U.S. patent number 3,913,676 [Application Number 05/480,737] was granted by the patent office on 1975-10-21 for method and apparatus for gravel packing.
This patent grant is currently assigned to Baker Oil Tools, Inc.. Invention is credited to John P. Barbee, Jr., Charles A. Richard.
United States Patent |
3,913,676 |
Barbee, Jr. , et
al. |
October 21, 1975 |
Method and apparatus for gravel packing
Abstract
Method and apparatus for gravel packing a well, in which a
packer is set in well casing above a production zone to isolate the
zone from the casing fluids thereabove, a perforated liner assembly
being disposed along the production zone, a pair of tubing strings
extending from the packer to the top of the casing to provide
separate flow passages for enabling fluids to be circulated to and
along the production zone for the purpose of conditioning the zone,
after which gravel can be pumped through one of the tubing strings
into the zone and along the exterior of the liner.
Inventors: |
Barbee, Jr.; John P. (Luling,
LA), Richard; Charles A. (Gretna, LA) |
Assignee: |
Baker Oil Tools, Inc. (Los
Angeles, CA)
|
Family
ID: |
23909152 |
Appl.
No.: |
05/480,737 |
Filed: |
June 19, 1974 |
Current U.S.
Class: |
166/278;
166/51 |
Current CPC
Class: |
E21B
34/06 (20130101); E21B 43/04 (20130101) |
Current International
Class: |
E21B
34/00 (20060101); E21B 34/06 (20060101); E21B
43/04 (20060101); E21B 43/02 (20060101); E21B
043/04 () |
Field of
Search: |
;166/51,278,276,134,217,224 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Novosad; Stephen J.
Attorney, Agent or Firm: Norvell, Jr.; William C.
Claims
What is claimed and desired to be secured by Letters Patent is:
1. An apparatus for use in a subterranean well having a production
zone and fluid in said well, comprising: isolation means for
isolating the production zone from the fluid in the well above the
zone, said means defining first and second fluid passages
communicating with the zone and having means adapted to receive
first and second tubular strings extending from said means to the
top of the well; a liner assembly carried by and depending from
said isolation means, said assembly including a first perforated
member through which fluid can flow between the exterior and the
interior of said member, said assembly having means for providing
fluid in communication with said first fluid passage and the
exterior of said perforated member; a second tubular member within
said liner assembly providing a fluid passageway communicating with
said second fluid passage and communicable with the interior of
said perforated member; and means for selectively controlling fluid
flow in said passageway.
2. The apparatus as defined in claim 1 wherein said means for
selectively controlling fluid flow includes a port in said second
tubular member opening into the interior of said perforated member;
and valve means in said second tubular member movable between
positions closing and opening said port.
3. The apparatus as defined in claim 1 wherein said means for
selectively controlling fluid flow includes a port in said second
tubular member opening into the interior of said perforated member;
a sleeve valve member closing said port; and means engaging said
sleeve valve member for shifting said sleeve valve member to port
opening position.
4. The apparatus as defined in claim 1 wherein said means for
selectively controlling fluid flow includes a port in said second
tubular member opening into the interior of said perforated member;
valve means in said second tubular member closing said port;
downwardly opening valve means in said liner member below said
perforated member through which fluid flowing through said second
tubular member can flow into the well externally of said liner
assembly; and means for shifting said first mentioned valve means
to port opening position.
5. The apparatus as defined in claim 1 wherein said means for
selectively controlling fluid flow includes a port in said second
tubular member opening into the interior of said perforated member;
a sleeve valve member closing said port; means engaging said sleeve
valve member for shifting said sleeve valve member to port opening
position; downwardly opening valve means in said liner assembly
below said perforated member through which fluid flowing through
said second tubular member can flow into the well externally of
said liner assembly.
6. An apparatus for use in a subterranean well having a production
zone and fluid in said well, comprising: a well packing mechanism;
a liner assembly connected to and extending below said packing
mechanism, said assembly including a perforated member having
perforations sized to prevent entry of particulate matter through
the perforations into the interior of said perforated member; first
and second interior seal receptacles on opposite ends of said
perforated member; means having first and second flow passages
therethrough and sealed within the well packing mechanism, said
first and second flow passages being adapted to be placed in
communication with first and second tubular strings, respectively,
extending to the top of the well; a tubular extension within said
liner assembly adapted to communicate with said first tubular
string and providing at least a part of said first fluid passage;
first and second seal means on said tubular extension for
respective selective sealing engagement with said first and second
interior seal receptacles; means on the liner assembly above said
first seal receptacle defining a fluid passageway providing at
least a part of said second fluid passage; and means for
selectively controlling fluid flow in said first and second flow
passages.
7. The apparatus as defined in claim 6, wherein said means for
selectively controlling fluid flow includes a port in said tubular
extension opening into the interior of said perforated member; and
valve means in said tubular extension movable between positions
closing and opening said port.
8. The apparatus as defined in claim 6 wherein said means for
selectively controlling fluid flow includes a port in said tubular
extension opening into the interior of said perforated member; a
sleeve valve member closing said port; and means engaging said
sleeve valve member for shifting said sleeve valve member to port
opening position.
9. The apparatus as defined in claim 6 wherein said means for
selectively controlling fluid flow includes a port in said tubular
extension opening into the interior of said perforated member;
valve means in said tubular extension closing said port; downardly
opening valve means in said liner member below said perforated
member through which fluid flowing through said tubular extension
can flow into the well externally of said liner assembly; and means
for shifting said first-mentioned valve means to port opening
position.
10. The apparatus as defined in claim 6 wherein said means for
selectively controlling fluid flow includes a port in said tubular
extension opening into the interior of said perforated member; a
sleeve valve member closing said port; means engaging said sleeve
valve member for shifting said sleeve valve member to port opening
position; downwardly opening valve means in said liner assembly
below said perforated member through which fluid flowing through
said tubular extension can flow into the well externally of said
liner assembly.
11. The apparatus as defined in claim 6; said tubular extension and
said means sealed within the well packing mechanism being
longitudinally shiftable to remove the upper of said seal means
from the upper of said interior seal receptacles while said seal of
said means within the well packing mechanism remains to enable
fluid to flow from the interior of said tubular extension into the
interior of said perforated liner for upward flow of fluid into the
second flow passage.
12. The apparatus as defined in claim 6 wherein said means for
selectively controlling fluid flow includes a port in said tubular
extension opening into the interior of said perforated member;
valve means in said tubular extension movable between positions
closing and opening said port; said tubular extension and said
means sealed within the well packing mechanism being longitudinally
shiftable to remove the upper of said seal means from the upper of
said interior seal receptacles while said seal of said means within
the well packing mechanism remains to enable fluid to flow from the
interior of said tubular extension into the interior of said
perforated liner for upward flow of fluid into the second flow
passage.
13. The apparatus as defined in claim 6 wherein said means for
selectively controlling fluid flow includes a port in said tubular
extension opening into the interior of said perforated member; a
sleeve valve member closing said port; means engaging said sleeve
valve member for shifting the said sleeve valve member to port
opening position; downwardly opening valve means in said liner
assembly below said perforated member through which fluid flowing
through said tubular extension can flow into the well externally of
said liner assembly; said tubular extension and said means sealed
within the well packing mechanism being longitudinally shiftable to
remove the upper of said seal means from the upper of said interior
seal receptacles while said seal of said means within the well
packing mechanism remains to enable fluid to flow from the interior
of said tubular extension into the interior of said perforated
liner for upward flow of fluid into the second flow passage.
14. A method for gravel packing a production zone in a well
comprising the steps of: running a well packing mechanism with a
perforated liner depending therefrom in the well and setting said
mechanism in the well above the production zone; providing first
and second fluid passages extending within the well packing
mechanism; providing first and second tubular strings communicating
with said first and second fluid passages, respectively, and
extending to the top of the well, said first fluid passage
extending into the perforated liner, said second fluid passage
communicating with the exterior of the perforated liner; pumping
fluid containing gravel down one of said strings and through its
associated fluid passage into the zone surrounding the perforated
liner, the fluid in advance of the fluid containing gravel and in
the zone surrounding the perforated liner flowing through the other
fluid passage and the other of said strings to the top of the well.
Description
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The present invention relates to an apparatus and method for
packing gravel within the bore of a subterranean well.
2. DESCRIPTION OF THE PRIOR ART
Of considerable magnitude in the production of hydrocarbons such as
oil and gas from a producing well is the problem of sand flow into
the well bore from unconsolidated formations. Production of sand
with the flow of hydrocarbons will cause the well bore to gradually
fill up with minute sand particles until production perforations in
the casing and, oftentimes, the end of production tubing inserted
therein are covered, resulting in a significant reduction in fluid
production. In many instances, sand production will cause the well
to die.
In addition to reduction of fluid production, flow of sand also may
cause severe damage to equipment such as pumps, chokes and the
like. In flowing wells, fluid velocity may be sufficient to
scavenge sand within the well bore and produce it with the fluid
hydrocarbon, resulting in holes being cut in the tubing and flow
lines.
One well known means of controlling flow of sand into the well bore
is the placement of gravel on the exterior of a slotted liner to
filter sand produced with the oil or gas and thus prevent its entry
into production tubing. The slotted liner or screen must be
designed to prevent entry of the gravel itself into the production
tubing.
The reverse circulation method of packing gravel provides for
pumping the gravel down the well in the annulus between the
production string and the well casing. The gravel is deposited on
the outer periphery of the screen assembly while the fluid returns
to the top of the well through the production tubing. A pressure
buildup is noted at the surface and fluid pumping stopped when the
gravel covers the screen. After gravel settlement, the tubing is
disconnected from the screen assembly and pulled out of the
hole.
Although other fluids have been used, treated and filtered
production or nearby well or surface water is preferably used in
most gravel packing processes during the cleaning and washing
procedure. The water is treated to remove contaminants such as
cement particles, scale, and other foreign material generally
resulting from the circulation of the water in the well bore.
Because the volume in the annulus between the production tubing and
the well casing may be as much as eight to ten times greater than
the volume of the production tubing, considerably more water must
be used and thus treated and filtered if clean fluid is to be used
in a reverse circulation process or method than is used in
conventional wash down methods.
In order to provide a gravel pack apparatus which is more efficient
than prior art apparatuses and, primarily, to drastically reduce
the amount of fluid which must be used during a gravel packing
process, crossover equipment has been developed for use with screen
assemblies and high performance packers. Such equipment now has
made it feasible to gravel pack using only a fraction of the volume
of fluid heretofore utilized because the fluid is maintained within
the tubing and is circulated only within the treatment zone which
is isolated by the packing element of the packer.
Although such an apparatus has provided many advantages over use of
conventional prior art techniques, its use may be confining because
it cannot be successfully utilized in high pressure wells which
require the use of high density fluids, such as highly weighted
muds, instead of water. If such an apparatus were utilized in
conjunction with a mud system, the screen as well as the gravel
pack would become plugged and would severely limit hydrocarbon
production therethrough.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide an
apparatus and method for gravel packing wherein the zone being
gravel packed is completely isolated from well control fluid (mud)
during the gravel pack operation and may remain isolated from it if
desired, after completion of the gravel pack operation.
It is also an object of the present invention to provide an
apparatus and method for packing gravel which reduces the required
movement of tubing during the process.
It is a further object of the present invention to provide an
apparatus and method for gravel packing wherein high pressures may
be utilized during acidizing and squeezing of gravel into the
formation.
Other objects of the present invention will be readily apparent
from a reading of the FIGS., the specification below, and the
claims.
The present apparatus for packing gravel within a well isolates the
zone to be gravel packed from well fluid normally used to contain
the well pressure. The apparatus utilizes plural or dual strings of
tubing associated with a packer, which is set within the well
casing with a liner assembly being attached to the packer and
positioned adjacent to perforations within the well casing. The
liner assembly comprises a production screen, preferably long
enough to cover or straddle substantially all casing perforations
to be gravel packed. The tubing strings are in sealed relation to
the packer, with one of the tubing strings extending to the lower
portion of the liner assembly and with another tubing string
extending from the top of the well to the packer. The apparatus
permits selective circulation down one string, around or through
the liner assembly and up through the other string for circulation
of treating fluid or placement of gravel. The invention also
incorporates a method utilizing the apparatus as above described
for selectively directing the flushing and gravel packing fluids
through the tubing strings and into and from the annulus around the
liner assembly, as well as the interior of the liner assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1a and 1b are schematic drawings of an apparatus showing a
packer with a liner assembly therebelow which has been set in a
well opposite casing perforations and with parallel tubing strings
associated therewithin, the apparatus being positioned for
circulating flushing fluids through the perforated casing region.
FIG. 1b is a lower continuation of the apparatus shown in FIG.
1a.
FIG. 2 is similar to FIGS. 1a and 1b, but shows the circulating
assembly in open position and the flow of fluid during gravel
packing indicated by arrows.
FIG. 3 shows the upper seal means disengaged and flow of fluid for
washing the interior of the liner assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention encompasses utilization of a packing mechanism 1 to
the lowered end of which has been affixed a liner assembly 2. The
particular packing mechanism 1 utilized is not critical to the
invention and may vary considerably in design, construction and
operation. It is adapted to be lowered in the well casing 9 and
anchored in a packed-off condition therewithin against longitudinal
movement in both upward and downward directions in a known manner.
The packing mechanism 1 may generally be similar to that as
detailed in U.S. Pat. No. 3,229,767. Because the packing mechanism
1 can be selected from a number of commercially available tools,
and its design not being a critical part of the present invention,
it is believed that the above description is more than sufficient
to teach one skilled in the art its use in conjunction with the
invention at hand. Therefore, further detailed elaboration of the
packing mechanism 1 is not believed to be necessary.
The liner assembly 2 includes upper and lower seal receptacles 3a
and 3b, each having a smooth cylindrical surface 11 extending
inwardly within the bore 12 of the liner assembly 2 for sealingly
engaging the upper and lower seal means 10a and 10b, respectively,
which are affixed to a long tubular string 13, the seal means 10a
and 10b each having an outer diameter only slightly larger than the
internal diameter of the seal receptacles 3a and 3b, so that when
each of the upper and lower seal means 10a and 10b are engagingly
positioned within their respective seal receptacles 3a and 3b,
fluid is prevented from traveling therebetween. This can generally
be accomplished by utilizing a seal means 10a and 10b having a
slightly flexible rubber-like outer lip surface 14 which will
compress slightly when urged into sealing position within the
respective seal receptacles 3a and 3b.
Spaced vertically on the liner assembly 2 on the lower portion
thereof below and adjacent to a tubing section 5 is a production
screen 6 having a desired permeability to allow the transfer of
flushing fluids but to block out the flow of sand and gravel. A
tell tale screen section 4 is spaced above and adjacent to the
tubing section 5 for a purpose which will hereinafter described.
Below the production screen 6 is a second section of tubing 15 and
a lower seal receptacle 3b for the sealing engagement of the lower
end of the long tubular string 13. Below the lower seal receptacle
3b is a discharge valve 7 which prevents entry of well fluids
within the liner assembly to the casing annulus 9a.
The liner assembly 2 and the packing mechanism 1 form a housing for
the dual string assembly 16 which comprises a parallel flow tube 17
threadedly connected to the tubular long string 13 run into the
well and serves to sealably engage a second string of tubing 19 and
to also sealably engage with the bore 1a of the packing mechanism 1
by means of circumferentially extending seals 22, which are of a
similar construction as seals 10a and 10b. Thus, when the dual
string assembly 16 is positioned within the packing mechanism 1,
there can be no communication of fluid from above to below the
packing mechanism 1 except through the tubular strings 13 and 19.
The parallel flow tube 17 provides separate passages 20 and 21
through the packing mechanism 1 for respective flowing engagement
between the tubing strings 13 and 19 and conducts fluid to or from
the liner assembly 2, as will be described in more detail
below.
The parallel flow tube 17 has a series of circumferentially
extending and slightly outwardly protruding seal means 22 to permit
adequate longitudinal movement of the tubular strings 13 and 19
without inadvertent disengagement of the seals 22 from the bore 1a
of the packing mechanism 1 during limited raising or lowering of
the tubular strings 13 and 19 in the practice of the method, as
will be described.
Immediately above the seal means 22 on the parallel flow tube 17 is
an enlargement or shoulder 23 which can engage the upper end of the
packer bore 1a of the packing mechanism 1 and which serves as a
stop to limit downward travel of the parallel flow tube 17 through
the packing mechanism 1. The first passageway 20 in the parallel
flow tube 17 houses a nipple 26 on the upper end for connection of
the upper portion 13a of the long tubular string 13. The passageway
20 provides a flow path between the upper portion 13a of the
tubular long string 13 and the lower portion 13b thereof in the
liner assembly 2. Forming the upper portion of passageway 21 is a
circumferentially extending smooth seal surface 25 which will
sealably engage with a seal assembly 27 run on the second or short
string of tubing 19. The lower end of the passageway 21 opens into
the bore 12 between the exterior of the lower portion 13b of the
long tubular string 13 and the interior of the liner assembly 2.
The upper portion 17a of the parallel flow tube 17 is concave with
its apex located on the same centerline as that of the second
passageway 21. Thus the seal assembly 27 on the lower end of the
short string of tubing 19 will be guided into its mating seal bore
in passageway 21 as it is lowered into place.
Immediately above the lower seal 31 of annular seal means 10b is a
circulating assembly 32 having a tubular housing 33 with a series
of circumferentially spaced ports 34 which are initially closed by
means of a vertical sliding internal sleeve 35 also initially
secured to the tubular housing 33 by means of a shear screw 36
within a bore 36a. The sliding sleeve 35 has a ball seat 37 in the
uppermost portion thereof as well as a series of elastomeric side
seals 38, which initially prevent escape of fluid between the
sleeve 35 and the tubular housing 33 when the ports 34 are in
initially close position as the result of the engagement of the
sleeve 35 by the shear screw 36. At the lower end of the tubular
housing 33 is a shoulder 39 for the limitation of lower travel of
the sliding sleeve 35. As detailed hereinafter, a ball 40 inserted
at the top of the well through the long tubular string 13 will
gravitate or can be pumped down the string 13 to sealingly engage
the seat 37.
The discharge valve 7 positioned on the lower portion of the liner
assembly 2 is a check valve permitting downward flow and preventing
upward flow of fluid. Although several common and known discharge
valves 7 could be utilized for this purpose, a spring loaded
mushroom shaped poppet valve 7 is depicted in open position in FIG.
1b.
The liner assembly 2 also has a series of circumferentially spaced
ports 8 above the seal receptacle 3a for the travel of fluid
between the bore 12 of the liner assembly 2 to the casing annulus
9a.
OPERATION OF THE METHOD
In order to establish a base to support the gravel pack, a bridge
plug B-P may be set below the lowermost end of the perforations
P.
The packing mechanism 1 with the liner assembly 2 attached thereto
is set at a predetermined depth within the casing annulus 9a in the
well prior to initiation of the gravel packing operation. The
setting mechanism is withdrawn and returned to the well surface.
After the packing mechanism 1 has been set, the parallel flow tube
17 is lowered into the well on the long tubular string 13a until
the tube 17 enters the bore 1a of the packing mechanism 1 and so
that the upper and lower seal means 10a and 10b, are respectively
sealingly engaged within their receptacles 3a and 3b of the liner
assembly 2 and, concurrently, the seal means 22 on parallel flow
tube 17 are sealingly engaged in the bore 1a of the packing
mechanism 1. The short tubular string 19 is then run into the well
and communicatingly affixed to the passageway 21 within the
parallel flow tube 17. The entire apparatus A now is in condition
for initiation of the gravel packing procedure.
At this point, a flushing fluid is pumped from the top of the well
through the long tubular string 13, exiting the long tubular string
13 through the opened discharge valve 7 (which is urged openly by
the pressure within the long tubular string 13) and travels to the
outside of the liner assembly 2 and into the annulus 9a of the well
casing 9. As the flushing fluid rises in the annulus 9a, the
contaminated well fluid is displaced from the annulus 9a into the
liner assembly 2 through the ports 8 in the upper portion of the
liner assembly 2 and flows through the tubular short string 19 to
the top of the well for disposal.
Upon completion of the step as described above, the ball 40 is
pumped down the long tubular string 13 until it comes to rest on
the seat 37. Application of pressure to the long tubular string 13
then pumps the sliding sleeve 35 downward, first shearing the shear
screw 36 and then exposing the ports 34. Downward movement of the
sliding sleeve 35 is limited by contact of the lower end of the
sleeve 35 with the shoulder 39. The placement of the ball 40 on the
ball seat 37 sealingly prevents subsequent pumping or flow of fluid
through the lower portion 13b of the long tubular string 13 and
will permit fluid to travel in the annulus 28 between the liner
assembly 2 and the long tubular string 13 because of the exposure
and open position of the ports 34.
Thereafter, flushing fluid is reverse circulated down the short
string 19 and through the ports 8 in the liner assembly 2 above the
upper seal receptacle 3a. The fluid travels downwardly in the
annulus 9a of the well casing 9 and re-enters the liner assembly 2
through the porous production screen 6 and the tell tale screen 4,
thereby cleaning each of the screens 6 and 4 and displacing well
fluid upwardly by means of opened ports 34 within the circulating
assembly 32 on the lower portion 13b of the tubular long string 13.
The fluid travels to the surface of the well upwardly through the
tubular long string 13 for subsequent disposal.
Thereafter, gravel is pumped down the short tubing string 19,
exiting the liner assembly 2 through the ports 8 and traveling into
the annulus 9a of the casing 9. The pumping of the gravel is
continued and pressure is exerted within the short tubing string 19
in order to squeeze the gravel behind the perforations P. A valve
(not shown) on the long tubular string 13 is opened at the surface
of the well and the gravel packing is continued until the bore 9a
is filled with gravel particles and until an increase in back
pressure indicates that the tell tale screen 4 has been covered
with gravel.
Upon notation at the well surface of an increase in back pressure,
the tubular strings 13 and 19 are raised so that the upper seal
means 10a are disengaged from the upper seal receptacle 3a. Fluid
then is circulated down the long tubular string 13 through the
annular area or bore 12 of the liner assembly 2 and back to the
surface through the tubular short string 19 to wash out any fine
particles of sand or gravel that may have passed through the
screens 4 and 6 to the annular area 12. The fluid exits the liner
assembly 2 through the opened ports 34 below the production screen
6 and travels in the annulus 12 between the lower portion 13b of
the tubular string 13 and the liner assembly 2 past the tell tale
screen 4 and exits the part of the liner assembly 2 below the upper
seal receptacle 3a through the canal 47 resulting from the
disengagement of the upper seal means 10a from the upper seal
receptacle 3a and continues upwardly to the top of the well through
the tubular short string 19. The circulating of the fluid may be
reversed if desired.
After the above described step is completed, both strings of tubing
13 and 19 may be lowered to their original position and the well
put on production. Alternatively, the strings 13 and 19 may be
pumped full of mud to kill the well so that the strings 13 and 19
can be safely removed from the well. Subsequently, the well can be
completed with one string of tubing with seals on its lower end
inserted into the bore 1a of the packing mechanism 1.
Although the invention has been described in terms of specified
embodiments which are set forth in detail, it should be understood
that this is by illustration only and that the invention is not
necessarily limited thereto, since alternative embodiments and
operating techniques will become apparent to those skilled in the
art in view of the disclosure. Accordingly, modifications are
contemplated which can be made without departing from the spirit of
the described invention.
* * * * *