover 20 and packer 18 back into the parent wellbore 14 above the packer.
As used herein, the term “gravel” broadly indicates any type of particulate material which is used in a well about a screen, for example, to prevent production of formation fines or sand. Gravel may be relatively large grain sand, ceramic particles, etc.
Since the gravel slurry is first pumped into the parent wellbore 14 before flowing into the branch wellbore 12, some of the gravel 26 tends to accumulate in the parent wellbore. This is particularly troublesome when the parent and/or branch wellbores 12, 14 are at or near a horizontal inclination as depicted in FIG. 1. This gravel accumulation may cause problems in other situations, as well.
Note that, in the method 10, the gravel 26 has accumulated in and around a window 28 formed at the intersection of the parent and branch wellbores 12, 14. To achieve a seal between the wellbores 12, 14, for example, to accomplish a wellbore junction known to those skilled in the art as a “Level 4” junction, the periphery of the window 28 will eventually need to be sealed. The presence of the gravel 26 in the window 28 hinders the ability to achieve such a seal, and thus it would be desirable to prevent such accumulation of gravel.
Representatively illustrated in
In the method 30, a gravel packing assembly 32 is conveyed into a well and positioned at an intersection between a parent wellbore 34 and a branch wellbore 36. A lower portion of the assembly 32, which includes a well screen 38 and a discharge device 40 (such as a crossover), is displaced through a window 42 from the parent wellbore 34 into the branch wellbore 36. An upper portion of the assembly 32, which includes a gravel packing packer 44, remains in the parent wellbore 34. A tubular string 46, which may be made up of multiple segments, is interconnected between the upper and lower portions of the assembly 32.
The packer 44 is set in a cased portion of the parent wellbore 34. A gravel slurry (indicated by arrows 48) is pumped through the packer 44 and tubular string 46 to the device 40, where it is discharged outwardly into the branch wellbore 36. A gravel portion 50 of the slurry 48 accumulates about the screen 38 while a fluid portion of the slurry flows inwardly through the screen and upwardly through the device 40.
The fluid portion of the slurry 48 flows through the tubular string 46 to the packer 44 and into the parent wellbore 34 above the packer. Note that the tubular string 46 both delivers the gravel slurry 48 into the branch wellbore 36 and returns the fluid portion of the slurry back to the parent wellbore 34. Thus, the tubular string 46 has multiple longitudinal passages therein, which may be provided in any manner, such as by using concentric or coaxial tubular members, providing adjacent flow passages, etc.
Since the gravel slurry 48 is flowed into the branch wellbore 36 without first being flowed into the parent wellbore 34 external to the assembly 32, the gravel 50 does not accumulate in the parent wellbore and does not accumulate in or about the window 42. This facilitates the later sealing between the wellbores 34, 36, as will be described further below. In particular, the lack of gravel accumulation at the intersection between the wellbores 34, 36 is especially helpful when the branch wellbore 36 is completed open hole as depicted in FIG. 2. Of course, the branch wellbore 36 could be cased or could have a liner cemented therein, in keeping with the principles of the invention.
Referring additionally now to
Cement (indicated by arrows 54) is pumped outwardly through the open ports of the cementing sub 52 and into the branch wellbore 36 about the assembly 32. As used herein, the term “cement” broadly indicates any hardenable mixture used, for example, to secure or seal equipment in a wellbore. Cement may be an epoxy or other polymer composition, a cementitious material, etc.
The cement 54 flows into the branch wellbore 36 between the window 42 and the gravel 50. A packer 56, such as an inflatable packer, may be included in the assembly 32 to separate the cement 54 from the gravel 50. The packer 56, if included, would be set in the branch wellbore 36 prior to pumping the cement 54.
Note that, if the packer 56 is used, then the packer 44 in the parent wellbore 34 is not necessary. Instead, the packer 56 could be set in the branch wellbore 36 prior to pumping the gravel slurry 48 into the branch wellbore. In that case, the packer 44 could be replaced by, for example, a hydraulic release.
A lower portion of the tubular string 46 is cemented in the branch wellbore 36. The cement 54 preferably flows about the lower portion of the tubular string 46, through the window 42 and into the parent wellbore 34. The objective is to use the cement 54 to seal about the periphery of the window 42, between the window and the tubular string 46, thereby sealing the intersection between the wellbores 34, 36.
To permit access to the parent wellbore 34 below the window 42, the packer 44 and the upper portion of the tubular string 46 are removed after the cement 54 has been allowed to harden. The packer 44 may be retrieved separately from the upper portion of the tubular string 46, for example, by unsetting the packer and disconnecting it from the tubular string 46.
To remove the upper portion of the tubular string 46, a cutting device, such as a mill or overshot (not shown) is used to cut through the tubular string where it extends into the parent wellbore 34 from the branch wellbore 36. That is, the tubular string 46 is cut as indicated by the dashed line 58 in FIG. 3. The portion of the cement 54 which extends through the window 42 into the parent wellbore 34 would also be removed in the same operation.
The result is that a sealed junction between the wellbores 34, 36 is accomplished with the branch wellbore gravel packed about the screen 38.
Of course, a person skilled in the art would, upon a careful consideration of the above description of a representative embodiment of the invention, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to the specific embodiment, and such changes are contemplated by the principles of the present invention. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/US01/46880 | Nov 2001 | WO | international |
This application claims the benefit of the filing date under 35 USC §119 of prior international application no. PCT/US01/46880, filed Nov. 8, 2001, the disclosure of which is incorporated hereby by this reference. Further, this application is a continuation-in-part of copending U.S. application Ser. No. 09/923,211, filed on Aug. 6, 2001 and entitled “GAS STORAGE AND PRODUCTION SYSTEM”, the disclosure of which is incorporated herein in its entirety by this reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2297308 | Layne | Sep 1942 | A |
| 2804926 | Zublin | Sep 1957 | A |
| 3277962 | Flickinger et al. | Oct 1966 | A |
| 3489216 | Armstrong et al. | Jan 1970 | A |
| 3891034 | Owen et al. | Jun 1975 | A |
| 4491178 | Terrell et al. | Jan 1985 | A |
| 4808029 | Grupping | Feb 1989 | A |
| 4878539 | Anders | Nov 1989 | A |
| 5033549 | Champeaux et al. | Jul 1991 | A |
| 5035285 | Dickinson et al. | Jul 1991 | A |
| 5419655 | Phillips et al. | May 1995 | A |
| 5526880 | Jordan, Jr. et al. | Jun 1996 | A |
| 5667023 | Harrell et al. | Sep 1997 | A |
| 5746274 | Voll et al. | May 1998 | A |
| 6070671 | Cumming et al. | Jun 2000 | A |
| 6125937 | Longbottom et al. | Oct 2000 | A |
| 6176307 | Danos et al. | Jan 2001 | B1 |
| 6311776 | Pringle et al. | Nov 2001 | B1 |
| 6397946 | Vail, III | Jun 2002 | B1 |
| 6457525 | Scott | Oct 2002 | B1 |
| 6675891 | Hailey et al. | Jan 2004 | B2 |
| 20030024700 | Cavender | Feb 2003 | A1 |
| Number | Date | Country |
|---|---|---|
| 0 462 567 | Dec 1991 | EP |
| Number | Date | Country | |
|---|---|---|---|
| 20030085037 A1 | May 2003 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09923211 | Aug 2001 | US |
| Child | 10191086 | US |
