US3460625A - Methods and apparatus for bridging a well conduit - Google Patents

Description

Aug. 12, 1969 METHODS AND APPARATUS FOR BRIDGING A WELL CONDUIT Filed April 14. 1967 5 Sheets-Sheet l I W 2 W M Y JO 4 E Z M .E 0 t m m d wa W M w V} B ZYAKEI H 4\\\\\\\ a 52; N N d.

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I H. J. HART ETAL- METHODS AND APPARATUS FOR BRIDGING A WELL CONDUIT Filed April 14, 1967 5 Sheets-Sheet 2 Aug. 12, 1969 J. HART ETAL METHODS AND APPARATUS FOR BRIDGING A WELL CONDUIT I Filed April 14. 1967 3 Sheets-Sheet 5 5 3 5 2 6 5 3 2 Z 9 I 7 7 Wm M ii $5 2 y N 5? a f m Z w 5% im J f M w w MM M Z w AA J// a mflm p fl Ir, 0,1. N 0 457/635 /0 2a 09/ Z ymmmiwwg y H fi W U W Z 2% i \\\/V|/ 7 5 j c :5 7 M J 4 0 r 04 36 6 2 7 m fix? w 4.4 l

ATTORNEY United States Patent U.S. Cl. 166-285 16 Claims ABSTRACT OF THE DISCLOSURE Methods and apparatus for plugging a well conduit, either cased or open hole. An inflatable packer can be lowered into the well through tubing and then expanded to several time its lowering size to effect a seal against the well conduit. The expanded packer is temporarily vented so that well fluid can pass from one side of the packer to the other as a cementitious material is deposited on top of the packer and allowed to harden. After the material has hardened, the vent can be closed. The venting procedure prevents produced fluids from disturbing the packer or the cementitious material as the plug is being formed.

The present invention concerns new and improved methods and apparatus for forming a pressure bridge or plug in the well conduit, either cased or open hole. More specifically, the present invention concerns new and improved methods and apparatus for effectively plugging a well conduit below open tubing extending into the well conduit.

It is often desirable to form a pressure bridge or plug in a well casing for preventing fluid flow therein in either longitudinal direction. This can be accomplished in a conventional manner by lowering a device having an expansible sealing element into the well and expanding the sealing element against the surrounding well wall. In some cases, however, a relatively small size pipe or tubing may have been placed within the well to extend downwardly from the earths surface into the well, and the pressure bridge or plug must be formed at a setting point below the lowermost end of the tubing.

In will be apparent that the relatively small bore size of the tubing places certain restrictions on the manner in which the plug can be formed and types of equipment which can be used. Of course, the tubing can be removed from the well, a conventional bridging plug set and the tubing reinserted into the well. However, this procedure can be time'consuming and expensive and can be avoided in accordance with the present invention, which permits the bridge to be placed inthe well without removing the tubing.

Typical prior art devices which are directed to this end are disclosed in United States Patent Nos. 2,815,817 and 2,618,344. Accordingly to these disclosures, a cementitious material can be displaced into an inflatable bag and allowed to harden so that the bag bridges the well bore. Accordingly to another United States Patent No. 3,208,530, a ribbed basket can be lowered into the well bore and a fusible material placed on top of the basket which can harden to form a plug.

The prior art devices have a common shortcoming, viz, that during the length of time required for the plug to form into a hardened mass capable of withstanding differential pressure, a zone below the plug may be producing fluid. The produced fluid can form channels either around the bag or through cementitious material placed on top of the bag, or both. The channels can provide "ice fluid communication paths through the plug which destroy its effectiveness; the plug will not hold pressure.

An object of the present invention is to provide new and improved methods and apparatus for forming a pressure bridge in a well conduit.

Another object of the present invention is to provide new and improved methods and apparatus for forming a pressure bridge in a well conduit at a point below the lowermost end of a much smaller well conduit and without removing the smaller conduit from the well.

Another object of the present invention i to provide new and improved methods and apparatus for forming a pressure bridge in a well conduit in a manner which prevents any channeling of fluids through the bridge as it is formed so that it will effectively hold fluid pressure differentials which may be imposed upon it.

Yet another object of the present invention i to provide new and improved methods and apparatus for forming a pressure bridge in a well conduit and which are simple to perform and reliable in operation and which are effective in providing a means for preventing fluid flow in either direction in the well conduit.

Briefly described, a method in accordance with the present invention includes the manipulative steps of lowering an expandable packer through a tubing string and into a well conduit below the lower end of the tubing string and then expanding the packer to several times its lowering size to form a bridge in the well conduit. The expanded packer is temprarily vented so that well fluids can pass longitudinally therethrough. With the packer vented, the method is further practiced by deposting a cementitious material on top of the packer and allowing the cementitious material to harden and then closing off the vent. The venting procedure prevents the development of any pressure differentials across the packer which may otherwise force fluid through the plug and form channels therethrough.

Briefly described, apparatus for plugging a well in accordance with the present invention includes a support adapted for lowering into a well bore. An inflatable packer means on said support is adapted to have a wide range of expansion upon inflation thereof, and means selectively operable from the earth surface are provided for inflating the packer means to expand it into sealing engagement with the surrounding well conduit wall. A vent passageway extends from a location below to a location above the packer means to provide a fluid communiction path therethrough so that well fluids can temporarily pass through the inflatable means in its inflated condition. Means are also provided for depositing a cementitious material on the top side of the packer means in its expanded condition to increase the overall length of the plug in the well bore and thereby increase its effectiveness in holding pressure. Also, a valve means is provided for selectively closing off the vent passageway when desired.

The invention has other objects and advantages which will become apparent in connection with the following detailed description. The novel features of the present invention being set forth with particularity in the appended claims, the present invention, both as to its organization and manner of operation, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a longitudinal sectional view of one embodiment of an apparatus for practicing the present invention with parts in retracted positions for lowering FIGURE 3 is a sectional view of various parts of the apparatus of the present invention which remain in the well conduit to form a plug therein;

FIGURE 4 is a longitudinal sectional view of another embodiment of an apparatus for practicing the present invention with parts in retracted positions for lowering into a well;

FIGURE 5 is a view similar to FIGURE 4 with various parts in set positions for plugging a Well conduit;

FIGURE 6 is a sectional view of the second embodiment apparatus which remains within the well conduit to form a plug therein;

FIGURE 7 is a longitudinal sectional view of yet another embodiment of an apparatus for practicing the present invention with parts in relative positions for lowering into a well;

FIGURE 8 is a sectional view of the lower portion of the apparatus of FIGURE 7 with the packer expanded to plug a well conduit; and

FIGURE 9 is a view similar to FIGURE 8 but with various parts operated for depositing cementitious material on the top side of the plug.

One embodiment of an apparatus for practicing the present invention is shown in FIGURE 1 and includes a packer section A coupled to an anchor section B which is, in turn, coupled to a pump section "C. The entire tool can be suspended in the well bore on a running-in string in the form of an armored electrical cable 10.

The packer section A includes a support tube 11 having a fluid passageway or vent 12 extending longitudinally in an axial direction therein from lower side ports 13 to an upper end surface of the support tube, An inflatable, expansible bag or packer element is mounted around the support tube 11 with its lower end connected to a sleeve 15 by suitable clamps 16, seal elements 17 preventing fluid leakage between the sleeve 15 and the support tube 11. The upper end portion of the bag 14 is also secured by a clamp 18 to an upper sleeve 20 which sealingly engages the support tube 11. Longitudinal or spiral folds (not shown) can be formed in the bag 14 to minimize its retracted diameter and to permit a wide range of expansion during inflation. The bag 14 can be appropriately made of a suitable material such as neoprene impregnated Dacron cloth which is impermeable as well as readily pliable. The upper sleeve 20 can be slidable on the support tube 11 so as to accommodate changes in vertical length of the bag 14 during its expansion. An inflation passageway 21 can extend in an axial direction in the support tube 11 from its upper end surface to a lateral port 22 which opens into the interior of the bag 14.

The anchor section B is suitably coupled to the packer section A by threads 24 or the like. The anchor section includes a generally tubular housing 25 having at least three radially directed recesses 26 which extend into an elongated central chamber 27, the recesses 26 each receiving anchor arms 28 which can be pivotally mounted on pins 29. The anchor arms have gripping surfaces 30 at their outer end as well as segments of gear teeth 31 at their inner ends, the gear teeth facing inwardly toward the central axis of the housing 25. The chamber 27 can receive an anchor actuating member 32 in the form of a sliding piston having threads 33 on its outer periphery which drivingly engage the gear teeth 31 on each anchor arm. An annular flange 34 on the upper end of the piston 32 extends outwardly and a coil compression spring 35 can be arranged to press against the upper face of the flange. The piston 32 is retained in an upper position, where the anchor arms 28 are retracted, by a releasing member 36 which can take the form of a conventional explosive bolt or stud which is coupled to both the housing 25 and the piston 32 and arranged to be electrically actuated in a conventional manner. In the upper position, the spring 35 is compressed and exerts downward force on the piston 32. It will be appreciated that operation of the releasing member 36 will permit the coil spring 35 to move the piston 32 downwardly within the chamber 27 and, due to the interengagement between the piston threads 33 and the gear teeth 31, to swing the lower ends of the anchor arms 28 outwardly so that the gripping surfaces 30 can engage a well conduit wall of much larger bore size than the outer diameter of the housing 25.

Although the anchor arms 28 are particularly adapted to resist downward movement, it will be appreciated that the anchor mechanism could include a second set of arms, an actuating piston and spring, and a releasing member of like construction to that shown, but oppositely disposed, so that the anchoring mechanism can positively resist movement in either longitudinal direction. Moreover, it will be equally appreciated that instead of a spring system for extending the arms 28 outwardly, a hydraulic system including a piston and an atmospheric chamber could be utilized for extending the anchor arms.

The actuating piston 32 can have axially extending bores 37 and 38 formed therein which slidably receive an inflation pipe 39 and a vent pipe 40, respectively. The pipes 37 and 38 can be threadedly secured to the housing 25 at the upper and lower ends of the chamber 27 and are in registry with axial bores 19 and 23 in the housing 25. The bores 19 and 23 are, in turn, axially aligned with the inflation and vent passages 21 and 12, respectively. Suitable seals 45 can be appropriately positioned between the lower end surface of the housing 25 and the upper end surface of the support tube 11 to prevent any fluid leakage from the inflation and vent passageways. A bore 41 in the housing 25 registers with the inflation pipe 39 and extends upwardly to the uppermost end surface of the housing and another bore 42 registers with the vent pipe 40 and extends upwardly to a lateral or side port 43 which can be located centrally of a reduced diameter upper section 44 of the housing 25.

The pump section C includes a tubular case 46 which has a bore 47 formed in its lower end which is telescopically received over the upper reduced section 44 of the anchor housing 25. A side port 48 in the wall of the case 46 registers with the side vent port 43 to normally communicate the vent passageway with the well annulus. A releasable connection between the case 46 and the anchor housing 25 is provided so that the pump section C can be selectively released for retrieval from the well. Although the releasable connection can take many forms, a simple shear screw 50 is shown which can be ruptured by upward pull on the cable 10 after the bag 14 has been inflated and the anchor arms 28 engaged with the well conduit wall. Alternatively a pressure actuated releasing pin could be used which would release the case 46 from the anchor housing 25. The pin could release at maximum inflation pressure to insure that the bag 14 is fully inflated.

The case 46 has upper and lower chambers 51 and 52, the lower chamber 52 providing a fluid inlet and the upper chamber 51 adapted to contain a suitable pump and motor 53. The intake side of the pump is connected to the lower chamber 52 by a suitable conduit 55 and the output side of the pump is provided with a conduit 56 which extends through the lower chamber 152 for registry with the inflation passageway 41. A suitable seal 54 prevents fluid leakage at this point. Several side ports 57 communicate the lower chamber 52 with the well annulus so the well fluids can be used as the fluent medium for inflation of the packer bag 14. If desired, a suitable filter or screen 58 can be provided in the lower chamber 52 to prevent undesired foreign particles in the well fluids from entering the pump 53.

The prime mover for the pump can take any conventional form such as an electric motor which can be supplied with power from the earths surface via the armored electrical cable 10. Operation of the motor will drive the pump to displace well fluids into the packer bag 14 to inflate it. A conventional one-way check valve 59 can be provided in the inflation passageway 41 which permits well fluids to be pumped into the bag 14 while preventing any return movement of the fluids. Moreover, it will be appreciated that a spring loaded secondary check valve (not shown) can be provided so that inflation fluids can be withdrawn from the bag 14 if desired.

In operation, the tool can be lowered through relatively small size tubing T and to a selected setting point within the larger casing P at a location below the lowermost end of the tubing as shown in FIGURE 2. The outer diameter of the tool can be, for example, 1 CD. for passing through small size tubing. The anchor arms 28 are initially in retracted positions within the housing recesses 26 and the packer bag 14 is in its retracted or folded condition. The vent passageway 12 is open to fluid flow.

When desired, electrical power is supplied from the earths surface via cable to operate the tool. The releasing member 36 is ruptured to release the anchor actuating piston 32 for downward movement within the chamber 27. As the compression spring 35 presses the piston 32 downwardly, the anchor arms 28 are pivoted outwardly until their outer ends engage the casing P to anchor the tool against downward movement. The casing P can be of relatively large size, such as 5 /2 or 7". The motor and pump 53 are also actuated to displace well fluids through the inflation passageway 21 and into the interior of the packer bag 14. As fluid pressure builds up within the bag 14, the bag will expand as shown in FIGURE 2 until its outer periphery firmly seals against the well casing wall. The check valve 59 prevents any undesired return movement of inflation fluid so that a desired inflation pressure is maintained within the bag 14.

After the bag has been fully inflated, the pump and motor 53 are shut off and an upward pull on the cable 10 will shear the screw 50 to release the pump section C for retrieval from the well. Thereafter, a conventional dump bailer (not shown) can be lowered through the tubing T and a batch of cementitious or other hardenable material 60 deposited on top of the bag 14 as shown in FIGURE 3. The material can be of sufficient volume to provide an eflective bridging plug. Inasmuch as the vent passageway 12 is still open, any fluids being produced from zones below the plug can pass through the vent passageway and into the well conduit above the plug while the cement is hardening. Thus, produced fluids cannot act to form channels in the cement which destroy its effectiveness in holding pressure.

After a sufficient length of time has elapsed for the cement to harden, a sleeve valve 62 having a connector head 65 for coupling to a suitable grapple (not shown) can be lowered through the tubing T and positioned on the reduced diameter section 44 of the anchor housing 25 as shown in FIGURE 3. The sleeve valve 62 can have seal elements 63 and 64 adapted for positioning above and below the side vent port 43 to block any flow through the vent passageway. With the vent passageway 12 closed, the entire cross section of the casing P is packed off to block fluid flow in either direction.

A second apparatus constructed and arranged for performing the present invention is shown in FIGURE 4 and includes a bag section D coupled at its lower end to an inflating section E and coupled at its upper end to an anchor section F. A setting tool assembly G is releasably connected to the anchor section F and the entire tool can be suspended on an armored electrical cable 110.

The bag or plug section D includes a central support tube 111 having a bore 112 therethrough which extends between a lower side port 113 and upper side ports 114. The support tube 111 can have a stepped portion 115 around which the lower end of an expansible bag 116 can be mounted, the bag being secured to the section 115 by a suitable clamp 117. The upper end of the bag 116 is similarly secured to a sliding sleeve 118 which can move downwardly along the support tube 111 while fluid leakage therebetween is prevented by a seal element 119. The bag 116 can be suitably constructed like its counterpart in the previously described embodiment so as to be pliable as well as substantially impermeable. The bag 116 can also have longitudinal or spiral folds (not shown) formed therein for reducing its diameter while enabling it to be expanded to a well conduit diameter of several times its folded size.

The inflation section E includes a tubular housing 121 having a chamber 122 therein adapted to contain an inflating medium 123 such as cement or plastic which is normally fluent and which is capable of hardening after a predetermined span of time. The chamber 122 is placed in communication with the interior of the bag 116 by an inflation passageway 125. A fluid displacing piston 126, which can take the exemplary form of a conventional swab, is normally positioned at the lower end of the chamber 122 and is capable of displacing or forcing the fluent material 123 through the inflation passageway 125 and into the bag 116 upon upward movement of the piston 126 within the chamber. A piston actuating member in the form of a pull wire 127 can be connected to the piston 126 and extend upwardly into the support tube bore 112 through a packing gland 128, the pull wire 127 continuing upwardly through the support tube bore 112 and then exiting through one of the upper vent ports 114. It will be appreciated that an upward pull on the actuating wire 127 can serve to move the piston 126 upwardly and displace the fluent material 123 into the interior of the bag 116 to inflate it.

The anchor section F includes an annular shoulder or flange 130 which can be integrally formed on the support tube 111 and which carries a plurality of outwardly extendible anchor arms 131. The anchor arms 131 are formed in pairs with each upper arm pivotally connected to a collar 132 which is slidably mounted on the support tube 111. The lower one of each pair of arms 132 is pivotally connected to the flange 130 and the arms are additionally pivotally connected to one another. The outer end of each arm 131 is provided with wickers or teeth 134 adapted to bite into and grip a well conduit upon being extended into engagement therewith. Extension of the arms 131 can be eflected by advancement of the collar 132 along the support tube 111 toward the flange 130, causing the arms 131 to pivot outwardly.

An annular setting head 135 is slidable on the support tube 111 above the collar 132 and a biasing spring 136 can be positioned intermediate the head and collar to permit a limited amount of relative motion therebetween. The setting head 135 has an internal annular recess 137 therein forming an inclined surface which is cooperable with outer inclined surfaces of a locking slip 138, the locking slip 138 having teeth 139 on its inner periphery engageable with the outer surface of the support tube 111. The locking slip 138 functions as a one-way clutch to permit downward movement of the setting head 135 relative to the support tube 111 for extending the anchor arms 131 and to prevent converse relative movement for maintaining the anchor arms extended.

The setting tool assembly G is conventional and familiar to those skilled in the art, an exemplary embodiment being shown in United States Patent No. 2,618,343. The tool can be selectively actuated by an electrical signal through the cable 110 and is capable of exerting upward force on the support tube 111 through a threaded tension member 140 and downward force on the setting head 135 through a compression sleeve 141. Such forces can cause the setting head 135 to be advanced relatively downwardly along the support tube 111 and toward the flange 130 to expand the anchor arms 131 outwardly into engagement with the well conduit wall. When a predetermined magnitude of setting force is reached, the tension member 140 will break in tension at a reduced neck portion 142. When the neck portion 142 breaks, the setting tool assembly G is freed from its connection to the upper end of the support tube 111 and can be hoisted 7 upwardly within the well by an upward pull exerted on the cable 110 at the earths surface.

For selectively closing the side vent ports 114, a sleeve valve 145 can be positioned between the compression sleeve 141 and the support tube 111 and adapted to slide on the support tube 111 adjacent to the side ports 114. Suitable seal elements 146 and 147 seal between the valve 145 and the support tube 111. An upper portion 148 of the sleeve valve 145 has its inner surface spaced laterally away from the outer surface of the support tube to form a passage space therebetween through which the piston actuating wire 127 can extend. The terminal end of the wire 127 can be connected to the setting tool tension member 140 by a suitable fastening device 149. The upper end of the vent valve 145 is provided with a connector head 150 which is arranged so that when the setting tool assembly G is eventually removed from the well, a grapple or other suitable means (not shown) can be lowered and connected to the connector head for pulling the sleeve valve 145 upwardly to a position where the seal elements 146 and 147 close off the vent ports 114.

In operation of the apparatus shown in FIGURE 4, the tool can be suspended on the cable 111) and lowered through a tubing string T to a setting point within a well casing P below the lowermost end of the tubing string. The bag 116 is in its folded condition and the entire tool can have a relatively small maximum outer diameter such as 1 for passing through small size tubing. However, when the tool is positioned below the lower end of the tubing string, the bag 116 can be expanded to pack off a relatively large size casing P which may be, for example, 5 /2 or 7". An electrical signal applied to the cable 110 will activate the setting tool assembly G for extending the anchor arms 131. The compression sleeve 141 is moved downwardly relative to the support tube 111 to advance the setting head 35 toward the support tube flange 130. As this occurs, the anchor arms 132 are pivoted outwardly until the teeth 134 grip the well casing P as shown in FIG- URE 5. The teeth 139 on the inner periphery of the locking slip 138 will grip the outer surface of the support tube 111 to hold the setting head 135 in the lowermost position to which it is moved, thereby locking the anchor arms 131 in their extended positions. When a predetermined magnitude of setting force is built up in the setting tool tension member 141), the tension member will part at the reduced neck portion 142 to release the setting tool assembly G for upward movement in the well bore. The piston actuating wire 127 remains connected to the tension member 140, however.

To inflate and expand the bag 116, the setting tool assembly G is moved upwardly by upward pull on the cable 110 at the earths surface. Upward motion is translated by the wire 127 to the pump piston 126 and upward motion of the piston will displace fluent material 123 into the bag 116 through the inflation passageway 125. As the bag 116 expands, the sliding sleeve 118 can move downwardly on the support tube 111 to accommodate changes in length of the bag. The amount of upward pull on the cable 110 controls the inflation pressure inside the bag 116 to insure that an effective seal is formed against the casing wall. The bag section D will not be moved upwardly by upward pull on the cable 110 because of the holding action of the anchor arms 13.1.

Inflation pressure can be maintained within the bag 116 by applying constant tension to the cable 11d and can be maintained for a suflicient length of time to allow the fluent material 123 to harden into a solid mass. When the material has hardened within the bag 116, an overpull on the cable 110 will serve to part the wire 127 and the setting tool assembly G can be withdrawn from the well. It will be noted that during the entire time that the fluent material 123 is hardening, the vent ports 113 and 114 are open. Accordingly, if a zone below the plug is producing fluid, the fluid can pass through the bag 116 via the support tube bore 112 and the fluid will not disturb the bag 116. When desired, a suitable grapple (not shown) can be lowered through the tubing string T and coupled to the connector head 156 so that the vent valve can be moved to its upper position for closing the vent ports 114 to fluid flow as shown in FIGURE 6. The vent valve 145 is pressure balanced so that it will not open in response to pressure from above or below.

If desired, a batch of additional cementitious material 152 can be deposited by a conventional dump bailer (not shown) on top of the bag 116 and allowed to harden to provide for additional overall length of the plug. If additional material is used, the vent valve 145 can be left in its open position to insure that the material will remain undisturbed as it hardcns. The valve can then be closed as previously described. Use of additional cementitious material on top of the bag 116 can further insure that the plug will remain immovable in the well and can withstand high pressure differentials acting from either direction.

A third apparatus constructed and arranged for performing the present invention is illustrated in FIGURE 7 and includes a control section H adapted for suspension on an electrical wire-line or cable (not shown). The control section H is coupled to a pump section I. A valve assembly L is coupled to the lower end of the pump section I and the valve assembly is in turn connected to a bridge plug assembly M. At the lower end of the bridge plug assembly M is a vent valve section N.

The control section H includes a tubular case 212 having a longitudinally extending chamber 213 therein. A piston 214 is movably received within the chamber 213 and a rod 215 connected to the piston extends downwardly through a bore 216 which opens axially into the chamber 213. The upper portion of the chamber 213 is arranged to receive a suitable hydraulic fluid, and a coil compression spring 218 is arranged in the lower portion of the chamber to urge the piston 214 and the rod 215 upwardly. Several side ports 219 in the wall of the case 212 below the piston 214 enable fluid pressures within the chamber 213 to be balanced with hydrostatic well fluid pressures as the tool is lowered into a fluid filled well bore. To permit placement of hydraulic fluid into the upper portion of the chamber 213, a one-way check valve 221 in an entry passage 221 is provided. An exit passage 222 extends from the chamber 213 to the exterior of the case 212 and has a remotely controllable valve 223 therein, such as a conventional solenoid operated valve, which normally prevents discharge of hydraulic fluid from the chamber so that the piston 214 and the rod 215 cannot move upwardly under the influence of the upward force being exerted by the coil spring 218.

The piston rod 225 extends downwardly through the bore 216 to a location within a recess 225 where it can operate a latch device. The latch device includes a plurality of upwardly extending, inwardly biased spring fingers 227, the spring fingers terminating in enlarged head portions 228. When the parts are in the relative positions shown in FIGURE 7, the head portions 228 are held outwardly by the rod 215 in engagement with a shoulder 230 formed by the recess 225. However, it will be appreciated that removal of the rod 215 from behind the head portions 228 will permit them to spring inwardly and out of engagement with the shoulder 230. The retention and release of the spring fingers 227 from the recess 225 controls the operation of the pump section I.

The pump section I includes a cylindrical housing 232 coupled at its upper end to the control section H and at its lower end to a bailer cylinder 237. The housing 232 has a bore 233 in which a weighted body member 234 is movable. The weighted member 234 can be an elongated tubular member formed with a rod 235 extending upwardly from its upper end, the rod having the previously described spring fingers 227 connected to its upper end and extending into the recess 225. A coil compression spring 236 can surround the rod 235 with its upper end pressing against the upper end of the bore 233 and its lower end pressing against the upper surface of the weighted member 234.

Positioned within the bore of the cylinder 237 and spaced below the lower end of the weighted member 234 is a piston 238 having an elastomer swa cup 239 connected to its lower end. The swab cup 239 defines the upper end of a fluent material chamber 240 Within the bore of the cylinder 237 and which is adapted to contain a suitable material, such as cement, which has liquid or flowable properties for a predetermined length of time and which is thereafter capable of hardening or setting up to form a solid mass. The lower end portion of the cylinder 237 has a reduced diameter section 242 which is sized for telescopic reception into a bore 243 formed in a tubular housing 244 which is a component of the valve assembly L. A shearable pin member 245 releasably couples the cylinder 237 to the valve housing 244.

The valve housing 244 has a central chamber 246 formed therein with stepped wall surfaces providing a first larger diameter portion 247 and a second smaller diameter portion 248. A valve element 250 is slidably received within the chamber 246, the valve element being in the form of a sleeve piston having an annular head 251 received in the first chamber portion 247, the valve element further having a tubular portion 251 extending downwardly into the second chamber portion 248. An O-ring seal 252 seals between the head portion 251 and the wall of the enlarged chamber portion 247, and a second O-ring seal 253 can be positioned to seal between the tubular portion 251 and the wall of the second chamber portion 248.

The valve element 250 further has a central bore 254 extending throughout its length which sealingly receives .a downwardly extending tubular member 255. The tubular member 255 is, in turn, connected to the upper end portion of a smaller diameter vent tube 256. The bores of the vent tube 256 and the tubular member 255 form a vent passageway 257 which is open to the exterior of the tool by a side port 258. The valve housing 244 has an axially extending oflset bore 2611 which is aligned with the bore 241 which communicates with the fluent material chamber 240 to provide an inflation passageway. It will be appreciated that the valve element 250 is arranged to prevent flow of the fluent material from the cylinder 237 as long as the valve element is in its upper position as shown in FIGURE 7. In this position, the valve element 251) is retained by a shear screw 261. A compressed coil spring 262 is arranged to exert downward force on the valve element 250 for moving it to a lower position within the chamber 246 when the shear screw fails. As the valve element 250 moves downwardly within the chamber 246, the head portion 252 can tele scope away from the tubular extension 255 to place the passage 241 in communication with the annulus 263 between the sleeve 251 and the vent tube 256, thereby permitting the fluent material within the chamber 240 to flow downwardly through the valve element 250.

The bridge plug assembly M includes a tubular body or support 270 which can be integrally formed with, and extend downwardly from, the valve housing 244. An expansible bag 271 is mounted around the support 274 with its lower end portion secured to a lower sliding sleeve 272 and its upper end similarly secured to an upper sliding sleeve 273. Suitable seals 274 and 275 fluidly seal between the sleeves and the support tube 2741 to prevent any fluid leakage from the bag 27.1. The upper sleeve 273 can be initially restrained against sliding motion relative to the support 278 by locating the inner portion of the seal element 275 within a peripheral groove around the support 270 so that the seal element itself can yielda'bly resist relative motion between the sleeve and the support.

The vent passageway 257 extends axially in the support 276 from a chamber 277 at the lower end portion of the support to the bore of the vent tube 256 at the upper end portion of the support. The chamber 277 is normally in communication with the Well annulus by way of side ports 278 so that well fluids can pass freely through the vent passageway 257. A vent valve 279 in the form of a sleeve is provided for selectively closing olf the vent passageawy 257 to fluid flow and is normally positioned at the lower end of the chamber 277 below the side ports 278. Seal elements 280 and 281 around the outer periphery of the valve 279 fluidly seal against the wall surfaces of the chamber 277 and are positioned so that when the valve is moved to its upper position, the seal elements will block fluid flow through the side ports 27% and thus the vent passageway 257. A valve actuating wire 282 can be suitably connected to the vent valve 27? and extend upwardly through the vent passageway 257 to a location within the lower end portion of the bailer housing 232 where it can be securely attached by any suitable means such as a threaded plug (not shown) extending through the wall of the lower section. It will be appreciated that an upward pull on the wire 282 can shift the valve 279 to its upper position for closing the vent passageway 257 to fluid flow. It will be noted that the seal arrangement of the sleeve valve 279 makes the valve pressure balanced so that it will not be moved in response to fluid pressure from either above or below.

An annular inflation passageway 285 extends in the upper portion of the support 270 and communicates with the interior of the bag 271 via several lateral ports 286 and is coextensive with the annulus passageway 263 between the valve element 250 and the vent tube 256. Accordingly, fluent material which passes through the valve element 250 can enter into the interior of the bag 271 to expand it against the surrounding well conduit wall. If desired, a rubber bumper sub 287 can form the lowermost end portion of the tool to insulate the tool from shock loads which may be imposed upon it while lowering into the well.

In operation, the tool is prepared for lowering into the well by latching the weighted member 234 in its upper position as shown in FIGURE 7 and filling the control chamber 213 above the release piston 214 with a suitable hydraulic fluid so that the rod 215 is properly positioned behind the latch fingers 2127. The compression spring 236 is initially in a compressed condition and exerts downward force on the weighted member 234. The inflation valve element 250 is secured in its upper closed position by the shear screw 261 and the chamber 240 within the cylinder 237 can be filled with predetermined volume of initially fluent but hardenable material such as cement. The vent valve actuating wire 276 is appropriately secured so that the vent valve 279 is in a lower position where the side ports 278 are open.

The tool is then lowered downwardly into the well on the electrical cable through the tubing T and to a selected setting point within the well casing P below the lowermost end of the tubing as shown in FIGURE 8. At setting depth, an electrical signal initiated at the earths surface will open the solenoid valve 223 in the control section H so the hydraulic fluid can exit from the chamber 213. As the fluid exits, the force of the spring 218 can move the piston 214 and the rod 216 upwardly. As the rod 216 moves upwardly, the latch fingers 227 are freed to spring inwardly and release from the recess 225.

When the rod 216 is released, the force of the spring 236 acts to accelerate the weighted member 234 downwardly so that it can strike the piston 238 with a jarring force. This coaction creates a substantial pressure surge in the fluent material within the chamber 240 which acts through the passageway 241 on the upper face of the valve element 250, thereby imparting a substantial force to the valve element which functions to shear off the valve retaining screw 261. Release of the retaining screw 261 permits the valve element 250 to move downwardly to its lower position shown in FIGURE 8 so that the fluent material can flow through the annulus 263, the passageway 285, the ports 286 and into the interior of the bag 271.

The weighted member 234 will then rest on the piston 238 and tend to gravitate downwardly, thereby forcing the swab cup 239 downwardly and generating pressure within the chamber 240 to displace fluent material into the bag 271. It will be appreciated that the inflation pressure which can be applied to the bag 271 is a function of the weight of the weighted member 234 and the crosssectional area of the swab cup 239. The weighted member 234 can be constructed of suitable heavy or dense metal such as tungsten carbide and be sized so that a suitable inflation pressure, such as, for example, 15-25 p.s.i. can be developed within the bag 271 to expand it into effective sealing engagement with the well conduit wall as shown in FIGURE 8.

After the bag 271 is fully inflated, it forms, in effect, a platform in the well bore on which an additional volume of material can be deposited. This can be accomplished by manipulation of the tool including an upward pull on the cable to shift the support 270 upwardly relative to the bag 271, thereby exposing the inflation ports 286 to the well annulus above the bag as shown in FIGURE 9. Movement of the inflation ports 286 above the seals 275 on the sliding sleeve 273 traps the inflation pressure within the expanded bag 271 and permits dumping the remainder of the cementitious material within the chamber 240 on top of the bag 271. With the tool parts in the relative positions shown, a suflicient period of time is allowed to pass such that the material both within the bag 271 and on top of the bag can harden into a solidified mass, the material on top of the bag increasing the overall length of plug formed and enhancing the plugs ability to withstand high pressure from above or below.

During the time that the material is hardening, the vent passageway 257 remains in open condition as shown in FIGURE 8 so that any produced fluids entering the casing P from below the bag can pass upwardly therethrough and enter the well annulus above the plug through the side vent port 258. Accordingly, it will be appreciated that such fluids will have no tendency to form channels either around the bag 271 or through the material on top of the bag, which disturbances may otherwise destroy the effectiveness of the plug to hold pressure. When the plug is fully formed, an upward pull on the cable will serve to shear the releasing pin 245 to disconnect the pump and control sections H, J from the packer and valve sections M, L and permit retrieval of the pump and control sections from the well. The initial upward movement of the pump section imparts upward movement to the valve actuating wire 282 which, in turn, moves the vent valve 279 to its upper closed position. Continued upward movement will cause the wire 282 to part as shown in FIGURE 9, leaving the vent valve 279 in a closed position to block all vertical movement of fluids within the well casing P. The bailer and control sections J and H can then be withdrawn to the earths surface through the tubing T.

New and improved methods and apparatus have been disclosed for effectively plugging a well conduit. In accordance with the present invention, the plug can be lowered through small tubing and then set or formed in a large size casing or open hole without removing the smaller tubing from the well. The invention is arranged in a manner for controllably bypassing or venting fluid flow while the plug is forming to prevent disturbance of the plug. Accordingly the plug will be effective in holding pressure differentials which may be imposed upon it.

Since certain changes and modifications may be made in the disclosed embodiments of the invention without departing from the concepts involved, it is the aim of the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the present invention.

We claim:

1. A method for forming a pressure bridge in a well conduit comprising the steps of: lowering an inflatable packer into a well through a tubing string and to a setting point in a well conduit below the lowermost end of the tubing string; selectively actuating a pump means from the earths surface to displace an inflating medium into the packer, thereby expanding the packer to a size several times its unexpanded size and against the surrounding well conduit wall to form a plug in the well conduit; temporarily venting the packer so that well fluid can pass through the packer from one side to the other even though the packer is expanded; releasing the pump means from the expanded packer; retrieving the pump means to the earths surface; and closing the vent so that the packer is effective to prevent fluid flow in either longitudinal direction past its sealing point.

2. The method recited in claim 1 further including the step of placing a cementitious material on top of the expanded packer and allowing the material to harden before closing the vent,

3. The method recited in claim 1 further including the step of anchoring the packer against movement in the well conduit.

4. A method for forming a pressure bridge in a well conduit comprising the steps of: lowering an inflatable packer and pump means into a well through a tubing string and to a setting point in the well conduit below the lowermost end of the tubing string; selectively actuating the pump means from the earths surface to displace an inflating medium into the packer, thereby expanding the packer to a size several times its unexpanded size and against the surrounding well conduit wall to form a plug in the well conduit; temporarily venting the packer so that fluid can pass through the packer from one side to the other; releasing the pump means from the expanded packer; retrieving the pump means to the earths surface; then lowering a valve means into the well for closing the vent; and closing off the vent with the valve means so that the packer is effective to prevent fluid flow in either longitudinal direction past its sealing point.

5. The method of claim 4 including the additional steps of anchoring the packer against movement in the well conduit.

6. Apparatus for bridging a well conduit below the lower end of a tubing string in a well conduit comprising: a bridging member adapted to pass through a tubing string and expandable in a well conduit to close off the cross section of the well conduit, said bridging member having a longitudinally extending central support with a vent passageway therethrough which is arranged to provide communication across said bridging member, the upper end of said vent passageway terminating in laterally extending sort means in the wall of said support, said support being adapted for receiving a closure member which spans said port means to close off said passageway.

7. Apparatus for bridging a well conduit below the lower end of a tubing string in a well conduit comprising: a bridging member including an expansible packing element adapted to pass through a tubing string and expandable in a well conduit to close off the cross section of the well conduit, means detachably coupled to said bridging member for expanding said packing element, said bridging member having a longitudinally extending support member with a vent passageway arranged to provide communication across said bridging member, one end of said passageway terminating in laterally extending port means, and sleeve valve means for closing off said port means.

8. A well apparatus for insertion into a well bore through a first well conduit and adapted for expansion to plug a second well conduit having a relatively large bore size, comprising: a support tube; an inflatable expansible member mounted around said support tube and adapted for a wide range of expansion upon inflation thereof; a vent passageway through said support tube and extending from a location below said expansible member to a location above said expansible member so that Well fluids can pass longitudinally through said expansible member in its inflated condition; pump means for displacing fluid into said expansible member to inflate it; an inflation passageway in said support tube extending between said pump means and the interior of said expansible member; means for releasably coupling said pump means to said support tube so that said pump means can be released and retrieved to the surface after inflation of said expansible member; and valve means for selectively closing said vent passageway.

9. A well apparatus adapted for insertion into a Well bore through a first smaller well conduit and for expansion to plug off a second larger well conduit, comprising: a support tube; an inflatable expansible member mounted around said support tube and arranged for a wide range of expansion upon inflation thereof; a vent passageway in said support tube and extending between locations on opposite sides of said expansible member so that fluid can pass therethrough; pump means for inflating said expansible member; an inflation passageway connecting said pump means and said expansible member; control means for enabling remote and selective operation of said pump means, said control means being controllable from the earths surface; means for releasably coupling said pump means to said support tube so that said pump means can be released and then retrieved from the surface after functioning to inflate said expansible member; and valve means operable from the earths surface for selectively closing said vent passageway.

10. The apparatus of claim 9 further including extendible means connected to said support tube and movable outwardly thereof for anchoring said apparatus in the well conduit.

11. The apparatus of claim 10 wherein said extendible means comprise arms which are pivotally mounted relative to said support tube, the outer ends of said arms have conduit gripping portions.

12. A well apparatus for insertion into a well bore comprising: a support tube; an inflatable expansible member mounted around said support tube and adapted for a wide range of expansion upon inflation thereof; a vent passageway in said support tube extending between locations above and below said expansible member; an inflation passageway in said support tube communicating with the interior of said expansible member and through which a fluent medium can be displaced for expanding said expansible member; pump means coupled to said support tube and adapted to displace a fluent medium through said inflation passageway; means for releasably coupling said pump means to said support tube; normally retracted anchor means extendible outwardly of said support tube for anchoring said support tube in a well conduit; selectively operable means for extending said anchor means; and valve means for closing 011 said vent passageway.

13. The apparatus of claim 12 wherein said vent passageway terminates above said expansible member in a laterally extending port means, and said valve means includes a sleeve member having seal means engageable with said support tube above and below said port means.

14. Packer apparatus for use in bridging a Well conduit, comprising: a support; an expansible packing sleeve mounted on said support and having a wide range of expansion whereby said packing sleeve can be passed through a relatively small diameter tubing string and then expanded to pack-oft a larger diameter well conduit below the lower end of the tubing string; means releasably coupled to said support for expanding said packing sleeve, said packing sleeve, when expanded, forming a bridge in the well bore for supporting a column of cementitious material thereabove; a flow passage through said support extending between a location in communication with the well bore below said packing sleeve to a location in communication with the well bore above the column of cementitious mateiral, whereby well fluids flowing through said passage cannot disturb the cementitious material as it hardens; and pressure balanced valve means for closing oflf said flow passage after the cementitious material has hardened.

15. The apparatus of claim 14 wherein one of said locations in communication with the well bore is formed by a laterally extending port in said support; said valve means including a sleeve member having seals engageable with said support above and below said port.

16. The apparatus of claim 14 wherein said expanding means includes means for developing a fluid pressure inside said sleeve member which is greater than the fluid pressure in the well bore outside said sleeve member.

References Cited UNITED STATES PATENTS 2,222,750 11/1940 Litolff 166187 2,618,344 11/1952 Turechek et al. 166-187 2,629,446 2/1953 Freling et al 166187 2,717,644 9/1955 Bell et a1. 166l87 2,769,498 11/1956 Huber 166187 2,978,029 4/ 1961 OReilly et a1 166187 3,066,739 12/ 1962 Saurenman et a1. 166187 JAMES A. LEPPINK, Primary Examiner US. Cl. X.R. 166-101, 187, 315

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