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Патент USA US3019852

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Feb. 6, 1962
3,019,842
B. P. NUTTER
WELL PACKER
Filed Nov. 19, 1958
3 Sheets-Shes?l 1
53
56
54
50
73
INVENTOR.
BENJAMIN P. NUTTER
27
BY
HIS ATTORNEY
Feb. 6, 1962
B. P. NUTTER
3,019,842
WELL PACKER
wh@ n@
73
INVENTOR.
-
BENJAMIN F? NUTTER
HIS ATTORNEY
Feb. 6, 1962
B. P. NUTTER
3,019,842
WELL PACKER
Filed NOV. 19. 1958
5 Sheets-Shes?, 3
M3
53
\
54
70
INVENTOR.
BENJAMIN P. vMUTTER
BY/QZZ [x ¿_?
HIS ATTORNEY
3,919,842
ice,
I nited rates Patent
Patented Feb. n 6„ 1962
2
1
the zone being straddled may be of theoretically unlimit
3,019,842
Beniaxnin P. Nutter, Houston, Tex., assignor to Johnston
edext‘ent.
WELL PACKER
bridge plug .structure including a tubular housing
tlllîtilml _tubular mandrel; slidably received within the hous
ing for-"limited longitudinal movements-*Carried by the
Testers, Inc., Houston, Tex., a corporation of Terras> `
Filed Nov. 19, 1958, Ser. No. 775,056
15 Claims. (Cl. 16d-_126)
v`housin‘g «are friction means for engaging the casing and
slip` means for., engaging thecasing having integral upper
and lowertapered portions, adapted to be pivotally andk
slidalzylyl moved outwardly into grippingvengagement with
The present invention relates to well packers and,
more particularly, to» a retrieyable >and resettable bridge
plug for use in cased boreholes.
Y
Thesle‘andother Iobjects of the invention are attained
`
In the interests of economy and efficiency, it is ad
vantageous to perform a plurality of completion and
remedial borehole operations, such as drill stem testing,
squeeze cementing, acidizin'g, Íluid fracturing, gun per
forating and the like, with a minimum of round trips of 15
tubing string into the borehole. - In View of the current
the casing. Longitudinally spaced expander means are
carried by themandrel and are-adapted to independently
engage and set opposite tapered portionsv of the slip>
means. The mandrel also carries »packer means for 'pack-l
ing oif the annulus between the casing and mandrel
against pressure diderentials acting upwardly and down
wardly thereon. Valve means for'releasably closing the
ñuid passage longitudinally through the mandrel and
housing are operative by flow of fluiditherethrough to
trend toward drilling to even greater depths, the desir
ability of multiple purpose tools which reduce rig time
by preferably requiring only one-round trip of tubing
string to perform an indicated sequence of completion 20 seal the interior of the plug `against iluid iiow in eitherV
direction. The valve means may also be opened to pro
and remedial operations is evident.
videÈa‘by-pass,passage for ñuid through the plug when
This invention is directed to a multiple purpose casing
traversing- the well casing.` Locking means may be pro
bridge plug especially useful in performing any one of
yi >ed between the housing and mandrel to prevent pre
or combination of the above-enumerated operations or
operations similar thereto without requiring withdraw-al
25
of the tubing string or the plug to the surface between
operations. 1n certain of these operations, such- -as
squeeze cementing, acidizing and lfluid .fracturing and
the like, a bridge plug provides a fluid seal for the casing
annulus below the zone to be worked on and must be 30
capable of setting and remaining packed off against dif
ferential pressures across the plug acting downwardly
mature setting of the slips. A retrieving head adapted
_.,tof’wbe operatively connected to a tubing string is releas
`¿ably connectedto the plug and is adapted to operate the
lockingmeans and’to-move the valve means to open
position.:y
-
Other and more specific features vof «the invention and
others of its objects and advantages may be perceived
by referring to the following detailed description'. when
taken `in _conjunction with the accompanying drawings
thereon. In others of these operations, such as Vdrill
wherein:
stem testing, for example, a bridge plug is used as the
FIG. l is a longitudinal sectional' view of a bridge
lower packer in »a straddl'e packer arrangement and at 35
plug constructed in accordance with‘tiieipresent inven
some point the portion of the casing annulus between
tion and shown in its running in position releasably lcon
the packers is reduced to a relatively low pressure.
Therefore, the bridge plug must be capable of setting
and remaining packed oif against pressure differentials
nected tothe retrieving head;
'
'
FIG. 2 is a cross-section of the yapparatus of FIG. ’l
40 taken on the line 2--2 thereof looking in the :direction
acting upwardly on it.
of the arrows;
Frequently it is desired to move to another zone in
FIGS. 3a to 3g are simplified >schematic representations
the well where another >sequence of completion »and reme
of an 'elevation View of the apparatus of the present in
dial operations is to be performed. It is therefore de
vention showing in particular the slots in the retrieving
sirable that a multiple purpose bridge plug be arranged
to be quickly and conveniently unseated and reset without 45 head and housing and the ‘positions of ‘the mandrel pins
in these slots for the various manipulations required to
withdrawing the tubing string. Such a resetting ar
rangement, of course, should desirably also .adapt the
operate the apparatus and for'th'e various >positions the
apparatus takes;
~
plug to be unseated yand retrieved >to the surface.
FIG. '4 is an elevational view partly in section and
It is therefore an object of this invention to provide
a new and improved casing bridge plug for use in per 50 partly in vdiagram form of a portion of the apparatus
of FIG. l shown in the position it takes when packing
forming any one of the above-enumerated operations
ott against pressure differentials across the apparatus
or similar operations or any combination of them with
only one trip of the tubing string .into the well.V
Another object of this invention -is to provide a new
acting upwardly thereon, the retrieving Aihea‘d -having 'been
removed;
and improved well packer which requires no mechanical 55 FIG. 5 is an elevational ‘View’ partly in .section l‘and
partly kin diagram form of a portion of the apparatus
linkage to the surface in order to set and remain packed
of FIG. 1 shown in the position it takes when packing
oif against pressure differentials acting in either direction
oit :against pressure diíferentials across the apparatus act
above and below the packer after it is lreleased from >its
ing downwardly thereon; and
parent tool.
tially set without mechanical linkage to the surface against
FIG. 6 is an elevational view partly in section and
partly in diagram form -of a `>portionof the »apparatus
of FIG. 1 ‘shown in the going out position, the retrieving
pressure diiferentials acting upwardly and downwardly
head having been reconnected.
Yet another object of this invention is to provide a 60
new and improved well packer which may be sequen- ’
In FIG. '1 is shown a well packer 10 constructed in
A further object of this invention is .to provide a new 65 accordance with the principles of the present invention
and extending through a well casing 11 which traverses
and improved casing bridge plug which may be quickly
earth formations. The well packer is specifically de
and conveniently unseated in vorder to be reset at another
signed to vfunction as a casing bridge plug and hereafter
zone in the well or .to be retrieved to the surface.
thereon.
.
A still further object of this invention is to provide
will be referred to as the bridge plug 10. The bridge
a new and improved well packer adapted for use as the 70 plug 10 comprises a housing 15 at its lower end within
which is concentrically and 'slidably received for limited
lower packer in a straddle packer arrangement >for -a d-rill
stem testing or treating or squeezing operation, whereby
longitudinal 'movement relative thereto the lower end
3,019,842
of a tubular mandrel 16. A retrieving head 17 is re
leasably secured to the upper end of the mandrel 16
facture and assembly, the surfaces 60 are included on a
and is adapted to be operatively connected to a tubing
tubular section 62 connecting the‘upper and lower ex
pander means. The lower annular portion 63 of the sub
61V slidably contacts the housing section 20 to assist in
lower mandrel sub 61 which is threadedly secured to a
string (not shown) for movement therewith.
The housing 15 includes an upper tubular section 20
and a lower tubular section 21 threadedly secured to
assuring that the wedging surfaces 60 apply substantially
gether. The exterior of the section 2l is formed with
equal radial forces to each of the slips 35. The upper
a plurality of ñat mounting surfaces 25 to each of which
expander means 50 is carried by the mandrel 16 at a
is fastened a friction pad assembly 27 providing fric
ñxed longitudinal distance from the lower expander
tion means for engaging the casing. Although but two l0 means 51 and includes downwardly and inwardly slop
are shown in this view, four such equally spaced mount
ing wedgíng surfaces 66 adapted toslidably engage the
ing surfaces 25 and friction pad assemblies 27 are pro
upper slip wedging surfaces 45 to apply an outwardly
vided in the preferred embodiment illustrated. Each
friction pad assembly 27 conventionally includes a mount
ing plate 3l), a flanged retainer frame member 31 iixed
thereto and a wall engaging pad 32 received within the
frame member 31 and spring urged outwardly against
directed setting force thereto when the bridge plug sets
’ against pressure differentials acting downwardly on the
plug.
The motion of the mandrel 16 relative to the housing
15 is limited and guided by a pin and slot arrangement.
the casing.
A pairvof diametrically opposite generally H-shaped index
A plurality of slips 35 are pivotally and slidably car
ried by the upper portion of housing section 20 for
pivotal radial movement outwardly into gripping en
gagement with the casing. The slips 35 are generally
rectangular members each having upper and lower por
tions rigidly connected together at their wide ends. The
outer faces of the upper and lower portions are sections 25
slots 7G and 71 are cut into the housing section 20 below
the slips 35. Received within each index slot is one of
of opposite slightly sloping frusto-conical surfaces. In
a pair of diametrically opposite setting pins 72 and 73
ñxed to and projecting laterally from the lower end of
the mandrel 16.
The shape of the index slots is better perceived from
any one of FIGS. 3a through 3g, which are simplified
diagrammatic views illustrating the manipulations re
the embodiment illustrated the slope of these surfaces is
quired to operate the bridge plug. Represented in these
about 2°, but if desired this slope may be somewhat less,
figures are the mandrel 16 received within the housing
i.e. substantially 0°, or somewhat greater. The outer
15. The housing is provided with the friction means
face of the upper portion of each of the slips is provided 30 27 yand the guiding and locking slot 71. Also shown is
with downwardly pitched serrations or wickers 36 and
the retrieving head 17 releasably secured to the upper
the outer face of the lower portion is provided with
end of the mandrel 16 by Ia pin and J-slot arrangement
upwardly pitched serrations 37. Each of the slips 35
to be described hereafter, and the upper and lower pack
is loosely slidably received within a rectangular open
ing 4@ in the housing section 20 (see FIG. 5) one is
positively secured to the section 20 by a horizontal pin
42 located midway relative to the length of the opening
4l). Each pin is spaced radially from the longitudinal
` ing cup assemblies 53 and 54.
The H-shaped slot 71 comprises a long leg 80 and
a short leg 81 circumferentially spaced from leg 80 along
housing 15 centered longitudinally relative to leg 80. A
centrally located connecting portion 82 extends between
axis of housing 15 and is received within a radially ex
legs 80 and 81. The slot 70 is identical to slot 71 and
tending slot 43 in its corresponding one of the slips 35, 40 has a similar circumferential orientation relative to
as best seen in FIG. 2.
housing 15 whereby the two setting pins 72 and 73 are
Formed on the inner surface of each of the slips 35
are upper and lower sloped ñat wedging surfaces 45
and 46, respectively. The upper surface 45 is sloped
upwardly and outwardly, while the lower surface 46 is
sloped downwardly and outwardly. These wedging sur
faces are adapted to be independently engaged by ap
propriate expander means on the mandrel 16 in such a
manner as to slide each slip 35 radially outward along
alt every position in corresponding portions of the two
s ots.
The dimensions and arrangement of the short leg 81
are chosen such that the expander means 50 and 51 are
prevented from moving into setting position when the
pin 73 is within this portion of the slot 71. The long
leg 80, however, is of suiiicient length to permit the
expander means to move upwardly or downwardly, as the
its slot 43 while initially simultaneously pivoting it ap
case may be, into full setting engagement with the slips
proximately 2° about its pin 42 to bring the wickers 36 50 35. When running in and going out, the pins 72 and 73
or 37 into parallelism with the casing. Thus, the down
are located within the short legs of their respective slots,
wardly tapering upper wickers 36 grip the casing when
and since rotation is required to move into the long legs,
the plug sets against pressure differentials acting down
it follows that this pin and slot means locks the bridge
wardly on the plug while the upwardly tapered lower
plug 10 against premature setting.
wickers 37 grip the casing when the plug sets against 55 As mentioned earlier, the mandrel 16 carries packer
pressure differentials acting upwardly from below the
means for packing olî the annulus between the mandrel
plug. Premature outward movement of the slips 35 such
Y 16 and the casing 11 against pressure differentials in
as in response to gravity, for instance, is prevented by
either direction acting upwardly or downwardly thereon.
upper and lower leaf springs 48 for each of the slips.
The leaf springs 48 are fastened to the housing section 60 This packer means is located above the expander means
50 and comprises the upper and lower packing cup as~
20 and engage upper and lower terminal portions of the
semblies
53 and 54 which are structurally identical, but
slips 35 to bias them to an inwardly retracted position.
oppositely directed. As shown in FIG. l, the lower pack
The mandrel 16 is an elongated tubular member carry
ing cup assembly 54 includes a flanged shoe member 9tì,
ing external vupper and lower slip expander means 50
a ring-like spider 91 therebelow in contact with the man
65
and 51. It> further has external, oppositely-directed
drel, and a packer cup 92 of an elastomer material se
packer cup assemblies 53 and 54 positioned above ex
cured between these elements. The free end of the cup
pander 50. In addition, valve means 56 is provided for
92 is inherently biased outwardly into engagement with
selectively blocking the ñuid passage through the man
the casing 11 and is spaced from the mandrel 16 whereby
drel.
More specifically, the lower expander means 51 is pro 70 Well fluid moving upwardly in the casing annulus in
vided by a plurality of upwardly and inwardly sloping
response to higher pressures below the plug 10 spreads
the cup 92 into sealing engagement with the casing.
flat surfaces 60 adapted to slidably engage the slips 35
The expander means 50 is carried by a mandrel sub
to apply an outwardly directed setting force thereto
95 threadedly connected at its upper end to a valve sub
when the bridge plug sets against a differential pres
sure acting upwardly on the plug. For ease of manu 75 96 having a longitudinal bore 97 and in turn, threaded
3,019,842
5
.
5
ing» cup assembly 53 to portion 96 of the m'andrel 1.6
in a manner resisting the high shear pressures involved,
the assembly 54 is received between opposing shoulders
100 and 101 on the subs 95and 96, respectively, which
are tightened toward each other to the desired degree.
when being lowered in the casing, the packing cup as
semblie‘s 53 and 54 trictionally engage the casing and the
retrieving head 17 exerts a downward force on the pin
130 urging 'it to the bottom of the mandrel slots. When
being raised withinthecasing, the head 17 exerts an
upward forceA on the retrieving pin 130 urging it to the
In similar fashion, the upper packing cup assembly 53
y top vof the mandrell slots. As will subsequently be more
to añ upper sub 98. In order to secure the lower pack
. including the upper cup 104 is wedged between opposing
shoulders on the subs 96 and 98.
It is evident that iluid . Y
the cup 104 spreads the 10
pressure acting downwardly on
cup 104 outwardly into sealing engagement with the cas
ing 11.
'
'
'
clear, the retrieving head cooperates with the upper valve
114 when the plug is being lowered through the casing to
prevent it from seating. When the plug is raised- through
the casing, the retrieving head actuates the stem 125 to
engage the lower valve ball 120 to prevent it from
seating.
To connect the bore of mandrel 16 with the casing
ln a typical operation employing the bridge plug 10, the
annulus, equalizing ports 107 are provided in sub 96
at a location between the packer cup assemblies 53 andk 15 retrieving head 17 is operatively connected to a tubing
string and opposite ends of the retrieving pin 130 are re
54. Additional equalizing ports 105 are located in sub
ceived within the J-slots 142 and 143. Ordinarilythe
97 in the vicinity of cup 104, while equalizing ports 169
bridge plug 111 is used in conjunction with a packer and
are provided in sub 95 adjacent cup 92.
the retrieving head is connected below the packer. For
The valve means 56 provides means for blocking the
instance, the bridge plug may be used with the full opening
fluid passage through the bore of mandrel 16 against the
packer by the same inventor which is described in appli
flow of fluid therethrough in either direction and is also
cation Serial No. 774,910, tiled November 19, 1958, and
arranged to allow the ilow of fluid therethrough in either
assigned to the same assignee as the present invention, in
direction, as is desired when lowering or raising the plug'
which case the retrieving head 17 is secured to the lower
within the casing 11. Specilically, valve means 56 in
cludes a chamfered upper valve head 114 which is mov 25 end of the packer mandrel. However, the bridge plug 10
may, if desired, be used as an independent unit without an
able into and out of engagement with an upper valve
seat 115 provided by the chamfered upwardly facing
upper packer or other parent tool in the tubing string.
When being lowered through the casing 11, the bridge
end 116 of sub 96. Valve 114 is actuated to a position
plug 10 is in the operating condition shown in FIG.r 1.
closing the bore of mandrel 16 in response to the down
ward flow of ñuid resulting when there is a higher 30 The upward ñow of fluid through the housing and man
drel lifts the lower valve ball 120 toward the lower valve
pressure of fluid above the plug 1t) than below. To block
seat 121. However, the retrieving head 17 exerts a down
the bore oi' mandrel 16 against the upward flow of lluid
ward force on the retrieving pin 130 maintaining it at the
resulting from higher pressures below the plug 1t) than
bottom of the mandrel slots 135 and 136. Thus, the stem
above, a lower valve is provided by a valve ball 120
which is movable into and out of engagement with a lower 35 125 extends below the lower valve seat 121 even though
valve seat 121 provided by the charnfered downwardly
facing end 122 of sub 96.
the lost motion connection 126, 127 is fully retracted due
to upward force exerted on the bottom of the valve head
extending longitudinally through the bore 99 of sub 96
legs 81 of the respective housing index slots 71 and 70,
retrieving pin 130 which has limited longitudinal move
ment within diametrically opposed slots 135 and 136 in
housing 15, the setting pins ordinarily remain at the
114 as a result of iluid ilow through the bore of mandrel
Control and connecting means are provided between
16. Since the stem 125 is positioned to prevent the
the upper and lower valves whereby only one valve may
be closed at any one time and whereby both valves may 40 lower valve ball 120 from seating, a fluid passage through
the plug is maintained.
move to open position to provide a iiuid by-pass when
It can be seen from FIG. 3a that when running in, the
raising and lowering the plug within the casing. To
setting pin 73 and also pin '72 are received within the short
this end, the upper valve head 114 is ñxed to a stem 125
and whose headed upper end 126 is slidable within a 45 whereby the bridge plug is locked against premature
setting. Since the friction means 27 frictionally engages
cylindrical lost motion housing 127. The cylinder 127
the casing during the descent and retards motion of the
is secured by a connector rod 128 to a laterally extending
bottom of the short legs 81, but in any event motion of
the mandrel sub 9S. The outer ends of the pin 130 are 50 the mandrel 16 relative to the housing 15 is restricted to
the path of the short leg 81 which is so arranged as to
headed in order to align the stem 125 in bore 97 to as
prevent the expander means 50 and 51 from being brought
sure proper seating of valve head 114 with the upper
into setting engagement with the slips 35.
valve seat 115. At the upper end of sub 95, a pin 138
On reaching the depth in the casing where it is desiredball 120. Thus, pin 138 prevents the valve ball 120 55 to set the' bridge plug, a series of operations are per
formed first to unlock the bridge plug and then to release
from blocking the bore of the mandrel 16 when the
the retrieving head 17 from the mandrel 16. The unlock
bridge plug is being retrieved.
ing operation requires moving the setting pins ’72 and 73
When being lowered or raised within the casing 11,
to the long legs ‘30 of the index slots 76 and 71, wherein
the bridge plug 1G is releasably connected at its upper
extends diametrically across at a location below the valve
most end to another well tool or directly to the tubing 60 suñicient longitudinal movement of the mandrel relative
to the housing enables the expander means 561 and 51 to
move into setting engagement with the slips 35. Here
head 17 includes a tubular housing 141 having an open
after the description will proceed with respect to only one
lower end to enable/it to slidably tit over the upper
set of pins and slots as illustrated in FIGS. 3a to 3g,
end of the mandrel 16 above the upper packing cup 104.
A pair of diametrically opposing J-slots 142 and 143 are ' it being understood that the diametrically opposite sets
string by means of the retrieving head 17. The retrieving
formed in the housing 141 to receive opposite ends of the
retrieving pin 135. As can be better seen in FIG. 3a, the
slot 143 includes a short, vertical leg 145 and a diagonal
leg 146 having a large downwardly opening entrance 146’
extending to the lower end of the housing 141.
The retrieving pin 130 is received within the J-slots
142 and 143 when running in and going out or when
moving to another depth within the casing 11 and is
accordingly urged toward one end or the other of their
of pins and slots have identical relative positions. The
arrows in these figures represent the rotation and longi
tudinal movement given to the tubing string at the surface
to move from the position illustrated in one ligure to that
of the next ligure.
.
To accomplish the unlocking, the tubing string is first
lowered to assure that the pin 73 is at the bottom of leg 81
and that the pin 130 is at the top of the curved portion
of the J-slot 143, as shown in FIG. 3oz.v Motion of the
respective mandrel slots 135 and 136> (FIG. 1). Thus, 75 housing 15 is retarded relative to mandrel 16 and retriev
3,019,842
8
lifted. These manipulations position the setting pin 73
movement of the lower portion of the slips 35 until the
outer surface thereof bearing the downwardly pitched
serrations 37 grippingly engages the casing. This grip
ping contact produces a resisting force which prevents
the bridge plug from moving upward in the casing due to
any lifting force created by the upwardly acting differen
at the top of the short leg 81 and the retrieving pin 130
tial pressure.
at the bottom of the short leg 1115 of the J-slot 143 as
seen in FIG. 3b. To position the setting pin in the long
outwardly directed sealing force on the lower packing
ing head 17 due to the engagement of the friction means
27 with the casing. The engagement of the packing kcup
assemblies 53 and 54 with the casing also retards motion
of the mandrel 16 to some extent. The tubing is then
turned to the left about two revolutions and subsequently
leg 8l) of index slot 71, the tubing next is simultaneously
lowered and rotated to the right about two revolutions.
This combination of forces moves the setting pin to near
the lower end of the long leg Sti of the index slot 71 and
r[he rresisting force increases, as does the
cup 92.y
Before describing the manner in which the plug 1@ is
unseated, operation in the case of higher pressure above
Vthe plug than below it will be considered such as is the
case when acidizingfluid fracturing, squeeze cementing
or the like. After the tool is lowered in the casing in the
positions the retrieving pin 131i at the top of the short leg
condition illustrated in FIG. l, fluid pressure above the
of the J-slot 142, as in FIG. 3c. This movement may
plug is increased to provide downwardly acting differen
partially set the slips 35 but does not move them into
tial pressure. This produces a downward flow of well
strong gripping engagement with the casing.
-fluid through the plug which acts on the valve head 114
To release the retrieving head 17 from the mandrel 16,
to urge it into seating engagement with the upper valve
the tubing is simultaneously rotated to the right about two
revolutions and lifted. This movement slides the curved 20 seat 115 as shown in FÍG. 5. The retrieving pin 13G,
being free of the retrieving head 17, of course, slides
portion of diagonal leg `1456 along the pin 130 and allows
downwardly within the slots 135 and 136, and the lower
the housing 141 to slide completely olf the upper end of
valve ball 121B drops and restson the pin 13S.
mandrel 16.
At this time there is no mechanical connection between
With the valve means 56 closed there is no fluid com~
the retrieving head 17 and the mandrel 16 and housing 15, 25 munication either through the plug or around-the plug,
the casing annulus being sealed by the engagement of the
these latter assemblies being maintained in place by the
upper packing cup 104 with the casing. As the differen
frictional engagement with the casing of the friction means
tial pressure across the plug builds up, the mandrel 16 is
27 and the packing cup assemblies 53 and 54. Full
forced downwardly within the housing 15 in the direc
setting of the slips 35 into gripping engagement with the
casing has not yet taken place. At this point in a cycle 30 tion of the long leg 89 of the index slot 71 (see FIG. 3e),
while friction pad assemblies 27 hold the housing essen
of operation the slips 35 may be set in response to pres
tially ñxed with respect to the casing. The mandrel
sure differentials in either direction above or below the
wedging surfaces 66 slide farther down along the slips
plug 10 inasmuch as setting does not require mechanical
wedging surfaces 45 and the upper downwardly sloping
linkage to the surface.
Let it be assumed, for example, that a Zone above the 35 wickers 36 are brought into parallel gripping engagement
with the casing wall in a manner similar to that described
plug is to be tested for fluid production. In other words,
above, i.e., the upper half of the slips 35 is initially ro
the plug 10 is to be set against higher pressures below
tated about 2° and moved radially outward. Thereafter,
than above it which creates an upward lifting force.
further engagement of the wedging surfaces produces only
For this condition, the lower expander means S1 should
move upwardly relative to the housing 15 to engage the 40 radially outward movement until the slips are set. As
heretofore explained, the initial movements of this set
lower slip wedging surface 46 and exert an outward force
ting action may take place when the plug is unlocked
thereon. The upward force to bring about this move
and the retrieving head 17 is released from the mandrel
ment is supplied when the pressure above the plug is
16. This gripping engagement produces a resisting force
reduced. As a consequence of the resulting pressure
proportional to the dilîerential pressure and prevents the
differential fluid flows upwardly through and against the
plug from being forced downwardly in the casing by
plug.
As can be seen in FIG. 4, Valve ball 120 and upper
» valve head 114 are lifted by this upward flow of fluid, and
they carry the stem 125 and retrieving pin 130 upwardly.
In the absence of retrieving head 17, the retrieving pin 130 50
slides upwardly in mandrel slots 135 and 136, thereby
permitting the stem 125 to rise a distance sufficient to
enable the valve ball 120 to seat on the lower valve
seat 121.
treating or squeezing pressures or the like applied above
the plug. The outward sealing force of the upper pack
ing cup 104 also increases as the pressure above it in
creases.
Since the setting of the slips takes place without any
mechanical linkage to the surface and since the valve
means 56 is arranged to seat from either longitudinal di
rection in response to flow of fluid through the plug, it
follows that any sequence of setting successively against
After the valve ball 120 seats, there is no fluid passage 55
differential pressures acting in either direction may be
accomplished. Thus, after being released from the re
annulus being now substantially fluid tight because of the
either through the plug or around the plug, the casing
trieving head 17, the bridge plug 10 may set in either
direction either against differential pressures acting down
built up, the upwardly acting force created thereby in 60 wardly or upwardly. Thereafter, the mandrel 16 moves
to the opposite setting position in response to the chang
creases until this lifting force lifts the mandrel 16 rela
ing
differential pressures and does so automatically for
tive to the housing 15 in the direction of the long vertical
any desired pressure sequence.
leg 80 of the index slot 71 (see FIG. 3d). Movement
To unseat the bridge plug 10 and bring it to the sur
of the housing 15 is inhibited because of the frictional
engagement of the casing by the friction pad assemblies 65 face, or for resetting it at another depth in the casing, the
retrieving head 17 may be reengaged with the mandrel
27. The lower mandrel surfaces 6€) are consequently
16 and the setting pin 73 must be repositioned in the
carried upward into sliding engagement with the lower
locking portion 81 of the index slot 71. In this way, lon
wedging surfaces 46, exerting an outwardly directed set
gitudinal travel of the lower expander means 51 is limited
ting force thereon which simultaneously urges the lower
portion of the slips 35 radially outward against the force 70 to prevent it fom setting the slips 35.
Referring to FIGS. 3f and 3g, the tubing is first lowered
of the leaf springs 48 and pivots the lower portion of
until the retrieving pin 130 enters the downwardly open
the slips 35 about 2° into parallelism with the casing.
ing wide-mouthed portion of the J-slot 143 and rides up
At this point in the cycle of operation, the wedging sur
wardly in the diagonal leg 146 to the top thereof. After
faces 46, 60 are parallel and further upward movement
of mandrel surface 6l) results solely in a radially outward 75 contact with the upper edge of the curved portion of the
engagement of the lower packing cup 92 with the casing
wall.
As the differential pressure across the plug is
3,019,842
10
trieved and removed from the well or it may be relocated
J-slot is made, weight is applied downwardly on the
tubing to position the setting pin 73 at the lower end of
the long leg Sli of the index slot. Of course, if the plug
had previously been in the position shown in FIG. 5
packing olf against a pressure differential acting _down
wardly, the pin 73 is already at the bottom of leg et?.
But if the plug has been in the FlG. 4 position, packing
with the full opening packer at a diûerent location in the
Wen;
l It is to be understood that the _invention has been
described and illustrated -with regard to a’preferred em
bodiment only, and that various changes and modifications
may be made and equivalents utiliized by those skilled in
the art without exercising invention or departing from the
spirit thereof as set forth in the following claims.
oif against a pressure differential acting upwardly,A the
application of weight to the tubing at this point slides
the pin 73 downwardly in the slot Sti. To move the pin
73 to the top of the short leg 81 of index slot 71 and
to move the pin 1.30 to the bottom of the short leg 14S of
the J-slot 145, the tubing is rotated to the left until a
small amount of resistive torque is noted and then is
lifted.
Y
The bridge plug is now ready to be retrieved.
During retrieving, the valve means HS6 assumes the
operating condition shown in FIG. 6. The upward force
exerted by head 17 on the retrieving pin 13€? causes it to
What is claimed is:
_ 1. In a bridge plug positionable within a casing: a tubu
15
lar housing, friction means carried by said housing for
engaging the casing, slip means pivotally and slidably
carried by said housing for pivoting and radial movement
outwardly into gripping engagement with said casing, a
tubular mandrel having a lower end slidably received
within said housing for limited longitudinal movement
relative thereto, longitudinally spaced expander means
carried by said mandrel for independently wedging al-w
move to the upper ends of Ytheimandrel slots 135 and 136, 20 ternate opposite ends of said slip means into gripping en-~
keeping the upper valve head 114 off its seat 115 even
gagement with the casing, elastomer packing means cará
though the downward ñow of fluid through 'the plug
ried by said mandrel above said expander means for
exerts a downward force thereon causing the lost mo
packing olf against pressure differentials acting upwardly
tion connection 126, 127 to become fully extended. The
and downwardly thereon, valve means received in said
lower valve ball 129 drops and rests against pin 138. 25 mandrel operative by ñow of fluid through said tubular
There is consequently a fluid by-pass through the plug
mandrel and housing for blocking the flow of fluid there
as it is withdrawn through the well to the surface or to
through in either longitudinal direction, and a retrieving
a lesser depth where it is desired to reset the plug as
already explained.
head adapted to be operatively connected to a tubing
string releasably connected to said mandrel and to por
Should it be desired to unseat the bridge plug 10 and 30 tions of said valve means and urging said valve means to
reset at a lower depth, the same unseating procedure as
open positions permitting liow of fluid through said man-`
set forth above is carried out, that is, the setting pin '73
drel and housing in either direction.
is moved to the upper end of the short leg S1 of the index
2. în a retrievable bridge plug positionable within a
slot and the retrieving pin 13@ is positioned at the closed
casing, a tubular housing, friction means c'ar'r'ied by said
end of the J-slot 143. Thereafter, however, the tubing 35 housing for engaging the casing, bridge plug slips each
string is lowered, and the pins and slots move to their
having oppositely tapering upper and lower portions
FÍG. 3a positions while the valve means 56 assumes the
rigidly connected together and bearing casing gripping
operating condition of FIG. l. At the new lower level the
serrations on the outer faces thereof, means mounting said
plug may be reset as explained with regard to FÍGS. 1,
slips on said housing' for radial and pivotal movement
40 outwardly into gripping engagement with the casing, a
4 and 5.
The bridge plug 1li thus may advantageously be un
tubular mandrel having a lower end slidably received with
seated and retrieved to the surface or may be reset at a
in said housing for limited longitudinal movement rela
new higher or lower level. A wide variety of operations
tive thereto, upper and lower expander means spaced
may be carried out with the plug constructed in accordance
from one another at a fixed distance and carried by said
with this invention since it sets against diiferentialpres 45 mandrel for independently wedging alternate opposite
sures acting upwardly or downwardly thereon without
mechanical linkage to the surface or a parent tool. Haw
ing set against differential pressures acting in one direc
tion, it is capable of automatically setting against dif
ferential pressures acting in the other direction, the setting
force being provided by the liow of fluid through the tool
and by the diiferential pressure itself. Only one trip of
the tubing string is necessary to initially lower the plug
into the well and to retrieve it to the surface at the corn
pletion of the final operation.
The plug 10 is especially suitable for use below a full
opening packer as the lower packer in a straddle packer
arrangement. The distance that may be straddled is vir
tually unlimited due to the fact that the bridge plug is
ends of said slips into gripping engagement» with the cas->
ing, packer means carried by said mandrel above- said ex
pander means for packing off against higher pressures
thereabove and therebelow, releasable valve means re
50 ceived in said mandrel operative by pressure differentials
for blocking the longitudinal flow of liuid through said
tubular mandrel downwardly and upwardly, and a re
trieving head releasably connected to said mandrel, said
retrieving head being arranged to cooperate with said
55 valve means to' hold said valve means in positions permit
ting now of ñuid through said tubular mandrel and hous
ing in either direction.
'
3. In a bridge plug positionable within a casing, a tubu
lar housing, friction means' carried by said housing for
released from the retrieving head after it is unlocked. 60 engaging the casing, bridge plug slips each having op
After being released, it will set and pack off against
posite'ly tapered upper and lower portions rigidly con
pressure differentials in either direction. With the plug
set below the casing perforations and the full opening
packer set above them, such operations as drill stem test
nected at their wide ends and bearing casing gripping
serrations on the outer arcuate faces thereof, pin and slot
means mounting said slips on said housing for pivotal and
65 radial movement: outwardly into engagement with the'
casing, a> tubular' rha'n‘dr'el having a lower end slidably
gun perforating may be carried out. When testing is to be l
ing, acidizing, fluid fracturing, squeeze cernenting and
included in the sequence of operations, a full opening`
testing tool such as that by the same inventor described in
received within said housing',- longitudinally spaced ex
pander means carried by said mandrel and arrar'ig'ed> to
independently engage alternate opposite ends of said slips
application Serial No. 775,023, filed November 19,- 1958
and application Serial No. 775,002, filed November 19, 70 to set said slips and limit longitudinal movement of said
1958 and assigned to the same assignee as the present
mandrell within said housing, upwardly and downwardly
invention, may be conveniently used in cooperation with
the full opening packer by the same inventor heretofore
identiñed. Following the completion of these operations
said expander' mealisifor' engaging the casing and packing
directed packer cup means carried by said mandrel above
off against pressure differentials in either direction above
at this interval in the well, the bridge plug may be re 75 and below the plug", valve means- mounted in said man~
3,019,842
M
12
drel for movement between positions blocking upward
ñow of fluid through said mandrel and blocking down
expander means ñxed to said mandrel for upward move
ment therewith into setting engagement with the lower
ward flow of ñuid through said mandrel, and a retrieving
head adapted to be operatively connected to a tubing
string releasably connected to said mandrel and coopera
portion of said slips, pin and slot means for releasably
limiting longitudinal movement of said mandrel relative
to said housing to prevent premature setting engagement
ing with said valve means to move said valve means to
of said expander means with said slips, upper and lower
positions allowing tlow of fluid through- said mandrel in
packing cups secured to said mandrel above said ex
either direction.
pander means for packing olf against pressure differentials
acting upwardly and downwardly thereon, an upper valve
within said tubular mandrel for blocking iluid iiow there
through and movable to a closed position by pressure dif
ferentials acting downwardly thereon, a lower valve with
in said tubular mandrel for blocking iiuid How there
through and movable to a closed position by pressure
_
4. In a retrievable and resettable bridge plug position
able within a casing, a tubular housing, friction means car
ried by said housing for engaging the casing, bridge plug
slips each having oppositely sloped upper and lower por
tions rigidly connected together and bearing casing
gripping serrations, means pivotally and slidably mount
ing said slips on said housing for pivotal and radial move
ment outwardly into gripping engagement with the cas
ing, a tubular mandrel having a tiuid passage longitudinally
diderentials acting upwardly thereon, a retrieving head
said mandrel `for engaging the casing and packing oí
against pressure differentials acting upwardly and down
portions rigidly connected together at their wide ends
adapted to be operatively connected to a tubing string,
and means for releasably connecting said retrieving head
therethrough slidably received within said housing, longi
to said mandrel, said means including portions cooperat
tudinally spaced upper and lower expander means se
ing with said upper and lower valves to urge said valves
cured to said mandrel and arranged to independently en 20 to open positions allowing ñuid flow through said tubular
gage alternate opposite inner ends of said slips to move
mandrel in `either direction.
said slips into gripping engagement with the casing, pin
7. ln a retrievable and resettable bridge plug, position
and slot means for limiting motion of said mandrel rela
able within a casing, a tubular housing, friction means
`for engaging the casing carried by said housing, bridge
tive to said housing to releasably prevent said expander
means from setting said slips, packing means carried by 25 plug slips each having oppositely tapered upper and lower
wardly thereon, valve means received in said mandrel op
erative by ñow of ñuid in either direction through said
and bearing casing gripping wickers on the outer arcuate
faces thereof, pin and slot means mounting said slips on
said housing for pivoting and sliding movement out
tubular mandrel for releasably blocking said ñuid pas 30 wardly into gripping engagement with the casing, a tubular
sage, and a retrieving head adapted to be connected to
mandrel received within said housing for limited longi
a tubing string releasably connected to said mandrel and
tudinal sliding movement relative thereto, said tubular
mandrel and housing defining a longitudinally extending
"alve means and urging said valve means to positions un
ñuid passage therethrough, oppositely directed packing
blocking said fluid passage.
5. In a retrievable and resettable bridge plug position
cup assemblies carried by said mandrel for packing olf
able within a casing, a tubular housing, friction means car
against said casing in response to pressure differentials act
ried by said housing for engaging the casing, bridge plug
ing upwardly and downwardly thereon, a retrieving head
slips having upper and lower oppositely tapered portions
adapted to be operatively connected to a tubing string for
rigidly connected together at their wide ends, means pivot
movement therewith, valve means within said tubular
40
ally and slidably mounting said slips on said housing for
mandrel, said retrieving head being releasably connected
pivotal and radial movement outwardly into gripping en
to said valve means to urge said valve means to open posi
gagement with the casing, means urging said slips inwardly
tions unblocking said ñuid passage, said valve means being
to an initially retracted position, a tubular mandrel having
arranged when released from said retrieving head to
a lower end slidably received in said housing for limited
move to closed positions blocking said ñuid passage in re
longitudinal movement relative thereto said mandrel hav
ing a fluid passage longitudinally therethrough, an upper
expander means carried by said mandrel for movement
downwardly therewith into setting engagement with the
sponse to upward and downward flow of fluid there
through, upper expander means carried by said mandrel
for movement downwardly therewith into sliding engage
ment with the upper portion of said slips to urge said
upper portion of said slips, lower expander means car
upper slip portion wickers into gripping engagement with
ried by said mandrel for movement upwardly there 50 the casing, and lower expander means carried by said
with into setting engagement with the lower portion of
mandrel for movement upwardly therewith into sliding
said slips, upper and lower packing cups carried by said
engagement with the lower portions of said slips to urge
mandrel above said expander means for packing olî
said lower slip portion wickers into gripping engagement
against differential pressures acting downwardly and up
wardly thereon, valve means received in said mandrel op
erative by ñow of ñuid longitudinally through said tubu
lar mandrel in either direction for blocking said ñuid
passage, and a retrieving head adapted to be operatively
connected to a' tubing string releasably connected to said
mandrel and to said valve means for holding said valve
means in positions unblocking said ñuid passage for ñuid
flow in either direction.
6. In a retrievable and resettable bridge plug position
able within a casing, tubular housing, friction means car
ried by said housing for engaging the casing, bridge plug
slips having oppositely sloped upper and lower face por
tions rigidly connected together and bearing casing
gripping wickers, means pivotally and slidably mounting
said slips on said housing for pivotal and radial move
ment outwardly into gripping engagement with the casing,
a tubular mandrel having a lower end slidably received
with the casing.
8. In a well packer positionable within a casing, a
tubular housing, friction means carried by said housing
for engaging the casing, bridge plug slips having op
positely tapered upper and lower portions rigidly con
nected together at their Wide ends, casing gripping
wickers on the outer faces of said upper and lower por
tions, means pivotally and slidably mounting said slips on
said housing for pivoting radial movement outwardly
into gripping engagement with the casing, 'a tubular
mandrel slidably received within said housing for limited
longitudinal movement relative thereto, said tubular man
drel and housing defining a longitudinally extending iiuid
passage therethrough, upwardly and downwardly directed
packing cup assemblies carried by said mandrel for pack
ing oft against said casing in response to pressure dilîer
entials acting upwardly and downwardly thereon, a re
trieving head adapted to be operatively connected to a
tubing string for movement therewith, valve means With
in saidl tubular mandrel, said retrieving head being re~
within said housing for limited longitudinal movement
relative thereto, upper expander means ñxed to said
mandrel for downward movement therewith into setting
leasably connected to said valve means to hold said valve
engagement with the upper portion of said slips, lower 75 means in positions allowing ñuid flow through said tluîd
3,019,842
13
passage in either direction, said valve means being ar»
ranged when said retrieving head is released therefrom to
move to positions blocking said fluid passage in response
to upward and downward fluid flow therethrough, upper
1d.
in response to upward iiuidV flo-w therethrough, longitu
dinally spaced upper and lower expandermeans iixed to
said mandrel for movement therewith, said mandrel mov
ing downwardly in response to pressure differentials act
ing downwardly thereon when said ñrst valve is closed to
slidably engage said upper expander means with said up~
expander means carried by said mandrel for movement
downwardly therewithin into sliding engagement with the
upper portions of said slips to urge said upper portions
into gripping engagement with the casing, lower expan
per tapered portion of said slips and urge said upper por
_tion wickers into gripping engagement with the casing,
der means carried by said mandrel for movement up
said mandrel moving upwardly in response to pressure »
wardly therewith into sliding engagement with `the lower l() differentials acting upwardly thereon when said second
valve is closed to slidably engage said lower expander
portions of said slips to urge said lower portions into
means with said lower tapered portion of said slips to
gripping engagement with the casing, land releasable lock,
urge said lower portion wickers into gripping engagement
ing means for preventing premature setting engagement
with the casing, pin and slot means for guiding the longi
of said expander means and said slips.
9. In a bridge plug positionable within a casing, a 15 tudinal movement of said mandrel relative to said hous
ing and for releasably limiting said longitudinal move
tubular housing, friction means carried by said housing
ment to prevent said expander means from moving into
for engaging the casing, bridge plug slips having opposite
setting engagement with said slips, a retrieving head
ly tapered upper and lower portions rigidly yconnected _to
adapted to be operatively connected to a tubing string,
gether at their wide ends and bearing casing gripping
wickers on the ,outer arcuate faces thereof, pin and slot 20 and means releasably connecting said retrieving head and
said upper valve and cooperating with said lower valve to
means pivotally and slidably mounting said 'slips on said
move said valves to open positions allowing fluid flow
housing for pivotal and radial movement outwardly into
through said mandrel in either direction.
gripping engagement with the casing, a tubular mandrel
11. In a packer positionable within a casing, a tubular
received within said housing for limited longitudinal
movement relative thereto, said tubular mandrel and 25 housing, friction means carried by said housing for engag
ing the casing, a plurality of bridge plug slips arranged cir
housing defining a longitudinally extending fluid passage
cumferentially about said housing, each of said slips in
therethrough, oppositely directed packing cup assemblies
cluding an upwardly tapered upper portion and a down
carried by said mandrel for packing olf against said cas
wardly tapered lower portion rigidly connected together
ing in response to pressure differentials acting upwardly
and downwardly thereon, a first valve in said tubular 30 at their wide ends, said upper and lower portions each
having an outer arcuate face provided with casing gripping
mandrel movable to a closed position blocking said fluid
passage in response to downward iluid iiow therethrough,
serrations, means pivotally and slidably securing each of
a second valve in said tubular mandrel movable to a
said slips to said housing intermediate said upper and low
closed position blocking said fluid passage in response to ’ erV portions, means for urging each of said slips to an in
upward ñuid flow therethrough, a retrieving head adapted` 35 Wardly retracted position, a mandrel slidably received in
to be operatively connected-to a~tu`oing string for move
said housing, upper expander means fixed to said mandrel
ment therewith, a pin on said mandrel and a slot on said l
and arranged to move downwardly therewith into wedging
retrieving head releasably connecting said retrieving head
engagement with said upper portions of said slips to pivot
and mandrel, means operatively connecting said pin and
said slips and slide said slips radially outwardly, whereby
said first valve and engageable with said second valve, 40 said upper portion serrations move into gripping engage
said pin and connecting means being urged by said re
ment with the casing, lower expander means fixed to said
trieving head to positions preventing said first and second
mandrel and arranged to move upwardly therewith into
valves from closing', whereby fluid by-passes said mandrel
wedging engagement with said lower portions of said slips
and housing, upper expander means carried by said man
to pivot said slips and slide said slips radially outwardly,
drel for movement downwardly therewith into sliding en
45 whereby said lower portion serrations move into gripping
gagement with the upper portion of said slips to urge
engagement with the casing, locking means for releasably
said upper portion wickers into gripping engagement with
limiting the longitudinal movement of said mandrel rela
the casing, lower expander means carried by said man
tive to said housing to prevent said expander means from
drel for movement upwardly into sliding engagement with
moving into wedging engagement with said slips, and
the lower portion of said slips to urge said lower portion
means for moving said mandrel relative to haid housing.
50
wickers into gripping engagement with the casing, and re
12. In a packer positionable within a casing, a tubular
leasable locking means for preventing premature engage
housing, friction means carried by said housing for en
ment of said expander means and slips.
gaging the casing, a plurality of bridge plug slips arranged
l0. In a retrievable and resettable bridge plug position
circumferentially about said housing, each of said slips in
able within a casing, a tubular housing, friction means
cluding an upwardly tapered upper portion and a down~
55
carried by said housing for engaging the casing, bridge
wardly tapered lower portion rigidly connected together
plug slips pivotally and slidably mounted on said housing
at their wide ends, said upper and lower portions each
for pivotal and radial movement outwardly into gripping
having an arcurate outer face provided with casing grip
engagement with the casing, Said slips each including an
ping serrations, pin and slot means pivotally and slidably
upwardly tapering upper portion having an outer arcuate
securing each of said slips to said housing intermediate
60
face provided with casing gripping wickers and also iu
said upper and lower portions thereof, means for urging
cluding a downwardly tapering lower portion rigidly con
said slips to an inwardly retracted position, a tubular man»
nected to said upper portion ‘and having an outer arcuate
face provided wtih casing gripping wickers, means for
drel slidably received within said housing, upper expander _
means fixed to said mandrel and arranged to move down
urging said slips to -a retracted position, a tubular man
wardly therewith into wedging engagement with said
drel having a lower end slidably received within said 65 upper portions of said slips to pivot said slips and slide
housing for limited longitudinal movement therealong,
said tubular mandrel and housing defining 'a longitudinal
ly extending fluid passage therethrough, upwardly and
said slips radially outwardly, whereby said upper portion
serrations move into gripping engagement with the casing,
lower expander means fixed to said mandrel and arranged
drel for packing off against the casing in response to 70 to move upwardly therewith into wedging engagement
downwardly directed packing cups mounted on said man
pressure differentials 'acting upwardly and downwardly
thereon, a first valve within said mandrel movable to a
with'said lower portions of said slips to pivot said slips and
slide said slips radially outwardly, whereby said lower por
tion serrations move into gripping engagement with the
closed position blocking said fluid passage in response to
casing, pin and slot means on said mandrel and housing
downwardly fluid flow therethrough, a second valve
movable to a closed position blocking said ñuid passage 75 for guiding the longitudinal movement of said mandrel
3,019,842
iii
16
relative to said housing and for releasably limiting said
said slips to place said slips into gripping engagement with
longitudinal movement to prevent said expander means
the casing, packing means carried by said mandrel for
packing otî against pressure differentials, valve means in
said mandrel selectively operable to open and close the
from moving into wedging engagement with said slips,
and hydraulically actuated means for moving said mandrel
longitudinally relative to said housing.
,Y
13. In a bridge plug positionable within a casing: a
tubular housing, slip means carried by said housing for
movement outwardly into gripping engagement with a cas
ing, said slip means including unitary elongated slip mem
bers for engaging the casing, said members each having
upper and lower inner surfaces inclined relative to one
another to provide tapered ends on said slip members, a
tubular mandrel having a lower end slidably received
within said housing for limited longitudinal movement
relative thereto, longitudinally spaced, oppositely inclined
passageway through said mandrel, and a retrieving head
adapted to be releasably connected to said mandrel to per
mit manipulation of said mandrel and said valve means.
l5. In a bridge plug positionable within a casing: a
tubular housing, a'tubular mandrel slidably received with
in said housing for limited longitudinal movement relative
thereto, bridge plug slips carried by said housing for move
ment outwardly into gripping engagement with a casing,
said slips individually having outer serrated surfaces and
inner tapered wedge surfaces, said wedge surfaces being
oppositely inclined; means to resiliently bias said slips
inwardly towards said tubular mandrel, a pair of longi
tudinally spaced expander means carried by said mandrel
expander means carried by said mandrel for independently
and alternately wedging said inner surfaces of said slip
and on opposite sides of said slips, said expander means
members to place said slip members into gripping engage
having inclined surfaces for independently and alternately
ment with the casing, elastomer packing means carried by
said mandrel for packing olf against pressure differentials, 20 wedging opposite ends of said slips into gripping engage
ment with the casing, packing means carried by said man
valve means in said mandrel for blocking the llow of iiuid
drel for packing oil against pressure differentials, valve
through said mandrel, and a retrieving head adapted to be
means in said mandrel selectively operable to open and
releasably connected to said mandrel and to portions of
close the passageway through said mandrel, and a retriev
'
~
14. In a bridge plug positionable within a casing: a 25 ing head adapted to be releasably cannected to said man
drel to permit manipulation of said mandrel and said valve
tubular housing, a tubular mandrel slidably received with
said valve means to operate said valve means.
in said housing for limited longitudinal movement rela
means.
tive thereto, bridge plug slips carried by said housing for
movement outwardly into gripping engagement with a cas
. References Cited in the file of this patent
ing, said slips having a unitary construction with upper 30
UNITED STATES PATENTS
and lower inner surfaces inclined relative to one another
to provide tapered ends on said slips, means to resiliently
bias said slips inwardly towards said tubular mandrel, a
pair of longitudinally spaced expander means carried by
2,607,424
2,751,012
2,799,346
Taylor _______________ __ Aug. 19, 1952
Baker et al ________ 2...-..- June 19, 1956
Baker et al _____________ .__ July 16, 1957
said mandrel and on opposite sides of said slips for in
2,802,534
Conrad ______________ _.. Aug. 13, 1957
dependently and alternately wedging said inner surfaces of
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