[0001] The invention relates to a wireline method and apparatus for sealing a well casing
having a length of smaller diameter production tubing therein, including a bridge
plug, and components therefor, which is passable through the production tubing and
into the well casing.
[0002] In the production of hydrocarbons, it is typical to provide a casing within the borehole
and to perforate the casing along its length adjacent a particular formation which
contains the hydrocarbons to be produced. Typically, production tubing is disposed
within the casing and the production tubing is sealed within the casing as by a conventional
packer. The hydrocarbons then flow from the producing formation through the perforations
in the well casing and upwardly to the surface via the production tubing.
[0003] Frequently, a particular formation, from which hydrocarbons had previously been flowing,
ceases to flow the desired hydrocarbons, but rather undesired fluids, such as water,
begin to flow into the casing. If another formation exists adjacent the casing, such
formation being located above the first formation which is now flowing undesired fluids,
the casing is sealed above the first group of perforations. Thereafter the casing
is again perforated along its length adjacent the second formation from which hydrocarbon
fluids are desired to be produced.
[0004] Although many devices exist which can be utilized to seal a well casing, and can
be readily passed through the well casing to the desired location along the well casing,
most of these devices cannot pass through conventional production tubing because of
their size. Thus, in order for these conventional devices to be utilized in the previously
described situation of a producing well having production tubing therein, it is necessary
to remove the production tubing in order to use such devices to seal off a section
of the well casing. This is a costly and time consuming operation, the cost and time
increasing proportional to the depth of the well and the length of the production
tubing. Furthermore, conventional devices require a work-over rig to be installed
at the well site, which results in considerable delay and expense.
[0005] Two wireline suspended devices have previously been proposed to seal a well casing,
such devices being capable of first passing through the production tubing disposed
within the well casing. One of these devices is a collapsible metal petal basket which
is lowered through the production tubing and into the well casing to the desired depth
where the casing is to be sealed. At that point within the well casing, the petals
of this device are caused to swing outwardly into engagement with the well casing.
Gravel and/or sand are then passed through the production tubing and land on top of
the metal petal basket. Thereafter, cement is poured on top of the gravel and/or sand.
Upon curing of the cement, a cement plug is provided at the desired depth in the well
casing. The disadvantages of utilizing this device are that it typically takes a long
period of time for the cement to properly cure. Since the undesired fluids flowing
in the well casing beneath the cement may be still flowing, and are frequently flowing
under substantial pressure, the cement does not cure properly and/or the integrity
of the seal between the cement and the well casing is not of the quality which is
desired due to a high differential pressure acting upon the cement, as well as from
the roughened ad contaminated surface conditions of the well casing due to corrosion,
sludge, paraffin, and/or carbonate. Additionally, the time required from the start
of the cement plugging process until the well can be placed back into service can
be excessive and often very expensive.
[0006] Another device (see US-A-3 460 624) which has been utilized to provide the desired
sealing of a well casing and which can be passed through the production tubing is
an inflatable rubber bladder. This bladder is placed at the desired depth where the
seal is to be placed within the well casing, and the bladder is then inflated. Typically,
the bladder is of thin-wall construction to facilitate its passage through the tubing
and its inflation. After the bladder has been inflated, cement is poured over the
bladder and the desired sealing is effected upon the cement curing. The disadvantages
with this device are that because of the pressure and temperature conditions existing
down-hole, as well as the roughened and contaminated surface conditions of the well
casing previously described, the bladder frequently ruptures upon being inflated,
or ruptures after the cement has been poured upon the bladder, but before the cement
has cured. Thus, it is necessary to start over to attempt the sealing procedure. Further,
some of these bladder devices have been provided with a vent tube about which the
bladder is secured. This vent tube is utilized to relieve pressure from below the
bladder until such time as the cement has sufficiently cured. After the cement has
cured, the vent tube is then sealed off. Frequently, the diameter of the vent tube
is not large enough to supply the necessary pressure relief, whereby the rubber bladder
frequently bursts due to the excessive pressure build-up exerted upon the rubber bladder.
[0007] Accordingly, prior to the development of the present invention, there has been no
method and/or apparatus for sealing a well casing, which: is first passable through
production tubing to the desired depth in the well casing; is not subject to damage
during installation; is not dependent upon cement which must be cured in order to
provide the desired sealing; provides 100% seal integrity; can withstand high temperature
and pressure conditions; is economical to manufacture and use; and quickly provides
the desired sealing. Therefore, the art has sought a method and apparatus for sealing
a well casing which is: passable through production tubing; does not require the use
of cement; provides high quality seal integrity; is efficient to manufacture ad use;
does not require excessive time to provide the desired sealing; can withstand high
pressure and temperature conditions; and is not readily subject to damage while being
utilized.
[0008] Patent US-A-3 706 342 (Woolley) discloses a brige plug for insertion through a tubing
to engage the casing at a point below the tubing. The bridge plug comprises a generally
tubular element of an elastomeric material disposed along a mandrel in an initial
unstressed configuration with a diameter less than the tubing diameter. Upon application
of endwise force to the element, the pressure will rupture weakened portions of the
element and will cause sections of the packing element to overlap or spiral upon each
other, converting the element into a multiple layer body of increased diameter.
[0009] Accordingly, one aspect of the present invention is directed to a bridge plug, for
use within a well casing and passable through production tubing, as set forth in claim
3.
[0010] Another aspect of the present invention is directed to a method for sealing off a
length of well casing as set forth in claim 1.
[0011] Other preferred features of the invention are set forth in the dependent claims.
[0012] In the drawings:
FIGS. 1 and 2 are partial cross-sectional views along the longitudinal axis of a well
bore schematically illustrating the intended use of the method and apparatus in accordance
with the present invention;
FIG. 3 is a partial cross-sectional view along the longitudinal axis of a bridge plug
in accordance with the present invention, when it is being passed through production
tubing;
FIG. 4 is a partial cross-sectional view along the longitudinal axis of a bridge plug
in accordance with the present invention, when it has been placed within the well
casing to seal the well casing;
FIG. 5 is a partial cross-sectional view of an elastomeric sealing element for a bridge
plug in accordance with the present invention;
FIG. 6 is a partial cross-sectional view along the longitudinal axis of an elastomeric
sealing element for a bridge plug in accordance with the present invention, illustrating
the sealing element as it is passed through the production tubing;
FIG. 7 is a partial cross-sectional view of an elastomeric sealing element for a bridge
plug in accordance with the present invention, illustrating the sealing element as
it is disposed when sealing the well casing;
FIG. 8 is a plan view of a blank used to form a reinforcing element for a bridge plug,
in accordance with the present invention;
FIG. 9 is a partial cross-sectional view along the longitudinal axis of a reinforcing
element for a bridge plug in accordance with the present invention, shown in its configuration
for passing through production tubing;
FIG. 10 is a cross-sectional view taken along line 10-10 of FIG. 9;
FIG. 11 is a plan view illustrating two reinforcing elements for a bridge plug in
accordance with the present invention, illustrating two superimposed reinforcing elements
in their configuration after being compressed and disposed within the well casing;
FIG. 12 is a side view of an anchoring assembly for a bridge plug in accordance with
the present invention;
FIG. 13 is a partial cross-sectional view taken along line 13-13 of FIG. 12;
FIG. 14 is a partial cross-sectional view taken along line 14-14 of FIG. 13;
FIG. 15 is a partial cross-sectional view along the longitudinal axis of a portion
of a bridge plug and its setting means in accordance with the present invention; and
FIGS. 16a and 16b are a cross-sectional views along the longitudinal axis of a pressure
intensifier for a bridge plug setting tool in accordance with the present invention.
[0013] While the invention will be described in connection with the preferred embodiment,
it will be understood that it is not intended to limit the invention to that embodiment.
On the contrary, it is intended to cover all alternatives, modifications, ad equivalents
as may be included within the spirit and scope of the invention as defined by the
claims.
[0014] In FIGS. 1 and 2, a borehole 170 is disposed in the earth's surface 171, which borehole
170 has been provided with a conventional well casing 172. As shown in FIG. 1, a first
set of perforations 173 have been provided in well casing 172 adjacent a hydrocarbon
producing formation 174. Conventional production tubing 175, having a diameter less
than the diameter of the well casing 172, is disposed within well casing 172 and is
sealed about its end in a conventional manner as by a packer 176. The hydrocarbons,
as illustrated by arrows 177, flow upwardly to the earth's surface 171 via production
tubing 175. Upon the formation 174 producing undesired fluids, such as water, it becomes
necessary to seal well casing 172 at a depth disposed above the first set of perforations
173. With reference to FIG. 2 a seal, or plug, shown schematically as 178, is disposed
within well casing 172 above the first set of perforations 173 adjacent formation
174, which now has water 179 and/or other undesired fluids flowing through perforations
173. After seal, or plug, 178 has been disposed within well casing 172, perforations
180 are provided in a conventional manner in well casing 172 adjacent another hydrocarbon
producing formation 181, through which hydrocarbons 182 may flow upwardly through
production tubing 175, as previously described. In order to most efficiently, expeditiously,
and economically provide seal 178 in well casing 172, it is necessary to utilize a
device capable of passing through the reduced diameter production tubing 175.
[0015] With reference to FIGS. 3 and 4, a bridge plug 183, in accordance with the present
invention, for use within a well casing 172 and passable through production tubing
175, is shown. FIG. 3 generally illustrates bridge plug 183 in its configuration when
it has a first diameter less than the diameter of the production tubing 175, in order
to allow the bridge plug 183 to be lowered through the production tubing 175 to the
desired depth within well casing 172 where the desired plug 178 is to be provided
as illustrated in FIG. 2. FIG. 4 illustrates the configuration of bridge plug 183
when it has been disposed within well casing 172 and has a second diameter which sealingly
conforms to the diameter of the well casing 172 in order to provide the desired seal
178.
[0016] Still with reference to FIGS. 3 and 4, bridge plug 183 generally comprises: an elongate
mandrel 184; means for sealing 185 the well casing 172, which sealing means 185 is
disposed about mandrel 184; a means for reinforcing 186 the sealing means 185, the
reinforcing means 186 being disposed about mandrel 184 and located above and below
seal means 185; means for anchoring 187 the sealing means 185 and the reinforcing
means 186 within well casing 172 and a means for compressing 188 the sealing means
185 to force the sealing means 185 to expand from its first diameter illustrated in
FIG. 3, which is less than the diameter of the production tubing 175, to a second
diameter as illustrated in FIG. 4, whereby sealing means 185 sealingly conforms to
the diameter of the well casing 172 to prevent fluids 179 (FIG. 2) disposed in the
well casing 172 below the sealing means 185 from flowing through the well casing 172
to above sealing means 185. Compression means 188 preferably includes a means for
moving the mandrel 184 upwardly as shown by arrow 189 in FIG. 3. Any suitable means
may be utilized to pull mandrel 184 upwardly to cause the compression of sealing means
185, such as a suitable hydraulic pump, electric motor, or explosive powered device,
which can cause the desired upward movement of mandrel 184. As will be hereinafter
described in greater detail, a preferred means for moving mandrel 184 will be described
in greater detail with reference to FIGS. 15, 16a and 16b. Preferably, bridge plug
183 is suspended within production tubing 175 and well casing 172 by a wireline (not
shown).
[0017] Still with reference to FIGS. 3 and 4, the bridge plug 183 will be described in greater
detail. Preferably, sealing means 185 includes at least one resilient, elastomeric
sealing element 190 carried by mandrel 184. In FIG. 3, one sealing element 190 is
shown in full cross-section, another sealing element 190' is partially shown, ad one
sealing element 190'' is shown within a restraining means to be hereinafter described
in greater detail with respect to FIG. 6. Sealing elements 190 may be made of any
suitable elastomeric material and/or construction, provided the sealing element 190
has the ability to be compressed to expand from its first reduced diameter, shown
in FIG. 3 to expand to its second diameter, shown in FIG. 4, wherein sealing elements
190 sealingly conform to the interior surface of well casing 172. A preferred embodiment
of sealing element 190 will hereinafter be described in greater detail with respect
to FIGS. 5-7.
[0018] Still with reference to FIGS. 3-4, anchoring means 187 preferably includes a first
and second set of anchor arms 191, 192 disposed about the mandrel 184, each set of
anchor arms 191, 192 including at least two anchor arms 193 equally spaced radially
and angularly about the longitudinal axis of mandrel 184. Preferably, three equally
spaced anchor arms 193 are utilized in each set of anchor arms 191, 192. The first
set of anchor arms 191 is shown disposed above the sealing means 185, and the second
set 192 is disposed below the sealing means 185. Anchor arms 193 are pivotably mounted
with respect to the mandrel 184. Each set 191, 192 of anchor arms 193 are disposed
in either a first non-operating position, as shown in FIG. 3 with their longitudinal
axis being substantially parallel with the longitudinal axis of the mandrel 184 to
allow passage of the anchoring means 187 through the production tubing 175, or are
disposed in a second operating position, as shown in FIG. 4, with the anchor arms
193 being pivoted outwardly into engagement with the well casing 172 as shown at 194
in FIG. 4.
[0019] Each anchor arm 193 may include a pivot pin 195 disposed adjacent sealing means 185,
whereby the first set 191 of anchor arms 193 pivot outwardly and downwardly toward
the sealing means 185, and the second set 192 of anchor arms 193 pivot outwardly and
upwardly toward the sealing means 185, as shown in FIG. 4. Anchoring means 187 may
include a camming member 196 (FIG. 4) which cooperates with the anchor arms 193 to
cause the anchor arms 193 to pivot outwardly toward their second operating position,
as shown in FIG. 4, upon compression of sealing means 185. As seen in FIG. 4, the
first and second sets 191, 192 of anchor arms 193 are mounted upon an anchor arm support
body 197 disposed in sliding engagement with mandrel 184. When anchor arms 193 are
initially disposed in their non-operating position, camming members 196 are spaced
from the ends of the anchor arms 193 which do not have the pivot pins 195 disposed
therein, and camming members 196 are disposed in sliding engagement with respect to
mandrel 184. Upon mandrel 184 being moved upwardly to compress sealing means 185,
the ends 198 of camming members 196 cooperate with anchor arms 193 to cause them to
pivot outwardly due to the relative motion between the camming members 196 and the
anchor arm support bodies 197, caused by the upward movement of mandrel 184. In this
regard, it should be noted that the lower end of mandrel 184 is secured to a conventional
nose piece 199, whereby upon mandrel 184 being raised, nose piece 199 bears against
the lower camming member 196 to force it in an upward direction.
[0020] With reference to FIG. 4, it should be noted that due to the resilient nature of
elastomeric sealing elements 190, once sealing elements 190 have been compressed,
as shown in FIG. 4, due to the upward movement of mandrel 184 and its associated nose
piece 199, it is desirable to retain sealing means 185 in sealing conformity with
the well casing 172. Accordingly, a means for retaining 200 sealing means 185 in sealing
conformity with the well casing 172 may be included with compression means 188. Preferably,
the means for retaining 200 comprises a mandrel lock 201 which fixedly secures the
mandrel 184 with respect to the sealing means 185 after the sealing means 185 has
been compressed to assume its second diameter as shown in FIG. 4. Mandrel lock 201
may be of conventional construction, wherein it includes a spring biased chuck member
202 and biasing spring 203, as shown in FIG. 4.
[0021] The reinforcing means 186 of bridge plug 183 preferably includes a plurality of reinforcing
elements 204 disposed about mandrel 184, and as seen in FIG. 3, reinforcing elements
204 have a first diameter less than the diameter of the production tubing 175 to allow
passage therethrough. As seen in FIG. 4, reinforcing elements 204 are compressible
to a second diameter which is greater than the diameter of the production tubing 175.
At least one of the reinforcing elements 204 contacts the top surface of sealing means
185, and at least one reinforcing element 204 contacts the bottom surface of sealing
means 185. Reinforcing elements 204 are provided because the compressive force exerted
upon the sealing means 185 should preferably be exerted over a surface whose area
approximates the expanded surface area of sealing means 185. Thus, the sealing elements
190 of sealing means 185 will be evenly compressed and sealing elements 190 will not
be punctured by anchor arm support bodies 197 upon mandrel 184 being raised, which
causes the compression of sealing elements 190 between the anchor arm support bodies
197. In this regard, it should be noted that bridge plug 183 may be provided with
a body member, or setting sleeve, 205 (FIG. 3) through which mandrel 184 passes, which
body member 205 remains substantially stationary with respect to well casing 172 as
mandrel 184 is moved upwardly. Reinforcing elements 204 may be made of any suitable
material, such as an elastomeric and/or metallic material and have any suitable construction
provided that it can have a first diameter less than the diameter of the production
tubing 175, and is compressible to a second diameter which is greater than the diameter
of the production tubing 175. A preferred embodiment of reinforcing element 204 will
be hereinafter described in greater detail with reference to FIGS. 8-11.
[0022] The method for using bridge plug 183 for sealing off a length of well casing 172
to prevent fluid disposed therein from flowing upwardly, or downwardly, into another
length of well casing 172, when the well casing 172 has a length of production tubing
175 disposed therein, may comprise the following steps. Sealing means 185 is first
disposed about mandrel 184 as previously described. Mandrel 184 and sealing means
185 are lowered downwardly through the production tubing 175 and into well casing
172, while the sealing means 185 has its first diameter as illustrated in FIG. 3.
Sealing means 185 may then be compressed as previously described to force the sealing
means 185 to assume its second diameter, as illustrated in FIG. 4, to sealingly conform
to the diameter of the well casing 172. Sealing means 185 may then be anchored within
the well casing by utilizing anchoring means 187 as previously described in connection
with FIG. 4. It should be noted that after mandrel 184 has been locked by mandrel
lock 201 to retain the sealing means 185 in sealing conformity with the well casing
172, mandrel 184 may be separated at a point disposed above the mandrel lock 201 after
the mandrel 184 has been pulled upwardly to compress sealing means 185. As seen in
FIG. 3, a mandrel release point 206 is disposed on mandrel 184 and is initially located
beneath mandrel lock 201. Upon mandrel 184 being raised to the position shown in FIG.
4, mandrel release point 206 is disposed above mandrel lock 201. After sealing means
185 has been anchored within well casing 172, mandrel 184 may be separated at the
mandrel release point 206 and the auxiliary equipment for bridge plug 183, to be hereinafter
described in greater detail with respect to FIG. 15, may be raised and removed through
production tubing 175 to the earth's surface 171. Production of hydrocarbons may once
again be initiated as previously described in connection with FIG. 2.
[0023] Turning now to FIGS. 5-7, a preferred embodiment of sealing element 190 in accordance
with the present invention is shown. Elastomeric sealing element 190 generally comprises:
a generally tubular-shaped elastomeric member 207 having first and second ends 208,
209 and a wall portion 210 therebetween. As shown in FIG. 5, elastomeric member 207
has a normal, unstressed configuration wherein the diameter of elastomeric member
207 varies along the longitudinal axis of the elastomeric member 207. The diameter
intermediate the ends 208, 209 of the elastomeric member 207 is larger than the diameter
at the ends 208, 209. When in the normal, unstressed configuration of FIG. 5, the
diameter intermediate the ends 208, 209 is larger than the diameter of the production
tubing 175 (FIG. 1), and is smaller than the diameter of the well casing 172 (FIG.
1). As shown in FIG. 6, elastomeric member 207 is elongatable along its longitudinal
axis, whereby its diameter intermediate the ends 208, 209 is substantially the same
as the diameter of its ends 208, 209 so that elastomeric member 207, after being elongated,
may pass through the production tubing 175. As shown in FIG. 7, elastomeric member
207 is compressible along its longitudinal axis whereby the ends 208, 209 of elastomeric
member 207 can be forced toward one another, and preferably contacting one another,
while a portion 211 of the wall portion 210 sealingly conforms to the interior surface
of well casing 172 upon elastomeric member 207 of sealing means 185 being compressed
along the longitudinal axis of mandrel 184.
[0024] With reference to FIG. 6, sealing element 190 may include a means for restraining
212 the elastomeric member 207 in its elongated configuration, whereby the diameter
intermediate the ends 208, 209 of the elastomeric member 207 is substantially the
same as the diameter of its ends 208, 209. Preferably, restraining means 212 is a
frangible, thin-walled tubular member 213, which upon compressive force being exerted
upon the elastomeric member 207 along the longitudinal axis of elastomeric member
207, the tubular member 213 breaks and allows elastomeric member 207 to assume its
normal, unstressed configuration shown in FIG. 5. Tubular member 213 may be formed
of a suitable cloth material or of a thin metallic material, which material has the
requisite properties to withstand utilization under the temperature and pressure conditions
found in well casing 172 and the ability to break away from elastomeric member 207
upon compression thereof. Further, as seen in FIG. 5, wall portion 210 intermediate
the ends 208, 209 of elastomeric member 207 may have a reduced wall thickness, as
shown by arrows 214, intermediate the ends 208, 209 of wall portion 210.
[0025] Still with reference to FIGS. 5-7 it is seen that each of the ends 208, 209 of elastomeric
member 207 has disposed therein a metallic flanged insert member 215, and each insert
member has an axial passageway 216 therethrough coextensive with the longitudinal
axis of the elastomeric member 207 and adapted to receive elongate mandrel 184 therethrough,
as seen in FIG. 7. As seen in FIG. 5, each insert member 215 may include a plurality
of radially spaced anchor wires 217 extending from the insert member 215 into the
wall portion 210 of the elastomeric member 207. At least some of anchor wires 217,
and preferably all of the anchor wires 217, have an eyelet 218, or other bond enhancing
structure, disposed at their ends which are disposed within elastomeric member 207.
Each eyelet 218 is seen to lie in a plane which is substantially parallel with the
longitudinal axis of the elastomeric member 207 as shown in FIG. 5. Anchor wires 217
serve the purpose of insuring that insert members 215 remain secured to the elastomeric
member 207.
[0026] In utilizing the sealing element 190 illustrated in FIGS. 5-6, to seal off a length
of well casing 172 to provide the desired seal 178, previously described in connection
with FIG. 2, the following method steps are followed. A generally tubular-shaped,
elastomeric member 207 having first and second ends 208, 209 and wall portion 210
therebetween is disposed about an elongate mandrel 184. The elastomeric member 207
has a normal-unstressed configuration as previously described in connection with FIG.
5. The elastomeric member 207 is then elongated along its longitudinal axis and is
restrained in its elongated configuration as previously described in connection with
FIG. 6. The mandrel 184 and the elastomeric sealing element 190 disposed upon mandrel
184 is then lowered downwardly through the production tubing 175 and into the well
casing 172 to the desired depth where seal 178 (FIG. 2) is desired. Elastomeric sealing
element 190 is then compressed along its longitudinal axis to break the restraining
means 212 to allow the sealing element 190 to assume its normal-unstressed configuration
of FIG. 5. Elastomeric sealing element 190 is then further compressed along its longitudinal
axis to force a portion 211 of the wall portion 210 of the elastomeric sealing element
190 to sealingly conform to the well casing 172, as previously described in connection
with FIG. 7.
[0027] Turning now to FIGS. 8-11, a preferred embodiment of a reinforcing element 204, previously
described in connection with FIGS. 3 and 4 is shown. Reinforcing element 204 for the
elastomeric sealing element 190 of sealing means 185 (FIGS. 3-4) generally comprises
two metallic plate members 219, one of which is shown in FIG. 8, with each plate member
219 having a center portion 220 with an axial passageway 221 extending therethrough
and adapted for receipt of elongate mandrel 184 (FIG. 4). A plurality of radially
extending projections 222 having first and second ends 223, 224, extend outwardly
from center portion 220 with the first ends 223 of radial projections 222 being preferably
formed integral with the center portion 220, as seen in FIG. 8. As shown in FIG. 9,
each of the radial projections 222 is bent downwardly to dispose the projections 222
in a plane which is substantially perpendicular to the center portion 220 of plate
members 219. As seen in FIG. 9, radial projections 222 are not bent downwardly to
be exactly perpendicular with center portion 220; however, are illustrated in FIG.
9 to be bent downwardly to form an angle, as shown by arrow "A" of approximately 100°.
It should be understood that the angle illustrated by arrow "A" in FIG. 9 could vary
from approximately 90° to 135°, dependent upon the length of radial projections 222
and the size of center portion 220. Preferably, the angle illustrated by arrow "A"
is within a range of 97° to 100°.
[0028] Still with reference to FIG. 9, it is seen that at least two of the second ends 224
of two of the radial projections 222 are fixedly secured to one another as at 225,
whereby the two fixedly secured plate members 219 form an elongate body which can
pass through production tubing 175. Upon exertion of a compressive force on the center
portions 220 of plate members 219, the radial projections 222 are then once again
disposed in a plane substantially parallel to the center portions 220 of each plate
member 219 appear as shown in FIG. 8, whereby the plate members 219 would be superimposed
upon one another.
[0029] Preferably, as shown in FIG. 8, each plate member 219 has eight radial projections
222, and upon bending the radial projections downwardly, four of the radial projections
222 would have their second ends 224 joined to one another as shown at 225 in FIG.
9. The second ends 224 may be fixedly secured to one another as by a spot weld at
225 or any other suitable connection. In order to facilitate the fabrication and joining
of the second ends 224 of the two plate members 219, a spacer member 226 may be disposed
adjacent the second ends 224 of the radial projections 222 of each plate member 219
as shown in FIG. 9. Spacer member 226 is provided with an axial passageway 227 through
which the mandrel 184 may slideably pass therethrough. As seen in FIG. 11, two reinforcing
elements 204 are illustrated in their compressed configuration with one of the reinforcing
elements 204, including its two superimposed plate members 219, being disposed over
a second reinforcing element 204, which also includes its two superimposed plate members
219. The top reinforcing element 204 illustrates the use of a weld relief means 228
provided on the second ends 224 of the four radial projections 222 which were previously
fixedly secured as by a spot weld at 225 (FIG. 9). Weld relief means 228 may preferably
be a slot 229 formed in the second end 224 of radial projection 222, a slot 229 being
disposed on both sides of the spot weld 225.
[0030] With reference to FIGS. 8, 9 and 10, a preferred method of fabricating reinforcing
element 224 is illustrated. The plate members 219, with an even number of radial projections
222 extending from the center portion 220 of plate member 219, have a first set of
alternating projections 222' bent downwardly and disposed in a plane which is substantially
perpendicular to the center portion 220 of plate member 219. A second set of the remaining
alternating projections 222'' are then bent downwardly and also disposed in a plane
which is substantially perpendicular to the center portion 220 of plate member 219.
The second set of projections 222'' are disposed in an overlying relationship with
the first set of projections 222' as shown in FIGS. 9 and 10. The second ends 224
of the first set of alternating projections 222' are then fixedly secured to one another
as by spot weld 225 as shown in FIG. 9. The weld relief slots 229 are provided in
the second ends 224 of the first set of alternating projections 222' as shown in FIG.
10. Accordingly, upon the compression of the reinforcing element 204 of FIG. 9, reinforcing
element 204 assumes the configuration illustrated in FIGS. 8 and 11, as is also previously
described in connection with FIG. 4.
[0031] With reference to FIGS. 12-14, another embodiment of the anchor means 187 described
in connection with FIGS. 3-4 is shown. Anchor means, or anchor assembly, 187 generally
comprises elongate mandrel 184; a set of elongate, pivotable primary anchor arms 193
and a set of elongate, pivotable anchor support members 230; each set of primary anchor
arms 193 and anchor support members 230 being disposed about mandrel 184. As shown
in FIG. 13 in solid lines, the sets of primary anchor arms 193 and anchor support
members 230 are initially disposed in a first non-operating position with their longitudinal
axis being substantially parallel with the longitudinal axis of mandrel 184 for passage
through the production tubing 175 (FIG. 2) and as previously described in connection
with FIG. 3. Anchoring assembly 187 further includes means for pivoting 231 the sets
of anchor arms 193 and anchor support members 230 outwardly into a second operating
position (illustrated in dotted lines in FIG. 13) with the set of anchor arms 193
in engagement with the well casing 172 upon relative motion occurring between the
pivoting means 231 and mandrel 184. The pivoting occurs after the sets of anchor arms
193 and anchor support members 230 have passed through the production tubing 175 and
into the well casing 172, as previously described in connection with FIG. 4, and as
will be hereinafter described in greater detail.
[0032] While in the second operating position, illustrated in dotted lines in FIG. 13, the
set of anchor support members 230 afford an abutment which limits the travel of the
anchor arms 193 to maintain the set of anchor arms 193 in its operating position in
engagement with the well casing 172. The motion of anchor support member 230 is illustrated
by dotted line 232, as will be further described in greater detail. The use of anchor
support members 230 provide the primary anchor arms 193 with substantial rigidity
and support, whereby anchor assembly 187 provides bridge plug 183 with appreciable
pressure differential capabilities when anchor arms 193 are in their second operating
position in engagement with well casing 172.
[0033] It should be noted that in FIG. 13 only the first set 191 of anchor arms 193 which
are disposed above the sealing means 185 as described in connection with FIGS. 3 and
4 are illustrated. The second set 192 of anchor arms 193, which are disposed below
sealing means 185 as previously described in connection with FIGS. 3 and 4, would
be of the same construction and the anchor assembly 187 having the second set 192
of anchor arms 193 and anchor support members 230 would be disposed about mandrel
184 as illustrated in FIG. 4, including the disposition of nose piece 199 at the lower
end of mandrel 184.
[0034] With reference to FIGS. 12 and 13, it is seen that pivoting means 231 includes a
camming member 196' whose function is similar to the camming member 196 previously
described in connection with FIGS. 3 and 4. Camming member 196' is slideably mounted
about mandrel 184 and cooperates with a camming surface 233 disposed on each of the
anchor arms 193, whereby upon relative motion occurring between the camming member
196' and the anchor arms 193, the anchor arms 193 are pivoted outwardly into the position
shown in dotted lines in FIG. 13. Preferably, camming surface 233 is formed by a ramped
groove disposed in the underside of each anchor arm 193, and camming member 196' has
a mating ramped, or camming, projection 234.
[0035] Preferably, the set of anchor arms 193 is disposed about an anchor arm support body
197', similar in function to the anchor arm support body 197 previously described
in connection with FIGS. 3 and 4. The set of anchor support members 230 are disposed
about an anchor support member body 235 which is also slideably mounted about the
mandrel 184. As seen in FIG. 13, anchor arm support body 197' is disposed intermediate
the camming member 196' and the anchor support member body 235. Pivoting means 231
further includes a camming surface 236 disposed on the anchor arm support body 197'
which cooperates with a camming surface 237 disposed on each of the anchor support
members 230. Accordingly, upon relative motion occurring between the anchor arm support
body 197' and the anchor support members 230, the set of anchor support members 230
are outwardly pivoted to afford an abutment which limits the travel of anchor arms
193 as shown in FIG. 13. As shown in FIG. 13, the length of the anchor arms 193 is
less than the length of the anchor support members 230 to allow the anchor support
members 230 to better brace and reinforce the anchor arms 193.
[0036] Still with reference to FIGS. 12-14, anchor assembly 167 may include a means for
retaining 238 the sets of anchor arms 193 and anchor support members 230 in their
non-operating position shown in solid lines in FIG. 13 and as previously described
in connection with FIG. 3. The retaining means may comprise a frangible wire 239 associated
with each anchor arm 193 and anchor support member 230, the wires 239 being broken
upon relative motion occurring between the pivoting means 231 and the mandrel 184.
As shown in FIG. 13, each anchor arm 193 and anchor support member 230 is provided
with a suitable wiring hole 240 to accept the frangible wires 239. Preferably the
anchor support member body 235, the anchor arm support body 197' and the camming member
196' include a safety means 241 for preventing accidental relative motion occurring
between camming member 196' and bodies 197' and 235. Safety means 241 also assists
in disposing the various components of anchor assembly 187 in its initial non-operating
position illustrated in FIG. 13 and as previously described in FIG. 3. Safety means
241 prevents the anchor arms 193 and anchor support members 230 from accidentally
pivoting outwardly while the anchor assembly 187 is being transported through production
tubing 175 in the event of a shock force being transmitted to camming member 196'
which would in turn initiate the outward pivotal motion of the anchor arms 190 and
anchor support members 230. Preferably, safety means 241 comprises a first frangible
connection 242 between the camming member 196' and the anchor arm support body 197',
and a second frangible connection 243 between the anchor arm support body 197' and
the anchor support member body 235, which frangible connections 242, 243 are broken
upon a pre-determined compressive force being exerted upon the camming member 196'.
The first and second frangible connections 242, 243 may each comprise a shear pin,
which is sheared upon a predetermined compressive force acting upon camming member
196' which force exceeds shock forces encountered in the borehole. Thus, the anchor
arms 193 and anchor support members 230 will only be pivoted outwardly when they are
disposed in the well casing 172 and a sufficient compressive force has been exerted
to shear the shear pins 242, 243.
[0037] It should be noted that although each set of anchor arms 193 and anchor support members
230 should include at least two anchor arms and anchor support members which are equally
spaced about mandrel 184, three equally spaced anchor arms and anchor support members
are preferred. It should be of course understood that any number could be utilized,
as well as not all anchor arms 193 require a mating anchor support member 230, so
long as at least two of the anchor arms 193 are provided with an anchor support member
230.
[0038] With reference now to FIGS. 15, 16a and 16b, a means for moving mandrel 184 in the
direction of arrow 189 in order to cause the compression of sealing means 185, as
previously described in connection with FIGS. 3 and 4, will be described in greater
detail. As seen in FIG. 15, a portion of well casing 172 is shown having sealing means
185, anchoring means 187 and mandrel locking means 200 disposed below body member,
or setting sleeve, 205. Although any suitable device, as previously described, may
be utilized to pull mandrel 184 upwardly, the use of a demand sensitive pressure intensifier
245 and positive displacement hydraulic pump 246, which is powered by an electric
motor 247, is preferred. Due to the size constraints imposed by the diameter of the
production tubing 175, it is preferable to use a pump and electric motor 246, 247
which conveniently fit within an outer setting tool housing 248, and then intensify
the fluid pressure output of that pump 246. The use of the demand sensitive pressure
intensifier 245 thus permits the use of a pump and electric motor which do not have
an excessive power requirement to be placed therein to pull the mandrel 184 upwardly.
In this regard, positive displacement hydraulic pump 246 has a maximum output fluid
pressure which would normally not exert enough fluid pressure to cause mandrel 184
to be raised with sufficient force to fully compress sealing means 185 and reinforcing
means 186, whereas were a different pump and electric motor to be utilized, which
did have a sufficiently high maximum fluid output pressure, the use of the demand
sensitive pressure intensifier 245 would not be necessary. It should be further noted
that the demand sensitive pressure intensifier 245 to be hereinafter described in
greater detail could also be utilized to move a mandrel 184 in some other type of
down-hole tool other than the bridge plug 183 of the present invention. Further, the
pressure intensifier 245 could be utilized in other types of down-hole tools wherein
it is desired to cause the movement of some other component of a down-hole tool by
the exertion of fluid pressure upon a portion of the down-hole tool.
[0039] With reference to FIGS. 16a and 16b, the demand sensitive pressure intensifier 245,
in accordance with the present invention is shown with its top half appearing in FIG.
16a and its lower half appearing in FIG. 16b, breakline 249' appearing in dotted lines
in FIG. 16a for ease of illustration purposes. Demand sensitive pressure intensifier
245 generally comprises a housing 249 disposed within down-hole tool housing 248;
a means for transmitting 250 a force associated with the housing 249 to move a portion
of the down-hole tool, or mandrel 184, the force transmitting means 250 having a first
fluid pressure receiving surface 251 associated with the force transmitting means
250; a first hydraulic fluid passageway 252 extending through the housing 249 and
in fluid communication between the pump 246 (FIG. 15, and indicated by arrow 246'
in FIG. 16a) and the first fluid pressure receiving surface 251 associated with force
transmitting means 250; and means for compressing 253 hydraulic fluid disposed in
the first hydraulic fluid passageway 252 to increase the fluid pressure, exerted upon
the first fluid pressure receiving surface 251 associated with the force transmitting
means 250, to a pressure which exceeds the maximum output pressure of pump 246. Demand
sensitive pressure intensifier 245 further generally comprises a means for selectively
actuating 254 the compression means 253 when the output pressure of pump 246 reaches
a predetermined value below the maximum output pressure of pump 246. The selective
actuation means includes a second fluid pressure receiving surface 255 associated
with the selective actuation means 254, and a second hydraulic fluid passageway 256
which is in fluid communication with the pump 246 and the second fluid pressure receiving
surface 255. Accordingly, upon fluid pressure acting upon the second fluid pressure
receiving surface 255 associated with selective actuation means 254, reaching a predetermined
value below the maximum output pressure of pump 246, the compression means 253 is
actuated and fluid pressure, greater than the maximum pressure output of pump 246,
selectively acts upon the first fluid pressure receiving surface 251 of force transmitting
means 250.
[0040] Still with reference to FIGS. 16a and 16b, the pressure intensifier 245 will be described
in greater detail. Disposed at the upper end of housing 249 is an upper intensifier
head 257 and a lower intensifier head 258 is disposed at the lower end of housing
249, both heads 257, 258 being fixedly secured to, and forming a part of housing 249.
Disposed between the upper and lower intensifier heads 257 and 258 is a piston assembly
comprised of a carrier piston 259 and a lower piston 260 carried upon the lower, or
second, end 261 of carrier piston 259 in sliding and sealing engagement therewith.
In this regard the second end 261 of carrier piston 259 is provided with an O-ring
seal 261' as shown in FIG. 16b. The second or lower end 262 of lower piston 260 is
in sliding and sealing engagement with hydraulic cylinder 263 formed within lower
intensifier head 258. The second end 262 of lower piston 260 is sealed with respect
to cylinder 263 by seal 264 which is secured in sealing engagement with lower intensifier
head 258 by bushing 265. The first fluid pressure receiving surface 251 is comprised
of seal 266 disposed adjacent the outer surface of lower intensifier head 258 in sealing
engagement with down-hole tool housing 248.
[0041] With reference to FIG. 16a, it is seen that the first, or upper end, 267 of carrier
piston 259 has a seal 268 disposed about it in a sealing relationship with the intensifier
housing 249. Seal 268 comprises the second fluid pressure receiving surface 255 as
will be hereinafter described in greater detail. Also mounted about the upper end
267 of carrier piston 259 is a collet member 269 having at least two collet fingers
270 extending therefrom. Upper intensifier head 257 has a depending projection 271
from which is suspended and fixedly secured thereto, an elongate alignment stop member
272 which is releasably engaged by the collet fingers 270. Alignment stop member 272
is provided with: a raised collet finger seating surface 273 disposed on the outer
surface of alignment stop member 272; and a stem stop surface 274 disposed on its
inner surface. In this regard, carrier piston 259 has disposed within its upper end
267 an elongate stem 275 which has a flanged end 275' at its upper end which cooperates
with stem stop surface 274 as will be further described in greater detail.
[0042] Stem 275 is fixedly secured to a releasable connection means 276, to be hereinafter
described in greater detail. A poppet 277 is also fixedly secured to releasable connection
means 276, and extends into carrier piston 259 as shown in FIG. 16a. Releasable connection
means 276 preferably comprises a body member 278 having two spring biased balls 279
and spring 280 disposed therein, which balls 279 mate with two sets of detents 281,
282 disposed within the interior of the upper end 267 of carrier piston 259. Body
member 278 is formed so as to permit hydraulic fluid flowing through stem 275 to flow
through body member 278 into and through poppet 277. As shown in FIG. 16a, balls 279
are disposed in the first set of detents 281, and this position corresponds to when
the selective actuation means 254 for compression means 253 has not been actuated,
as will be hereinafter described in greater detail. Poppet 277 is provided with a
seal 283 on its outer surface which sealingly engages the interior, cylindrical poppet
cylinder 284 disposed within carrier piston 259. A poppet spring 285 is disposed within
poppet cylinder 284, and carrier piston 259 is provided with a restroking hole or
holes 286 which can be in fluid communication between poppet cylinder 284 and the
interior of housing 249, as will be hereinafter described.
[0043] Upper intensifier head 257 may be provided with an adapter member 287 through which
the previously pressurized hydraulic fluid from pump 246 enters into the first fluid
passageway 252. In this regard, it should be noted that pressurized hydraulic fluid
can initially pass from adapter member 287 and then through the upper intensifier
head 257, stem 275, releasable connection 276, poppet 277, carrier piston 259, lower
piston 260, fluid passageway 288 in the lower intensifier head, and then into contact
with the first fluid pressure receiving surface 251, or seal 266. A fluid bulkhead
(not shown) is sealingly disposed downstream of fluid passageway 288 to force the
pressurized hydraulic fluid to exert a pressure force upon seal 266. A means for attaching
289 a mandrel 184 to the lower intensifier head 258 is shown in FIG. 16b, whereby
upon fluid pressure being exerted upon first fluid pressure receiving surface 251,
or seal 266, the upper and lower intensifier heads 257, 258, and the housing 249 secured
thereto, travel upwardly within down-tool housing 248, whereby mandrel 184 may exert
its upward force to compress the sealing means 185 as previously described in connection
with FIGS. 3 and 4. If desired, first fluid passageway 252 may include a plurality
of conventional filters to screen out any impurities from the hydraulic fluid. For
example, a filter 290 may be disposed between adapter member 287 and the upper intensifier
bead 257 and a filter 291 may be disposed between poppet spring 285 and the end of
the poppet cylinder 284 disposed within carrier piston 259. Lower intensifier head
258 is provided with a check valve 292 which prevents hydraulic fluid from flowing
upwardly through lower intensifier head 258.
[0044] Still with reference to FIGS. 16a and 16b, the selective actuation means 254 for
compression means 253 will be described in greater detail. Pressurized hydraulic fluid
from pump 246 enters the second hydraulic fluid passageway 256 as it flows through
upper intensifier head 257 and enters passageway 293 of second hydraulic fluid passageway
256 formed in upper intensifier head 257. Passageway 293 allows the pressurized hydraulic
fluid from pump 246 to act upon the second fluid pressure receiving surface 255, or
collet 269 and seal 268 disposed against the upper end 267 of carrier piston 259.
It should be noted that the pressure below seal 268 of second fluid pressure receiving
surface 255 is at ambient pressure due to the venting of intensifier housing 249 by
opening 294 in housing 249 and spline 295 formed in lower intensifier head 258 adjacent
hole 294 in housing 249. When the fluid pressure acting upon seal 268 exceeds a predetermined
value, which is less than the maximum fluid pressure output of pump 246, carrier piston
259 will be moved downwardly, thus simultaneously moving collet 269 and its collet
fingers 270 as well as stem 275, releasable connection means 276, poppet 277 and lower
piston 260. Hydraulic fluid contained in hydraulic cylinder 263 will then be further
compressed and pressurized by lower piston 260.
[0045] The fluid pressure of the hydraulic fluid is increased by a factor equal to the ratio
of the area across seal 268 of the second fluid pressure receiving surface and the
area across the seal 264 on the lower piston 260. The predetermined value below the
maximum output pressure of pump 246, which will cause carrier piston 259 to begin
its downward movement and cause collet fingers 270 to be unseated from alignment stop
member 272 and pass over collet stop surface 273, is a function of the design of collet
fingers 270 which collet 269 and collet fingers 270 provide a means for restraining
the motion of carrier piston 259 until the fluid pressure acting on seal 268 exceeds
the predetermined pressure value. The greater the clamping force of collet fingers
270 upon alignment stop member 272, the greater the predetermined fluid pressure acting
upon seal 268 must be in order to allow carrier piston 259 to be moved downwardly.
[0046] When carrier piston 259 approaches the end of its downward stroke, flanged end 275'
of stem 275 will engage stem stop surface 274 of alignment stop member 272. Upon further
downward movement of carrier piston 259, the engagement of the flanged end 275' of
stem 275 will completely stop the movement of the stem 275, poppet 277 and releasable
connection means 276. As carrier piston 259 and lower piston 260 continue downwardly,
balls 279 of releasable connection means 276 will be compressed inwardly and poppet
spring 285 biases poppet 277 upwardly, along with releasable connection means 276
and stem 275, whereby balls 279 then enter second detents 282 in carrier piston 259.
As carrier piston 259 continues its downward movement and after poppet 277 has been
biased upwardly, restroking holes 286 in carrier piston 259 will be uncovered allowing
pressurized hydraulic fluid to flow through restroking holes 286 and through passageway
294 in intensifier housing 249. The pressurized fluid will flow upwardly through the
anular space between intensifier housing 249 and down-hole tool housing 248 and through
a return fluid passageway 297 formed in upper intensifier head 257 and opening 298
in intensifier housing 249 disposed adjacent fluid passageway 297. Fluid may then
flow back to a conventional hydraulic fluid reservoir associated with pump 246. The
venting of this hydraulic fluid allows return spring 296, which is disposed about
carrier piston 259 and lower piston 260, to force carrier piston 259 upwardly. As
carrier piston 259 moves upwardly stem 275 and poppet 277, along with releasable connection
means 276, are also carried upwardly. Upon flanged end 275' of stem 275 bearing upon
stem spring 299 disposed within upper intensifier head 257, stem spring 299 forces
the downward movement of stem 275 until balls 279 of releasable connection means 276
are compressed and are then reseated within the first set of detents 281 within carrier
piston 259. As poppet 277 moves back downwardly into carrier piston 259 poppet 277
once again seals off restroking holes 286 disposed in carrier piston 259. As carrier
piston 259 finishes its upward restroking movement, collet fingers 270 once again
are disposed about alignment stop member 272 in the position shown in FIG. 16a. At
this point in time, pressurized hydraulic fluid may either flow directly from pump
246 through first hydraulic fluid passageway 252 directly to seal 266; or, if the
pressure acting upon seal 268 exceeds the predetermined pressure value, compression
means 253 is once again selectively actuated to increase the pressure of the hydraulic
fluid disposed within hydraulic cylinder 263 of lower intensifier head 258.
[0047] With reference to FIG. 16b, it is seen that lower piston 260 has disposed therein
a check piston 300, check piston spring 301 and check valve 302. Check valve 302 serves
to prevent hydraulic fluid, being pressurized within hydraulic cylinder 263 in lower
intensifier head 258, from passing upwardly through the first hydraulic fluid passageway
252 when lower piston 260 of compression means 253 has been actuated. Check piston
300 and check piston spring 301 serve as an accumulator, whereby as carrier piston
259 and collet 269 begin their downward movement, no pressure force is being exerted
upon the lower end 262 of lower piston 260.
[0048] It is to be understood that the invention is not limited to the exact details of
construction, operation, exact materials, or embodiment shown and described, as obvious
modifications and equivalents will be apparent to one skilled in the art. Accordingly,
the invention is therefore to be limited only by the scope of the appended claims.
1. A method for sealing off a length of well casing (172) to prevent fluid disposed therein
from flowing upwardly, or downwardly, into another length of well casing, the well
having a length of production tubing (175) disposed within the well casing, the method
comprising the steps of:
lowering a mandrel (184) and a means (185) for sealing the well casing disposed
about the mandrel, downwardly through the production tubing (175) and into the well
casing (172), with the sealing means (185) restrained in an elongated configuration
wherein the diameter thereof is less than the diameter of the production tubing (175),
said sealing means (185) having a normal, unstressed configuration wherein the diameter
thereof is larger than the diameter of the production tubing (175) and smaller than
the diameter of the well casing (172);
compressing the sealing means (185) to eliminate the restraint and allow the sealing
means to assume its normal, unstressed configuration; and
further compressing the sealing means (185) to sealingly conform to the diameter
of the well casing (172).
2. The method of claim 1, further comprising the step of reinforcing the compressed sealing
means (185) by a reinforcing means (186) disposed about the mandrel (184) above and
below the sealing means.
3. A bridge plug for use within a well casing (172) and production tubing (175) comprising
an elongate mandrel (184) and means (185) for sealing the well casing disposed about
the mandrel, said sealing means comprising at least one generally tubular-shaped elastomeric
member (207) having first and second ends (208,209) and a wall portion (210) therebetween,
the elastomeric member (207) being compressible along the longitudinal axis whereby
the ends of the elastomeric member can be forced toward one another while a portion
of the wall portion (210) sealingly conforms to the well casing, characterized in
that:
the elastomeric member (207) has a normal, unstressed configuration, wherein the
diameter thereof varies along the longitudinal axis of the elastomeric member, with
the diameter intermediate the ends of the elastomeric member being larger than the
diameter at the ends of the elastomeric member; and
the elastomeric member (207) is elongatable along the longitudinal axis whereby
the diameter intermediate the ends of the elastomeric member is substantially the
same as the diameter of its ends so that the elastomeric member may pass through the
production tubing.
4. The bridge plug of claim 3, characterized in that the wall portion (210) intermediate
the ends (208,209) of the elastomeric member (207) has a reduced wall thickness intermediate
the ends of the wall portion.
5. The bridge plug of claim 3 or 4, characterized in that the elastomeric member (207)
has disposed in each of its ends (208,209) an insert member (215) having an axial
passageway (216) therethrough adapted to receive said elongate mandrel (184) therethrough,
each insert member (215) including a plurality of radially spaced anchor wires (217)
extending into the wall portion of the elastomeric member.
6. The bridge plug of any one of claims 3 to 5, characterized by a means (212) for restraining
the elastomeric member (207) in its elongated configuration.
7. The bridge plug of claim 6, characterized in that said restraining means comprises
a frangible, thin-walled tubular member (213), whereby upon compressive force being
exerted upon the elastomeric member (207), the tubular member (213) breaks and allows
the elastomeric member to assume its normal, unstressed configuration.
8. The bridge plug of claim 7, characterized in that the tubular member (213) is formed
of a cloth material.
9. The bridge plug of claim 7, characterized in that the tubular member (213) is formed
of a metallic material.
10. The bridge plug of any one of claims 3 to 9, characterized by elements (204) for reinforcing
the sealing means (185), said reinforcing elements (204) being disposed about the
mandrel (184) above and below the sealing means.
11. The bridge plug of claim 10, characterized in that said reinforcing element (204)
comprises:
two metallic plate members (219), each plate member having a center portion (220)
with an axial passageway (221) extending therethrough for receiving said mandrel (184)
and a plurality of radially extending projections (222) having first and second ends
(223,224), each first end (223) being formed integral with the center portion (220);
each of the projections (222) being bent to dispose each projection in a plane
which is substantially perpendicular to the center portion (220) of the plate member
(219); and
the second ends (224) of at least two of the projections (222) for each plate member
(219) being fixedly secured to second ends (224) of corresponding projections (222)
of the other plate member (219), whereby the plate members (219) form an elongate
body which can pass through the production tubing and upon exertion of a compressive
force on the center portions (220), the projections (222) are disposed in a plane
substantially parallel to the center portion (220) of each plate member (219).
12. The bridge plug of claim 11, characterized in that an even number of projections (222)
extend from the center portion (220) of each plate member (219), a first set of alternating
projections (222') are first bent downwardly in a plane which is substantially perpendicular
to the center portion (220), and a second set of alternating projections (222'') are
bent downwardly in a plane which is substantially perpendicular to the center portion
(220) and in an overlying relationship with the first set of projections (222').
13. The bridge plug of claim 11 or 12, characterized in that each second end of a projection
(222) which is fixedly secured to another second end of a projection (222) is fixedly
secured by a spot weld (225).
14. The bridge plug of claim 13, characterized in that each second end of a projection
(222) which is fixedly secured to another second end of a projection has a weld relief
means, comprised of a slot (229) disposed on both sides of the spot weld (225).
1. Ein Verfahren zum dichtenden Absperren eines Abschnitts einer Bohrlochauskleidung
(172) zum Hindern von darin befindlichem Fluid an der Aufwärts- oder Abwärtsströmung
in einen anderen Abschnitt der Bohrlochauskleidung, wobei das Bohrloch einen Förderrohrabschnitt
(175) innerhalb der Auskleidung aufweist, welches Verfahren die Schritte umfaßt:
Absenken eines Dorns (184) und eines rings um den Dorn angeordneten Mittels (185)
für das Abdichten der Bohrlochauskleidung nach unten durch das Förderrohr (175) in
die Bohrlochauskleidung (172), wobei das Abdichtmittel (185) in eine langgestreckte
Konfiguration deformiert ist, in der der Durchmesser desselben kleiner ist als der
Durchmesser des Förderrohres (175), welches Abdichtmittel (185) eine normale spannungsfreie
Konfiguration besitzt, in welcher sein Durchmesser größer ist als der Durchmesser
des Förderrohres (175) und kleiner als der Durchmesser der Bohrlochauskleidung (172);
Komprimieren des Abdichtmittels (185) zum Eliminieren der Deformation und Ermöglichen
des Abdichtmittels, seine normale spannungsfreie Konfiguration anzunehmen; und
weiteres Komprimieren des Abdichtmittels (185), um es abdichtend an den Durchmesser
der Bohrlochauskleidung (172) anzupassen.
2. Das Verfahren nach Anspruch 1, ferner umfassend den Schritt der Verstärkung des komprimierten
Abdichtmittels (185) durch ein Verstärkungsmittel (186), das um den Dorn (184) herum
über und unter dem Abdichtmittel angeordnet ist.
3. Ein Brückenstopfen zur Verwendung innerhalb einer Bohrlochauskleidung (172) und eines
Förderrohres (175), umfassend einen langgestreckten Dorn (184) und Mittel (185) zum
Abdichten der Bohrlochauskleidung, welches um den Dorn herum angeordnet ist, welches
Abdichtmittel mindestens ein generell rohrförmiges Elastomer-Glied (207) umfaßt mit
einem ersten und einem zweiten Ende (208, 209) und einem Wandungsabschnitt (210) dazwischen,
welches Elastomer-Glied (207) längs der Längsachse komprimierbar ist, wodurch die
Enden des Elastomer-Gliedes gegeneinander spannbar sind, während ein Abschnitt des
Wandungsabschnitts (210) sich abdichtend an die Bohrlochauskleidung anpaßt, dadurch
gekennzeichnet, daß das Elastomer-Glied (207) eine normale spannungsfreie Konfiguration
aufweist, in der sein Durchmesser sich in Richtung der Längsachse des Elastomer-Gliedes
ändert mit dem Durchmesser zwischen den Enden des Elastomer-Gliedes größer als dem
Durchmesser an den Enden des Elastomer-Gliedes; und
das Elastomer-Glied (207) längbar ist in Richtung der Längsachse, wodurch der Durchmesser
zwischen den Enden des Elastomer-Gliedes im wesentlichen derselbe wird wie der Durchmesser
seiner Enden, so daß das Elastomer-Glied durch das Förderrohr hindurch paßt.
4. Der Brückenstopfen nach Anspruch 3, dadurch gekennzeichnet, daß der Wandungsabschnitt
(210) zwischen den Enden (208, 209) des Elastomer-Gliedes (207) eine verringerte Wanddicke
zwischen den Enden des Wandungsabschnitts aufweist.
5. Der Brückenstopfen nach Anspruch 3 oder 4, dadurch gekennzeichnet, daß das Elastomer-Glied
(207) in jedem seiner Enden (208, 209) ein Einsatzglied (215) aufweist mit einem Axialdurchlaß
(216), der ausgebildet ist zur Aufnahme des sich hindurch erstreckenden langgestreckten
Dorns (184), wobei jedes Einsatzglied (215) eine Mehrzahl von im Radialabstand angeordneten
Ankerdrähten (217) umfaßt, die sich in den Wandungsabschnitt des Elastomer-Gliedes
erstrecken.
6. Der Brückenstopfen nach einem der Ansprüche 3 bis 5, gekennzeichnet durch ein Mittel
(212) für die Deformation des Elastomer-Gliedes (207) in seine langgestreckte Konfiguration.
7. Der Brückenstopfen nach Anspruch 6, dadurch gekennzeichnet, daß das Deformationsmittel
ein aufbrechbares dünnwandiges Rohrglied (213) umfaßt, wodurch bei Ausübung von Kompressionskraft
auf das Elastomer-Glied (207) das rohrförmige Glied (213) bricht und dem Elastomer-Glied
ermöglicht, seine normale spannungsfreie Konfiguration anzunehmen.
8. Der Brückenstopfen nach Anspruch 7, dadurch gekennzeichnet, daß das rohrförmige Glied
(213) aus einem Gewebematerial gebildet ist.
9. Der Brückenstopfen nach Anspruch 7, dadurch gekennzeichnet, daß das rohrförmige Glied
(213) aus einem Metallmaterial gebildet ist.
10. Der Brückenstopfen nach einem der Ansprüche 3 bis 9, gekennzeichnet durch Elemente
(204) für die Verstärkung des Abdichtmittels (185), welche Verstärkungselemente (204)
um den Dorn (184) herum über und unter dem Abdichtmittel angeordnet sind.
11. Der Brückenstopfen nach Anspruch 10, dadurch gekennzeichnet, daß das Verstärkungselement
(204) umfaßt:
zwei metallische Plattenglieder (219), wobei jedes Plattenglied einen Zentralabschnitt
(220) mit einem Axialdurchtritt (221) aufweist, der sich hindurch erstreckt zur Aufnahme
des Dorns (184), und mit einer Mehrzahl von sich radial erstreckenden Fortsätzen (222)
mit ersten und zweiten Enden (223, 224), wobei jedes erste Ende (223) einstückig mit
dem Zentralabschnitt (220) ausgebildet ist;
wobei jeder der Fortsätze (222) gebogen ist, um jeden Fortsatz in einer Ebene anzuordnen,
die im wesentlichen senkrecht zum Zentralabschnitt (220) des Plattengliedes (219)
ist; und
wobei die zweiten Enden (224) mindestens zwei der Fortsätze (222) für jedes Plattenteil
(219) starr an zweiten Enden (224) von zugeordneten Fortsätzen (222) des anderen Plattenteils
(219) befestigt haben, wodurch die Plattenteile (219) einen langgestreckten Korpus
bilden, der durch das Förderrohr hindurch paßt, und wodurch, bei Ausübung einer Kompressionskraft
auf die Zentralabschnitte (220), die Fortsätze (222) in einer Ebene angeordnet werden,
die im wesentlichen parallel zum Zentralabschnitt (220) jedes Plattenteils (219) ist.
12. Der Brückenstopfen nach Anspruch 11, dadurch gekennzeichnet, daß eine geradzahlige
Anzahl von Fortsätzen (222) sich von dem Zentralabschnitt (220) jedes Plattenteils
(219) erstreckt, wobei ein erster Satz von abwechselnden Fortsätzen (222') zunächst
nach unten in eine Ebene gebogen ist, die im wesentlichen senkrecht zum Zentralabschnitt
(220) ist, und ein zweiter Satz von abwechselnden Fortsätzen (222'') nach unten in
eine Ebene gebogen ist, die im wesentlichen senkrecht zu dem Zentralabschnitt (220)
ist und in überlappender Beziehung steht mit dem ersten Satz von Fortsätzen (222').
13. Der Brückenstopfen nach Anspruch 11 oder 12, dadurch gekennzeichnet, daß jedes zweite
Ende eines Fortsatzes (222), das starr befestigt ist an einem anderen zweiten Ende
eines Fortsatzes (222), durch eine Punktschweißung (225) befestigt ist.
14. Der Brückenstopfen nach Anspruch 13, dadurch gekennzeichnet, daß jedes zweite Ende
eines Fortsatzes (222), der starr an einem anderen zweiten Ende eines Fortsatzes befestigt
ist, ein Schweißentlastungsmittel aufweist, umfassend einen Schlitz (229), der beidseits
der Punktschweissung (225) angeordnet ist.
1. Procédé pour boucher une longueur de tubage de puits (172) afin d'empêcher le fluide
disposé à l'intérieur de s'écouler vers le haut, ou vers le bas, vers une autre longueur
de tubage de puits, le puits possédant une longueur de tube de production (175) disposée
à l'intérieur du tubage de puits, le procédé comprenant les étapes de :
descendre un mandrin (184) et un moyen (185) pour boucher le tubage de puits disposé
autour du mandrin, à travers le tube de production (175) et dans le tubage de puits
(172), avec le moyen de bouchage (185) retenu dans une configuration de forme allongée
dans laquelle son diamètre est inférieur au diamètre du tube de production (175),
ledit moyen de bouchage (185) ayant une configuration normale, non contrainte dans
laquelle son diamètre est supérieur au diamètre du tube de production (175) et inférieur
au diamètre de tubage de puits (172) ;
comprimer le moyen de bouchage (185) pour éliminer la force de retenue et permettre
au moyen de bouchage de prendre sa configuration normale, non contrainte ; et
comprimer encore le moyen de bouchage (185) pour l'adapter de façon étanche au
diamètre du tubage de puits (172).
2. Procédé selon la revendication 1, comprenant de plus l'étape de renforcement du moyen
de bouchage comprimé (185) par un moyen de renforcement (186) disposé autour du mandrin
(184) au-dessus et au-dessous du moyen de bouchage.
3. Bouchon pour utilisation dans un tubage de puits (172) et un tube de production (175)
comprenant un mandrin de forme allongée (184) et un moyen (185) pour boucher le tubage
de puits disposé autour du mandrin, ledit moyen de bouchage comprenant au moins un
élément élastomère généralement de forme tubulaire (207) ayant une première et une
seconde extrémité (208, 209) et une partie de paroi (210) entre elles, l'élément élastomère
(207) étant compressible le long de l'axe longitudinal par quoi les extrémités de
l'élément élastomère peuvent être amenées de force l'une vers l'autre tandis qu'une
section de la partie de paroi (210) s'adapte de façon étanche au tubage de puits,
caractérisé en ce que :
l'élément élastomère (207) possède une configuration normale, non contrainte dans
laquelle son diamètre varie le long de l'axe longitudinal de l'élément élastomère,
avec le diamètre intermédiaire entre les extrémités de l'élément élastomère supérieur
au diamètre au niveau des extrémités de l'élément élastomère ; et
l'élément élastomère (207) est capable de s'allonger le long de l'axe longitudinal
par quoi le diamètre intermédiaire entre les extrémités de l'élément élastomère est
sensiblement le même que le diamètre à ses extrémités de sorte que l'élément élastomère
peut passer à travers le tube de production.
4. Bouchon selon la revendication 3, caractérisé en ce que la partie de paroi (210) intermédiaire
entre les extrémités (208, 209) de l'élément élastomère (207) possède une épaisseur
de paroi réduite au niveau intermédiaire entre les extrémités de la partie de paroi.
5. Bouchon selon la revendication 3 ou 4, caractérisé en ce que l'élément élastomère
(207) possède disposé à chacune de ses extrémités (208, 209) un élément d'insert (215)
ayant à travers lui un passage axial (216) adapté pour recevoir à travers ce dernier
ledit mandrin de forme allongée (184), chaque élément d'insert (215) incluant une
pluralité de fils d'ancrage espacés radialement (217) s'étendant dans la partie de
paroi de l'élément élastomère.
6. Bouchon selon l'une quelconque des revendications 3 à 5, caractérisé par un moyen
(212) pour retenir l'élément élastomère (207) dans sa configuration de forme allongée.
7. Bouchon selon la revendication 6, caractérisé en ce que ledit moyen de retenue comprend
un élément tubulaire, fragile, à paroi mince (213), de façon qu'une force de compression
étant exercée sur l'élément élastomère (207), l'élément tubulaire (213) se casse et
permet à l'élément élastomère de prendre sa configuration normale, non contrainte.
8. Bouchon selon la revendication 7, caractérisé en ce que l'élément tubulaire (213)
est formé d'un matériau textile.
9. Bouchon selon la revendication 7, caractérisé en ce que l'élément tubulaire (213)
est formé d'un matériau métallique.
10. Bouchon selon l'une quelconque des revendications 3 à 9, caractérisé par les éléments
(204) pour renforcer le moyen de bouchage (185), lesdits éléments de renforcement
(204) étant disposés autour du mandrin (184) au-dessus et au-dessous du moyen de bouchage.
11. Bouchon selon la revendication 10, caractérisé en ce que ledit élément de renforcement
(202) comprend :
deux éléments de plaque métallique (219), chaque élément de plaque ayant une partie
centrale (220) avec un passage axial (221) s'étendant à travers elle pour recevoir
ledit mandrin (184) et une pluralité de prolongements s'étendant radialement (222)
ayant des premières et secondes extrémités (223, 224), chaque première extrémité (223)
étant formée solidairement à la partie centrale (220) ;
chacun des prolongements (222) étant plié pour disposer chaque prolongement dans
un plan qui est sensiblement perpendiculaire à la partie centrale (220) de l'élément
de plaque (219) ; et
les secondes extrémités (224) d'au moins deux des prolongements (222) pour chaque
élément de plaque (219) étant fixées solidement aux secondes extrémités (224) des
prolongements correspondants (222) de l'autre élément de plaque (219), par quoi les
éléments de plaque (219) forment un corps allongé qui peut passer à travers le tube
de production et, en exerçant une force de compression sur les parties centrales (220),
les prolongements (222) sont disposés dans un plan sensiblement parallèle à la partie
centrale (220) de chaque élément de plaque (219).
12. Bouchon selon la revendication 11, caractérisé en ce qu'un nombre pair de prolongements
(222) s'étendent à partir de la partie centrale (220) de chaque élément de plaque
(219), un premier jeu de prolongements en alternance (222') sont pliés en premier
vers le bas dans un plan qui est sensiblement perpendicilaire à la partie centrale
(220), et un second jeu de prolongements en alternance (222'') sont pliés vers le
bas dans un plan qui est sensiblement perpendiculaire à la partie centrale (220) et
dans une relation de recouvrement avec le premier jeu de prolongements (222').
13. Bouchon selon la revendication 11 ou 12, caractérisé en ce que chaque seconde extrémité
d'un prolongement (222) qui est fixée solidement à une autre seconde extrémité d'un
prolongement (222) est fixée solidement à l'aide d'une soudure par points (225).
14. Bouchon selon la revendication 13, caractérisé en ce que chaque seconde extrémité
d'un prolongement (222) qui est solidement fixée à une autre seconde extrémité d'un
prolongement possède un moyen d'évacuation de la soudure, composé d'une fente (229)
disposée sur les deux côtés de la soudure par points (225).