US3695368A

US3695368A - Apparatus for perforating earth formations

Info

Publication number: US3695368A
Application number: US132013A
Authority: US
Inventors: C P Lanmon
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 1971-04-07
Filing date: 1971-04-07
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03

Abstract

As representative embodiments of the present invention, each of the new and improved well tools disclosed herein include a perforator provided with one or more sets of longitudinally spaced, selectively fired perforating devices respectively directed along parallel or slightly convergent perforating axes. A wall-anchoring assembly is cooperatively arranged on the tool to permit longitudinal movement of the perforator in relation to the anchoring assembly over a distance which is slightly less than the longitudinal spacing between adjacent perforating devices. Upon positioning of the apparatus in a well bore, the first of two perforating devices in each set is actuated to produce a first perforation extending into the adjacent earth formations. By manipulating the suspension cable, the perforator is then shifted longitudinally in relation to the stationary anchoring assembly for locating the second perforating device in each set immediately adjacent to the previous position of the first perforating device. In this manner, upon actuation of the second perforating device, a second perforation will be produced which at least closely parallels the first perforation so as to be contiguous therewith for displacing compacted, crushed formation materials from the walls of the second perforation into the first perforation so that at least a portion of these walls will be cleared of such unwanted flow-blocking materials.

Description

United States a Patent Lanmon, II Oct. 3, 1972 y [54] APPARATUS FOR PERFORATING [57] 1 ABSTRACT EARTH FORMATIONS As representative embodiments of the present inven- [72] Inventor: C. P. Lanmon, ll, Friendswood, tion, each of the new and improved well tools dis- Tex.

tion, New York, N.Y. [22] Filed: April 7, 1971 [21] Appl. No.: 132,013

[73] Assigneez. Schlumberger Technology Corpora- 7/1971 Lebourg l 75/452 Primary Examiner-David H. Brown Attorney-Ernest R. Archambeau, Jr., William J. Beard, Stewart F. Moore, David L. Moseley, Edward M. Roney and William R. Sherman closed herein include a perforator provided with one or more sets of longitudinally spaced, selectively fired perforating devices respectively directed along parallel or slightly convergent perforating axes. A wall-anchoring assembly is cooperatively arranged on the tool to permit longitudinal movement of the perforator in relation to the anchoring assembly over a distance which is slightly less than the longitudinal spacing between adjacent perforating devices. Upon positioning of the apparatus in a well bore, the first of two perforating devices in each set is actuated to produce a first perforation extending into the adjacent earth formations. By manipulating the suspension cable, the perforator is then shifted longitudinally in relation to the stationary anchoring assembly for locating the second perforating device in each set immediately adjacent to the previous position of the first perforating device. In this manner, upon actuation of the second perforating device, a second perforation will be produced which at least closely parallels the first perforation so as to be contiguous therewith for displacing compacted, crushed formation materials from the walls of the second perforation into the first perforation so that at least a portion of these walls will be cleared of such unwanted flow-blocking materials.

14 Claims, 9 Drawing Figures PATENTEDncra m2 3.695.368

sum 1 or 2 FIG] s L WAY W C P LanmonJI FIG 5 INVENTOR ATTORNEY sum 2 0r 2 PAIENTEDnms I972 f m V /N VE N TOR C P Lcmmon, 1T

ATTORNEY APPARATUS FOR PERFORATING EARTH FORMATIONS Heretofore, substantial efforts have been directed toward devising completion apparatus and techniques for perforating a well bore and then injecting formation-consolidating agents in those situations where the perforated formation is substantially composed of loose or incompetent formation materials which must 'be chemically bonded to limit the subsequent production of these loose materials. For example, in US. Pat. No. 3,153,449, unique methods and apparatus are disclosed for producing a single perforation that is first flushed of loose formation materials and then injected with a suitable treating agent for consolidating the immediately surrounding portions of the formation. Similarly, U. S. Pat. No. 3,329,204, US. Pat. No. 3,347,314 and US. Pat. No. 3,347,3l respectively disclosed new and improved completion techniques and tools for perforating a well casing at two closely spaced points and, after clearing the perforations of loose formation materials, injecting suitable consolidating agents.

It will be appreciated, however, that none of these completion techniques or injection tools are particularly suited for perforating relatively competent formations which do not require the injection of a consolidating agent. Even'if such techniques or tools were employed in such situations, only one or, at best, two usable perforations would be produced for each operation. Thus, if a formation interval of substantial length required perforation at several spaced points, the aforementioned tools would have to be repetitiyely employed before the entire interval could be adequately perforated.

Of far more significance, however, it has been found that a perforation in a well-consolidated formation will often be incapable of efficient production even after the perforation has been substantially cleaned of the usual shaped charge debris which typically lines the walls of the perforation. Experiments have shown that, in many instances, such low rates of productivity can be significantly attributed to the presence of a relatively impervious envelope of tightly compacted, crushed formation materials surrounding at least a major portion of the perforation. As a result, even though shaped charge debris and loose materials are cleared from the perforation, these experiments have shown that the full production capability of the perforation cannot be realized unless at least a portion of this tightly compacted envelope is removed or broken down.

Accordingly, it is an object of the present invention to provide new and improved perforating apparatus for producing perforations at one or more locations along a well bore interval traversing competent earth formations in such a manner that at least a portion of the envelope of crushed, compacted formation materials surrounding such perforations is removed.

This and other objects of the present invention are attained by arranging one or more sets of selectively actuated perforating devices at spaced longitudinal intervals along a supporting carrier, with the perforating devices in each set being cooperatively directed so that their perforating axes are either parallel or very slightly converged toward an intersection within an earth formation ahead of the carrier. Wall-anchoring means are cooperatively arranged on the carrier for permitting limited longitudinal shifting of the carrier in relation to the anchoring means over a distance which is slightly less than the longitudinal spacing between the perforating devices in each set. In this manner, when the new and improved perforating apparatus of the present invention is employed, sequential operation of the perforating devices in each set will produce a pair of closely paralleled substantially contiguous perforations, with crushed, compacted formation materials around the perforations being displaced into the perforations for clearing such flow-blocking materials from at least a portion of the walls of the perforations.

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:

FIGS. 1 and 2 schematically depict a preferred embodiment of perforating apparatus incorporating the principles of the present invention as this apparatus will successively appear while positioned in a well bore for conducting a perforating operation;

FIGS. 3 and 4 are enlarged cross-sectional views of typical perforations which will be produced upon the sequential operation of the apparatus as depicted in FIGS. 1 and 2;

FIGS. 5 and 6 are cross-sectional views respectively taken along the lines 5-5 and 6-6 of FIG. 4;

FIGS. 7 and 8 are views similar to FIGS. 1 and 2 for schematically illustrating an alternative embodiment of new and improved perforating apparatus also arranged in accordance with the present invention; and

FIG. 9 is similar to FIG. 4 but illustrates a typical pair of perforations produced by the sequential operation of the perforating apparatus as shown in FIGS. 7 and 8.

Turning now to FIG. 1, a somewhat-schematic representation is shown of perforating apparatus 10 arranged in accordance with the present invention as it will appear while suspended in the usual manner from a typical electrical cable 11 within a well casing 12 secured in a borehole 13 by an annular column of cement 14. The suspension cable 11 is spooled from a powered winch (not shown) located at the earths surface and adapted for selectively moving the perforating apparatus 10 through the casing 12 and into position adjacent to an earth formation 15 which is to be perforated. A suitable power supply (not shown) is provided at the surface for selectively supplying electrical current to the suspension cable 11. As is typical, the perforating apparatus 10 further includes suitable depth-indicating means such as a casing-collar locator 16 arranged on or near the upper end of the tool. For reasons that will subsequently be explained in greater detail, electrical control means 17 are cooperatively arranged on the lower portion of the perforating apparatus 10.

In the preferred embodiment of the perforating apparatus 10 of the present invention, an elongated body or carrier 18 includes two or more separate fluid-tight compartments, as at 19 and 20, which are arranged therein at longitudinally spaced intervals. The perforating apparatus 10 is further provided with electrically responsive perforating means including a plurality of typical shaped charges, as at 21 and 22, which are respectively mounted in each of the compartments l9 and 20 with their forward ends facing lateral ports in the forward wall of the carrier 18 that are each sealingly closed by an expendible port-closure member as at 23. it will, however, be appreciated that whenever one of the shaped charges, such as at 22,is detonated, the resulting perforating jet will readily penetrate the closure member 23 in front of it. Those skilled in the art will, of course, recognize that the carrier 18 can include any reasonable number of of longitudinally spaced compartments, as at 19 and 20, so that a corresponding number of shaped charges, as at 21 and 22, can be arranged therein. However, only the one set of the

shaped charges

21 and 22 is illustrated for simplifying the drawings and facilitating the explanation of the invention. Although the shaped

charges

21 and 22 may, of course, be of any suitable design, the charges may be similar or identical to those shown in US. Pat. No. 3,329,2l8.

As illustrated in FIG. 1, wall-anchoring means 24 are cooperatively mounted on the lower end of the carrier 18 and adapted for providing a temporarily fixed support along which the carrier can be selectively shifted. In the preferred embodiment of the apparatus 10, the anchoring means 24 include a tubular housing 25 which is coaxially mounted and co-rotatively secured, as by a spline and groove arrangement 26, on a depending extension 27 of the carrier 18 for limited longitudinal travel along the extension. Wall-engaging anchors, such as two or more outwardly bowed springs as at 28, are mounted in an upright position at circumferentially spaced intervals around the tubular housing 25 and biased outwardly for maintaining sliding frictional engagement with the well casing 12. The springs 28 are cooperatively arranged to provide a sufficient anchoring force for temporarily securing the tubular housing 25 in relation to the casing 12 when the carrier 18 is to be shifted relative thereto. This anchoring force is, of course, insufficient to unduly hinder the passage of the perforating apparatus through the casing 12. To limit the extent of relative longitudinal movement between the carrier 18 and the anchoring assembly 24, oppositely facing

shoulders

29 and 30 are respectively arranged on the carrier and the lower end of the depending member 27 for engagement with

opposed shoulders

31 and 32 defined by the upper and lower ends of the housing 25 so that the maximum span of longitudinal travel of the carrier in relation to the anchoring assembly will be slightly less than the longitudinal spacing between the

perforating axes

33 and 34 of each set of the shaped charges, as at 21 and 22. The significance of this particular spacing will subsequently be explained.

Accordingly, it will be appreciated by those skilled in the art that once the new and improved apparatus 10 of the present invention is suspended in the well casing 12, the weight of the perforating apparatus will be suffi cient to overcome the frictional restraint provided by the engagement of the bow springs 28 with the casing when it is desired to move the perforating apparatus downwardly to a selected position adjacent the earth formation 15. It will be recognized, of course, that upon downward travel of the perforating apparatus 10 through the casing 12, the weight of the carrier 18 will shift it downwardly in relation to the anchoring assembly 24 so as to place the

opposed shoulders

29 and 31 into engagement with one another. Conversely, upward travel of the perforating apparatus 10 through the casing 12 will shift the carrier 18 upwardly in relation to the anchoring assembly 24 until the

opposed shoulders

30 and 32 are brought together. Moreover, until one or the other of the two associated pairs of the opposed shoulders 29-32 are respectively engaged, the carrier 18 can be freely shifted over a selected span of longitudinal travel relative to the anchoring assembly 24 whenever the assembly is stationary in relation to the casing 12. Thus, of particular importance to the present invention, it will be appreciated that the anchoring assembly 24 can be selectively stationed at a desired location in the casing 12 for providing a temporarily fixed support along which the carrier 18 can be moved in relation thereto between upper and lower positions having a predetermined longitudinal spacing. This predetermined spacing is, of course, established by the longitudinal spacing between the opposed shoulders 29 and 31 (as well as the shoulders 30 and 32).

Those skilled in the art will, of course, appreciate that there are many control systems for selectively detonating a plurality of shaped charges by successive electrical signals. In general, these control systems function to selectively supply an electrical current of sufficient magnitude for detonating electrically responsive detonating means such as a blasting cap connected to a detonating cord or an explosive initiator, as at 35 and 36, operatively associated with each of the shaped charges, as at 21 and 22. For example, FIGS. 1 and 5 of US. Pat. No. 3,246,707 respectively show two control systems by which a first set of one or more shaped charges can be selectively detonated by a first electrical signal; and then, only upon closing ofa switch, a second set of one or more shaped charges is enabled for detonation by a second electrical signal. Similarly, U.S. Pat. No. 3,327,79l as well as US. Pat. No. 3,380,540 also illustrate electrical control systems respectively employing a selectively actuated switch for independently detonating two or more sets of shaped charges in succession in response to successive electrical signals. Thus, thoseskilled in the art will appreciate that appropriate electrical circuits can be readily arranged in the apparatus 10 in such a manner that the controlled actuation of an electrical switch can be employed to selectively enable first and second sets of one or more shaped charges, as at 21 and 22, for successive detonation upon successive applications of electrical current to the suspension cable 11.

Accordingly, in the preferred embodiment of the electrical control means 17 as schematically illustrated in FIG. 1, an electrical switch 37 of suitable design is mounted in a sealed chamber 38 in the carrier 18 and cooperatively associated with an actuating member, such as a longitudinally movable rod 39 or the like, arranged for selectively shifting the switch between its switching positions in response to longitudinal movements of the carrier in relation to the anchoring assembly 24. As depicted in FIG. 1, the switch 37 is a single-pole double-throw switch having its movable switch member connected by an electrical conductor 40 to the central conductor 41 of the suspension cable 11. One

of the switch contacts is connected by means of an electrical conductor 42 to the electrically responsive detonator or explosive initiator 35 for the shaped charge 21; and the other switch contact is connected by way of an electrical conductor 43 to the electrically responsive initiator 36 for the shaped charge 22. The metallic armor sheath 44 of the suspension cable 11 is electrically connected to the body of the carrier 18 to serve as a return path for the flow of electrical current to the surface from the

initiators

35 and 36.

It will be appreciated, therefore, that the electrical control means 17 cooperate for selectively connecting the power supply (not shown) at the surface to the

initiators

35 and 36 for the shaped

charges

21 and 22 in accordance with the longitudinal position of the carrier 18 in relation to the anchoring assembly 24. Thus, if the perforating apparatus is positioned in the casing 12 so as to elevate the carrier 18 in relation to the stationary anchoring assembly 24 as shown in FIG. 1, the switch 37 will be effective for enabling the shaped charge 21 for selective detonation and electrically isolating or disabling the other shaped charge 22. Conversely, as shown in FIG. 2, by cooperatively lowering the carrier 18 in relation to the stationary anchoring assembly 24, the switch 37 will be effective for connecting the initiator 36 of the other shaped charge 22 to the central cable conductor 41 and similarly isolating the initiator 35 of the shaped charge 21. Any reasonable number of. shaped charges can, of course, be respectively associated with the two illustrated

charges

21 and 22 so as to be simultaneously detonated as these two shaped charges are successively detonated.

In a typical operation of the perforating apparatus 10 of the present invention, the tool is lowered into the casing 12 by the suspension cable 11 for bringing the carrier 18 into the proximity of the formation and preferably somewhat below the depth at which perforations are desired. It will be recognized, of course, that inasmuch as the power supply (not shown) atthe surface typically includes suitable disconnecting circuits (not shown), there is no danger of prematurely actuating either of the shaped

charges

21 and 22 irrespective of the particular position of the switch 37. Thus, as the perforating apparatus 10 is initially being positioned in the casing 12, longitudinal shifting of the carrier 18 in relation to the anchoring assembly 24 will harmlessly actuate the switch 37 without creating a safety hazard since the source of electrical detonating current (not shown) at the surface will be disconnected from the

cable conductors

41 and 44 until just before it is desired to operate the perforating apparatus.

Accordingly, once the perforating apparatus 10 has reached a position somewhat below the depth at which one or more groups of longitudinally spaced perforations are to be produced, the carrier 18 is shifted upwardly slightly by raising the suspension cable 11 from the surface) and when halted. As the cable 11 is moved upwardly, the carrier 18 will, of course, shift upwardly in relation to the stationary anchoring assembly 24 as depicted in FIG. 1. With this being the case, the switch 37 will be effective for first connecting the initiator 35 for the shaped charge 21 to the central cable conductor 41. Thus, upon application of sufficient detonating current from the power supply (not shown) to the surface ends of the

cable conductors

41 and 44, the shaped charge 21 will be detonated for producing a first perforation 45 through the casing 12 and the cement l4 and on into the earth formation 15. Other shaped charges (not shown) which are cooperatively associated with the shaped charge 21 will, of course, be simultaneously detonated by this initial application of electrical current.

As schematically represented in FIG. 2, once the first perforation 45 is produced, the carrier 18 is then slowly lowered by appropriately moving the suspension cable 11 for bringing the

shoulders

29 and 31 into engagement with one another without producing a corresponding downward movement of the still-stationary anchoring assembly 24. Thus, as illustrated in FIG. 2, once the carrier 18 is shifted downwardly in relation to the frictionally supported anchoring assembly 24, the switch 37 will be effective for connecting the initiator 36 for the second shaped charge 22 to the central cable conductor 41. Then, once sufficient detonating current is connected to the surface ends of the

cable conductors

41 and 44, the shaped charge 22 will be detonated to produce a second perforation, as at 46, closely paralleling the first perforation 45. Hereagain, this second application of electrical current will also be effective for simultaneously detonating any other shaped charges that are associated with the shaped charge 22. It should be noted that to further assure that the second shaped charge 33 is accurately positioned when it is detonated, the power source (not shown) can be left connected to the

cable conductors

41 and 44 after the first shaped charge 21 is detonated This will serve to detonate the second shaped charge 22 immediately upon actuation of the switch 37 to connect the initiator 36 to the conductor 41.

As previously mentioned, the carrier 18 can be arranged to carry any reasonable number of longitudinally spaced shaped charges and the only requirement is that the individual initiators (as at 35) for every other one of the charges (as at 21) be connected to the conductor 42 and that the initiators (as at 36) for the remaining or alternate charges (as at 22) be connected to the conductor 43. As a result, when the first shaped charges, as at 21, are detonated, there will be a first group of widely spaced perforations similar to the perforation 45 produced at intervals along the casing 12. Similarly, when the second shaped charges, as at 22, are detonated, a second group of perforations will be produced in the casing 12, with each of these being respectively located immediately adjacent to each of the first group of perforations so as to be substantially contiguoustherewith. Each associated set of these first and second groups of perforations will, of course, be spaced relative to one another in the same manner as the illustrated

perforations

45 and 46. It should be noted that although the longitudinal spacing between the associated perforations, as at 45 and 46, in a given set is of paramount importance to the present invention, the spacing between adjacent sets of these perforations is discretionary. It should also be noted that other pairs of shaped charges need not be angularly oriented in the same lateral direction as are the shaped

charges

21 and 22. For example, each pair of the shaped charges, as at 21 and 22, could just as well be faced in other lateral directions such as in angular increments of Referring now to FIG. 3, it will be appreciated that once the perforating apparatus is moved into position adjacent to the formation and the first shaped charge 21 is detonated, the perforation 45 will be produced along the axis 33. The detonation of the shaped charge 21 will produce a perforating jet which, as is well known in the art, will leave debris such as a slug 47 in the forward portion of the perforation 45 as well as a relatively impermeable sheath or layer of debris, as at 48, lining the walls of at least a substantial portion of the perforation. Moreover, by experiments with simulated test targets, it has been found that the forces resulting from the perforating jet of a shaped charge, as at 21, will severely crush adjacent formation materials and compact these crushed materials into an envelope, as at 49, surrounding the perforation 45 with these materials defining a substantial portion of the walls of the perforation.

Accordingly, in keeping with the objects of the present invention, the detonation of the second shaped charge 22 will, as depicted in FIG. 4, produce the second perforation 46 which substantially parallels the first perforation 45 and is in close proximity thereto. In this manner, as seen in FIGS. 4-6, the close proximity of the

perforations

45 and 46 will be such that the debris, as at 50, and the envelope 51 of compacted crushed formation material which would otherwise remain in and around the walls of the second perforation will instead be displaced into the overlapping perforations by the force of the perforating jet so as to leave at least portions, as at 52, of their common side walls relatively free of these unwanted flow-blocking materials. Those skilled in the art will, of course, appreciate that the displacement of at least substantial portions of the

envelopes

49 and 51 as well as the debris and other loose materials, as at 48 and 50, which will otherwise define a relatively impermeable barrier around the

perforations

45 and 46 will greatly enhance the subsequent flow of fluids, as at 53, from the formation 15 into the well casing 12. Production of connate fluids will, in time, flush at least a substantial quantity of these loose materials from the

perforations

45 and 46 to clear them for subsequent treating operations as well as improved production flows.

Turning now to FIGS. 7 and 8, an alternative embodiment is illustrated of perforating apparatus 100 which is also arranged in accordance with the principles of the present invention. Inasmuch as the perforating apparatus 100 is substantially identical to the perforating apparatus 10, those components of the perforating apparatus 100 which are similar or identical to those components previously described with reference to the perforating apparatus 10 are simply identified by the same reference numeral increased by 100.

Accordingly, it will be appreciated by comparison of FIGS. 1 and 2 with FIGS. 7 and 8 that the perforating apparatus 100 differs significantly from the perforating apparatus 10 only in that different electrical control means 117 are depicted and that the shaped

charges

121 and 122 are respectively oriented so that one or both of their respective perforating axes 133 and 134 are slightly tilted or converged. Thus, instead of producing precisely paralleled perforations, as at 45 and 46 in FIGS. 2 and 4, the

perforations

145 and 146 will be slightly convergent as best illustrated in FIG. 9

so as to hopefully provide a longer extent of the adjacent side walls of the perforation and 146 which will be relatively free to loose materials and debris.

To represent a different mode for achieving the objects of the present invention, the electrical control means 117 are illustrated as being operated independently of longitudinal movements of the carrier 118 in relation to the anchoring assembly 124. Thus, by employing a switching arrangement such as any ofthose shown in the three aforementioned patents relating to control systems, the electrical switch 137 can be selectively actuated for detonating the shaped charge 122 after the carrier 1 18 has been lowered in relation to the temporarily fixed anchoring assembly 124 so as to position the upper shaped charge 122 slightly above the perforation 145 produced previously by the lower shaped charge 121. The importance of the anchoring assembly 124 remaining stationary as the carrier 118 is lowered is, of course, readily apparent.

It will be recognized that by placing the second perforation 146 close to the first perforation 145, debris and the like will be displaced from the walls of the perforations into the interior of the perforations in much the same manner as described in relation to FIGS. 4-6. The slight convergence of the perforating

axes

133 and 134 will, however, in some instances result in a somewhat-longer common boundary or overlapping portions of the

perforations

145 and 146. Otherwise, the net result of this convergence will be the same as that obtained by the precisely paralleled perforating axes as at 33 and 34.

Accordingly, it will be appreciated that the present invention has provided new and improved apparatus by which one or more sets of closely grouped perforations can be produced at selected intervals along a well bore, with these perforations being at least partially cleared of crushed formation materials surrounding the walls of the perforations to subsequently block the flow of fluids therethrough. By selectively producing one or more sets of perforations at closely shaped longitudinal intervals from one another with each set of two perforations either being generally parallel to one another or approaching a slight convergence in respect to each other, the first perforation will serve as a receptacle for at least a substantial part of the compacted, crushed formation materials which would otherwise tend to line or surround the walls of the second perforation. Moreover, by causing sloughing of such flow-blocking matter from the adjacent or contiguous wall portions of each set of the two closely spaced perforations, the net result will be that substantially permeable walls will be left on opposite sides of the spaced perforations.

While only 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 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:

l. Perforating apparatus comprising: a body adapted for suspension in a well bore; first and second selectively actuated perforating means mounted on said body at a predetermined longitudinal spacing for firing laterally along a common plane; anchoring means cooperatively signals.

arranged on said body and adapted to be anchoringly engaged with a well bore wall for permitting longitudinal movement of said body in relation to said anchoring means between first and second spaced positions separated only slightly less than said predetermined longitudinal spacing; and selectively operable control means adapted for actuating said first perforating means when said body is in its said first spaced position to provide a first perforation in a well bore wall and for thereafter actuating said second perforating means when said body is in its said second spaced position to produce a second perforation in a well bore wall contiguous with said first perforation.

2. The perforating apparatus of claim 1 wherein said first and second perforating means are respectively oriented for firing along parallel first and second perforating axes lying in said common plane.

3. The perforating apparatus of claim 1 wherein said first and second perforating means are respectively oriented for firing along convergent first and second perforating axes lying in said common plane.

4. The perforating apparatus of claim 1 wherein said first and second perforating means are actuated in response to electrical signals; and wherein said control means further include switching means adapted for selectively enabling said first and second perforating means for actuation by first and second electrical 5. The perforating apparatus of claim 1 wherein said first and second perforating means are actuated in response to electrical signals; and wherein said control means further include switching means selectively operable in response to movement of said body to said first and second spaced positions for respectively enabling said first and second perforating means for actuation by first and second electrical signals.

6. The perforating apparatus of claim 5 wherein said first and second perforating means are respectively oriented for firing along parallel first and second perforating axes lying in said common plane.

7. The perforating apparatus of claim 5 wherein said first and second perforating means are respectively oriented for firing along convergent first and second perforating axes lying in said common plane.

8. Perforating apparatus comprising: a body adapted for suspension in a well bore traversing earth formations and having at least first and second longitudinally spaced compartments arranged for isolating shaped explosive charges; electrically responsive perforating means on said body and including at least first and second independently actuatable shaped explosive charges respectively arranged in said first and second compartments at a predetermined longitudinal spacing and adapted for firing laterally along a common plane; anchoring means adapted to be anchoringly engaged with a well bore wall and cooperatively arranged on said body for permitting longitudinal movement of said body in relation to said anchoring means between first and second longitudinally spaced positions separated by a distance only slightly less than said predetermined spacing; and electrical control means adapted for selectively actuating said first shaped charge when said body is in its said first spaced position to produce a first perforation in adjacent earth formations and for thereafter selectivel actuatin said second sha ed char e when said d; IS in lts said second spgced pos ition to produce a second perforation in adjacent earth formations which is substantially contiguous with said first perforation.

9. The perforating apparatus of claim 8 wherein said first and second shaped charges are respectively oriented for firing along parallel first and second perforating axes lying in said common plane.

10. The perforating apparatus of claim 8 wherein said first and second shaped charges are respectively oriented for firing along slightly convergent first and second perforating axes lying in said common plane.

11. The perforating apparatus of claim 8 wherein said electrical control means include electrical switching means on said body and cooperatively arranged for selectively enabling said first and second shaped charges for actuation in response to successive electrical signals.

12. The perforating apparatus of claim 8 wherein said electrical control means include electrical switching means on said body and cooperatively arranged for selectively enabling said first and second shaped charges for actuation in response to successive electrical signals, and switch-actuating means operable for operating said electrical switching means only upon movement of said body to its said first and second spaced positions to insure that said second perforation is contiguous with said first perforation.

13. As a subcombination, perforating apparatus comprising: an elongated perforating carrier having at least first and second longitdudinally spaced compartments respectively adapted for receiving first and second shaped explosive charges to be mounted on said carrier for firing laterally along first and second perforating axes lying in a common plane and having a predetermined longitudinal spacing; and wall-anchoring means including a body slidably coupled to said carrier, at least one wall-engaging member cooperatively arranged on said body and adapted for engagement with a well bore wall to releasably secure said body against movement relative to a well bore wall, and stop means cooperatively arranged between said body and said carrier for limiting longitudinal movement of said carrier in relation to said body to a selected span of travel only slightly less than said predetermined longitudinal spacing.

14. The perforating apparatus of claim 13 further including electrical switching means operatively associated with said carrier and body for operation only upon movement of said carrier to the upper and lower limits of said selected span of travel.

Claims

1. Perforating apparatus comprising: a body adapted for suspension in a well bore; first and second selectively actuated perforating means mounted on said body at a predetermined longitudinal spacing for firing laterally along a common plane; anchoring means cooperatively arranged on said body and adapted to be anchoringly engaged with a well bore wall for permitting longitudinal movement of said body in relation to said anchoring means between first and second spaced positions separated only slightly less than said predetermined longitudinal spacing; and selectively operable control means adapted for actuating said first perforating means when said body is in its said first spaced position to provide a first perforation in a well bore wall and for thereafter actuating said second perforating means when said body is in its said second spaced position to produce a second perforation in a well bore wall contiguous with said first perforation.

4. The perforating apparatus of claim 1 wherein said first and second perforating means are actuated in response to electrical signals; and wherein said control means further include switching means adapted for selectively enabling said first and second perforating means for actuation by first and second electrical signals.

5. The perforating apparatus of claim 1 wherein said first and second perforating means are actuated in response to electrical signals; and wherein said control means further include switching means selectively operable in response to movement of said body to said first and second spaced positions for respectively enabling said first and second perforating means for actuation by first and second electrical signals.

8. Perforating apparatus comprising: a body adapted for suspension in a well bore traversing earth formations and having at least first and second longitudinallY spaced compartments arranged for isolating shaped explosive charges; electrically responsive perforating means on said body and including at least first and second independently actuatable shaped explosive charges respectively arranged in said first and second compartments at a predetermined longitudinal spacing and adapted for firing laterally along a common plane; anchoring means adapted to be anchoringly engaged with a well bore wall and cooperatively arranged on said body for permitting longitudinal movement of said body in relation to said anchoring means between first and second longitudinally spaced positions separated by a distance only slightly less than said predetermined spacing; and electrical control means adapted for selectively actuating said first shaped charge when said body is in its said first spaced position to produce a first perforation in adjacent earth formations and for thereafter selectively actuating said second shaped charge when said body is in its said second spaced position to produce a second perforation in adjacent earth formations which is substantially contiguous with said first perforation.