Boring or penetrating the earth – Processes – Boring curved or redirected bores
Reexamination Certificate
1999-06-25
2001-03-27
Pezzuto, Robert E. (Department: 3671)
Boring or penetrating the earth
Processes
Boring curved or redirected bores
C175S079000
Reexamination Certificate
active
06206111
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to apparatus used in drilling branch wells from a main well, and more specifically to apparatus for drilling lateral wells from cased wells for purposes of producing oil and gas from subsurface formations.
DESCRIPTION OF THE PRIOR ART
Conventional technology provides for the drilling of a well from the surface to a predetermined depth below the surface into a subterranean formation containing hydrocarbon reserves. Most conventional wells have traditionally been substantially vertical. However, current technology provides for the drilling of deviated or non-vertical wells using directional drilling technology.
Since its usage began, horizontal drilling has offered dramatic reservoir exposure improvements. More recently, the trend has developed towards drilling multiple laterals, thus further increasing production. Until recently, laterals typically were not cased and tied back, which meant when workovers or cleanouts were required, reentry was difficult and completions were virtually impossible.
Now, the technology allows multiple laterals to be cased and tied back. Multilaterals may be drilled into predetermined producing formation quadrants at any time in the productive life cycle of wells and can be used in vertical, directional or horizontal applications.
Minimizing the distance hydrocarbons must travel to the wellbore is an important goal. One surface hole installation can now incorporate an integral casing drainage system that takes the wellbore to the hydrocarbons in place.
The same directional bottomhole assembly used to initiate the kickoff is used to drill the build or turn portion of the lateral wellbore. Once a lateral has been drilled, a secondary liner and hanger system is placed into the newly drilled wellbore and mechanically tied back to the main casing string, allowing future re-entry into the new leg. The deflection device can immediately be moved to the next window joint upon installation of the lateral string.
Either the drilling cycle can commence on the next lateral, or the deflection device can be retrieved to surface, enabling access to all casing strings. The deflection device can, alternatively, be left on bottom, to be available if additional laterals are drilled at some other time, to further improve reservoir recovery based on performance of the original wellbore and its added lateral or laterals.
Additional benefits are that the system creates a natural separator for oil and gas production in vertical applications, and it creates the opportunity to drill, complete and produce from several different formations tied to one surface-hole casing string.
An integral part of the system for drilling either a single lateral well, or a multiple lateral well scenario, is the so-called casing window joint, a joint of steel casing having a pre-cut or pre-formed window which is easily drillable. The casing window system is available in various oilfield-tubular material grades. The completed casing window is then overwrapped with composite materials, similar to fiberglass.
U.S. Pat. No. 4,415,205, issued on Nov. 15, 1983, to William A. Rehm et al., discloses in its Col. 1, lines 56-59; Col. 2, lines 5-8; Col. 3, lines 17-25; and Col. lines 2-8, the use of a special window cut into the steel casing which is covered by fiberglass to provide an easy exit port through which a lateral hole can be easily drilled. In the absence of such a pre-cut hole, the steel casing can be very difficult to drill through, typically requiring the use of a conventional casing mill.
A similar system is described in U.S. Pat. No. 5,458,209, issued on Oct. 17, 1995, to Hayes et al., in which there is disclosed with respect to its
FIGS. 11A
,
11
B and
11
C, the use of a pre-cut opening in the steel casing, covered by fiberglass, which can be easily drilled.
In U.S. Pat. No. 5,615,740, issued Apr. 1, 1997, to Comeau et al., assigned to the assignee of the present invention and incorporated herein by reference, there is disclosed a system for use in pressure environments typical in oil and gas drilling. Comeau et al utilize a pre-cut window in the casing which is covered with an easily drillable material, such as fiberglass. In addition, a retrievable pressure sleeve is fixed within the interior of the casing, adjacent the window in the casing. The sleeve is pressure sealed to the interior of the casing and the window space or cavity between the sleeve and the drillable material wrap filled with fluid to provide protection from pressure damage to the drillable material window covering. Once the casing has been cemented in place, the sleeve can be retrieved to the surface and drilling through the window can commence.
However, the use of such a prior art systems, in which a pre-cut or pre-formed hole is covered with an easily drillable covering, for example, fiberglass, creates an additional problem. The fiberglass covering simply cannot withstand the high pressures frequently encountered in drilling oil and gas wells, sometimes being at 5,000 to 10,000 psi levels. For example, in U.S. Pat. No. 4,415,205, in Col. 5, commencing on line 5, the prior art recognizes the inability of the fiberglass to withstand the pressures encountered at greater depths and that conventional casing mills should be used instead to create the window in the casing. Further, an internal sleeve system such as that described in Comeau et al has not proven entirely satisfactory when dealing with high pressures often encountered in drilling or the cyclic high pressures commonly encountered during the cementing operation, due to the difficulty of creating a high pressure seal between the sleeve and the casing while having the sleeve being easily retrievable from within the casing.
It is therefore the primary object of the present invention to provide a system for drilling lateral wells in high pressure environments using casing having an easily drillable exit port, using an internal pressure sleeve which is easily retrievable from within the casing.
SUMMARY OF THE INVENTION
The objects of the invention are accomplished, generally, by the use of a retrievable pressure sleeve pinned within the interior of the casing, adjacent the window in the casing. The sleeve includes a high pressure sealing system at both ends thereof to seal against high pressure and pressure surges from either inside or outside the casing. Once the casing has been cemented in place, the sleeve is retrieved to the earth's surface.
As an additional feature of the invention, the window cavity between the sleeve and the drillable material covering is filled with a fluid to prevent the covering over the window from deforming inwardly through the window in response to the external pressures encountered in the downhole environment.
REFERENCES:
patent: 4174846 (1979-11-01), Scott
patent: 4415205 (1983-11-01), Rehm et al.
patent: 4765404 (1988-08-01), Bailey et al.
patent: 5215151 (1993-06-01), Smith et al.
patent: 5353872 (1994-10-01), Wittrisch
patent: 5458209 (1995-10-01), Hayes et al.
patent: 5484017 (1996-01-01), Coon
patent: 5579829 (1996-12-01), Comeau et al.
patent: 5615740 (1997-04-01), Comeau et al.
patent: 5884698 (1999-03-01), Hughes et al.
Halliburton Energy Service,s Inc.
Kuharchuk Terrence N.
McCully Michael D.
Pezzuto Robert E.
Shull William
LandOfFree
High pressure internal sleeve for use with easily drillable... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with High pressure internal sleeve for use with easily drillable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High pressure internal sleeve for use with easily drillable... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2516600