US3463248A - Apparatus for discharging fluent substances into well bores - Google Patents

Description

ELL BORES W. T. BELL APPARATUS FOR DISCHARGING FLUENT SUBSTANCES INTO w Original Filed Nov. 6, 1967 4 Sheets-Sheet l U R e 0 w w W "a 5% w B 4 3 5 8 3 6 9 2 M Wu 0/ ll 5 665 2 flu fl iw BRL WMMWW fi M II llll .l l l l I a G N O w A Y M A p w W \.i....:i::...l g 4 3 3 m 5 G 5 4 E H 4 4 5 H M 3 2 FIG. 7A

A118. 6, 1969 w. 1'. BELL 3,463,248

APPARATUS FOR DISOHARGING FLUENT SUBS'I'ANCES INTO WELL BORES Original Filed Nov. 6. 1967 4 Sheets-Sheet 2 FIG.3B

FIG. 3A

RQQR

William 7'. Bell INVENTOR.

avg/62E Z ATTORNEY s- 26. 9 w. T. BELL 3,463,248

APYARATUS FOR DISCHARGING FLUENT SUBSTANCES INTO WELL BORES Original Filed Nov. 6, 1967 l {Sheets-Sheet 5 William 1. Bell INVENTOR.

A TTORNEY Aug. 26, 1969 w. T. BELL 3,463,248

APPARATUS FOR DISCHARGING FLUENT SUBSTANCES INTO WELL BORES Original Filed NOV. 6, 1967' 4 Sheets-Sheet 4 FIG. 6

William T. Bell INVENTOR.

A TTORNE Y United States Patent 3,463,248 APPARATUS FOR DISCHARGING FLUENT SUB- STANCES INTO WELL BORES William T. Bell, Houston, Tex., assignor to Schlumberger Technology Corporation, New York, N.Y., a corporation of Texas Original application Nov. 6, 1967, Ser. No. 680,648. Divided and this application Oct. 23, 1968, Ser. No. 769,805

Int. Cl. E21b 43/119, 43/11, 33/138 U.S. Cl. 175-452 12 Claims ABSTRACT OF THE DISCLOSURE The particular apparatus described herein as illustrative of the invention are operative for replacing fluids in a selected interval of a well bore with suitable fluent substances. The various embodiments of apparatus of the invention described herein include a reservoir adapted to contain a fluent substance and a perforator for perforating earth formations adjacent to the selected well bore interval. Each of the disclosed tools are arranged so that selective movement of the perforator into the well bore interval is operative to induct well bore fluids into the reservoir as the fluent substance is discharged into the well bore interval around the perforator.

This application is a division of application Ser. No. 680,648, filed Nov. 6, 1967.

It is widely recognized that the entrance of well control fluids or so-called mud into newly formed perforations in an earth formation may, in time, plug the perforations so tightly that subsequent production of oil and/or gas from the formation will at least be impaired if not halted altogether. To counter this damage, suitable oilsoluble liquids and the like are commonly injected into the well bore at least in the vicinity of where perforations are to be made and a perforator is then actuated while these protective liquids are hopefully still in place. In this manner, it is believed that the soluble protective liquids will immediately rush into the perforations as they are made and block the subsequent entry of the well control fluids. Then, when connate fluids are produced through perforations protected in this manner, the produced fluids can easily flow into the well bore and wash away the soluble protective liquids.

Various proposals have been made heretofore for injecting such protective liquids around a perforator just before it is actuated to produce perforations at a desired location in a well bore. For one reason or another, however, these proposed techniques and devices have not been commercially accepted by the industry. For example, one tool proposed heretofore employs a self-contained pump that will supposedly pump a limited supply of protective liquids into the annulus around the perforator and completely displace the Well control fluids in this space into the well bore above an inflated packer on the tool. A similar previously proposed tool employs a source of high-pressure gas for discharging protective liquids around the perforator to displace the well control fluids upwardly away from the perforator.

It will be appreciated, however, that for the latter one of these tools to accomplish its intended function, the protective liquids must displace a significant volume of the well control fluids against the extreme hydrostatic pressure typically encountered in well bores. Moreover, with either of these techniques, there is no assurance that the protective liquids will not merely be diffused into the surrounding well control fluids rather than enveloping the perforator in a substantially homogeneous mass of the protective agent that will remain in position until "ice the perforator is actuated. Similar problems are also encountered where it is desired to perforate a formation interval and then inject a treating agent, such as acid or the like, to clean the perforations.

Accordingly, it is an object of the present invention to provide new and improved apparatus for reliably discharging a homogeneous mass of selected fluent substances into a selected well bore interval around a well perforator before it perforates earth formations adjacent thereto so that the fluent substances will enter the resulting perforations rather than being diluted by or being dispersed through other fluids in the well bore.

This and other objects of the present invention are accomplished by various embodiments of well-completion tools which, by selective movement, are each adapted to displace the well bore fluids around the tool and discharge a suitable treating agent into the resulting voided space upon such selective movement. By including a perforator with each of these tools, as the perforator is moved into the selected well bore interval, fluids in the well bore are removed from the space to be occupied by the perforator and simultaneously replaced with the fluent treating substance. Thus, upon actuation of the perforator, the treating substance will enter the resulting perforations into the adjacent earth formations without interference from the displaced well bore fluids.

The novel features of the present invention are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may be best understood by way of the following description of exemplary apparatus employing the principles of the invention as illustrated in the accompanying drawings, in which:

FIGURES 1A and 1B are cross-sectional views of the reservoir section of a completion tool arranged in accordance with the principles of the present invention;

FIGURE 2 is a cross-sectional view taken along the lines 22 in FIGURE 1B;

FIGURES 3A and 3B are views similar to FIGURES 1A and 1B but showing various elements thereof in their final position;

FIGURE 4 is a schematic representation of an alternative embodiment of a tool arranged in accordance with the present invention;

FIGURE 5 is an elevational cross-sectioned View of a portion of the completion tool shown in FIGURE 4; and

FIGURE 6 is a schematic view of still another completion tool incorporating the principles of the present invention.

Turning now to FIGURES 1A and 1B, the central portion of a Well-completion tool 10 arranged in accordance with the principles of the present invention is shown. As seen there, the tool 10 is comprised of an elongated housing 11 having an adapter head 12 connected to its upper end and adapted for coupling the housing to other tools (not shown) thereabove which preferably include a typical centralizer and a casing-collar locator such as that shown in Patent No. 3,114,876. The lower end of the housing 11 is suitably adapted for connection to another tool centralizer (not shown) and a perforator (not shown). This perforator may, of course, be any one of the various types customarily employed in well-perforating operations. Although it is customary to fabricate well tools in a number of separable sections for ease of manufacture and assembly, various portions of the tool 10 are shown in the drawings as being integral with other portions so that minor constructional details of the tool will not affect an understanding of the invention.

In addition to the aforementioned perforator, the tool 10 includes a reservoir 13 adapted to carry a supply of a suitable fluent substances; and means, such as a flow diverter 14, adapted to displace the fluent substance from the reservoir in response to movement of the perforator into a selected well bore interval. In the preferred embodiment of the present invention depicted in FIGURES 1A and 1B, the well-completion tool further includes a control section for selectively enabling the diverter 14 and the perforator upon command from the surface. The interrelation of these various elements 11-15 and the perforator therebelow will subsequently become more apparent.

The reservoir 13 in the upper portion of the housing 11 is formed by an enlarged longitudinal bore 16 of uniform diameter extending an appropriate distance between the upper adapter head 12 and the upwardly facing shoulder 17 formed by the junction of the enlarged bore and a smaller coincidental bore 18 extending downwardly toward the lower end of the housing. A tubular conduit 19 is dependently secured and fluidly sealed to the adapter head 12 and extended downwardly along the central axis of the reservoir 13 to a position at least adjacent to the shoulder 17 for enclosing an electrical conductor 20. The electrical conductor 20 is passed through a typical fluid seal 21 in the adapter head 12 and extended on upwardly through the tool 10 for appropriate connection to one or more conductors enclosed in a typical suspension cable (not shown).

An annular piston member 22 is slidably disposed in the enlarged bore 16 and fluidly sealed therein by one or more external sealing members, as at 23, engaging the housing 11 and an internal sealing member 24 engaging the conduit 19 to define upper end lower enclosed spaces 25 and 26 in the reservoir 13. In its initial position shown in FIGURE 1A, the piston member 22 is located as near as possible to the adapter head 12 to enable the lower enclosed space 26 of the reservoir 13 to receive a maximum quantity of a treating agent (not shown). One or more lateral ports 27 (FIGURE 1A) are provided in the upper portion of the housing 11 to admit well control fluids into the upper enclosed space 25 of the reservoir 13 as the tool 10 is being operated. Similarly, one or more normally closed ports 28 (FIGURE 1B) are provided in the lower portion of the housing 12 and adapted, when open, for discharging a fluent substance from the lower enclosed space 26 of the reservoir 13. Accordingly, as will subsequently be explained, once the lower ports 28 are opened and the tool 10 is operated so as to admit a flow of well control fluids into the upper ports 27, the piston 22 will move downwardly in the reservoir 13 and displace a corresponding volume of the treating agent from the lower space 26 through the lower ports as the well control fluids enter the upper ports and fill the upper space 25.

To facilitate the movement of the tool 10 through a fluid-filled well bore to a starting position, the diverter 14 is initially retracted to provide suflicient clearance therearound between the housing 11 and internal wall of the well casing (not shown). Similarly, although the piston 22 will normally tend to remain in its elevated position within the bore 16 as shown in FIGURE 1A so long as the diverter 14 is retracted, it is preferred to keep the ports 28 closed so that the fluent substance will not be lost from the lower space 26.

As shown in FIGURE 1B, the diverter 14 is preferably comprised of a flexible sleeve 29 of an elastomeric material that is secured at its upper end around the central portion of the housing 11. The outer diameter of the housing 11 is reduced just below the upper end of the elastomeric sleeve 29 and appropriately formed to provide longitudinally spaced external surfaces 30* and 31 that are separated from one another by an external surface 32 of a more-reduced diameter. An elongated sleeve member 33 having an enlarged-diameter upper portion 34 is slidably mounted around the reduced central portion of the housing 11 and fluidly sealed thereto by sealing members 35 and 36, respectively, encircling the spaced external surfaces 30 and 31.

The elastomericdiverter sleeve 29 is disposed around a plurality of longitudinally extending, outwardly bowed flexible strips 37 that are circumferentially spaced around the housing 11 and have their upper and lower ends secured between opposed shoulders 38 and 39 on the housing and enlarged portion 34 of the slidable sleeve member 33 respectively. The lower end of the elastomeric sleeve 39 is carried below the lower end of the bowed spring strips 37 and secured around the enlarged sleeve portion 34. To insure that the spring strips 37 will remain in the slightly bowed position depicted in FIGURE 1B, the enlarged portion 34 of the slidable sleeve member 33 is extended upwardly to about the middle of the spring strips and progressively enlarged so as to engage the rear surface of each strip and keep the central portions of the strips bowed outwardly.

It will be appreciated, therefore, that so long as the slidable sleeve member 33 remains in the position illustrated in FIGURE 1B, the elastomeric sleeve 29 will retain its generally relaxed position. By moving the slidable sleeve 33 upwardly in relation to the housing 11, however, the sleeve shoulder 39 is moved toward the housing shoulder 38 to shorten the distance between the opposite ends of the spring strips 37 and cause their central portions to bow radially outwardly. Thus, as the slidable sleeve member 33 is moved upwardly, the outward movement of the mid-portions of the spring strips 37 will radially expand the central portion of the elastomeric sleeve 29 a corresponding distance. Conversely, upon return of the sleeve member 33 downwardly, as the spring strips 37 relax, the elastomeric sleeve 29 will be restored to its original position.

Accordingly, it will be recognized that by releasably securing the slidable sleeve 33 in the position shown in FIGURE 1B, the elastomeric diverter sleeve 29 will be maintained in its fully retracted position and the tool 10 can be readily moved in a well bore with the well fluids therein freely bypassing the tool by way of the annular clearance around the diverter 14. To releasably secure the sleeve 33, one or more ball members 40 are loosely confined in lateral openings 41 spaced around the lower portion of the slidable sleeve and adapted to be partially retained in a peripheral groove 42 around the housing 11 by a second sleeve member 43 that is telescoped over the slidable sleeve and releasably coupled to the housing 11.

An inwardly projecting lug 44 on the retaining sleeve 43 is normally engaged with a dog 45 disposed in a housing recess 46 below the retaining sleeve and pivotally mounted therein on a shaft 47 journalled to the housing 11. To retain the pivoted dog 45 in engagement with the lug 44, an electrically responsive detonator or so-called explosive squib 48 is adapted for abutting engagement with the dog to prevent it from rotating into a non-abutting position. A compression spring 49 is arranged between opposed shoulders on the sleeves 33 and 43 to urge the retaining sleeve upwardly in relation to the slidable sleeve member once the explosive squib 48 has freed the dog 45 for rotation.

Accordingly, once the retaining sleeve 43 is allowed to move upwardly in relation to the slidable sleeve 33, a diametrical enlargement within the retaining sleeve, such as provided by longitudinal grooves or slots 50 that are respectively longitudinally aligned with the balls 40, is moved into juxtaposition with the retaining balls. It will be appreciated, therefore, that by appropriately sizing the retaining balls 40 in relation to the annular clearances between the inner surface of the peripheral groove 42 and the inner surface of the sleeve 43, on the one hand, and the inner surface of the slots 50 on the other hand, the balls cannot be freed from the peripheral groove until the retainer sleeve has moved upwardly to 'bring the slots into registration with the balls.

By extending the retainer sleeve 43 upwardly and fluidly sealing it around the slidable sleeve 33 by sealing members 51 and 52 spaced above and below one or more ports 53 in the slidable sleeve and approximately in registration with the lower housing ports 28, the retainer sleeve also serves as a valve that selectively blocks the flow of a treating agent from the lower space 26 until the squib 48 is detonated and the diverter 14 is extended. Once, however, the squib 48 is detonated and the retainer sleeve 43 is moved upwardly relative to the slidable sleeve 33 by the spring 49, lateral ports 54 in the retainer sleeve are brought into registration with the housing ports 28 and ports 53 in the slidable sleeve to allow the treating agent to be exhausted therethrough as the piston 22 moves downwardly.

From the description of the tool to this point, it will be seen that once all of the various elements described so far are in their respective positions depicted in FIGURES 1A and 1B, the diverter 14 will be retained in its retracted position so long as the explosive squib 48 is not detonated. When the squib 48 in the control section 15 is detonated, the spring 49 will urge the retainer sleeve 43 upwardly in relation to the slidable sleeve 33 which, at this time, is still secured to the housing 11 by the retainer balls 40. Once, however, the retainer sleeve 43 moves a sufiicient distance upwardly to bring the slots 50 into registration with the outer surfaces of the balls 40, the combined force of a compression spring 55 carried between opposed shoulders on the slidable sleeve 33 and the housing 11 and another compression spring 56 will cause the balls to be cammed out of the circumferential groove 42 and into the enlarged annular space between the outer surface of the housing 11 and the inner surfaces of the slots 50. The spring 56 is engaged between a fixed shoulder 57 on the sliding sleeve 33 and an abutment 58 releasably secured at this time to the housing 11. The function of this movable abutment 58 and the manner of securing it will be subsequently explained.

Accordingly, it will be appreciated that once the balls 40 are released from the circumferential groove 42, the sliding sleeve 33 will be shifted upwardly by the combined force of the springs 55 and 56 to begin bowing the spring strips 37 outwardly. The retainer sleeve 43 is, of course, carried further upwardly by the sliding sleeve 33. It will be recognized, therefore, that the spring 49 will move the retainer sleeve 43 upwardly in relation to the sliding sleeve 33 to a position where the ports 53 and 54 are in registration with one another. Thus, once the sliding sleeve 33 reaches its elevated position, the sleeve ports 53 and 54 will be in registration with the housing ports 28. At this point, the bowed spring strips 37 will have been expanded outwardly a sufficient distance to bring the elastomeric sleeve 29 either very near to or into engagement with the inner wall of the casing. This will, therefore, block the annular space between the tool 10 and the casing.

Once the diverter 14 is fully expanded and the ports 28 opened, it will be appreciated that upward movement of the tool 10 will force the well bore fluids through the ports 27 at the upper end of the housing 11 and into the upper enclosed space 25 therein. Thus, continued upward movement of the tool 10 will be effective to move the piston 22 downwardly in relation to the housing 11. As the piston 22 moves downwardly, the treating agent in the lower enclosed space 26 will, of course, be forced therefrom by way of the lower ports 28 and into the annulus between the tool 10 and well casing below the expanded diverter 14 to envelop the perforator suspended below the reservoir 13.

When the piston 22 nears the lower limit of its travel, a depending tubular probe 59 thereon will engage the inwardly-projecting ends of a plurality of inclined dogs 60 that are each carried in a housing recess 61 on a pivot pin 62 journalled to the housing 11 and have their outwardly extending upper ends a'butted against the lower face of the abutment 58. Biasing means, such as reversely bent springs 63, are provided to normally maintain the upper ends of the dogs 60 extended in the position shown in FIGURE 1B to support the abutment 58 against the force of the spring 56.

As seen in FIGURES 3A and 3B, once the lower end of the depending probe 59 from the piston 42 engages and passes the inwardly projecting lowe rends of the pivoted dogs 60, the dogs will be cammed to a generally erect position once the piston has reached the shoulder 17. Once the dogs 60 are pivoted into an upright position, the compressive force of the spring 56 will shift the sliding abutment 58 downwardly in relation to the sleeve member 33 until an inwardly projecting shoulder 64 thereon halts further travel of the abutment. With the spring 56 confined between the shoulders 57 and 64 on the sleeve member 33, the spring 56 will, of course, no longer be effective to urge the sleeve member upwardly in relation to the housing 11 and only the force of the spring 55 will be maintaining the sleeve member in its elevated position. Although the elastomeric sleeve 29 is shown still extended in FIGURES 3A and 3B for purposes of illustrating that position, it will be recognized, of course, that once the abutment 58 is released, the spring strips 37 will begin expanding.

Accordingly, by selecting the spring 55 to have an effective spring force somewhat less than that required to bow the spring strips 37 outwardly against pressure forces act ing downwardly on the diverter 14, once the spring 56 is immobilized between the shoulders 57 and 64, the forces tending to straighten the bowed spring strips will be effective to return the sleeve member back to its initial position. It will be realized, however, that although the spring 55 must be appropriately selected to have a spring force which, when combined with that of the spring 56, will be sufiicient to bow the spring strips 37 outwardly in the previously described manner, the spring 55 by itself will not be sufiiciently strong to prevent relaxation of the spring strips once the spring 56 is immobilized. Thus, it will be appreciated that the function of the releasably secured abutment 58 is to selectively enable and disable the spring 55 by initially maintaining the spring 56 in a first position aiding the spring 55 and then, once the abutment is released, allowing the spring 56 to move to a second position in which the spring 55 is no longer effective to maintain the elastomeric sleeve 29 in its extended position.

Return of the slidable sleeve 33 will, of course, carry the outer sleeve 43 back downwardly with little or no change in its position in relation to the slidable sleeve. It will also be noted from FIGURES 3A-3B that by providing ports 65 in the upper end of the tubular probe 59, once the probe enters the bore 18 the remaining treating agent in the lower enclosed space 26 of the reservoir 13 will continue flowing therefrom to allow the piston 22 to move to a final position abutting the shoulder 17.

To selectively detonate the explosive squib 48 from the surface without risking a premature actuation of the perforator, a so-called single-pole double-throw switch 66 (FIGURES 1B and 2) is mounted in the housing recess 46 and adapted for movement between a first switching position electrically connecting the explosive squib 48 to the conductor 20 and a second switching position electrically connecting the conductor 20 to the perforating devices (not shown) in the perforator therebelow. To accomplish this, the switch 66 is provided with an actuator 67 that is normally engaged with a flat 68 formed on a shaft 69 that is journalled at its opposite ends to the housing 11. A crank arm 70 secured to the shaft 69 and extending laterally therefrom is provided with a bifurcated end portion or clevis 71 that is movably coupled, as by a pin 72, to one end of an extension 73 dependingly secured from the lower end of the sleeve 33. In this manner, so long as the slidable sleeve member 33 remains in the position shown in FIGURES lA-lB, only the explosive squib 48 will be electrically connected to the conductor 20.

7 Then, as seen in FIGURES 3A-3B, once the sleeve 33 is released, the switch 66 will be operated to electrically connect the conductor 20 to the perforator mounted therebelow.

To employ the tool 10 in a well-completion operation, a suitable nonplugging liquid or some selected fluent treating substance of a similar or different nature is introduced into the lower enclosed space 26 of the reservoir 13 as by a filling port that is then closed by a plug 74. Typical treating agents that may be used are acid, propping agents containing particulate solids of sand, metal, glass, plastic and the like as well as various cleaning agents, and suitable temporary plugging agents such as gelled kerosene, gelled carbon tetrachloride, or such commerically-available protective formulations as Black Magic sold by Oil Base, Inc., of Houston, Tex., or Plug Ban" as sold by Humble Oil and Refining Co. of Houston, Tex. Any suitable agent can be used, of course, so long as it does not react adversely :with formation materials and fluids and can be removed from a perforation when it is produced. It should also be noted that as far as the tool 10 is concerned, improved results will be obtained where the treating substance has a lower density than that of the well control fluids so that once it is injected into the well bore, the fluent substance will not tend to settle downwardly away from the diverter 14.

Once the reservoir 13 is filled and the other elements of the tool 10 are in their respective positions shown in FIG- URES lA-lB, the tool is suspended from a suitable cable (not shown) and lowered into a well bore to a position somewhat below the formation interval that is to be completed. Once the tool 10 is in position, electrical current is applied from a power source at the surface to the conductor to detonate the explosive squib 48 and the tool 10 is raised to bring the perforator into position adjacent the formation interval to be perforated.

When the squib 48 is detonated, the retaining sleeve 43 is moved upwardly by the spring 49 to free the balls 40 from the circumferential groove 42 and release the slidable sleeve member 33. Once the sleeve 33 is released, the combined spring force of the springs 55 and 56 will move the slidable sleeve member upwardly to extend the diverter 14 against the downwardly acting pressure forces thereon. The outer sleeve 43 will have moved upwardly relative to the slidable sleeve 33 to bring the ports 53 and 54 into registration so that, once the slidable sleeve member has moved upwardly a distance sufficient to extend the diverter, the ports 53 and 54 will be in alignment with the housing ports 28.

While the diverter 14 is being extended, the tool 10 is still being moved upwardly so that once the ports 28, 53 and 54 are in alignment and the diverter is extended, the continued upward movement of the tool will divert the well bore fluids above the expanded elastomeric sleeve 29 through the upper housing ports 27 and into the upper reservoir space 25. As the well bore fluids are diverted into the upper reservoir space 25, the piston 22 will be moved downwardly in relation to the housing 11 to discharge whatever fluent substance there is in the lower reservoir space 26 through the lower housing ports 28 and into the well bore below the elastomeric sleeve 29.

It will be recognized that the treating agent being expelled into the well bore is moving into the annulus from which the well bore fluid entering the upper enclosed space has just been displaced by the swabbing action of the diverter 14 resulting from the upward movement of the tool 10. Thus, there will be little or no chance that the treating agent will be dispersed into the well bore fluids. In this manner, the continued upward travel of the tool 10 will insure that a substantially homogeneous mass of the fluent substance will simultaneously envelop the lower portion of the tool 10 below the diverter 14. Accordingly, by the time that the perforator on the tool 10 has been moved into a position adjacent the formation interval to be perforated, the perforator will be completely enveloped by a homogeneous mass of the selected treating agent.

Once it is determined that the perforator is correctly positioned, electrical current is applied from a power source at the surface to the suspension cable to actuate the perforator. It will be recalled that the release of the retaining sleeve 43 will have actuated the switch 66 to connect the perforator to the conductor 20. Although the tool 10 can be halted before the perforator is actuated, it is preferred to continue moving the perforator upwardly as it is actuated to insure that the last portion of the treating agent is expelled from the reservoir 13 a short time after the well bore is perforated. It will be appreciated, of course, that the position of the perforator in relation to the formation interval being completed will be known at all times by virtue of typical depth indiactors at the surface whose accuracy is confirmed by depth-correlation devices on the tool 10 such as the aforementioned casingcollar locator.

The effective volume of the reservoir 13 must, of course, be determined to insure that when the perforator is actuated, it is completely surrounded by the fluent substance. Moreover, where an enclosed retrievable carrier perforator is employed, the effective volume of the reservoir 13 should be suflicient to accommodate the volume of the fluent substance that will fill the carrier once it is perforated. In a typical arrangement of the tool 10 where an enclosed retrievable carrier perforator is used, the effective length of the lower enclosed space 26 will accordingly be in the order of about 1.5 to 2.0 times the length of the carrier. With relative proportions of this order, a continuing discharge of the fluent substance will be obtained as the tool 10 is moved further upwardly after the perforator is actuated.

Once the piston 22 reaches the lower limit of its travel as determined by the shoulder 17, the tubular probe 59 thereon will have actuated the pivoted latch fingers 60 to release the movable abutment 58 and disable the spring 55. Once the spring 55 is disabled, the elastomeric sleeve 29 will be restored to its retracted position and well bore fluids can again freely bypass the tool 10 as the tool is returned to the surface.

Turning now to FIGURE 4, a somewhat schematic view is shown of a second completion tool 200 which is also arranged in accordance with the principles of the present invention. As seen there, the tool 200 is suspended from a cable 201 in a cased well bore 202 just above an earth formation 203 which is to be completed. The completion tool 200 preferably includes one or more typical centralizers 204 and 205 longitudinally spaced along the tool to maintain it centered in the well bore 202 as well as some means, such as a casing-collar locator 206, for determining the depth of the tool. A typical well perforator 207, such as an enclosed carrier 208 with one or more perforating devices or shaped charges 209 therein, is coupled below the collar locator 206 and electrically connected to the suspension cable 201 in such a manner that the perforator can be selectively actuated upon command from the surface. The lower portion of the tool 200 is comprised of a selectively actuated fluid diverter 210 and a reservoir 211 adapted to contain a fluent substance for carrying out the particular completion operation.

As best seen in FIGURE 5; the fluid diverter 210 is preferably arranged in a similar fashion to the tool 10 previously described. Accordingly, as will be seen from a comparison of FIGURES lA-lB with FIGURE 5, the fluid diverter 210 includes an elastomeric sleeve 212 that is releasably secured in a relaxed position by a sleeve 213 slidably mounted around the tool body 214. The slidable sleeve 213 is held in an elevated position on the body 214 by one or more retaining balls 215 that are loosely disposed in lateral openings in the sleeve and are normally retained in a circumferential groove 216 by an outer sleeve 217 slidably mounted around the upper portion of the inner sleeve 213. An electrically responsive release,

such as an explosive squib 218 engaging a pivoted latch 219, is employed to prevent a spring 220 mounted between opposed shoulders on the sleeves 213 and 217 from moving the outer sleeve downwardly in relation to the inner sleeve until the squib is detonated upon command from the surface.

Once the outer sleeve 217 is released and has moved downwardly a suflicient distance to allow the balls 215 to move outwardly into longitudinal slots 221 in the outer sleeve, the inner sleeve 213 will be urged downwardly by a compression spring 222 retained between opposed shoulders 223 and 224 on the body 214 and inner sleeve respectively. Once the inner sleeve 213 begins moving downwardly in relation to the body 214, the spring force of the spring 222 will be suflicient to bow a plurality of circumferentially spaced, longitudinal spring strips 225 that are confined within the elastomeric sleeve 212 and have their opposite ends engaged with opposed shoulders 226 and 227 on the tool body 214 and inner sleeve 213, respectively. Thus, downward movement of the inner sleeve 213 will cause the elastomeric sleeve 212 to be expanded outwardly a sufficient distance to at least approach the inner surface of the well casing.

It will also be appreciated that the initial downward movement of the outer sleeve 217 by the spring 220 will bring one or more ports 228 in the sleeve into alignment with a corresponding number of ports 229 in the inner sleeve 213. Then, as the inner sleeve 213 is subsequently moved downwardly by the spring 222 and carries the outer sleeve 217 along with it, the ports 228 and 229 will be brought into registration with a plurality of ports 230 in the upper portion of the tool body 214. Once the ports 230 are uncovered, the upper end of a longitudinal bore 231 in the tool body 214 forming the upper end of the reservoir 211 is opened. Thus, once the elastomeric sleeve 212 is expanded and the ports 230 uncovered, downward movement of the tool 200 through the well bore 202 will force the well bore fluids 232 into a plurality of ports 233 in the upper end of the reservoir 211 to displace the treating agent 234 upwardly from the reservoir 211 and expel the agent through the ports 230 into the well bore 202 above the diverter 210. To insure that the treating agent 234 is displaced from the reservoir 211, a tubular member 235 is connected to the tool body 212 at the lower end of the bore 231 and extended downwardly therefrom to about the bottom of the reservoir.

Accordingly, to employ the tool 200, a selected treating substance is disposed in the reservoir 211. Although this substance may be one of those previously described, it is preferred that this substance have a density somewhat greater than the density of the well bore fluids 232 to insure that the treating agent will remain as a homogeneous mass in the well bore 202 just above the expanded diverter 210.

Once the tool 200 has been brought into position just above the selected formation 203, the explosive squib 218 is detonated to expand the elastomeric sleeve 212 and open the ports 230. Thus, as the tool 200 is lowered further into the well bore 202, the Well bore fluids 232 will be forced into the ports 233 to expel the treating agent 234 out of the ports 230 and envelop the annular clearance around the tool. Then, once the tool 200 has been lowered a suflicient distance to bring the perforator 207 into position opposite the formation 203, the perforator will be completely surrounded by the treating substance 234 and, upon detonation of the shaped charges 209, only the treating substance can enter the resulting perforations into the formation.

The tool 200 is simply raised to retrieve it to the surface following the actuation of the perforator 207. It will be recognized, of course, that the expanded diverter 210 will not materially hamper retrieval of the tool 200 since the well bore fluids 232 will pass freely through the tool by way of the ports 230 and 233 since they are interconnected by the tubular extension 235 and the bore 231.

Turning now to FIGURE 6, another completion tool 300 is shown in a cased well bore 301 suspended from a cable 302 and maintained in the center of the well bore 301 by a typical centralizer 303 mounted on the upper portion of the tool. A casing-collar locator 304 is also preferably included with the tool 300 for providing indications at the surface of the position of the tool in relation to an earth formation, as at 305, to be completed.

The completion tool 300 is comprised of a reservoir section 306 having a fluid diverter 307 and an anchor 308 mounted thereon. A typical perforator 309 dependently secured below the reservoir section 306 is provided with one or more perforating devices, such as shaped charges 310, that may be selectively actuated upon command from the surface. If desired, another centralizer (not shown) similar to the centralizer 303 may be arranged on the perforator 309 to assure that the perforator is centrally located in the well bore 301.

The reservoir section 306 is comprised of an outer tubular housing 311 that is slidably telescoped around an elongated axial tubular member 312 dependently coupled, as by an adapter 313, to the upper portion of the tool 300 and connected, as by another adapted 314, to the upper end of the perforator 309. The upper portion of the tubular housing 311 is reduced in diameter, as at 315, and provided with a fluid seal, such as an O-ring 316, to slidably seal the upper end of the housing in relation to the depending tubular supporting member 312. The central portion of the tubular support 312 is enlarged in diameter, as at 317, and provided with a fluid seal 318 that is slidably engaged with the inner wall of the tubular housing 311 so as to define an enclosed space 319 within the housing between the reduced upper end 315 thereof and the enlarged portion of the depending support member.

A somewhat larger tubular member 320 is dependently secured to the enlarged central portion 317 of the elongated tubular support 312 and coaxially extended downwardly around the lower portion of the support to about the upper end of the perforator 309. A passage 321 through the enlarged-diameter portion 317 is adapted to provide fluid communication from the enclosed space 31 9 to the annular space 322 between the depending support 312 and the tubular member 320. Selectively-operable valve means, such as an explosively actuated valve 323, are provided to normally close the passage 321 and retain a treating agent 324 in the enclosed space 319 until the valve is actuated upon command from the surface. It will be appreciated that the axial passage 325 will permit suitable electrical conductors (not shown) to be passed from the upper portion of the tool 300 to the valve 323 and perforator 309.

The diverter 307 is comprised of one or more annular discs 326 of a thin, flexible material, such as may be cut from an elastomeric sheet, that are secured around the lower portion of the housing 311 and suitably sized to engage the inner walls of the cased well bore 301. It will be appreciated, however, that passage of the tool 300* through the well bore 301 will not be unduly hampered inasmuch as the well bore fluids 327 can readily pass around the flexible discs 326.

For reasons that will subsequenty become apparent, the anchor 308 is adapted to frictionally engage the innor walls of the cased well bore 301 with a force greater than the restraining force provided by the centralizer 303 and any centralizer (not shown) mounted on the perforator 309. The restraining force provided by the anchor 308 is not so great, however, that the combi'rEd weight of the tool 300 will not carry the tool on downwardly into the well bore 301 as the cable 302 is unspooled from the surface. The anchor 308 is typically comprised of a number of sol-called drag-blocks or bowed spring strips 328 arranged in the usual fashion.

Accordingly, once the enclosed space 319 is filled with the treating agent 324, it will be recognized that as the suspension cable 302 is unspooled at the surface, the tool 300 will descend into the well bore 301. As the tool 300 descends, the flexible elas'tomeric diverter 307 will deflect as necessary to allow the well bore fluids 327 to pass around the tool. It will be appreciated that so long as the valve 323 remains closed, the fluent substance 324 in the reservoir space 319 will retain the housing 311 and support member 312 in the positions illustrated and prevent their relative movement. Once the collar locator 304 indicates that the tool 300 is so located with respect to the formation 305 that the lower end of the reservoir 306 is about even with the upper limit of the formation interval and the upper end of the perforator 309 is about even with the lower limit, the tool is halted.

Then the tool 300 is selectively enabled by opening the explosively actuated valve 323. Once the valve 323 is opened, upward movement of the suspension cable 302 will be effective to displace the treating agent 324 from the reservoir space 319 as the central support 312 and its enlarged portion 315 are moved upwardly in relation to the housing 311 which is now held stationary by the anchor 308. As the treating agent 324 is discharged through the passage 321 and annular clearance 322, the well fluids 327 will, of course, fill the void below the enlarged portion 317 as it is moved upwardly into the nowstationary housing 311. Thus, the well fluids 327 in that portion of the well bore 301 below the elas'tomeric diverter 307 will be drawn upwardly into the reservoir housing 311 as these fluids are replaced by the treating agent 324. By extending the tubular member 320 to near the upper end of the perforator 309, the perforator will be progressively enveloped in a homogeneous mass of the fluent substance 324 as the perforator is brought upwardly into position. It will be recognized that by selecting the fluent substances 324 to have a lower density than that of the well fluids 327, the diverter 307 will keep the substances from moving on up the well bore.

As a result, once the perforator 300 is at the upper limit of its travel (as determined by the collar locator and other typical depth-measuring devices at the surface), the movement of the cable 302 is halted. The perforator 309 is at this time completely surrounded by the fluent substance 324 so that when the perforator is actuated, only the fluent substance can enter the resulting perforations (not shown). The tool 300 is then simply withdrawn.

As described above, the tool 300 is arranged so that when the perforator 309 is at its upper limit of travel and is in position for actuation, the upper end of the perforator is somewhat below the lower end of the reservoir housing 311. It will be appreciated, however, that the tool 300 could also be so arranged that the perforator 309 would enter the lower open end of the reservoir housing 311 and be at least partially received by the reservoir 306 when the shaped charges 310 are detonated. This would, of course, require that the housing 311 either be expendable or have appropriately located replaceable wall portions through which the perforating jets. would pass. The advantage of this alternative arrangement would be that the overall length of this alternate tool would be reduced by a significant amount.

Accordingly, it will be appreciated that the present invention has provided new and improved apparatus by which a well bore can be perforated to allow only selected fluent substances to enter the perforations. It is quite apparent, therefore, that the present invention will enable a homogeneous mass of a selected substance to envelop a perforator before it is actuated so that only the substance will contact the formations when they are perforated. It should be realized, of course, that these fluiddisplacement tools are also suitable for use either alone or with other well tools aside from a perforator.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects; and, therefore, the

12 aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. A well-completion tool adapted to be supported by a suspension member in a well bore containing fluids and comprising: a reservoir adapted to contain fluent substances; first means adapted to isolate a selected interval of such a well bore; second means operable upon movement of such a suspension member supporting said well-completion tool for simultaneously withdrawing well bore fluids from around said well-completion tool into said reservoir and discharging fluent substances contained therein into such an isolated interval; and perforating means on said well-completion tool and adapted to be moved into fluent substances discharged into such an isolated interval in response to movement of such a suspension member for operation of said second means.

2. The well-completion tool of claim 1 wherein said movement-responsive means include: first and second passage means respectively providing communication between first and second spaced portions of said reservoir and spaced locations on the exterior of said tool; and means normally blocking communication through said first passage means and adapted for opening such communication in response to a command from the surface.

3. The well-completion tool of claim 2 wherein said movement-responsive means further include: piston means movably disposed in said reservoir for isolating said first and second reservior portions from one another.

4. The well-completion tool of claim 2 wherein said movement-responsive means further includes: an elongated member extending through said reservoir and adapted for connection at its upper end to a suspension member; piston means on an intermediate portion of said elongated member and slidably sealed within said reservoir for isolating said first and second reservoir portions from one another; means slidably sealing said reservoir to said elongated member between said piston means and one of said ends of said elongated member for enclosing a fluent substance in said one reservoir portion; and means for securing said reservoir against movement in relation to a well bore whenever said passageblocking means are opened so that said elongated member can be moved in relation to said reservoir to shift said piston means toward said sealing means.

5. A well-completion tool adapted for suspension from a cable in a well bore containing fluids and traversing an earth formation to be completed, comprising: a body having an internal chamber adapted to contain a fluent substance; means in said chamber dividing said chamber into first and second portions; first and second passage means respectively providing fluid communication between said first and second chamber portions and first and second spaced exterior locations on said body; and flow-diverting means mounted around said body between said spaced exterior locations and responsive to movement of said tool into an interval of a well bore for diverting well bore fluids from that interval into said first passage means to displace a fluent substance contained in said chamber from said second passage means and into that interval.

6. The well-completion tool of claim 5 wherein: said chamber-dividing means include a piston sealingly disposed in said chamber and movable in response to entrance of well bore fluids into said first chamber portion on one side of said piston to displace a fluent substance confined in said second chamber portion on the other side of said piston through said second passage means into that well bore interval.

7. The well-completion tool of claim 6 further including: a well perforator connected adjacent to said second exterior location and adapted for selective actuation 13 from the the surface for perforating an earth formation adjacent such a well bore interval.

8. The well-completion tool of claim 5 wherein: said chamber-dividing means comprise a transverse partition across said chamber between said first and second chamber portions, and a tubular member extending into said first chamber portion and providing fluid communication between said chamber portions.

9. The well-completion tool of claim 8 further including: a well perforator connected adjacent to said Second exterior location and adapted for selective actuation from the surface for perforating an earth formation adjacent such a well bore interval.

10. A Well-completion tool comprising: perforating means adapted for suspension in a well bore containing fluids; a reservoir adapted to contain a fluent substance; and means responsive to movement of said perforating means into a selected interval of such a well bore for simultaneously withdrawing fluids from such a selected interval into said reservoir and discharging a fluent substance from said reservoir into such a selected interval around said perforating means.

11. A well-completion tool adapted for suspension from a cable in a well bore containing fluid and traversing an earth formation to be completed, comprising: a tubular body having an internal longitudinal bore; an elongated member extending through said internal bore of said tubular body and having first means on its upper end adapted for connection to a suspension cable and second means on its lower end adapted for connection to a well perforator; piston means on said elongated member fluidly sealed within said internal bore and adapted for movement in relation to said tubular body from a first lower position to a second upper position relative thereto; sealing means fluidly scaling to upper portion of said tubular 'body to said elongated member for defining an enclosed chamber in said internal bore above said piston means; selectively operable passage means normally blocking fluid communication from said enclosed chamber and adapted for opening upon command from the surface; and wall-engaging means on said tubular body adapted to secure said body a Well bore wall whenever said selectively operable passage means are opened.

12. The well-completion tool of claim 11 further including: a well perforator connected to said second connection means and adapted for selective actuation from the surface.

References Cited UNITED STATES PATENTS 2,934,146 4/1960 Laval 166110 X 3,097,698 7/ 1963 Corley et al 166-23 X 3,118,503 1/1964 Rike et al. 166162 3,138,206 6/1964 Bruce et al 166-35 X 3,212,576 10/1965 Lanmon 166100 X 3,379,251 4/1968 Bohn 16623 DAVID H. BROWN, Primary Examiner US. Cl. X.R. 166-55.1, 162

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