U.S. patent application number 10/638836 was filed with the patent office on 2005-02-17 for vented gravel packing system and method of use.
Invention is credited to Caillier, Michael.
Application Number | 20050034859 10/638836 |
Document ID | / |
Family ID | 34135746 |
Filed Date | 2005-02-17 |
United States Patent
Application |
20050034859 |
Kind Code |
A1 |
Caillier, Michael |
February 17, 2005 |
Vented gravel packing system and method of use
Abstract
An apparatus and method are disclosed for gravel packing an
interval of a wellbore. The apparatus comprises a sand control
screen generally comprising three main sections; a filter section,
a blank pipe section, and a vent section. In one embodiment, the
vent section comprises a removable vent. In another embodiment, the
vent section comprises a vented valve assembly may remain downhole
after gravel packing is complete. Both embodiments include a sand
height control check valve for ensuring that the proper sand height
of the gravel pack is achieved.
Inventors: |
Caillier, Michael; (Breaux
Bridge, LA) |
Correspondence
Address: |
ADAMS AND REESE, L.L.P.
4500 ONE SHELL SQUARE
NEW ORLEANS
LA
70139-4596
US
|
Family ID: |
34135746 |
Appl. No.: |
10/638836 |
Filed: |
August 11, 2003 |
Current U.S.
Class: |
166/278 ;
166/51 |
Current CPC
Class: |
E21B 43/04 20130101;
E21B 43/045 20130101 |
Class at
Publication: |
166/278 ;
166/051 |
International
Class: |
E21B 043/04 |
Claims
1. An apparatus for gravel packing an interval in a wellbore
comprising: a tool body capable of being lowered into the wellbore;
and a sand control vent screen positioned within the wellbore and
having an upper and lower end, the upper end of the sand control
vent screen comprising a removable vent section, coupled to the
tool body, such that the tool body is capable of removing removable
vent section.
2. The apparatus of claim 1, wherein the sand control vent screen
further comprises a blank pipe section having an upper and lower
end, the upper end coupled to the removable vent sections, and a
filter section having an upper and lower end, the upper coupled to
the lower end of the blank pipe section.
3. The apparatus of claim 2, wherein the upper end of the blank
pipe section further comprises one or more shear pins, coupling the
upper end of the blank pipe section to the removable vent
section.
4. The apparatus of claim 2, wherein the blank pipe section further
comprises a check valve, disposed within the lower end of the blank
pipe section such that fluid flow from within the blank pipe
section to within the filter section is prohibited.
5. The apparatus of claim 4, wherein the check valve further
comprises one or more shear pins, coupling the check valve to the
lower end of the blank pipe section.
6. The apparatus of claim 5, wherein the shear pins are designed to
fail when exposed to a predetermined shear force which results in
the de-coupling of the check valve from the lower end of the blank
pipe section.
7. The apparatus of claim 6, wherein the check valve is a ball-type
check valve.
8. A method of gravel packing an interval in a cased wellbore
comprising the steps of: running into the cased wellbore, a tool
body coupled to a sand control vent screen, the sand control vent
screen defining an annulus relative to the cased wellbore and
having an upper and lower end, the upper end comprising a removable
vent section; disposing sand control media within the annulus
defined by the sand control vent screen and the cased wellbore;
employing the tool body coupled to the sand control vent screen to
remove the removable vent section: and installing a mechanical
packer to isolate the annulus defined by the sand control vent
screen and the cased wellbore.
9. The method of claim 8, wherein the sand control vent screen
further comprises: a blank pipe section having an upper and lower
end, the upper end coupled to the removable vent sections; a filter
section having an upper and lower end, the upper end coupled to the
lower end of the blank pipe section; and a check valve, disposed
within and coupled to the lower end of the blank pipe section such
that fluid flow from within the blank pipe section to within the
filter section is prohibited.
10. The method of claim 9, further comprising the step of: causing
the check valve to de-couple from the blank pipe section after
depositing a predetermined quantity of sand control media within
the annulus defined by the sand control vent screen and the cased
wellbore.
11. An apparatus for gravel packing an interval in a wellbore
comprising: a tool body capable of being lowered into the wellbore;
and a sand control vent screen positioned within the wellbore and
having an upper and lower end, the upper end of the sand control
vent screen comprising a vented valve assembly, the vented valve
assembly comprising an upper housing having a plurality of openings
defined therethrough a check valve disposed below and coupled to
the upper housing, and a vent section disposed below and coupled to
the check valve, such that when the check valve is open the vent
section is in fluid communication with the upper housing.
12. The apparatus of claim 11, wherein the sand control vent screen
further comprises a blank pipe section having an upper and lower
end, the upper end coupled to the vent section of the vented valve
assembly, and a filter section having an upper and lower end, the
upper end coupled to the lower end of the blank pipe section.
13. The apparatus of claim 12, wherein the upper end of the blank
pipe section is removably coupled to the vent section of the vented
valve assembly.
14. The apparatus of claim 13, wherein the upper end of the blank
pipe section further comprises. one or more shear pins, coupling
the upper end of the blank pipe section to the vent section of the
vented valve assembly.
15. The apparatus of claim 12, wherein the blank pipe section
further comprises a second check valve disposed within the lower
end of the blank pipe section ad such that fluid flow from within
the blank pipe section to within the filter section is
prohibited.
16. The apparatus of claim 15, wherein the second check valve
further comprises one or more shear pins coupling the check valve
to the lower end of the blank pipe section.
17. The apparatus of claim 16, wherein the shear pins are designed
to fail when exposed to a predetermined shear force which results
in the de-coupling of the check valve from the lower end of the
blank pipe section.
18. The apparatus of claim 17, wherein the check valve of the
vented valve assembly and the second check valve are ball-type
check valves.
19. A method of gravel packing an interval containing production
fluids in a cased wellbore comprising the steps of: running into
the cased wellbore, a tool body coupled to a sand control vent
screen the sand control vent screen defining an annulus relative to
the cased wellbore and having an upper and lower end, the upper end
comprising a vented valve assembly, the vented valve assembly
comprising an upper housing having a plurality of openings defined
therethrough, a check valve disposed below and coupled to the upper
housing, and a vent section disposed below and coupled to the check
valve, such that when the check valve is open the vent section is
in fluid communication with the upper housing; disposing sand
control media within the annulus defined by the sand control vent
screen and the cased wellbore; installing a mechanical packer to
isolate the annulus defined by the sand control vent screen and the
cased wellbore.
20. The method of claim 19, wherein the sand control vent screen
further comprises: a blank pipe section having an upper and lower
end, the upper end coupled to the vent section of the vented valve
assembly; a filter section having an upper and lower end, the upper
end coupled to the lower end of the blank pipe section; and a
second check valve disposed within and coupled to the lower end of
the blank pipe section such that fluid flow from within the blank
pipe section to within the filter section is prohibited.
21. The method of claim 20, further comprising the step of causing
said second check valve to de-couple from the blank pipe section
after depositing a predetermined quantity of sand control media
within the annulus defined by the sand control vent screen and the
cased wellbore.
Description
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0001] Not Applicable
FIELD OF THE INVENTION
[0002] The present invention relates to an improved vented gravel
packing system for gravel packing production wells.
BACKGROUND OF THE INVENTION
[0003] In the petroleum industry, completion of a well drilled
through subterranean formations generally involves lining the well
with a casing and using a perforation gun to create perforation
tunnels through the casing and the formation adjacent to the
casing. The perforation tunnels are usually created adjacent to the
formation production zones, which allow reservoir fluids to flow
from the formation into the casing and to the surface. If the
formation contains unconsolidated sand, the unconsolidated sand may
flow from the formation into the well during production of the
reservoir fluids. Typically, this production of sand is not
desirable since the sand may choke surface equipment, erode the
production string and the wellhead, and bridge the well such that
further production from the well is prevented.
[0004] Production of sand along with reservoir fluids is not a new
problem. Conventional means for control the production of sand
include the technique know as gravel pack completion. Gravel pack
completion involves placing a screen in the well adjacent to the
perforation tunnels and filling an annular area between the screen
and the casing, as well as the perforation tunnels, with coarse
sand. The sand is delivered to the perforation tunnels as a fluid
slurry by a liquid carrier. The slurry is pumped down to the
perforation tunnels through the workstring and into the annular
area between the screen and casing. Once complete, the resulting
gravel pack is a highly porous, permeable layer of coarse sand,
which filters formation sand form the reservoir fluids entering the
well.
[0005] One commonly used techniques for the placement of sand in a
gravel pack completion is the "squeeze technique." Gravel is
squeezed through the perforations to pack outside the casing and in
the screen annulus without circulation. A squeeze packer with a
crossover tool is used to place the gravel pack. The screen and the
blank pipe are run in the hole and positioned across the productive
interval. The packer is set and the crossover opened. The slurry is
then "bullheaded" down a workstring, through the crossover tool,
into the screen-casing annulus, and through the perforations in the
casing. Pumping is continued until a pre-determined pressure
increase or "sandout" pressure occurs, indicating that no more
gravel can be "squeezed" outside of the casing or into the annulus.
Once a "sandout" is achieved, pumping is discontinued and treatment
pressures are vented before physically pulling the crossover tool
to the "upper" circulating position. After the upper circulating
position has been accomplished, pumping is resumed to circulate any
excess gravel remaining in the workstring to the surface.
[0006] Another commonly used technique is referred to as the "one
trip circulating technique." A washpipe is positioned inside and
extending through the screen to accommodate the circulation of
fluids and gravel to the bottom of the screen. A gravel slurry is
circulated down the tubing, through a crossover tool, down the
screen-casing annulus, through the screen, up the washpipe, through
the crossover tool and returns up the workstring-casing annulus.
Gravel contained in the slurry is separated out of the circulating
fluid as it passes through the screen.
[0007] As the screen is covered with gravel, the circulation
pressure increases, forcing gravel into the perforations. Pumping
is continued until a pre-determined pressure increase or "sandout"
occurs indicating that no more gravel can be circulated outside of
the casing or into the annulus. Once a "sandout" is achieved,
pumping is discontinued and treatment pressures are vented before
pulling the crossover tool to the "upper" circulating position.
After the upper circulating position is accomplished, pumping is
resumed to circulate out any excess gravel remaining in the
workstring.
[0008] It has been found, however, that it is difficult to
completely gravel pack production intervals. This is particularly
true for deviated production intervals.
[0009] Conventional gravel pack systems generally include a pipe,
referred to as a vent screen, consisting of three main sections. A
lower most filtering section, a blank pipe section above the
filtering section and a vent section above the blank pipe section.
The filtering section of the pipe is located across the production
zone of the formation and is the portion of the vent screen through
which reservoir fluids will flow. The blank pipe section creates an
annular region, along with the casing, in which the gravel pack is
set to a predetermined height above the production zone of the
formation. This predetermined height, or sand height, ensures the
gravel pack remains in place and prevents reservoir fluids from
bypassing the vent screen and flowing through the annular region
between the vent screen and casing, an occurrence referred to as a
failed gravel pack. The vent section maintains equilibrium inside
the vent screen and in the annular region and prevents the collapse
of the vent screen during gravel packing operations.
[0010] During gravel packing operations, pressure differential
between the annular region created by the blank pipe section and
the casing and the central portion of the vent screen may cause the
liquid carrier to flow through the vent section and into the
central area of the vent screen. When this occurs, sand may bridge
across the outer surface of the vent section to the casing thereby
preventing the proper sand height of the gravel pack from ever
being achieved. The vent section can also become choked with sand,
thereby hindering production of reservoir fluids.
[0011] In addition to the bridging of sand at the vent section,
another problem associated with conventional gravel packing is the
fact that the vent section of the vent screen adds additional
pressure drop to the well, which reduces the flow of reservoir
fluids from the formation. Also, if the vent section becomes
choked, the pressure differential could potentially cause failure
of the gravel pack.
SUMMARY OF THE INVENTION
[0012] The present invention addresses the problems associated with
conventional gravel packing systems, by providing an improved vent
screen and gravel pack operation. One preferred embodiment of the
present invention generally comprises a vent screen with a
removable vent section. After the gravel pack is completed, the
vent section of the vent screen, which is attached to the vent
screen by means of shear pins, is detached and recovered through
the production string. After removal of the vent section, reservoir
fluids are passed across the complete diameter of the vent screen,
which eliminates the potential for choking and the resulting
failure of the gravel pack. In another preferred embodiment of the
present invention, a vented valve system is employed. The vented
valve system generally comprises a check valve installed above the
vent section of the vent screen. The check valve acts as a plug in
the top of the vent screen during gravel pack operations, however,
once reservoir fluids are allowed to flow through the vent screen,
the reservoir fluids lift the check valve and flow upward to the
production tubing. The vented valve system may also be attached via
shear pins to allow the vented valve to be removed if the need
arises. Mechanical packers may be used in both embodiments to
prohibit reservoir fluids from flowing through the gravel pack as
the pressure drop across the filter section of the vent screen
builds.
[0013] In addition to the improved vent section, the present
invention also includes a means for ensuring that the proper sand
height is achieved at sandout. A check valve, referred to as a
sand-height valve, is installed above the filter section and within
the vent screen. The sand-height valve prevents the gravel pack
carrier fluid from entering the filter section and flowing through
to the perforation tunnels. The sand-height valve is attached to
the vent screen with shear pins. The shear pins are designed to
fail once sandout pressure is achieved, thus ensuring that the
proper sand height has been attained in the annulus between the
vent screen and the casing. Once the shear pins fail the
sand-height valve drops to the bottom of the vent screen where it
remains.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a cross-sectional view of a production well
illustrating a conventional vent screen and sand bridging across
the vent section.
[0015] FIG. 2 is a cross-sectional view of production well
illustrating one preferred embodiment of the present invention,
featuring a removable vent and sand-height valve shown during
gravel packing operations.
[0016] FIG. 3 is a cross-sectional view of production well
illustrating one preferred embodiment of the present invention,
featuring a removable vent and sand-height valve shown after
completion of gravel packing operations and back on production.
[0017] FIG. 4 is a cross-sectional view of a production well
illustrating another preferred embodiment of the present invention,
featuring a vented valve vent section and sand height valve shown
during gravel packing operations.
[0018] FIG. 5 is a cross-sectional view of a production well
illustrating another preferred embodiment of the present invention,
featuring a vented valve vent section and sand height valve shown
after completion of gravel packing operations and back on
production.
PREFERRED EMBODIMENTS OF THE INVENTION
[0019] In the following detailed description of the preferred
embodiments, reference is made to the accompanying drawings, which
form a part hereof, and in which are shown by way of illustration
specific embodiments in which the invention may be practiced. It is
to be understood that other embodiments may be utilized and
structural changes may be made without departing from the scope of
the present invention.
[0020] FIG. 1 illustrates, a conventional vent screen application.
Tubing 10 within casing 20 delivers the gravel pack slurry 25 to
the production interval 30. The vent screen 50 generally comprises
three main sections: the filter section 52; the blank pipe section
54; and the vent section 56. Gravel pack slurry 25 is diverted into
the annular region 60 between vent screen 50 and casing 20 by vent
screen plug 58. However, as the gravel pack 70 builds and the
pressure in annular region 60 rises, the fluid carrier of gravel
pack slurry 25 is forced into vent section 56 and travels down the
internal area 65 of vent screen 50. Vent section 56 filters out the
sand in gravel pack slurry 25 and the sand can form a bridge 70 in
the annular space 62 between the vent section 56 of vent screen 50
and the casing 20. The bridge 70 of sand prohibits the completion
of gravel pack.
[0021] FIGS. 2 and 3 illustrate one preferred embodiment of a vent
screen application of the present invention. The figures show a
schematic representation of a production well. The wellbore extends
through the various earth strata including formation 110. A casing
is cemented within wellbore by cement. The workstring 103 includes
gravel packing apparatus 100 for gravel packing an interval of the
wellbore adjacent to formation 110 and between mechanical packers
101, 102. The workstring 103 may also include other various
tools.
[0022] Even though the Figures depict a vertical well, it should be
noted by one skilled in the art that the apparatus for gravel
packing an interval between mechanical packers is equally suited
for use in deviated wells.
[0023] Gravel packing apparatus 100 includes vent screen 150, which
comprises three main sections: filter section 152; blank pipe
section 154; and removable vent section 156. During gravel packing
operations, as shown in FIG. 2, gravel pack slurry 125 is delivered
to the perforation tunnels 111 by workstring 103. Gravel pack
slurry 125 is diverted around vent screen 150 by vent screen plug
158 and forced into the annular area 160 between vent screen 150
and casing 120. Check valve 170 is attached to the internal wall of
vent screen 150 above filter section 152. Carrier fluid of gravel
pack slurry 125 enters the vent section 156 of vent screen 150 and
fills vent screen 150 internally from and above check valve 170.
Check valve 170 prevents carrier fluid from entering filter section
152 and eliminates the potential for sand bridging as described
above. Check valve 170 may be any type of check valve suitable for
downhole use, but is preferably a ball type check.
[0024] Check valve 170 is attached to the internal wall of vent
screen 150 by means of one or more shear pins 171, 172. Shear pins
171, 172 are designed such that when sandout pressure is achieved,
shear pins 171, 172 will fail. By controlling the failure of shear
pins 171, 172, the proper sand height 175 above formation 110 can
be achieved. After failure of shear pins 171, 172, as shown in FIG.
3, check valve 170 falls to the bottom of vent screen 150, where it
remains out of the direct path of reservoir fluids flowing from
formation 110 into vent screen 150.
[0025] After sandout pressure has been achieved, vent section 156
may be removed from vent screen 150 by conventional means. Vent
section 156 is attached to vent screen 150 by one or more shear
pins 157, 158. Shear pins 157, 158 are sheared and vent section 156
is removed utilizing the appropriate tools and vent section 156 is
removed to the surface through production string 103, leaving the
full open diameter of vent screen 150 accessible to reservoir
fluids. After vent section 156 has been removed, mechanical packer
104 is installed to minimize potential failure of the gravel pack.
Mechanical packer 104 maybe installed as a stinger and sealed on
the internal surface of vent screen 150, as shown in FIG. 3, or it
may be installed as an overshot, which seals on the outside surface
of vent screen 150 (not shown).
[0026] The exact design of filter section 152 and vent section 156
is not critical to the present invention as long as it is suitable
designed for the characteristics of the formation fluids and solids
and the gravel pack slurry. Filter section 152 and vent section 156
may comprise perforated pipe having wire wrap directly thereupon,
or alternatively, may comprise a plurality of ribs around which
wire is wrapped. Other suitable alternatives include sintered wire
mesh or sintered metal.
[0027] FIGS. 4 and 5 illustrate another preferred embodiment of the
present invention featuring a gravel packing apparatus 200 having a
vented valve 280 that remains attached to the vent screen 250 after
completion of the gravel pack. As described earlier, vent screen
250 comprises a filter section, 252, a blank pipe section 254, and
a vent section 256. Vent section 256 comprises a lower screen
portion 281 and a vented valve 280 mounted on top of the lower
screen portion 281. Vented valve 280 comprises a check valve 282
that opens up into a vented, or slotted head 283.
[0028] Gravel packing operations employing gravel packing apparatus
200 is substantially similar to that for the removable vent gravel
packing apparatus 100, shown in FIGS. 2 and 3. Gravel pack slurry
is prevented from flowing down through slotted head 283 by check
valve 282. Check valve 282 may be any suitable type of check valve,
but is preferably a ball or plug type check. FIGS. 4 and 5
illustrate a ball type check having ball 284 and seat 286. Gravel
pack slurry is further prevented from flowing through filter
section 252 by check valve 270. Once the gravel pack is complete
and shear pins 271, 272 fail causing check valve 270 to fall to the
bottom of vent screen 250, mechanical packer 204 is installed which
seals the annular region between packers 201,204 and formed by the
external surface of vent screen 250 and the internal surface of
casing 220. Once reservoir fluids are produced, ball 284 of check
valve 282 lifts and allows reservoir fluids to flow through the
seat 286 check valve 282, through the slots 285 of slotted head
283, and through production string 203 where the fluids will
eventually reach the wellhead.
[0029] Although the present invention has been described in terms
of specific embodiments, it is anticipated that alterations and
modifications thereof will no doubt become apparent to those
skilled in the art. It is therefore intended that the following
claims be interpreted as covering all alterations and modifications
that fall within the true spirit and scope of the invention.
* * * * *