U.S. patent number 3,776,250 [Application Number 05/243,726] was granted by the patent office on 1973-12-04 for float collar with differential fill feature.
This patent grant is currently assigned to Halliburton Company. Invention is credited to Lloyd C. Knox.
United States Patent |
3,776,250 |
Knox |
December 4, 1973 |
FLOAT COLLAR WITH DIFFERENTIAL FILL FEATURE
Abstract
A valved collar for allowing a pipe string to fill up as it is
lowered in a bore hole while controlling the rate of fill up
through a differential fill feature, utilizes a valve plunger in a
valve body with the plunger opening against spring means and having
an elastomeric collar intermediately located on the plunger shaft
for allowing fill up to occur above a predetermined differential
pressure.
Inventors: |
Knox; Lloyd C. (Duncan,
OK) |
Assignee: |
Halliburton Company (Duncan,
OK)
|
Family
ID: |
22919879 |
Appl.
No.: |
05/243,726 |
Filed: |
April 13, 1972 |
Current U.S.
Class: |
137/71; 166/320;
137/512.3 |
Current CPC
Class: |
E21B
21/10 (20130101); F16K 15/063 (20130101); Y10T
137/7842 (20150401); Y10T 137/1789 (20150401) |
Current International
Class: |
F16K
15/06 (20060101); F16K 15/02 (20060101); E21B
21/10 (20060101); E21B 21/00 (20060101); F16k
015/06 (); E21b 033/00 () |
Field of
Search: |
;137/68,71,515,512.3
;166/224,225 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schwadron; Martin P.
Assistant Examiner: Gerard; Richard
Claims
What is claimed is:
1. Valve apparatus for controlling flow and backflow of a fluid
through a pipe string in a well during run-in and cementing
operations, comprising:
a. tubular body means having a bore passage therethrough;
b. valve seat means within said tubular body;
c. first valve member means located movably within said body
adapted to seat in said valve seat means in fluidically sealed
engagement, and having a longitudinal axial valve stem attached
thereto;
d. valve guide means slidably enclosing a portion of said valve
stem and allowing longitudinal movement of said valve stem
therethrough, said valve guide means being connected to said
tubular body;
e. spring means between said first valve member means and said
valve guide means, said spring means arranged to bias said valve
member means towards said valve seat means;
f. means dividing the bore passage through said tubular body means
into an upper chamber, a lower chamber and a lower bore passage,
said upper chamber containing said first valve member means and
said spring means;
g. port means through said dividing means communicating said upper
chamber with said lower chamber;
h. resilient second valve member means located within said lower
chamber and arranged to control fluid flow to and from said upper
chamber through said port means and said lower chamber from said
lower bore passage; said second valve member means further
comprising a resilient elastomeric sleeve having an extended sleeve
portion capable of being compressed into a shorter bulging member,
and having one or more annular exterior shoulders capable of
sealingly engaging the inner wall of said lower chamber and closing
off said lower chamber to fluid flow therethrough; said sleeve
providing an opening bias for said exterior shoulders;
i. means for holding said second valve member means in said lower
chamber and holding said second valve means against movement to a
full open position and for further preventing said first valve
member means from seating in said valve seat means; and
j. frangible means between said holding means and said valve stem
and arranged to selectively release said holding means thereby
allowing said first valve means to move upward sufficiently enough
to seat in said valve seat means, and simultaneously allowing said
second valve means to move downward allowing full fluid
communication between said upper chamber, said lower chamber, and
said lower bore passage.
2. The apparatus of claim 1 wherein said resilient second valve
member means further comprises a thin rigid retainer member adapted
to transmit compressive forces to said elastomeric sleeve; and said
elastomeric sleeve is further adapted to compress enough under a
predetermined differential pressure to move said annular exterior
shoulders a sufficient distance to expose said port means to said
lower bore passage.
3. The apparatus of claim 1 wherein said tubular body means further
comprises a tough metallic outer housing, a drillable inner housing
located concentrically and centrally within said outer housing and
spaced a predetermined distance therefrom and a drillable composite
material between said inner housing and said outer housing.
4. The apparatus of claim 3 wherein said outer housing is made of
steel; said inner housing is comprised of an upper body removably
connected to a lower body, both made of high strength drillable
plastic; and said composite material comprises drillable concrete
which was flowed in wet slurry form into the space between said
inner housing and said outer housing and allowed to harden.
5. The apparatus of claim 1 wherein said first valve members means
comprises a plunger head having a conical surface adapted to seat
in said valve seat means in sealing engagement and said valve stem
further comprises an upper stem and a lower stem assembly, said
upper stem being connected to said plunger head and said lower stem
assembly being fixedly attached by removable connector means to
said upper stem, said lower stem assembly further comprising an
inner rod member attached to said removable connector means and
having an enlarged lower end defining an annular perpendicular
shoulder, and a tubular case telescopically mounted over said rod
member and attached thereto by said frangible means, said case
having an inner annular shoulder projecting inward arranged to abut
said annular perpendicular shoulder upon shearing of said frangible
means.
6. The apparatus of claim 5 wherein said first valve means further
comprises an elastomeric cover located on said plunger head and
adapted to contact said valve seat means and provide sealing
engagement between said plunger head and said valve seat means, and
said elastomeric cover further comprises an annular lip extending
past said plunger head periphery and adapted to receive fluid
back-flow and provide further sealing arrangements with said valve
seat means.
7. The apparatus of claim 1 wherein said valve guide means is
connected to said tubular body means by one or more vane members
attached to said valve guide means and said tubular body means;
said vane members serving to define said port means by their
passage through the space between said valve guide means and said
tubular body means.
8. The apparatus of claim 7 wherein said valve guide means further
comprises a generally cylindrical collar arranged to encircle said
valve stem in slidable relationship and having an upper portion
extending above said vane members, said upper portion adapted to
receive said spring means in abutting relationship.
Description
BACKGROUND OF THE INVENTION
In preparing an oil well bore hole for production, it is desirable
to run in a string of casing and cement the space between the
casing and the bore hole. Usually, the bore hole contains some
fluid which must be partially displaced by the casing when
running-in. If the fluid is not allowed to flow into the casing as
it goes into the hole, the casing will become completely buoyant
after reaching a certain depth and further insertion of the casing
becomes increasingly difficult and dangerous. If the casing is
inserted into the fluid far enough the hydrostatic pressure on it
could cause collapse of the casing.
To prevent this buoyancy effect and possible casing collapse, it
has long been the practice to place at or near the bottom of the
casing string a valved collar or shoe which allows the fluid to
flow into the casing as it is being run-in.
The difficulties encountered in this type of tool have been to
develop a valve that would allow the fluid to flow into the casing
at a precontrolled rate during running-in, then allow the fluid to
be pumped out of the casing after it is in place and also allow
cement slurry to be pumped down the casing and back up the annulus
between the casing and the bore hole, with the valve then being
capable of sealing off the casing so that none of the cement slurry
can backflow out of the annulus and back into the casing.
After the cementing operation the float collar must act as a back
pressure valve while during the running-in of the casing it must
act just the opposite and serve as a self-fill valve, allowing
fluid to flow into the casing. Thus, several valves whch are
seemingly incompatible are required in carrying out casing
placement, cementing and related operations. One conventional
method of controlling the flow in a well casing is to use plug
members or balls which are dropped through the casing string to
trip a valve or seat in a valve to open or close it. It is clear
that if such valves are used, it would be necessary to have a clear
passage through the entire casing string to permit the plug members
or balls to pass down through the casing to the valves near the
bottom. If intermediate tools are inserted in the casing string,
such as multiple stage cementing tools or packers, then the use of
plugs or balls to operate valves below these tools may be awkward,
or even impossible.
An obvious disadvantage of other prior art devices is their
tendency to allow an inrush of fluid through the casing, which
fluid usually shoots to the surface causing a dangerous, slippery
situation in the drilling area, contaminating the rig floor and
everyone in the general area of the well.
Devices which are able to perform these functions are disclosed in
U. S. Pat. No. 3,385,370 and 3,385,372. Although these tools offer
specific advancements in the art, the present invention is an
improvement thereover, providing a differential fill feature and
more dependable operation.
The present invention, unlike the prior art devices, allows fluid
to flow into the casing regardless of how high the pressure
differential may be between the annulus and the casing bore. This
obviates the necessity of filling the casing with fluid from the
top in order to open the self-fill valve when the casing has been
run-in too quickly and built up too high a differential pressure
between the casing and the annulus.
The prior art devices also lack a satisfactory means of circulating
downward through the self-fill valve without causing the self-fill
valve to transform into the back-flow valve until desired.
The disadvantages of the prior art devices are overcome by the
present invention which provides in a casing string a valve
assembly having a flow rate valve element which can be selectively
converted into a check valve. The assembly provides an upwardly
opening differential fill valve arrangement for allowing the fluid
in the annulus to flow into the casing as the casing is being
run-in the hole. Another feature is that fluid can be flowed in
both directions through the valve assembly to circulate and reverse
circulate fluid through the valve until it is desirable to
transform the valve assembly into a check valve allowing flow in
one direction only, and preventing back-flow therethrough.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of the float collar as it is
placed into the casing string prior to run-in of the casing.
FIG. 2 illustrates the position of the valve assembly as the casing
is being run-in.
FIG. 3 illustrates the valve assembly during a limited flow rate
circulation through the valve assembly into the bore hole.
FIG. 4 illustrates the valve assembly during cementing after it has
been transformed into a check-valve type assembly.
FIG. 5 is a view of the float collar after cementing is
completed.
FIG. 6 is a top view of the float collar taken at line 6--6 in FIG.
1.
FIG. 7 is an alternative embodiment of the float collar having an
alternate lower valve arrangement.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 the float collar 1 comprises an outer cylindrical housing
2 made of a durable material such as steel. Centered within the
housing 2 by concrete fill 3 is the lower valve body 4 and upper
valve body 5 joined together by a releasable connection such as
matching threads 6.
Lower valve body 4 has an integral valve guide 7 with a bore
passage extending vertically therethrough located centrally therein
and one or more vanes 8 passing from valve guide 7 to the outer
wall 9 of the lower valve body and further defining flow parts 10
through the lower valve body. Valve body 4 also contains a lower
central recessed opening 11 communicating with the flow ports
10.
Passing through valve guide 7 and in slidable relationship
therewith is valve member 12 having plunger head 13, valve stem 14,
and threaded rod 15. Plunger head 13 has conical valve surface 16
which matches upper valve seat 17 formed in upper valve body 5.
Elastomeric covering 18 sufficiently encases plunger head 13 to
provide better sealing engagement between head 13 and valve seat
17.
Plunger head 13 has an integral collar 19 formed at the bottom
thereof, around stem 14, and of substantially the same diameter as
the upper part of valve guide 7. Also formed in the plunger head 13
at the junction of collar 19 and the plunger head is spring recess
20 arranged to receive coil spring 21 which passes in fitting
arrangement over collar 19 and the upper shoulder 22 of valve guide
7.
Valve stem 14 passes through valve guide 7 and extends into recess
11 and out past the bottom 23 of lower body 4. Elastomeric valve
ring 24 is located about valve stem 14 within recess 11 and has
upper sleeve 25, intermediate shoulder 26, and sealing shoulder 27.
Valve ring 24 is retained on valve stem 14 by retainer washer 37
located below ring 24 and slidably mounted on a lower bolt 28 which
is threaded onto threaded rod 15. Encasing lower bolt 28 is bolt
housing 29 which is a cylindrical tubular housing having an upper
bore passage 30 and an enlarged lower passage 31 which lower
passage defines an annular recess 32 between bolt 28 and housing
29.
Bolt 28 has a lower enlarged portion 33 which is formed by an
annular shoulder 34 passing circumferentially around the lower
portion of the bolt. The annular shoulder 34 is just large enough
to leave a small annular gap 35 between the shoulder and the
enlarged lower bore 31 in housing 29.
Passing transversely through housing 29 and bolt 28 through
shoulder 34 is shear pin 36 which serves to attach housing 29 to
bolt 28 in the uppermost position of housing 29. In this uppermost
position as shown in FIGS. 1 through 3, housing 29 abuts retainer
washer 37 and maintains valve ring 24 substantially within recessed
opening 11 in lower valve body 4.
Coil spring 21 which is in a compressed position in FIGS. 1 through
3 and pushes down against valve body 4 and upward against plunger
head 13, works through valve stem 14, threaded rod 15, lower bolt
28, shear pin 36 and housing 29 to maintain washer 37 and valve
ring 24 in their upper initial position as shown in FIG. 1.
Spring 21 also biases plunger head 13 toward valve seat 17 and has
sufficient travel to seat head 13 in valve seat 17 when bolt 28 has
been freed from housing 29 allowing the plunger head to move
upward.
In operation, the float collar as shown in FIG. 1 is inserted in
the casing string either at the bottom or at one or two joints up
from the bottom. After the casing string is made up, it is run in
the well and the float collar assumes the position as shown in FIG.
2. In FIG. 2 the elastomeric valve ring 24 has been pressed into
the opening 11. This occurs because the sealing shoulder 27 of ring
24 sealingly engages the wall of opening 11 and, due to the fluid
in the bore hole and the unfilled area in the casing, a
differential pressure arises across valve ring 24 immediately upon
entering the bore hole fluid with the casing. As the casing
progresses deeper into the bore hole fluid, the differential
pressure across shoulder 27 increases, compressing the valve ring,
causing sleeve 25 to bulge and take up the compression forced on it
by pressure on shoulder 27. As the sleeve 25 bulges and is
compressed as shown in FIG. 2, shoulder 27 moves upward into the
opening 11. At a predetermined differential pressure, preset by
adjusting the length and stiffness of valve ring 24, shoulder 27
moves past the lowermost tip 38 of ports 10 and allows fluid
communication from the open bore area 39 in housing 2 through ports
10 and out through upper bore 40 into the casing string. Any time
the differential pressure across valve ring 24 drops below the
preset opening pressure, the valve ring expands to close ports 10.
Referring now to FIG. 3, if at any time during or after the descent
of the casing into the bore hole fluid it is desired to flow down
the casing and into the bore hole and still retain the reverse
circulation feature, this can be done at a relatively low flow rate
as long as the flow rate used does not exceed that which is
predetermined to shear pin 36 and convert to a check-valve type
operation. This conversion flow rate can be preset at any desirable
level; for instance, it is desirable in some circumstances to set
this at three barrels per minute. Thus, downward flow can occur
through the collar at any rate below three barrels per minute
without shearing pin 36 and preventing any further reverse
circulation.
When it is desirable to convert to check-valve type of operation
(for instance, when cementing is to begin), this is achieved as
shown in FIG. 4 by pumping down the casing at a rate in excess of
the predetermined conversion rate, which excessive rate places
sufficient downward shearing force on valve ring 24, which force is
transmitted through washer 37 to housing 29 thereby shearing pin 36
which passes through the housing. The downward force on pin 36 is
resisted by upward force of spring 21 pushing upward on plunger 13,
valve stem 14, threaded rod 15 and through lower bolt 28, thus
shearing the shear pin 36 and releasing housing 29 from bolt
28.
The release of bolt 28 from housing 29 allows valve ring 24 to move
out of opening 11 thereby fully opening ports 10 into open bore 39.
Housing 29 drops down until shoulder 41 of the housing abuts
shoulder 34 of the bolt, thereby preventing the housing from
dropping off of the float collar and possibly interfering with any
tools which may be located below the float collar.
After the valve ring 24 moves out of the opening 11 in response to
hydraulic forces above it pushing it downward, the downward force
on bolt 28 drops to a negligible amount allowing spring 21 to
expand forcing plunger head 13 upward. Cement flowing through upper
bore 40 is sufficient to maintain spring 21 compressed and plunger
head 13 in an open valve position. When cement flow is stopped,
spring 21 pushes plunger head 13 into valve seat 17, thereby
closing the tool against reverse flow of cement. Hydrostatic
pressure now being higher in the annulus than in the casing, cement
will attempt to flow back into the casing through the valve but
will act on the backside of plunger head 13 and in conjunction with
lip 42 on the lower periphery of elastomeric covering 18 to form a
tighter better seal of the valve assembly by forcing plunger head
13 tighter into seat 17 and by further acting upward against the
back side of lip 42 forcing it into sealing arrangement with the
lower part 43 of seat 17.
The advantages achieved by the use of this invention are partly a
result of the ability of the valve ring 24 to compress sufficiently
to allow the casing string to fill up as it enters the bore hole.
Due to the limited ability of the valve ring to compress, a flow
restrictive orifice is always present during back-flow between the
valve ring and the lower end 23 of the lower valve body 4, thereby
tending to prevent the casing from filling too quickly and
overflowing at the surface.
Whereas the prior art devices utilize a resilient washer to limit
back-flow, the present device utilizes a rather lengthy valve ring
24. The valve ring is advantageous over the washer due to the
tendency of the washer to extrude out of position in high pressure
hot wells and also due to the lateral movement of the valve stem
which can occur within the rather loose-fitting valve guide.
The present invention also allows the casing to be filled at a
controlled rate regardless of how high the pressure differential is
between the bore hole and the casing bore, whereas if too high a
pressure differential occurs across the prior art devices, the
casing string must be pulled upward in the hole or filled from the
surface to reduce the pressure differential and allow further
back-flowing.
The present invention allows the fluid to be forward-flowed or
back-flowed as many times as desired as long as the conversion flow
rate is not reached. As soon as the operator desires to convert to
check-valve type operation (for instance, to begin cementing), this
is easily and simply achieved from the surface without having to
drop mechanical devices through the casing or run a stinger into
the casing. The conversion is easily accomplished by increasing
flow rates through the casing to above the present conversion flow
rate.
All the parts of the present invention within the housing 2 can be
made of easily drilled materials such as concrete, plastic, rubber,
aluminum and brass, to allow the collar to be drilled out after the
cementing operation has been completed and the cement set up. The
drilling out leaves a full-open passage through the collar to pass
other tools down the casing for further work, production or
testing.
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 instance, it is contemplated that different numbers of
vanes could be used between the valve guide and the lower body to
vary the number and size of ports through the collar. It would also
be possible to use other spring means to replace the sleeve portion
of the valve ring and still maintain the differential fill feature.
The invention is declared to cover all changes and modifications 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.
* * * * *