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Патент USA US3048237

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Aug. 7, 1962
Filed July 24, 1958
3 Sheets-Sheet 1
Aug, 7, 1962
3 Sheets-Sheet 2
Filed July 24, 1958
Aug. 7, 1962
Filed July 24, 1958
3 Sheets-Sheet 3
United States harem @?fire
such tubing may be raised again and relatched into posi
tive contact with the bumper block.
Lloyd D. Cason and Kennedy J. Dugas, Erath, La., as
. signors to Texaco Inc” a corporation of Delaware
Filed July 24, 1958, Ser. No. 750,791
11 Claims. (Cl. 166—114)
This invention is generally concerned with a down
hole tool for deep wells. More speci?cally, it is concerned
with a disconnectable tubing support. Such tubing sup
port is applicable for work-over operations in wells that
have ‘been completed with reduced diameter tubing at the _
bottom of the string.
A procedure is known, which is employed in working
over a permanently completed well, i.e. a Well that has
been cased and tubed, without pulling the tubing of the
Patented Aug. 7, 1962
This known procedure avoids the use of a wire
Briefly the invention is concerned with a downhole
releasable bumper block, for use in at least partially sup
porting a tubing string on a packer. Such bumper block
comprises a latching head adapted to be connected to said
tubing string, and a hollow cylindrical body member, hav
ing friction means exteriorly thereof for engaging the
walls of said hole. The bumper block also comprises a
bowl assembly in said body member which includes means
for releasably engaging the latching head. The said hole
assembly and said latching head, are so constructed and
arranged that said latching head may be lowered axially
relative to said body member for any desired distance _
after unlatching, and may be relatched after raising the
latching head back within said bowl assembly.
The invention may be also briefly described as a method
that is applicable in a permanent type well completion.
line operated “tail pipe”_ for such work over operation.
Such completion being one that has a pre-determined
The foregoing known procedure, brie?y, involves ce
men-ting-oif a given producing zone prior to re-perforating 20 length of reduced'diameter tubing at the bottom of the
tubing string in said well. The method is one that is in
and commencing production anew from the same or a
higher zone. In the course of such operation, it is neces
sary to wash out the old producing zone that is to be
cemented. This may be done by fluid circulation accom
panied by lowering the tubing down into the zone that
is being washed. Following such washing the old zone
volved in a work-over procedure.
The work-over pro
cedure involving a lowering of said tubing string, rela
tive to a packer located adjacent to said reduced diameter
tubing. The method includes the steps of unlatching said
tubing from a hollow cylindrical body member adapted
to rest on said packer, and lowering said tubing through
said packer and body member to carry out circulation of
cementing. The squeeze cementing operation involves
?uid through said tubing, Also the step of raising and
applying cement to the zone, using forward circulation
out through the bottom of the tubing. After the cement 30 relatching said tubing to said body member, and also re
leasing sui?cient of the weight of said tubing string to
slurry has been applied thus, excess cement is reversed out
withstand the pressure involved in a squeezing operation.
by reverse circulation, i.e. from the annulus into the tubing.
The foregoing and other objects and bene?ts of this
Then some pressure‘ is held on the cement while it is
invention, are set‘ forth in the detailed description that
given time to set. To apply these pressures, the annulus
follows, and are illustrated in the drawings, in which:
is sealed around the tubing by employing a seal nipple
FIG. 1 is an elevation assembly partly in cross section,
on the tubing and locating it within a packer that has
showing the bumper block in place, resting on a packer
been set in the casing above the zone being squeezed.
that is schematically shown in cross section, and with a
Since the pressures involved in the squeeze operation
tubing string shown passing through the bumper block
mentioned above, are quite high, the vforce tending to
and packer;
raise the seal nipple and tubing up out of the packer
FIG. 2 is an enlarged fragmentary elevation, largely
becomes quite substantial. For this reason it has been
shown in longitudinal cross-section along the line 2—2
found dif?cult to carry out the squeeze cementing opera~
of FIG. 1, illustrating the elements of the ‘bumper block
tion without loss of pressure (due to the forcing of the seal
according to a preferred embodiment of the invention;
nipple or nipples, up out of the packer). It is not feasible
FIG. 3 is an enlarged detail showing of certain of the
to apply tubing weight on the string, in order to counter
elements that go to make up the upper portion of the
act this upward force. This is because the string is sus
bumper block;
pended from the surface, and to attempt this would mean
FIG. 4 is an enlarged detail elevation view showing the
that the tubing string would be released and tend to be
coil spring that is employed within the bowl assembly of
lowered, ‘which would force the seal nipple out of the
is cemented under pressure, which is known as squeeze
packer in a downward direction, and again create a loss
of pressure by breaking the seal. The reason this is
‘the bumper block;
FIG. 5 is an enlarged detail elevation partly broken
away in cross-section and illustrating a spring guide on
so is because of the length of the tubing string involved,
which the bottom of the coil spring shown in FIG. 4, rests;
which is relatively so great that compression on the tub
FIG. 6 is an enlarged detail elevation, partially broken
ing from the lower end, can create substantially large
changes in the length thereof. Thus for example, the seal 55 away in cross section, illustrating the expanding thread
segments that have the load bearing female threads on the
nipple or nipples can be moved several feet upward under
inner periphery thereof;
the force involved duringthe squeeze operation, without
FIG. 7 is another enlarged detail elevation, partially
moving the top of the tubing string at the well head,
at all.
broken away'in cross-section, illustrating the stabilizer
Consequently, it is an object of this invention to pro 60 ring, that is located beneath the expanding-thread seg
vide a method and apparatus for overcoming the above
FIG. 8 is an enlarged detail elevation partially broken
mentioned difficulties.
away in cross-section, illustrating the latching head that is
It is another object of this invention to teach a method
adapted to be connected into the tubing string;
of releasably latching a bumper block to the tubing string,
so that the tubing string may be lowered through the 65 ‘FIG, 9 is an enlarged fragmentary detail'elevation of
the lower‘pontion of the bumper block at the bowl assem
block (and a packer underneath) for carrying out de
bly portion thereof. This showing is broken away in cross
section to show the internal structure including an axially
Another object of this invention is to provide a bumper
block which has releasable latching structure so that 70 extending key that coaoperates with the thread segments
illustrated in FIG. 6;
tubing may be unlatched from direct supporting contact
FIG. 10 is a transverse cross-section view, taken along
therewith, andbe lowered through the block. Thereafter
sired operations.
the lines 10-10 of FIG. 2 looking in the direction of
the arrows;
FIG. 11 is another transverse cross-section view taken
There is a latching head 35 (FIG. 2 and FIG. 8) that
may be called a tubing support or latching nipple and
is connected into the tubing string 31, as indicated by the
broken line showing of the tubing string in FIG. 2. Such
connection with the string 31, by the latching head or
tubing support 35, is made by means of upper internal
pipe threads 36 for the upper portion of the tubing string,
and lower pipe threads 37 for the tubing string connected
below the tubing support or latching head 35. On the
Referring to FIG. 1, it is pointed out that there is illus
trated a fragmentary portion of a deep well 21, which has
outer surface at the upper end of the tubing support 35,
when viewed as shown in the drawings, there is a set of
been drilled into the earth to reach under-lying strata
such as formations 22 and 23 illustrated. Such a deep
well is ordinarily lined with a casing 24, although if the
male buttress type load bearing threads 38. At the other
end of the latching head or tubing support 35, there is
an enlarged cylindrical collar section 39.
The structure of the bumper block proper (that acts to
support the latching head or tubing support 35) includes
a hollow cylindrical body portion, or body member 43
(FIG. 2). This is made up of two separable portions,
including an upper sleeve-like unit 44 (FIGS. 2 and 3) that
has a relatively short, thick walled hollow cylinder 45
surrounding part of the lower end thereof. Cylinder 45
along the lines 11——1»1 of FIG. 2 looking in the direction
of the arrows; and
FIG. 12 is a fragmentary cross-sectional view, showing
a modi?ed form for the elements of the bumper block
that provide frictional engagement with the walls of the
formations are su?iciently hard a casing might not always
be required.
Throughout this ‘description, wherever the walls of the
hole are referred to, it is contemplated that such walls
include the casing, if the hole is cased, or the walls of
the hole formed by the vformation, if the hole is uncased.
There is a conventional type of production packer 25,
schematically illustrated. This packer 25 has been ex
panded to provide a tight high pressure seal with the
casing 24. There is shown situated within packer 25 a
is welded to a sleeve 47, at the upper edge of the cylinder
45 as indicated at reference number 46.
conventional seal nipple 30 that is connected into a re
The lower portion of the body member 43, includes a
lower eylinder-and-sleeve unit 48‘ (FIGS. 2 and 9) that
duced ‘diameter tubing string 31, which passes through
includes an outer sleeve 56 that has internal threads 51
the bumper block 32 that is shown resting upon the top
edge of the packer 25.
The type of operation in which this invention is em
at one end thereof, adapted for meshing with threads
53 on the outside lower portion of the hollow cylinder
45 of the upper unit 44. The lower end of the sleeve 50
ployed, has been briefly indicated above. Such operation 30 surrounds, and is securely attached to, the upper end of
(when applied to the apparatus shown in FIG. 1) in
a lower cylindrical portion 54. This attachment may be
cludes a lowering of the tubing string 31 through the
accomplished in any feasible manner, such as by means
bumper block 32 and the packer 25, after the tubing
of a weld 52 illustrated.
string has been unlatched from the bumper block internally
Attached .to the thick walled portion of cylinder 54,
thereof. It will be appreciated that the reduced diameter ' there is a plurality of hole-wall-engaging bowed springs
tubing string 31 is attached at the lower end of the normal
56. Springs 56 are attached to the cylinder 54 in any
sized, full diameter tubing string (not shown) in the well.
feasible manner, such as by employing cap bolts 57, as il
Such reduced diameter tubing string will have been at
lustrated. At the other end of the springs 56 there is a
tached to the main tubing string as the well is completed,
supporting ring 58, to which the bowed springs 56 are
in order that the procedures for re-working the well may
attached by means of ?ush head bolts 59, as illustrated.
be carried out, without removing the tubing from the
Generally within the sleeve 50, there are located the
elements of a bowl assembly. These bowl assembly
The operation involves a lowering of the reduced diam
elements include the main element of the latching struc
eter tubing string 31, su?iciently to move the seal nipple
ture, viz. a plurality of frusto-conical annularly situated
30 out ‘of contact with the packer 25 in order to provide
segments v63 (FIGS. 2 and 6). These segments 63 have
free passage for ?uids ‘from the annulus above the packer
on the inner peripheral surface thereof, female buttress
25 to the annulus beneath the packer. Thus a circulation
type threads 64, which are cut for engagement with the
male buttress threads 38 on the tubing support or latch
of ?uids may be carried out under such circumstances;
ing head 35. Segments 63 rest within a frusto-conically
and any accumulation of sand or debris may be washed
walled chamber 65, that is formed by the widening por
clear, prior to a squeeze cementing operation. A squeeze
tion of the upper extremity of cylinder ‘54, where it ex
cementing operation involves applying pressure to the
tends within the outer sleeve 50. Underneath the seg
cement following injection thereof through the tubing 31.
ments 63 in the bowl assembly, there is a stabilizer ring
And, in order to apply and maintain such pressure, the
66 (FIGS. 2 and 7), which rests upon a shoulder 67
tubing string 31 is raised until the seal nipple 30 again
formed in the cylinder 54. On top of the segments 63
rests within the packer 25 (in the manner illustrated in
there is a spring-guide ring 70‘ (FIGS. 2 and 5). Guide
FIG. 1). When this condition exists, and the tubing string
ring 70 supports a coil spring 71 (FIGS. 2 and 4). The
31 has been re-latched into positive contact with the
other end of spring 71 rests against the lower edge of
bumper block 32, squeezing pressures may be applied
to the cement, and will be maintained without forcing 60 the upper cylinder 45.
‘It is pointed out that the threads 51 and 53 which join
the seal nipple 30 up out of the packer 215. This is so
the upper and lower portions of the body member 43
because tubing-string-weight may be applied to the bumper
together, are a tight ?t so that when assembled, the entire
block 32, since the string 31 is now latched into positive
bumper block 32 acts as a unitary whole.
connection with the bumper block 32.
Ordinarily the full weight of the tubing string 31 will 65 Referring to FIGS. 10 and 11 it will be observed that
the segments 63 are so proportioned as to be in contact
not be applied, for fear of causing a buckling in the tubing
with one another at the edges thereof, with the exception
string. However, by reason of the bumper block being
of a space 74 that is vformed between segments 63a and
attached to the string 31 with a positive ‘connection, suffi
6312. This space 74 is provided to accommodate a key
cient tubing weight may be applied to insure that the
75 that is welded to the upper extension of the cylinder
squeeze pressure will not be able to lift the seal nipple
54, above the shoulder 67. Key 75 thus prevents rela
30 up out of the packer. The excess of such tubing weight
tive rotation between the cylinder-and-sleeve unit 48 and
. will be carried in a supporting manner by the upper edge
the segments 63. However, the segments 63 are free to
of the packer 25, upon which the bumper block 32 rests.
move longitudinally (i.e. parallel to the axis of the
Referring to FIGS. 2—ll, the details of the structure
bumper block 32) against the spring pressure of spring
of the bumper block 32 will be described.
75 71. Such longitudinal axial movement of the segments 63,
permits their spreading apart to‘ provide an “expanding
ratcheting action of the buttress threads over one an-v
other. However, in any event, it is most advisable to
rotate the tubing string 31 for a full revolution in the
backward or unscrewing direction prior to a release of
the tubing string Weight ‘for support thereof on the packer
thread” action for the female buttress threads 64.
Referring especially to FIGS. 1 and 2, the operation
may be explained in accordance with the following.
With the elements in the relative positions illustrated, the
tubing string 31 is connected to the tubing support or
latching head 35, and the tubing string is therefore latched
Such reverse rotation will make sure that the threads
of all of the segments 63 are properly meshed at the
same level without any cross threading.
Method Steps
to the bumper ‘block 32. When it isdesired to unlatch 10
It will be observed that the apparatus which has been
the tubing string 31, it will be raised to lift the bumper
described may be employed to carry out a method that is
block 32 off of the packer 25, so that the bumper block
applicable to the procedure that is involved‘ in a permanent
32 is supported by means of the buttress threads 38 and
type Well completion operation. Such operation is in- <
64 in addition to the large collar section 39 on the latch
ing head 35. Now when the tubing string 31 is rotated, 15 volved in the working over of the well following ‘the
aforementioned permanent type completion. The pro~
the latching head 35 will of course rotate therewith.
cedure has been described in general terms above.
However, by reason of the bowed springs 56, the bumper
‘It will be clear that in such a procedure the apparatus
block 32 and particularly the cylinder 54 thereof, will
may be employed to carry out the following steps, in
tend to remain stationary by reason of the drag friction
cluding unlatching the tubing from the hollow cylindrical
between bowed ‘springs 56 and the casing 24 of the well
body member that is adapted to rest on a packer, lower
21. Thus, by rotating the latching head 35 by means of
ing said tubing through the packer and body member
the tubing string 31, in the proper direction, the body
in order to be able to carry out ?uid circulation opera—
member '43 of the bumper block will become discon
tions where ?uid is circulated either down the annulus
nected from the string on account of unscrewing the
thread connection at the loose ?tting buttress threads 38 25 between the casing and the tubing and up inside of the
tubing or the reverse. In addition, the procedure may
and 64.
include the additional steps of raising and re-latching the
If- the tubing string 31 is held vertically stationary
tubing string to the body member, as well as releasing
while it is rotated, body member 43 will climb upward
sufficient of the weight of the tubing string so as to
as the threads are unscrewed from one another.
‘ After the buttress threads have become completely 30 provide downward force to withstand the pressure in
volved in a squeezing operation when the tubing string is
unscrewed ‘from one another the tubing support or latch
latched in position (the seal nipple is located within the
ing head 35 may be lowered along with the tubing string
31, as far as desired, depending upon the length of the
Modi?ed Friction Springs _
reduced diameter tubing that has been installed and the
depth to the bottom of the hole. When the tubing string 35
FIG. 12 illustrates a different hole-Wall engaging fric
31 is thus lowered, carrying tubing support 35rtherewith,
tion drag means, to replace the bowed springs 56 of the
the bottom edge of cylinder 54 of the bumper block 32,
modi?cation described in the previous ?gures.
will contact the packer 25 once more and remain there
Referring to FIG. 12 it will be observed that there is
as the tubing is lowered therethrough. Lowering of the
a plurality of friction blocks at} that are mounted partially
tubing will, of course, lower the seal nipple 30 out of ‘the
recessed in the lower cylindrical portion 54a of the body
packer 25 and permit ?ow of ?uids through the annulus
past the packer.
‘After the completion of a washing operation, or other
steps that may be. taken while the tubing string is un
latched ‘from the bumper block 32, the tubing string may
be again raised to bring the latching head 35 into contact 45
once more with the threads ‘64 of the segments 63.
Following such contact, the tubing ‘string will be raised
sufficiently to'lift .the body member 43 for a distance
above the packer 25 that is s'u?icient to allow for the
downward movement of the body member 43, as the re 50
latching operation takes place. Such re-latching is ac
complished by merely reversing the earlier steps, i.e. by
Irotating the tubing string 31, and the latching head 35
therewith, in the ' proper direction to screw the loose
fitting buttress threads'of latching head 35 and of seg
ments '63, back together.
As explained above, the body member 43 will not
member. These friction blocks 30 are designed to pro
vide more frictional force against the walls of the hole
than would be applied with the other style friction wall
engaging springs 56. Thus the friction blocks 80‘ are
spring biased radially outward into extended positions as
‘illustrated in FIG. 12, by means of a double set of coil
‘springs 81 and 82 located in each of a set of three re—
cesses 85, 86 and 87, in turn located in each of the fric
tion blocks 80. Each of the friction blocks 80‘ is held in
position in an elongated recess 90‘ in the wall of the cyl
inder 54a. Each block 80 is held in position in its re
cess 90, against the force of the coil springs 81 and 82,
.by means ofa pair of ?at headed machine screws 91 and
92. The heads of these screws 91 and 92 overlap the
edge of the recess 90, and make contact with the block
80 in notches 93 and 94 respectively.
All of the other elements of the bumper block, remain
the same as already illustrated and described above.
It is pointed-out that while FIG. 12 illustrates only two
friction blocks 80 it will be clear that more than two
rotate, vfreely with the latching head 35 as it is rotated,
because of the friction drag effect at the walls of the hole
that is created by the bowed springs 56.
(preferably four) could be employed if desired.
In order to be sure that the threads 64, of all of the
While certain embodiments of the invention have been
segments 63, are properly meshed with the threads 38 of
illustrated and described in considerable detail in accord
the latching head 35, it is advisable to rotate the latching
ance with the aplicable statues, this is not to be taken
head 35 for a full revolution in the opposite (or unscrew
ing) direction prior to the rotation in the forward, or 65 as in any Way limiting the invention, but merely as being
screwing direction, when proceeding to relatch the string
descriptive thereof.
What is claimed as the invention is:
to the bumper block.
1. For use in a well bore having an internal packer
It will be noted that, by reason of the expanding thread
?xedly mounted therein, a tubing string adapted to pass
structure of segments ‘63 and the tapering chamber walls
65, latching head 35 may be re-latched to the body mem 70 freely through the packer, and said tubing string being
provided with a seal nipple engageable with the packer
ber 43 without any rotation thereof. In other words,
‘ the mere straight lifting action of latching head or tub
in sealing relationship; means for selectively holding the
seal nipple in the packer comprising a bumper block about
ing support 35 will cause the segments 63 to rise and
the tubing string above the packer and adapted to rest
spread, so that the meshing of the threads on latching
head or tubing support 35 may be accomplished‘ bythe 75 thereon, a tubing support connected into said tubing
string, and means controlled from the well head for latch
friction means exteriorly thereof for engaging the walls
of said hole, a bowl assembly in said body member, said
assembly comprising a plurality of tapered thread seg
ments adapted for threaded cooperation with said load
bearing threads, a tapered chamber for receiving said
segments, and key means for preventing relative rota~
tion between said segments and said body member, said
ing said tubing support to said bumper block when said
seal nipple is engaged in said packer to hold said seal nip
ple therein, said latching means being selectively releas
able to permit downward movement of the tubing string
in the well.
2. In the combination according to claim 1, the said
latching means including load bearing means on said tub
tapered chamber having an axial dimension greater than
the corresponding axial dimension of said segments to
ing support, and complementary means on said bumper
block for meshing with said load bearing means.
provide for radial expansion of said tapered thread seg
3. The invention according to claim 2 further includ
ments, spring bias means for urging said segments ax
ing friction means on said bumper block for restraining
ially into radially contracted position within said ta
the bumper block against rotation in the well.
pered chamber, said tapered chamber being relatively sit
4. The invention according to claim 3 wherein said
uated in said body with the minimum diameter of the
load bearing means comprises machine threads.
taper at the lower end when said bumper block is in place
5. The invention according to claim 4 wherein said
above said packer.
complementary means comprises a plurality of segments
11. A down hole releasable bumper block for use in at
having threads on the inner surfaces thereof matching
least partially supporting the weight of a tubing string on a
with said machine threads.
packer, comprising a hollow body member, hole wall en
6. The invention according to claim 5 wherein said 20 gaging friction drag means mounted exteriorly on said
plurality of segments include a tapered outer circumfer
body member and having means for biasing said drag
ential con?guration to allow for diametrical expansion
means radially outward against the walls of said hole, a
bowl assembly on the interior of said body member, said
7. The invention according to claim 6 further includ
bowl assembly comprising a frusto-conical walled cham
ing a bowl assembly integral with said bumper block for
ber with the minimum diameter at the end nearest said
housing said segments, and bias means for urging the
packer, a plurality of frusto-conical annular segments
segments into diametrically contracted position.
8. A disconnectable tubing support assembly for use
within said chamber having load bearing female threads
for latching and unlatching with said bumper block, and
load bearing male threads thereon for engagement with
a plurality of segments having a tapered outer circum
ferential con?guration to allow for diametrical expansion
said female threads on said segments, the outside diam
eter of said male threads being less than the inside diam
eter of said body member below said bowl assembly, so
that said tubing string may be unlatched and lowered out
of said body member for reversing operations and re
latched thereafter for squeeze operations and the like.
on the inner surfaces thereof and including a predeter
in deep well operations, comprising in combination a tub
mined circumferential space between two of the seg
ing support adapted to be connected into a tubing string, 30 ments, a key attached to said body member and located in
a bumper block freely embracing said tubing support for
said circumferential space for insuring against rotation
permitting free downward movement of said tubing sup
of said segments relative to said-body member, a spring
port relative to said bumper block when disconnected
for urging said segments toward the minimum diameter
therefrom, said bumper block including a frusto-conically
end of said chamber, a latching nipple adapted for con
Walled chamber, machine threads on said tubing support
nection into said tubing string, said latching nipple having
thereof and being located within said chamber and having
threads on the inner surfaces thereof matching with said
machine threads, said bumper block being so constructed
and arranged that by surface manipulation of said tubing
string said tubing support may be connected and discon
nected relative thereto as desired.
9. The invention according to claim 8 further including
bias means for urging the segments into diametrically con
tracted position.
=10. A down hole releasable bumper block for use in
at least partially supporting the weight of a tubing string
on a packer, comprising a latching nipple adapted to be
connected to said tubing string, load bearing threads on
said latching nipple for carrying said tubing string load,
a hollow body member adapted to receive said tubing
string extending therethrough, said body member having
References Cited in the ?le of this patent
Marr _______________ __ Sept. 22,
Fulkerson ____________ __ May 2,
Baker ______________ __ Ian. 16,
Baker ______________ __ Jan. 16,
Baker _______________ __ July 7,
Hodges _____________ __ Aug. 31,
Baker _______________ .. Mar. 6,
Wooddy _____________ _._ June 19,
Brown ______________ __ July 7,
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