U.S. patent number 3,768,562 [Application Number 05/256,870] was granted by the patent office on 1973-10-30 for full opening multiple stage cementing tool and methods of use.
This patent grant is currently assigned to Halliburton Company. Invention is credited to Eugene E. Baker.
United States Patent |
3,768,562 |
Baker |
October 30, 1973 |
FULL OPENING MULTIPLE STAGE CEMENTING TOOL AND METHODS OF USE
Abstract
A full opening cementing tool particularly suitable for
cementing an oil well, and allowing the completion of as many
cementing stages as desired, utilizes a cylindrical housing, a
sliding valve sleeve within the housing, and an opening positioner
and a closing positioner located on a pipe string within the casing
for actuating the sliding valve sleeve at the appropriate times.
Other tools such as isolation packers and circulating valves may be
used advantageously in conjunction with one or more of the
cementing tools.
Inventors: |
Baker; Eugene E. (Duncan,
OK) |
Assignee: |
Halliburton Company (Duncan,
OK)
|
Family
ID: |
22973933 |
Appl.
No.: |
05/256,870 |
Filed: |
May 25, 1972 |
Current U.S.
Class: |
166/289;
166/332.1; 251/74 |
Current CPC
Class: |
E21B
33/146 (20130101); E21B 34/14 (20130101) |
Current International
Class: |
E21B
33/13 (20060101); E21B 33/14 (20060101); E21B
34/00 (20060101); E21B 34/14 (20060101); E21b
033/13 (); E21b 033/00 () |
Field of
Search: |
;166/289,224
;251/74 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leppink; James A.
Claims
What is claimed is:
1. A full opening cementing tool for multiple stage oil well
cementing comprising:
a. an outer cylindrical housing having a plurality of ports through
the wall;
b. a valve sleeve located telescopically within said housing and
having a plurality of ports through the wall capable of fluidically
communicating with said ports in said housing in a first open
position and fluidically sealed from said housing ports in a second
closed position;
c. spring tension means between said housing and said sleeve for
preventing premature or unwanted movement of said sleeve in said
housing;
d. means attached to said housing for inserting said housing into a
standard casing string;
e. first means for engaging said sleeve and moving said sleeve from
said first position to said second position; and
f. second means for engaging said sleeve and moving said sleeve
from said second position to said first position, said first and
second means for engaging said sleeve being fixedly attached to a
drill string or tubing string located concentrically within said
sleeve and telescopically movable within said sleeve.
2. The cementing tool of claim 1 wherein said tool further
comprises seal means between said housing and said sleeve arranged
to prevent fluid communication between the walls of said housing
and said sleeve, and said housing further having an inner annular
circumferential recess communicating with said ports in said
housing and an inner annular ridge having sloping walls and located
inside said housing.
3. The cementing tool of claim 2 wherein said sleeve further has a
first inner annular recess in said sleeve, having a sloping side
wall, a perpendicular side wall, and a circumferentially coaxial
wall; a second inner annular recess having a sloping side wall, a
perpendicular side wall, and a circumferential coaxial wall; a
beveled end at one end of said sleeve; a skirt at the opposite end
of said sleeve, said skirt being formed by an enlargement in the
bore through said sleeve; and an outer annular recess in said
sleeve arranged to receive said inner annular ridge in said
housing.
4. The cementing tool of claim 1 wherein said spring tension means
comprises a plurality of collet fingers located around one end of
said sleeve, an inner annular ridge on said housing, an inner
annular recess in said housing between said ridge and said means
for inserting said housing into a casing string; with said collet
fingers having an outer annular ridge adapted to abut said ridge
and fit within said recess.
5. The cementing tool of claim 1 wherein said spring tension means
comprises one or more circular rings made of an elastic metal and
located within an outer annular recess in said sleeve, said rings
adapted to project outward from said sleeve and being capable of
being contracted sufficiently to place the outer surface of said
rings flush with the outer surface of said sleeve; said housing
having two inner annular recesses having sloping walls, one of said
recesses adapted to receive said rings in a closed sleeve position
and the other of said recesses adapted to receive said rings in an
open sleeve position.
6. The cementing tool of claim 1 wherein said first and second
means for engaging said sleeve each comprises a plurality of spring
arms integrally attached to a spring collar, said spring collar
encircling and fixedly attached to a spring mandrel, said spring
mandrel containing a plurality of shielding drag lugs, one for each
said spring arm, and said spring mandrel being adapted to be
interposed between two sections of standard drill pipe or
tubing.
7. The cementing tool of claim 6 wherein said spring arms each
contain a perpendicular shoulder capable of and adapted to engage a
mating perpendicular shoulder within said sleeve and also adapted
to transmit sufficient force to said sleeve to move said sleeve
within said housing from an open to a closed position and from a
closed to an open position; and said spring arms each further
comprise an outer shoulder arranged to engage an inward projecting
shoulder in said means for inserting said housing in a casing
string, said shoulder arranged to disengage said spring arms from
said sleeve after moving said sleeve a predetermined distance.
8. Oil well cementing apparatus capable of cementing any number of
annulus cementing stages and adapted to be interposed between
sections of oil well casing comprising:
a. one or more sliding sleeve cementing valves adapted to be
interconnected within a casing string, each said valve comprising
ported sliding inner sleeve means and a ported stationary outer
housing, said sleeve valves each being movable from a closed
position to an open position and from an open position to a closed
position an indefinite number of times, each said valve adapted to
be placed one at each cementing stage location;
b. opening means adapted to be arranged axially on a drill string
or tubing string to be moved telescopically within the casing and
through said cementing valves, said opening means adapted to engage
said inner sleeve means so as to move said inner sleeve means to a
valve-open position; and
c. closing means adapted to be arranged axially on a drill string
or tubing string, to be moved telescopically within the casing and
through said cementing valves, said closing means adapted to engage
said inner sleeve means so as to move said inner sleeve means to a
valve-closed position.
9. The apparatus of claim 8 further comprising:
a. isolation packer means located on the drill string and in close
proximity to said opening and closing means;
b. circulating valve means on the drill string capable of providing
fluid communication from the interior of the drill string tubing to
the annulus between the drill string and the casing; and
c. means for sealing the bottom end of the drill string against
fluid flow therethrough.
10. The apparatus of claim 9 wherein said isolation packer means
comprises an upper packer and a lower packer, said upper packer
having two annular elastomeric cups, one said cup being concave
upward and one said cup being concave downward; said lower packer
having one elastomeric cup, which cup is concave upward and said
upper and lower packers adapted to fluidically seal off a cross
section of the casing against fluid flowing from the direction of
concavity of each said elastomeric cup.
11. The apparatus of claim 10 wherein said opening means is located
above said closing means on the drill string, said upper packer is
located on the drill string between said opening and said closing
means, said lower packer is located below said closing means on the
drill string, said circulating valve is located below said lower
packer; and said isolation packer means further comprises a tubular
mandrel body to which said elastomeric cups are attached, said
mandrel body having ports therethrough capable of communicating
fluidically between the inner bore of said tubular mandrel and the
annulus between the tubing string and the casing, said ports
located directly below said upper packer cups.
12. The apparatus of claim 11 wherein said tubular mandrel body
further comprises a packer bypass channel within the wall of said
mandrel body providing fluid communication from the annulus area
above said upper packer to the annulus area below said lower
packer, and said circulating valve means is adapted to be actuated
by remote control from ground surface to provide pressure balance
when coming out of the hole with the drill string.
13. The apparatus of claim 8 further comprising spring tension
means in said sliding sleeve cementing valves adapted to prevent
opening or closing of said valves until a certain predetermined
tensile or compressive force is applied to said inner sleeve means,
and seal means between said sleeve means and each of said housings
preventing fluid flow between the walls of said sleeve means and
said housings.
14. A method of cementing the outer casing annulus of a well bore
in any desired number of stages wherein the casing in the well bore
has a predetermined number of casing valves located in the casing
wall in preset locations therein; said method comprising:
a. flowing a precalculated quantity of cement slurry down the
interior of the well casing, out the bottom of the casing and back
up the annulus between the casing and the well bore;
b. inserting a wiper plug in the casing immediately behind said
cement slurry;
c. pumping a working fluid behind the wiper plug, said fluid having
the consistency and specific gravity near that of the cement
slurry, thereby forcing the wiper plug and cement slurry to the
bottom of the casing;
d. applying pressure to said working fluid until the wiper plug
seats in sealing engagement in the bottom of the casing thereby
causing an indicative rise in fluid pressure in the casing;
e. running in a string of tubular pipe in the well casing, said
string of pipe having an opening positioner and a closing
positioner located thereon;
f. engaging said opening positioner in the lowermost of said casing
valves and thereby opening said valve and providing fluid
communication channels between the annulus inside the casing to the
annulus outside the casing;
g. pumping a second predetermined quantity of cement slurry down
the interior of the pipe string and out the bottom end of the pipe,
whereby said second slurry flows through said casing valve and into
the second stage of the exterior casing annulus;
h. engaging said closing positioner in said lowermost casing valve
and thereby closing said valve against additional fluid flow;
i. lifting the string of pipe to the next adjacent area of the
casing to be cemented, which area contains another casing valve;
and
j. repeating said steps (f) through (i) above until all stages of
cementing in the exterior casing annulus have been completed.
15. A method of cementing the annulus between a well casing and the
well bore hole in a plurality of separate distinct stages wherein
the casing contains a casing valve for each stage to be cemented,
said casing valves being interposed between sections of casing in
predetermined locations; the method comprising the steps of:
a. inserting a string of pipe within the casing into fluidically
sealed engagement with the lower end of the casing, said string of
pipe having an internal bore passage communicating through the
bottom of the casing, said sealed engagement serving to close off
the bottom of the annulus area between the pipe and the casing,
said string of pipe also having valve opening means and valve
closing means attached exteriorly thereto;
b. pumping a predetermined quantity of cement slurry through the
pipe string inner bore, out the bottom of the casing, and up the
annulus between the casing and the well bore;
c. placing a latch-down plug in the pipe behind said cement
slurry;
d. pumping into the pipe behind said plug a working fluid having a
specific gravity similar to that of the cement slurry, thereby
forcing said plug down the pipe string into latching engagement
with the bottom of the casing, thereby effecting a seal across the
entire casing passage at the bottom;
e. lifting the pipe string partially out of the casing until said
opening means engages and opens the lowermost of said casing valves
and the bottom of the pipe string is slightly above the opened
valve;
f. pumping a second predetermined quantity of cement slurry down
the pipe bore and through the opened casing valve into the exterior
casing annulus thereby effecting a cementing of the second
stage;
g. engaging said closing means in said casing valve thereby closing
the valve;
h. lifting the pipe string to the next adjacent casing valve at the
next stage to be cemented; and
i. repeating said steps (e) through (h) above until the entire
annular area to be cemented has been cemented.
16. A method of cementing the annulus between a well casing and a
well bore hole in a plurality of distinct and separate stages
wherein the casing contains a casing valve for each stage to be
cemented, said casing valves being interposed between sections of
casing in predetermined locations; the method comprising the steps
of:
a. pumping a precalculated quantity of cement slurry down the
interior of the casing, out the bottom of the casing, and back up
the annulus between the casing and the well bore;
b. inserting a wiper plug in the casing immediately behind the
cement slurry;
c. pumping a working fluid behind the wiper plug, said fluid having
similar specific gravity to that of the cement, thereby forcing the
wiper plug and cement slurry to the bottom of the casing, forcing
all of the cement into the annulus, and sealingly engaging the
wiper plug in the bottom end of the casing;
d. running in a string of pipe in the casing, said string of pipe
containing casing valve opening means, upper isolation packer means
below said valve opening means, cementing ports through the pipe
wall below said upper packer means, casing valve closing means
below said cementing ports, lower packer means below said valve
closing means, seal means closing off the lower end of the drill
pipe, fluid bypass means providing fluid communication from the
annular area above said upper packer means to the annular area
below said lower packer means, and circulating valve means in said
pipe for providing fluid communication between the internal pipe
bore and the casing bore, and being opened only when coming out of
the hole with the pipe string;
e. engaging said valve opening means in the lowermost of said
valves in the lowermost uncemented stage thereby opening said valve
and providing fluid communication through the casing;
f. aligning said cementing ports in the pipe with said opened
casing valve;
g. pumping another predetermined amount of cement slurry into the
pipe string, out the cementing ports in the pipe below said upper
packer, and through the casing valve into the area of outer casing
annulus to be cemented during this stage;
h. engaging said closing means in said opened casing valve by
lifting up and then setting down on the pipe string sufficiently
enough to move said closing means upward and downward through said
valve, thereby closing said valve;
i. lifting the pipe string to align the opening means with the next
upper adjacent casing valve in order to accomplish the next
cementing stage; and
j. repeating the above said steps (e) through (i) until all desired
cementing stages have been completed.
17. The method of claim 16 further comprising the step of reversing
out after each cementing stage the excess cement slurry remaining
between said upper and lower packer means and in the pipe string,
said reversing out comprising pumping a working fluid into the
annulus between the pipe and casing, through the fluid bypass means
into the annular area below the lower packer means, and up past the
lower packer means, thereby forcing the excess cement through the
cementing ports in the pipe and up the bore of the pipe in front of
the working fluid.
18. The method of claim 17 further comprising the steps of opening
said circulating valve by manipulation from the surface and
removing said pipe string from the borehole.
19. A method of cementing the annulus between a well casing and a
well bore hole in a plurality of distinct and separate stages
wherein the casing contains a casing valve for each stage to be
cemented, said casing valves being interposed between sections of
casing in predetermined locations, the method comprising the steps
of:
a. running in a string of pipe in the casing, said string of pipe
containing casing valve opening means, upper isolation packer means
below said valve opening means, cementing ports through the pipe
wall immediately below said upper packer means, casing valve
closing means below said cementing ports, lower packer means below
said valve closing means, fluid bypass means providing fluid
communication from the annular area above said upper packer means
to the annular area below said packer means, and circulating valve
means in said pipe for providing fluid communication between the
pipe bore and the casing bore when said pipe string is coming out
of the well;
b. engaging said pipe string in a sealing adapter in the bottom of
the casing thereby sealing off the annulus between the pipe and the
casing while maintaining a clear passage from the bore of the pipe
through the bottom of the casing;
c. pumping a first latch plug down the pipe to sealingly engage in
the float shoe;
d. pumping a predetermined quantity of cement slurry behind the
first latch plug, down the pipe, through the bottom of the casing,
and back up the annulus;
e. inserting a second plug in the pipe immediately behind the
cement slurry;
f. pumping working fluid into the pipe behind the second plug, said
fluid having a similar specific gravity to that of the cement
slurry, thereby forcing the second plug and cement slurry to the
bottom of the pipe, forcing all of the cement into the exterior
casing annulus and sealingly engaging the second plug in the bottom
end of the pipe;
g. engaging said valve opening means in the lowermost of said
valves in the lowermost uncemented stage thereby opening said valve
and providing fluid communication through the casing;
h. aligning said cementing ports in the pipe with said opened
casing valve;
i. closing said circulating valve means;
j. pumping another predetermined amount of cement slurry into the
pipe string, out the cementing ports in the pipe and through the
casing valve into the area of outer casing annulus to be cemented
during this stage;
k. engaging said closing means in said casing valve by
appropriately manipulating the pipe string, thereby closing said
casing valve;
l. lifting up on the pipe string to bring the opening means to the
next upper adjacent casing valve in order to begin the next cement
stage; and
m. repeating the above said steps (g) through (l) until all desired
cementing stages have been completed.
20. The method of claim 19 further comprising reversing out after
each cementing stage the excess cement slurry remaining between
said upper and lower packer means and in the pipe string, said
reversing out comprising pumping a working fluid into the annulus
between the pipe and casing, through the fluid bypass means into
the annular area below the lower packer means, and up past the
lower packer means thereby forcing the excess cement through the
cementing ports in the pipe and up the bore of the pipe in front of
the working fluid.
21. A tool for passing inside a sleeve valve to selectively open
and close said sleeve valve, comprising:
a. tubular body means adapted to be connected to a string of pipe
and passed axially into the sleeve valve;
b. first collar means encircling said body means and snugly
attached thereto;
c. second collar means encircling said body means and attached
thereto, below said first collar means;
d. a plurality of first spring arms attached to said first collar
means, and adapted to engage said sleeve valve when closed and move
said sleeve valve into an open position when passing in one
direction therethrough;
e. a plurality of second spring arms attached to said second collar
means, and adapted to engage said sleeve valve when open and move
said sleeve valve into a closed position when passing in one
direction therethrough;
f. means on said first spring arms for disengaging said first
spring arms after said sleeve valve has been opened; and
g. means on said second spring arms for disengaging said second
spring arms after said sleeve valve has been closed.
22. The tool of claim 21 further comprising:
a. upper packing means comprising two upper back-to-back concave
elastomeric sealing cups located circumferentially on said tubular
body means between said first and second collar means;
b. lower packing means comprising a lower concave elastomeric
sealing cup located circumferentially on said tubular body below
said second collar means and adapted so that the concave portion of
said lower sealing cup faces said upper packing means;
c. said tubular body having cementing ports passing through the
wall thereof and located between said upper packing means and said
second collar means, in close proximity to said upper packing
means;
d. said tubular body having fluid bypass means adapted to
fluidically communicate the exterior of said tubular body above
said upper packing means to the exterior of said tubular body below
said lower packing means; and
e. means for sealing the bore passage through said tubular body,
said means adapted for sealing the ends of said tubular body below
said lower packing means.
23. The tool of claim 22 further comprising circulating valve means
located on said tubular body wall below said lower packing means
and adapted to selectively provide fluid communication from the
interior of said tubular body to the exterior of said tubular body.
Description
BACKGROUND OF THE INVENTION
In preparing oil well boreholes for oil and/or gas production a
most important step involves the process of cementing.
Basically, oil well cementing is a process of mixing a cement-water
slurry and pumping it down through steel casing to critical points
located in the annulus around the casing, in the open hole below,
or in fractured formations.
Cementing a well protects possible productive zones behind the
casing against salt water flow and protects the casing against
corrosion from subsurface mineral waters and electrolysis from the
outside.
Cementing eliminates the danger of fresh drinking and recreational
water supply strata from being contaminated by oil or salt water
flow through the bore hole from those types of formations. It
prevents oil well blowouts and fires caused by high pressure gas
zones behind the casing and in addition prevents the collapsing of
the casing from high external pressures building up
underground.
A cementing operation for protection against the above described
downhole conditions is called primary cementing. Secondary
cementing includes the cementing processes used on a well during
its productive life and includes remedial cementing and repairs to
existing cemented areas.
The present invention is directed primarily to the first type of
cementing operation, primary cementing.
In the early days of oil field production when wells were all
relatively shallow, cementing was accomplished by flowing the wet
cement slurry down the casing and back up the outside of the casing
in the annulus between the casing and the borehole wall.
As wells were drilled deeper and deeper to locate petroleum
products it became difficult to cement the entire well
satisfactorily from the bottom of the casing and multiple stage
cementing was developed to allow the annulus to be cemented in
separate stages, beginning at the bottom of the well and working
up.
This process was achieved by placing cementing valves in the casing
or between joints of casing at one or more locations in the
borehole, flowing through the bottom of the casing, up the annulus
to the lowest valve in the wall, closing the bottom and then
flowing through the valve to the next higher valve, then repeating
until the cement reached the uppermost annulus region to be
cemented.
There are prior art devices available today which can be used to
perform a successful three-stage cementing operation. With
modifications and under certain conditions, it is even possible to
obtain a four-stage cementing operation with these types of
cementing tools.
There are several types of devices known as "multiple stage
cementing tools" which may be used for introducing cement slurry
into the outer annular space from within the casing at any desired
location along the casing. These tools, which are interposed in the
string of casing at each such desired location, have covered ports
which are exposed for discharging cement slurry into the annular
space and then subsequently covered back up.
The exposing and covering steps are generally accomplished by
dropping or pumping a pair of plugs, or other type devices down the
well casing, the first of which engages a lower sleeve within the
cementing tool and exposes the ports, and the second of which
engages an upper sleeve which covers the ports. These plugs are
retained within the cementing tool so that it is first necessary to
drill them out before regaining access to the casing below each
such tool.
What the prior art has needed has been a full-opening cementing
tool capable of performing an unlimited number of cementing stages
in a deep well. Such a tool is disclosed in the present invention
and comprises one or more ported cylindrical housings interposed in
the casing string, a valve sleeve telescopically located in a
recessed area in each housing and capable of opening and closing
the ports in the housing for cement flow, and an opening positioner
and closing positioner to be used on a drill string in conjunction
with the closing sleeves and the housings. In addition, the use of
this invention can be advantageously coupled with one or more
cementing plugs, isolation packers, and circulating valves.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional side view of the full opening cementing
tool.
FIG. 2 is a partial cross-sectional side view of the opening
positioner.
FIG. 3 is a partial cross-sectional side view of the closing
positioner.
FIG. 4 is a cross-sectional axial view of the opening and closing
positioners of FIGS. 2 and 3.
FIG. 5 shows a schematic view of a drill string setup containing
the opening and closing positioners for use with the sleeve valve
of the cementer.
FIG. 6 is a schematic view of a drill string containing the opening
and closing positioners, isolation packers, and a circulating
valve, all for use with the sleeve valve cementer.
FIGS. 7 through 10 are schematic views of the full opening
multi-stage cementer of this invention in operation with several
different types of associated apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
I. SLIDING SLEEVE VALVE
Referring to FIG. 1, the cementing tool 1 comprises an outer
cylindrical housing 2, an inner valve sleeve 3 telescopically
mounted within the housing 2, and upper body 4 and lower body 5.
Housing 2 has one or more cementing ports 6 through the wall in the
area where valve sleeve 3 is slidably located. Valve sleeve 3 has
matching cementing ports 7 through the wall arranged so that the
ports 7 will align with ports 6 when sleeve 3 is in its uppermost
position within housing 2 which, in the drawing, would be in the
left portion of housing 2 abutting shoulder 8 of upper body 4. In
the open sleeve position of the uppermost position, shoulder 9 of
sleeve 3 abuts shoulder 8.
Valve sleeve 3 and housing 2 have appropriate inner and outer
diameters so that sleeve 3 fits just loosely enough within housing
2 to allow it to slide in housing 2 and sleeve 3 has substantially
the same inner diameter as that of the standard casing being used,
thus providing a full opening tool.
Housing 2 may be fixedly attached and fluidically sealed to upper
and lower bodies 4 and 5 by threaded connections 10 and 11
respectively, and welds 12 and 13 respectively.
Housing 2 also contains a wide flat inner annular ridge 14 having
sloping shoulders 15 and 16 at its top and bottom respectively.
An inner annular recess 17 runs circumferentially around the
interior wall of housing 2 intersecting ports 6 therein. A
corresponding outer annular channel 18 runs circumferentially
around the exterior of sleeve 3 in the area of and intersecting
ports 7 therein. When the tool is assembled, ports 7 are placed in
exact alignment with ports 6, but is is contemplated that rotation
of sleeve 3 may occur within housing 2; and ports 6 and 7, while
being in the same diametral plane, might still not allow cement to
flow. Thus, recess 17 and channel 18 allow fluid communication
through ports 6 and 7 should these ports not be exactly in line
when sleeve 3 is moved to its open position abutting shoulder
8.
Sleeve 3 is provided with inner annular recesses 19 and 20 for
engagement with the opening positioner 40 (see FIG. 2), and closing
positioner 60 (see FIG. 3). Recess 19 has a perpendicular shoulder
21 and a sloping shoulder 23. Recess 20 has perpendicular shoulder
22 and sloping shoulder 24. Sleeve 3 also has an annular
enlargement 25 at its lower end consisting of outwardly sloping
shoulder 26 and skirt 27. In addition, sleeve 3 is provided with a
broad, shallow external annular recess 28 in which annular ridge 14
may fit as shown in FIG. 1. Recess 28 is defined by sloping faces
29 and 30 and longitudinal face 31.
Recesses 32 can be provided in the outer face of sleeve 3 to
contain seal rings 33 which sealingly contact housing 2 and prevent
fluid communication between housing 2 and sleeve 3. Sleeve 3 also
has beveled edges 34 and 35 at its upper and lower ends to
facilitate movement of the opening and closing positioners 40 and
60 through it. Upper body 4 also has beveled edges 36 and 37 to
provide easy movement therethrough and lower body 5 has a beveled
edge 38 for easier passage of a tool string therethrough.
Recess 39 is cut in sleeve 3 to allow an O-ring seal 41 or other
appropriate annular seal to be placed between housing 2 and sleeve
3 below ports 7 to prevent fluid flow between the housing 2 and
sleeve 3.
Collet fingers 42 are formed around the bottom circumference of
sleeve 3 by machining equi-spaced slots 43 longitudinally in skirt
27 of sleeve 3. This provides a spring clip effect on the skirt 27
through the spring ability of each finger 42.
Recess 31 in sleeve 3 extends partially along each finger 42 and
defines at shoulder 30 a ridge-like ring 44 remaining on skirt 27
and on each finger 42. Sloping face 30 on ridge 44 abuts sloping
face 16 on ridge 14 and prevents premature opening of cementing
valve 1 which would occur by movement of sleeve 3 upward in housing
2.
The spring force holding sleeve 3 in the lowermost position in
housing 2 can be adjusted by adjusting the spring tension of
fingers 42. This can be done by machining larger or smaller slots
43 in skirt 27, or by making fingers 42 thicker or thinner by
changing the machined size of enlargement 25. Thus, sleeve 3 can be
prevented from sliding until a preset force is applied to the
sleeve, which force will overcome spring tension in fingers 42. In
this specific embodiment, opening tension is set at 20,000 pounds
force.
Fingers 42 also have an external bevel at their exposed end which
defines face 45 on each fingers 42. When the cementing tool 1 is in
the fully opened position with sleeve 3 at its uppermost point,
lining up ports 6 with ports 7, face 45 will be above shoulder 15
and in close relationship to it. The abutment of these two faces
together prevents premature or unwanted closure of the cementing
tool. The same force required to overcome collet finger 42 to move
sleeve 3 upward from its closed position will be required to move
it downward out of its open position.
II. THE OPENING AND CLOSING POSITIONERS
Referring now to FIG. 2, disclosed is a preferred embodiment of the
opening positioner 40 for engaging and moving sleeve 3 from a
closed position in housing 2 to an open position, whereby ports 6
are lined up with ports 7 and fluid communication can occur between
the inner bore portion 46 of sleeve 3 to the exterior of housing
2.
Opening positioner 40 consists primarily of mandrel body 47 which
contains a plurality of spring arms 48 fixedly attached to spring
collar 49 which encircles mandrel body 47 and fits snugly against
annular shoulder 50 on body 47.
Attached to mandrel body 47 by threaded connection 53 is upper
adapter 51 which abuts spring collar 49 at shoulder 52 of adapter
51 and which serves to hold collar 49 firmly and snugly against
shoulder 50.
Below arms 48 on body 47 are located a plurality of drag lugs 54
projecting outward from body 47 and having sloping faces 55, and
aligned longitudinally one with each arm 48.
At the lower end of body 47 is lower adapter 56 which is an
internally and externally threaded collar-like adapter attached to
body 47 by matching threads 57. Adapters 51 and 56 are inserted in
a standard tubing or drill string and connected to the tubing ends
by threads 58 and 59 respectively. Circular seals 61 and 62 are
positioned in recesses 63 and 64 respectively, to provide a fluid
tight seal between the body 47 and the upper and lower adapters 51
and 56 respectively.
Located on each spring arm 48 is a shoulder 65 in which is imbedded
one or more carbide buttons 66.
Shoulder 65 has sloped surfaces 67 and 68 which act as wedges to
drive arm 48 down when contacting projections in sleeve 3.
Shoulders 65 act as centralizers for the positioner 40 and keep it
centered in the casing. Buttons 66 reduce friction wear on the
positioner.
Arms 48 also have a perpendicular shoulder 69 which engages a
corresponding perpendicular shoulder 21 in sleeve 3 and allows
sleeve 3 to be pulled up into the open position by lifting up on
the drill string containing the opening positioner 40.
Tips 70 located at the free end of arms 48 project inwardly towards
the axis of the opening positioner 40 and are located on a smaller
radius than the outer surface of drag lugs 54. Thus drag lugs 54
provide a centering and shielding function for arms 48 as the
positioner 40 enters the sleeve 3. Sloping face 71 of the lower end
of arm 48 provides a wedging action which pushes down on arm 48
when an inner projection in sleeve 3 is encountered, allowing the
positioner to travel downward through sleeve 3 relatively
unimpeded.
Arms 48 are thus arranged so that, on downward movement through the
sleeve 3, no part of the arm will engage the sleeve sufficiently
enough to move the sleeve downward and overcome the spring tension
of collet fingers 42 on flat annular ridge 14. Thus, downward
movement of opening positioner 40 has no effect on cementing valve
1, and positioner 40 can pass downward entirely through sleeve 3
without changing its porting orientation.
Shoulder 65 on arm 48 also serves the function of a releasing cam
when arm 48 is engaged in sleeve 3 and has moved sleeve 3 to the
uppermost position in housing 2, thereby opening ports 6 and 7. In
order that the opening positioner 40 may be pulled out of sleeve 3
after the sleeve has been opened, shoulder 65 is located on arm 48
so that when sleeve 3 is at the top of its travel, shoulder 65
abuts beveled edges 37 and 36 which drives shoulder 65 and arm 48
inward, disengaging shoulder 69 of arm 48 from shoulder 21 of valve
sleeve 3.
Referring now to FIG. 3, the closing positioner 60 is illustrated.
The closing positioner contains the identical parts of the opening
positioner but with a differnt orientation.
The closing positioner has upper adapter 72, lower adapter 73,
mandrel body 74, spring arms 75, spring collar 76, and drag lugs
77. The only difference between the closing positioner 60 and the
opening positioner 40 is that the mandrel body, containing the
spring arm and spring collar assembly, has been removed from the
upper and lower adapters, rotated end for end 180.degree., and
reconnected to the adapters. The spring arms 75 of closing
positioner 60 point upward whereas the arms 48 of opening
positioner 40 point downward. Spring arms 75 have an actuating
shoulder 78 near the tips 79 of the arms. This perpendicular
shoulder 78 is arranged to engage shoulder 22 of sleeve 3 as the
closing positioner moves downward through the opening cementing
tool 1. The abutment of shoulder 78 against shoulder 22 in the
sleeve 3 allows the sleeve to be pushed down into its closed
position from the open position. When the sleeve reaches the closed
position, shoulder 80 with sloping surfaces 81 and 82, engages
beveled surface 38 of lower body 5 which provides a wedging action
forcing spring arms 75 inward, toward mandrel 74, and out of
engagement with sleeve 3 at shoulder 22.
Shoulder 80 also has friction buttons 83 on its outer surface to
prevent drag and unnecessary wear on the spring arms. Drag lugs 77
also shield arms 75 as do lugs 54 for spring arms 48 on opening
positioner 40. Seals 84 prevent fluid communication between the
joined parts.
Referring now to FIG. 5, opening positioner 40 is adapted to be
placed in a drill string by threading it between two standard
joints of tubing. The closing positioner 60 is placed in the drill
string also, below the opening positioner and can be any desired
distance below the opening positioner depending upon the length of
tubing placed between them.
III. ASSOCIATED APPARATUS
Apparatus which is advantageously utilized with the cementing tool
of this invention, as illustrated in FIG. 6, and FIGS. 7 through
10, includes a circulating valve 90 located on the exterior of a
drill string or tubing string 89 and slidably movable on the drill
string to open and close ports 88 which pass through the wall of
the drill string 89 and provide fluid communication between the
interior bore 87 of the drill string and the annulus 86 between the
casing 85 and the drill string 89. Circulating valve 90 can be any
one of the commercially available valves suitable for such use and
which can be actuated from the surface when desired.
Also particularly useful with this tool under certain cricumstances
are isolation packers 91 and 92. Packer 91 is the upper packer and
comprises sealing cups 93 and 94 which are circular cups made of an
elastomeric material which is capable of sealingly engaging the
interior of casing 85. Cup 93 on packer 91 is facing upwards and is
capable of sealing flow of fluids in a downward direction, which
downward flow presses into cup 93 and spreads it out into sealing
contact with the casing 85. Cup 94 is concave downward and suitable
for sealing against upward flow in the same manner as cup 93 seals
against downward flow.
Packer 92 primarily comprises only one elastomeric cup which is
arranged concave upward for preventing downward flow thereby.
Packer 92 does not prevent upward flow past it through the annulus
86.
FIGS. 7 through 10 illustrate other equipment which is used with
the multi-stage cementing tool 1, including a standard cementing
plug 95 with a plurality of circumferential elastomeric wiper cups
96 located on the plug. Also utilized is a standard commercially
available cementing shoe 97 having a common check valve arrangement
98 in the passage therethrough. Cementing shoe 97 is fixedly
attached to the casing 85 at its lowermost edge. Cementing plug 95
is designed to pass snugly within casing 85 and is used to separate
two different types of fluids, drilling fluid and cement, and also
wipes the interior of the casing clean as it passes down the
casing.
Another system, as shown in FIG. 8, uses a different type
latch-down plug 99. This plug is designed to pass down the drill
string rather than the casing and is therefore necessarily of
smaller diameter. The latch-down plug 99 contains elastomeric wiper
collars 100 just as does plug 95.
Sealing adapter 101 is located on the lower end of the tubing 89
and serves to retain latch-down plug 99 within tubing 89 and
fluidically seal off the bottom end of the tubing.
The corresponding apparatus to seal off the tubing when cementing
plug 95 and packers 91 and 92 are used in the casing is bull plug
102 which sealingly plugs the bottom end of tubing 89 and is passed
down the drill string or tubing at the desired instant and seats at
the bottom of the drill string thereby sealing it off.
IV. METHODS OF OPERATION
Referring now to FIG. 7, a simple method of operating the present
invention is to cement the first or lower stage through the casing
with the drill string out of the hole. One or more of the cementing
tools 1 will have been placed in the casing string in their closed
state at the desired cementing points for the different stages,
before the casing was placed in the well. A cementing shoe 97 was
placed on the lowermost section of casing.
The lower stage of the annulus is then cemented by flowing a
precalculated amount of cement slurry down the casing, through the
shoe 97 and up the annulus 106. A plug 95 is placed in the casing
at the end of cement flow and then working fluid is flowed into the
casing behind plug 95, forcing all cement in the casing ot flow
through the shoe and into the annulus. When plug 95 seats in sh e
97 and seals off the passage therethrough, valve 98 prevents
backflow of cement through the shoe. Immediately after plug 95
seats, pressure in casing 85 starts to rise sharply, indicating to
the operator at the surface that the first stage of cementing is
completed, and the second stage is ready to begin.
The drill string or tubing 89 containing the opening positioner 40
and the closing positioner 60 is then placed into the casing and
lowered until the closing positioner 60 and the opening positioner
40 have passed through the lowermost cementing tool 1. During the
running in of the drill string 89 the inner bore 87 of the drill
string remains open to allow fluid to flow upward into the drill
string as it goes into the casing, thereby facilitating placement
of the drill string in the casing.
After the opening positioner 40 has passed downward through the
closed cementing tool 1, the drill string is then picked up just
enough to pull the opening positioner 40 through the valve sleeve
3. As it passes upward through the valve sleeve, the opening
positioner engages the valve sleeve by abutment of positioner
shoulder 69 against sleeve shoulder 21 which allows the required
lifting force to be applied to valve sleeve 3 overcoming spring
tension in collet fingers 42 and moving the valve sleeve upward
until ports 7 are in alignment with ports 6. At this moment
shoulders 65 on spring arms 48 engage beveled edges 37 and 36
pushing the spring arms down, and disengaging shoulder 69 from
shoulder 21.
The sleeve valve 3 is then held snugly in the open position by
collet fingers 42 abutting shoulder 15. The drill string and
closing positioner 60 can then be withdrawn from the sleeve until
the lower end of the drill string is approximately even with ports
7 and 6. Cement is pumped down the drill string and through ports 7
and 6 into the annulus area 106 to be cemented during this second
stage.
The working fluid, which for instance could be drilling fluid,
remaining in the casing from below the drill string down to the top
of cementing plug 95, acts as a fluid cushion which directs the
cement slurry through the ports 7 and 6 instead of down the casing.
Only a negligible amount of the cement slurry will mix with or
enter the working fluid and this will settle harmlessly to the
bottom.
After the second stage of cementing is completed, the drill string
is set down enough to pass closing positioner 60 through the sleeve
3 without allowing opening positioner 40 to also pass through. In
order to facilitate this, when the frill string was assembled at
the surface, a sufficient length of drill pipe was placed between
the opening positioner 40 and the closing positioner 60. For
instance, a 30-foot section would normally be sufficient.
As the closing positioner 60 passes downwardly through the valve
sheet 3, the actuating shoulder 78 engages shoulder 22 in the
sleeve which allows a sufficient amount of force to be applied to
sleeve 3 to overcome the tension in collet fingers 42 and move
sleeve 3 to a closed position. This closing movement is felt at the
surface as a sharp jerk as the collet fingers release and allow the
sleeve to drop a short distance and then stop abruptly. The drill
string can then be lifted to the third cementing stage, if any, or
removed from the well if desired. Thus it is obvious that as many
stages of cementing as desired can be accomplished with this
method, merely by inserting the desired number of cementing tools 1
in the casing string and appropriately maneuvering the drill string
or tubing containing the opening and closing positioners.
It should be noted that it may be advantageous to temperarily
attach sleeve 3 to housing 2 by shear means to prevent premature
opening of the sleeve when going into the hole or when performing
operations other than cementing. When it is desired to open the
tool, the shear means can then be sheared by applying sufficient
additional lifting force over that required to contract collet
fingers 42, to shear the means and allow sleeve 3 to move
upward.
It is also emphasized that with the valve sleeve 3 in a closed
position, closing positioner 60 can pass downward through the
sleeve relatively unhindered due to the fact that beveled edge 38
of the lower body 5 engages shoulders 80 on spring arms 75, pushing
the arms down and preventing engagement of shoulder 78 with
shoulder 22 in sleeve 3.
FIG. 8 involves a modification of the method of cementing shown in
FIG. 7. In this method all cementing, including the first stage, is
performed through the drill string and the cement slurry never
comes in contact with the inside of the casing.
In FIG. 8 a drill string is lowered into the casing to be cemented.
The drill string contains a sealing adapter 101 at its lower end
for contacting and fluidically sealing the drill string to the
cementing shoe 97. After the drill string is lowered into sealing
contact with the cementing shoe 97, a predetermined amount of
cement slurry is pumped down the drill string, out shoe 97, and
into the annulus 106 around the casing 85. A latch-down plug 99 is
placed behind the cement slurry and working fluid is pumped in
behind the plug to insure that the entire charge of cement is
delivered to the desired annulus area. Latch-down plug 99 has wiper
collars 100 made of elastomeric material and designed to clean the
drill string inner surface of cement slurry.
After the first stage of cement has flowed through shoe 97,
latch-down plug 99 engages and latches to shoe 97 and seals its
passageway off. This indicates to the surface by the rapidly
increasing drill string pressure that the first stage is cemented
and then the following stages can be completed as described in the
method above in conjunction with FIG. 7.
Referring now to FIG. 9, another method of using the cementing tool
of this invention for multi-stage cementing is illustrated. This
method is advantageous for cementing when the annulus around the
casing does not contain fluid all the way to the surface. Under
those circumstances the fluid in the annulus outside of the casing
becomes balanced with the fluid between the casing and the drill
string by flowing out of the inner annulus 86 in the casing and
into the outer annulus 106. Thus when a cement slurry is flowed out
of the drill string and into the casing it will pass up the inside
of the casing as well as passing through the cementing tool and
into the outer annulus.
This will result in as much cement in the inner annulus 86 between
the drill string and casing as there is in the outer annulus 106
exterior of the casing. Normally the inner annulus is full of fluid
which prevents cement from passing up the inner annulus and forces
it into the outer annulus, and the outer annulus is full of working
fluid also.
Under some conditions, such as encountering a lost circulation
formation, the outer annulus fluid may have flowed into a cavity or
porous permeable formation, leaving the outer annulus partially or
completely empty.
Use of the cementing tool of this invention in conjunction with the
bull plug, isolation packer and circulating valve as disclosed in
FIG. 9, allows a multistage cementing operation to be performed
when the outer annulus can not be filled with working fluid.
In operation, the first stage of cementing is accomplished through
the casing without having the drill string in the hole. A
premeasured quantity of cement slurry is pumped into the casing
followed by a cement plug 95 which separates the cement from the
working fluid and also wipes the interior casing wall clean of
cement. Working fluid is pumped into the casing behind plug 95
until all of the cement is forced out through cementing shoe 97 and
up the outer annulus. At this point, plug 95 seats in shoe 97,
sealing off the passage therethrough and indicating to the operator
at the surface that the second stage is ready to begin.
Then the drill string is run in the casing to begin the subsequent
cementing stages. Circulating valve 90 is in the closed position
when running in the hole. A by-pass 105 is provided in the
isolation packer to allow fluid to flow around the sealing cups of
packers 91 and 92, and through by-pass channel 105 as the drill
pipe string is lowered or raised in the hole. Fluid can enter the
drill pipe string since it is free to flow past the lower sealing
cup 92 and into the drill pipe through the port hole 103 connecting
the interior of the drill pipe to the outside of the isolation
packer between the two sets of sealing cups of packers 91 and 92.
This will allow the drill pipe to fill as it enters the hole
thereby cancelling the natural tendency of the pipe to be buoyant
in the heavy working fluid. Fluid could not otherwise enter the
drill string because of bull plug 102 sealing the bottom end of the
drill string.
The drill string is lowered in the casing far enough to pass
through the cementing tool 1 at the next stage to be cemented. The
lower packer 92, closing positioner 60, upper packet 91,
circulating valve 90, and opening positioner 40 all pass downward
through the cementing tool 1, which is initially in the closed
position. The drill string is then lifted sufficiently to bring the
opening positioner 40 into engagement with valve sleeve 3 thereby
opening it and aligning ports 6 and 7. Closing positioner 60 is
also drawn up through the cementer 1 but the lower packer 92 is
not. Circulating valve 90 is then closed and cementing of the
second stage is achieved by flowing cement slurry down the drill
string and out one or more ports 103 in packer mandrel 104 of upper
packer 91 The cement slurry is prevented from traveling up the
inner annulus 86 by packer 91 and from traveling down the inner
annulus by packer 92.
After the predetermined amount of cement has been pumped into the
annulus 106 in the second stage, the drill string is set down
enough to pass the closing positioner 60 through the cementing tool
1, thereby engaging sleeve 3 and moving it downward into the closed
position. Excess cement remaining in the drill string and in the
section of inner annulus between the packers is then reversed out
by pumping working fluid down the inner annulus 86, through bypass
channel 105 in the isolation packer mandrel 104, into the inner
annulus below lower packer 92, up past packer 92 forcing the excess
cement back through ports 103, and into the drill string bore 87
where it is carried by the working fluid to the surface and out of
the string.
FIG. 10 illustrates a method of cementing all stages including the
first stage through the drill string 89 when the outer annulus is
not filled with fluid as was the case in FIG. 9. In this operation
the drill string is run in the casing until it seats on the
cementing shoe 97 and is fluidically sealed by sealing adapter 101
which may be initially attached to either the drill string or the
cementing shoe. The drill string contains the same elements as did
the drill string of FIG. 9 except for bull plug 102 which is not
needed in this operation.
Cement is then pumped through the drill string in a predetermined
amount and out through shoe 97 into the outer annulus 106. When the
desired amount of cement has been pumped into the drill string, two
latch plugs 107 and 108 are placed in the drill string behind the
cement and working fluid is pumped in behind the first latch plug
107.
As the two latch down plugs 107 and 108 are pumped down the drill
pipe string, the first plug 107 latches into the top of the float
collar or float shoe to provide a second back pressure valve in
addition to the float shoe or collar. If the fluid level in the
hole is low, this latch down plug will also prevent the overbalance
of fluid inside the drill pipe from flowing downward through the
float shoe forcing the cement up the casing annular area beyond the
casing shoe area where it is imperative that you have
uncontaminated, durable cement. This plug also signals the surface
by rising drill string pressure that the first stage of cement is
completed and the second stage is ready to begin. The second latch
down plug 108 can be entered in the drill pipe string immediately
behind the first plug or after the first plug has landed in the
float shoe or collar. The drill pipe will be raised to break the
seal with the float collar; thereby, allowing the second plug to be
pumped to a shut off in the end of the drill pipe string sealing
off the passage of fluid therethrough. The inside diameter of the
latch down seat in the end of the drill pipe is necessarily larger
than the inside diameter of the latch down seat provided in the top
of the float collar or shoe.
The drill string is then lifted up through the cementing tool 1 at
the next stage to be cemented and the method is continued identical
to the second stage cementing of the method of FIG. 9. Latch plug
108 remains in the drill string 89 and serves the same purpose as
bull plug 102 in FIG. 9. The process is repeated for each
additional cementing stage until the cementing is entirely
completed.
Thus by the use of the methods and apparatus of this invention, a
smooth, uniform, homogeneous sheath of cement can be applied to the
outer annulus in a casing lined well bore thereby overcoming the
difficulties of the prior art.
Although a specific preferred embodiment of the present invention
has been described in the detailed description above, the
description is not intended to limit the invention to the
particular forms or embodiments disclosed herein, since they are to
be recognized as illustrative rather than restrictive and it will
be obvious to those skilled in the art that the invention is not so
limited. For example, hollow cementing plugs could be used in the
above described invention rather than the solid plugs, which have
to be inserted into the pipe from the top. The hollow plugs would
be placed in the casing and drill string prior to being inserted in
the bore hole and could be activated by dropping balls or plugs
into seats in the hollow plugs, pressuring up the tubing and
shearing the shear pins holding the cementing plugs in place. It
would also be possible to alter the distance between the opening
and closing positioners to gain more latitude in the lifting up and
setting down steps of the operation.
It is further contemplated that instead of collet fingers on the
lower end of valve sleeve 3, one or more circular rings could be
placed around the sleeve in grooved channels in the sleeve, which
rings would project outward from the vlave sleeve wall and act as
spring clips sliding in and out of matching sloped wall grooves in
the housing 2, as sleeve 3 moved up and down in the housing. The
spring constant of the rings could be preset to prevent premature
or unwanted movement of sleeve 3 in housing 2. The invention is
declared to cover all changes and modification of the specific
example of the invention herein disclosed for purposes of
illustration, which do not constitute departures from the spirit
and scope of the invention.
* * * * *