Wells – Processes – Assembling well part
Reexamination Certificate
1999-07-09
2001-06-05
Bagnell, David (Department: 3672)
Wells
Processes
Assembling well part
C166S050000
Reexamination Certificate
active
06241021
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to subterranean well completions and, in an embodiment described herein, more particularly provides a method of completing an uncemented wellbore junction.
When a junction of intersecting wellbores is completed, it is generally considered desirable to isolate the formation surrounding the wellbore junction from one or more tubulars extending through the junction. This is due to the fact that fluids produced or injected through the tubulars should typically not be commingled with fluids from the formation surrounding the junction and/or should not be injected into the formation.
In order to isolate the formation surrounding the junction from the tubulars, various methods and apparatus have been developed. While being well suited for their intended purpose, they often require a large number of trips into the well, are time-consuming and, therefore, quite expensive in operation.
There exist situations in which it may not be necessary to isolate a tubular extending through a wellbore junction from a formation or zone surrounding the junction. For example, where the formation is relatively impermeable, it may be acceptable to permit fluid communication between the tubular and the formation. As another example, the formation may be a producing zone, in which case it may be desirable to permit fluid communication between the tubular and the formation in order to produce fluid from the formation through the tubular.
In those situations in which it is not necessary to isolate a tubular extending through a wellbore junction from a formation or zone surrounding the junction, the completion may be greatly simplified by eliminating procedures for providing such isolation, such as cementing the tubular within the junction. Additionally, such a simplified completion may also permit cost savings to be realized when the time comes to abandon the well.
SUMMARY OF THE INVENTION
In carrying out the principles of the present invention, in accordance with an embodiment thereof, a method is provided for completing an uncemented wellbore junction.
In broad terms, the method includes the steps of installing a tubular assembly through a wellbore junction and then sealingly engaging each opposite end of the assembly within a respective one of the intersecting wellbores. The sealing engagement of the assembly within the wellbores is accomplished without cementing the assembly within the junction. In this manner, fluid communication is permitted between the assembly and a formation surrounding the junction.
In one aspect of the invention, the tubular assembly is conveyed through a main wellbore and a lower end of the assembly is inserted into a branch wellbore intersecting the main wellbore while the upper end of the assembly remains in the main wellbore. The assembly, thus, extends across the main wellbore. In order to provide fluid communication between the main wellbore above and below the assembly, at least one opening is provided through a sidewall of the assembly.
In another aspect of the invention, a whipstock assembly may be utilized in drilling the branch wellbore and/or in deflecting the tubular assembly into the branch wellbore from the main wellbore. A fluid passage may be opened or formed through the whipstock assembly to facilitate fluid communication through the main wellbore. This may be accomplished before or after the tubular assembly is installed in the junction.
In yet another aspect of the invention, a fluid passage may be formed through the whipstock assembly at the same time one or more openings are provided through the assembly sidewall. For example, a perforating gun may be conveyed into the assembly and fired, thereby perforating the assembly and an upper closure plate of the whipstock at the same time. Alternatively, the whipstock assembly may be provided with a plug which is retrieved prior to installing the tubular assembly. As further alternatives, the whipstock may be provided with an inner core which is drilled through prior to installing the tubular assembly, which is dispersed prior to installing the tubular assembly, or which is dissolved after installing the tubular assembly.
In still another aspect of the invention, the tubular assembly may include a screen or a perforated liner. The screen or perforated liner may be positioned adjacent the wellbore junction when the tubular assembly is installed in the well. In this manner, fluid communication is provided through the assembly sidewall without requiring a separate operation to form openings therethrough.
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.
REFERENCES:
patent: 5477925 (1995-12-01), Trahan et al.
patent: 5526880 (1996-06-01), Jordan, Jr. et al.
patent: 5813465 (1998-09-01), Terrell et al.
Bagnell David
Dougherty Jennifer R.
Halliburton Energy Service,s Inc.
Imwalle William M.
Smith Marlin R.
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