US3104710A

US3104710A - Perforating of pipe strings

Info

Publication number: US3104710A
Application number: US52280A
Authority: US
Inventors: William A Pitts
Original assignee: Jersey Production Research Co
Current assignee: Jersey Production Research Co
Priority date: 1960-08-26
Filing date: 1960-08-26
Publication date: 1963-09-24
Anticipated expiration: 1980-09-24

Description

2 Sheets-Sheet 1 T ORNE Sept. 24, 1963 w. A. PlTTS PERFORATING OF PIPE STRINGS Filed 26. 1960 FlG.l.

United States Patent Filed Aug. 26, 1960, Ser- No. 52,280 16 Claims. (Cl. 166-55.1)

The present invention is directed to apparatus for perforating a selected pipe string. More particularly, the invention is concerned with perforating one of a plurality of pipe strings without perforating other of the pipe strings. In its more specific aspects, the invention is concerned with perforating one pipe string which is in side by side relationship to another pipe string without perforating the other pipe string.

This application is a continuation-in-part of Serial No. 756,600, entitled Perforating of Pipe Strings filed August 22, 1958, for William A. Pitts, now abandoned.

The invention may be briefly described as apparatus for use in a well which comprises a plurality of substantially parallel eccentric pipe strings extending through a plurality of subsurface earth intervals which may be productive of hydrocarbons. One of the pipe strings is provided with at least one mandrel interconnected therein, the mandrel having a passageway therethrough and being formed with a recess having a diameter greater than the diameter of the one pipe string. A resilient means is arranged in the recess which is normally urged out of the recess to project into and to restrict the passageway. A body member which is lowerable through the one pipe string is provided with means for perforating the one pipe string. The body member is provided with a guide means which has one fiat side but which may have two fiat sides opposite each other. When the guide member has two flat sides the fiat sides are connected by a curved surface. The guide member may have no more than two opposite fiat sides. The mandrel is positioned in the pipe string such that the resilient means and guide means on cooperative engagement on a flat side of the guide means orient the guide means and the perforating means carried thereby to a position and/ or a direction whereby the fiat side of the guide means, when extended, avoids intersecting the periphery of any of the other pipe strings and the perforating means is in a position such that when it is fired it is pointed in a direction away from the pipe strings other than the one that is to be perforated. Thus, the perforating means is carried by or positioned on the body member such that when it is operated, it perforates only the one pipe string when the resilient means and guide member cooperatively engage on a flat side to orient the guide member and, therefore, the body member.

The guide means may suitably be a separate member which may be attached either to the upper end of the body member or which may be attached to the lower end of the body member. Suitably the guide means is an opposite flat-sided rigid member having beveled or rounded edges. The guide member, however, may suitably be formed on the body member with the body member generally rounded, otherwise, in cross-section.

The recess in the mandrel may extend around the internal periphery of the mandrel or may be a recess only on one side of the mandrel. The recess may be formed to accommodate a flat-sided spring or a circular spring having a flat side. The spring may have an exposed curved surface to contact the flat side of the guide means. The recess may accommodate opposing springs or resilient means which project into the passageway to restrict the passageway of the mandrel. The recess may be provided with a shoe which is urged out into the passageway by a helical coil or a leaf spring. The resilient means Patented Sept. 2 1963 may also comprise an inflatable or deformable member such as a rubber sleeve and the like.

The spring may be continuous. When it is circular it may be retained on the recess by arrangement over a pin. The spring or resilient means may be held on a plurality of pins in the recess. I

The passageway through the mandrel is full opening when the resilient means is urged back into the recess. That is, the mandrel has a passageway of approximately the same diameter of that of the pipe string while the diameter of the recess and the passageway through the mandrel is greater than the diameter of the pipe string.

The present invention is quite useful and advantageous in that it may be used to position or orient a perfora-tor which is lowerablethrough at least one of a plurality of pipe strings. It is now common practice to complete wells in a plurality of hydrocarbon productive zones, horizons, intervals, sands, strata, formations, and the like, from which hydrocarbons such as oil and gas may be produced. This may be accomplished by arranging a plurality of tubing strings in a well casing or by arranging a plurality of pipe strings in a well and cementing the pipe strings in place for perforation of each pipe string in one of a plurality of vertically spaced-apart hydrocarbon productive zones. The present invention may be used wherever more than one pipe string is employed in a well and where it is desired to perforate one pipe string adjacent another pipe string Without perforating the other pipe string.

The present invention will be further illustrated by reference to the drawing in which:

FIG. 1 illustrates a preferred embodiment of the invention where it is desired to complete a well in a plurality of zones with the well equipped for permanent well completion in each of the zones;

FIG. 1a is a cross-sectional view of the guide means in one of the pipe strings of FIG. 1;

FIG. 1b is a cross-sectional view of the other of the guide means of FIG. 1;

FIG. 2 is another preferred embodiment of the invention where parallel eccentrically-placed pipe strings are placed in a well bore;

FIG. 2a is a cross-sectional view of the guide means of FIG. 2;

FIG. 3 is a modification of the FIGS. 1 and 2;

FIG. 3a is a cross-sectional view of the guide means of FIG. 3;

FIG. 4 is a sectional view of one embodiment of the mandrel of the present invention;

FIG. 5 is a View taken along the lines S 5 of FIG. 4;

FIG. 6 is another modification of the mandrel of the present invention;

FIG. 7 is a view taken along the lines 7-7 of FIG. 6;

FIG. 8 is a further modification of the mandrel showing a plurality of resilient means;

FIG. 9 is a still further embodiment of the mandrel showing a resilient shoe or a rigid shoe engaged by a resilient means; and

FIG. 10 is an embodiment of the present invention in cross-section where the guide means is formed on the perforator.

Referring now to the drawing and particularly to FIGS. 1, 1a and 1b, numeral 11 designates a well bore drilled from the earths surface to penetrate a plurality of hydrocarbon

productive zones

12, 13, 14, and 15 from which perforating means of it may be desired to obtain hydrocarbon production. Ar-

ranged in the well bore 11 is a casing 16 cemented in place with cement 17. A first tubing string 18 is arranged in the casing 16 and extends with its lower end 19 immediately above the zone 13. A second tubing string 20 extends with its lower end 21 immediately above the zone 15 with the space between the lower end 19 and the zone 15 being closed by lower packer 22, while the casing tubing annulus 23 between the

zones

13 and 12 is closed by an upper packer 24.

From this arrangement, it will be clear that the zone 12 is isolated from the

zones

13 and 14 and the zone 15 is isolated from the

zones

13 and 14.

It may be desirable to produce simultaneously from zone 12 or from either of the

zones

13 or 14 and the zone 15. By perforating in the zone 15, production may proceed up the tubing 20 and by perforating in the

zones

13 or 14, production may proceed up the tubing 18. It may be desired under some circumstances to plug off the tubing Ztl in the bore 25 of packer 22 and perforate the tubing 2% for production in the zone 12 through the casing 16. Ordinarily, however, it would be desirable not to perforate the tubing 2th in the zone 12, but to perforate the casing 16 in that zone and let the production proceed up the annulus 23. However, for purposes of illustration only, reference is made to perforating the tubing 29 in the upper zone 12.

The

tubings

18 and 20 are suitably connected together by clamp couplings or

mandrels

26 and 27, the mandrel 26 being provided with a recess28 which has a spring or resilient means 29 connected into the recess 28 and extending out into the passageway 36 to restrict same. It is to be noted that the mandrel or clamp coupling 26 is affixed to the tubing 18 and is so arranged that the mandrel 26 and recess 28 are oriented with respect to the tubing 18.

Likewise, with respect to the mandrel or clamp coupling 27, the clamp or mandrel 27 is provided with a recess 31 in which is arranged a spring 32 arranged on pins 33 and 34- which projects into the passageway 35 and restricts same.

Lowered on a conductor cablesuch as 36 is a perforat ing means 37 formed as an elongated body provided with a perforating means 33 for perforating preferably in the zone 15 and optionally in the zone 12.

The elongated body 37 is provided with a guide member 39 which is oppositely flat-sided and which has beveled edges 39a and 3% such that when it is within the passageway 30 a flat side engages with the spring 29 and orients the body member 37 such that the perforating means 38 is pointed away from the tubing 18.

In the tubing string 18, there is lowered on conductor cable til an elongated body 41 such as a gun perforator provided with perforating means 42 The perforator 41 is provided with an elongated guide bar 43 which is oppositely flat-sided and has beveled

edges

43a and 43b and engages with the spring 32 and causes the perforating means to be positioned or oriented such that it will perforate the casing 16' but not the tubing 20 when operated.

It is to be noted that the

mandrels

26 and 27, as shown in FIG. 1, are spaced vertically above the

zones

12, 13, and 14, respectively, such that when the

guides

39 and 43 are oriented in the

mandrels

26 and 27, the perforating means 38 and 42 on operation perforate the desired zone on positioning the

body members

37 and 41 into the zone to be perforated.

Referring now to FIGS. 2 and 2a, a borehole 50 has been drilled from the earths surface to penetrate a plurality of hydrocarbon

productive formations

12, 13, 14, and 15. Arranged in the bore hole 50 is a plurality of

pipe strings

51 and 52 which are cemented in place with cement 53. The pipe strings 51 and 52 are interconnected by connection means 54 providing a fluid passageway .55. The pipe strings 51 and 52 are also interconnected by a clamp coupling or mandrel 56 provided with a recess 57 in which a resiliently biased shoe 58 is urged out into the passageway 59 of the mandrel 56 to restrict same. Lowered on a conductor cable such as 60 is a perforator bl provided with perforating means 62. "The conductor cable 60 is connected to a flat-sided guide bar or guide member 63 having beveled edges 63a and 635 which, in turn, is attached to the perforator 61. When a flat side of the guide member '63 is in the passageway 59, the guide member is so positioned that the direction of fiat side is known with respect to the periphery of the pipe string 52 or any other pipe string which may be in the well :such that on properly orienting the perforating means 62 with respect to this known reference, only the pipe string 51 is perforated when the said perforating means is operated.

Arranged in the pipe string 52 is a flow tube 64 which may be suitably seated above the passageway 55 and anchored therein in a suitable landing nipple 65. The flow tube 64- is sealed on its upper end with a seal 66 and sealed below the passageway 55 with a seal 67 such that fluid passing up the pipe string 52 may proceed through the flow tube 64- and such that production may be simultaneously had through the two pipe strings 5'1 and 52.

By virtue of the perforating means 61 and the guide 63, it is possible to perforate the pipe string 51in its co-extensive portion with pipe string 52 without perforating the pipe string 52.

Referring now to FIGS. 3 and 3a, a modification of the other embodiments is shown wherein a perforator such as 68, provided with perforating means 681;, is employed. The perforator 68 is lowered on a conductor cable such as 3-6 or 60 to position it properly in a mandrel such as shown in the other figures of the drawing. In embodiment the guide means or fiatsided guide bar 69 having beveled

edges

69a and 69b is attached to the lower end of the perforator 68 such that the perforator tionship thereto. It is noted that pipe string 74 may be inserted in passageway 74a such that pipe strings 73 and 74 may be run in independently.

Arranged in the recess 72 is a spring 75 which projects into the passageway 71, the spring being maintained over the pins 76. Lowered through the pipe string 73 is a p I perforator, not shown, connected to an oppositely flatsided guide means 77 such that a flat side engages with the spring 75 to cause the guide member to be oriented properly as shown more clearly in FIG. 5. By virtue of the spring member 75 engaging with a fiat side of the guide bar 77, the gun perforator which is attached thereto, when operated, will perforate the pipe string 73 in the direction as indicated by the arrows in FIG. 5 such that the pipe string 74 is never perforated.

Referring now to FIGS. 6 and 7, a mandrel such as 80 is arranged or connected into a pipe string 81 and is provided with a recess 82 in which a circular spring 83 is arranged over a retaining pin 84- to project into the passageway 85. The clamp 80 is provided with a passage 86 through which another pipe string may suitably be arranged. A flat sided guide means 87, attached to a gun perforator, not shown, is lowered through the pipe string 81 and the cooperative engagement between the spring 83 and guide 87 orients the guide and the perforator such that when operating the perforating means noted again that passageway 88a is larger than pipe string $8 and that passage 86 is sufiiciently large for insertionof a third pipe string such that each pipe string may be run into the well separately and independently.

Referring now to FIG. 8, a mandrel such as '90 has a recess 91 which extends around the internal periphery of the mandrel 90 in which are arranged

springs

92 and 93 over

pins

94 and 95, the

springs

92 and 93 projecting out into the passageway 96 and restricting same and cooperatively engaging with the major axis of the guide means 97 to orient same and the gun perforator, not shown, attached thereto. Like the

mandrels

70 and 80, the mandrel 90 is provided with a passageway 98 through which another pipe string such has been illustrated by the other figures may be run in independently and separately and thus arranged in the well.

Referring now to FIG. 9, a mandrel 100 is provided with a recess 101 and has a passageway 102. 'The mandrel 104) has a shoe 103 projecting into the passageway 102, the shoe being attached in the recess 101 by hinge 104 and retained by a limit stop 105 on its lower end. A helical coil spring such as 106 urges the shoe 103 out into the passageway 192 for engagement with the guide bar 107 to orient a perforator means (not shown) attached thereto. Like the other embodiments, the mandrel 100 has a passageway 1&8 through which another pipe string may be arranged parallel to the pipe string 109 into which the mandrel 108 is connected. The passageway 108 is designed to allow another pipe string to be run into the well separately from the pipe string 109.

Referring now to FIG. l0, a cross-sectional view is presented of another modification of the present invention in which a clamp coupling means or mandrel such as 110 is provided with a passageway 111 for one pipe string which is run in separately and has a second pipe string connected to a passageway 112. The mandrel 1111 has a recess 113 provided with a spring 114 which is urged out of the recess 113. The spring 114 may have a fiat side 115 which restricts the passageway 112. Lowered through the passageway 112 is a perforator 116 provided with perforating means 117 designed to perforate the pipe string attached to the passageway 112 in a direction as indicated by the arrows.

It is noted that the perforator 116 is formed to provide a flat side 118 for operative engagement with the flat side 115 of the spring 114, the perforato-r 116 being otherwise rounded.

It will be clear from the several figures of the drawing that the flat sides and the resilient means form cooperative surf-aces which are dimensioned to maintain the guide means in oriented position on cooperative engagement of a flat side with the resilient means.

By virtue of the fact that dewices lowered or Wire lines or conductor cables in a pipe string rotate in view of the torque or spring the wire line or conductor cable, it is possible to orient using the apparatus of the present in vention which pcrforates only when the perforating means is properly positioned and only a selected one of a plura ity of pipe strings will be perforated. When the flat side of the guide means engages with the spring means, which substantially completely restricts a substantial portion of the passageway through the mandrel, the guide means and the perforating means rigidly attached thereto are necessarily oriented such that the perforating means points away from any other pipe string in the Well.

A suitable electrical circuit may be completed when the guide member is properly oriented by engagement with the spring to fire the perforating means.

It is understood, of course, that the mandrel with its recess must 'be properly oriented and positioned relative to the other pipe strings such that when the guide member comes in contact with the resilient means or spring, the guide member with its attached perforator is properly positioned and thus the perforator will perforate oniy the selected pipe string.

It is also to be understood as shown in the drawing particularly referring to FIGS. 1 to 3, inclusive, that the mandrels must be spaced vertically from the zone or interval which is to be perforated such that the guide member when properly oriented therein positions the perforator adjacent the interval to be perforated. Thus, the mandrels may be spaced vertically above or below the zone to be perforated dependent on where the guide member is arranged on the body member.

The perforating means carried by the elongated body is preferably a shaped charge commonly known as a jet charge but may be a bullet gun perforator, a chemical perforator, a mechanical perforator, a hydraulic perforator using a stream containing abrasive such as sand.

The present invention is advantageous and useful over other devices in that the pipe string in which the mandrel is placed with its resilient means allows the passageway of well tools therethrough without obstructing the passage of such tools. Furthermore, it is unnecessary to build special gun perforators other than provide a guide means (which may be reusable) attached thereto or formed thereon. The present invention, is therefore, quite advantageous and useful.

While the invention has been described relative to two and three substantially parallel eccentric pipe strings in a well, it is contemplated that the invention is applicable to four, or more pipe strings so arranged in a well. Likewise, as shown in FIG. 1, a plurality of mandrels may be arranged in one or more pipe strings to orient the perforator to perforate the selected pipe string in one or more selected zones for immediate use or to produce other Zones for future use, without perforating any other pipe string when firing the gun.

The nature and objects of the present invention having been completely described and illustrated, what I wish to claim as new and useful and to secure by Letters Patent is: I

1. For use in a well, apparatus which comprises a plurality of substantially parallel eccentric pipe strings in said well extending through a plurality of subsurface earth intervals, at least one mandrel connected into one of said pipe strings adjacent one of said intervals and having a first passageway therethrough and formed with a recess having a diameter greater than the diameter of said one pipe string, said mandrel having a second passageway adapted to receive another of said pipe strings, resilient means in said recess normally urged out of said recess to project into and restrict said first passageway, and a body member provided with means for perforating said one pipe string, said body member being provided with a guide means, said guide means having a flat side for cooperative engagement with said resilient means, said mandrel and said recess being positioned in said one pipe string relative to said another pipe string such that said resilient means and guide means on cooperative engagement on the flat side of the guide means orient said guide means to a predetermined position, said fiat side and said resilient means forming cooperative surfaces dimensioned to maintain said guide means in oriented position on said cooperative engagement, said perforating means being carried by and positioned in said body member to perforate said one pipe string only when said resilient means and guide means cooperatively engage on said fiat side to orient said guide means, said perforating means being positionable adjacent said one of said intervals when said guide means is in cooperative engagement with said resilient means such that the perforating means is directed away from said another pipe string.

2. Apparatus in accordance with claim 1 in which the guide means is attached to the upper end of said body member.

3. Apparatus in accordance with claim 1 in which the guide means is attached to the lower end of said body member.

4. Apparatus in accordance with claim 1 in which the guide means is an elongated member attached to the body member on one of its ends.

5. For use in a Well, apparatus which comprises a plurality of substantially parallel eccentric pipe strings in said well extending through a plurality of subsurface earth intervals, at least one mandrel connected intoone of said pipe strings adjacent one of said intervals and having a first passageway therethrough and formed with a recess having a diameter greater than the diameter of said one pipe string, said mandrel having a second passageway adapted to receive another of said pipe strings, resilient means in said recess normally urged out of said recess to project into and restrict said first passageway, and an elongated body member provided with means for perforating said one pipe string, said body member being provided with a flat-sided guide means attached thereto, said guide means having two opposite fiat sides connected by curved surfaces, said mandrel and said recess being positioned in said pipe string such that said resilient means and guide means on cooperative engagement on one of the flat sides of the guide means orient said guide means and the perforating means to a predetermined position whereby the direction 'of said penforating means, when extended, avoids intersecting the periphery of said another of said pipe strings, said perforating means being carried by and positioned in said body member to perforate said one pipe string only when said resilient means and guide means cooperatively engage on said one of the fiat sides to orient said guide means, said fiat sides and said resilient means forming cooperative sunfaces dimensioned to maintain said guide means and perforating means in oriented position on said cooperative engagement, said perforating means. being positioned adjacent said one of the intervals when said guide means is in cooperative engagement with said resilient means such that the perforating means is directed away from said another pipe string.

6. Apparatus in accordance with claim in which the second passageway through said mandrel is larger in diameter than the diameter of said another pipe string such that said pipe strings may be run in independently.

7. For use in a well, apparatus which comprises a plurality of substantially parallel eccentric pipestrings in said well extending through a plurality of subsurface earth intervals, at least one mandrel connected into one of said pipe strings adjacent one of said intervals having a first passageway therethrough and for-med with a recess having a diameter greater than the diameter of said one pipe string, said mandrel having a second passageway adapted to receive another of said pipe strings, spring means in said recess normally urged out of said recess to project into and restrict said first passageway, and a body member provided with means for perforating said one pipe string, said body member being provided with guide means, said guide means having two opposite flat sides connected by curved surfaces, said mandrel and said recess being positioned in said pipe string such that said spring means and guide means on cooperative engagement on one of the flat sides of the guide means orient said guide means and the perforating means to a position whereby the direction of said perforating means, when extended, avoids intersecting the periphery of said another pipe string, said perforating means being carried by and positioned in said body member to perforate said one pipe string only when said spring means and guide means cooperatively engage on one of said fiat sides to orient said guide means, said flat sides and said resilient means forming cooperative surfaces dimensioned to maintain said guide means and perforating means in oriented position on said cooperative engagement, said perforating means being positioned adjacent said one of the intervals when said guide means is in cooperative engagement with said spring means such that the perforating means is directed away from said another pipe string.

Y 8.! Apparatus in accordance with claim 7 in which the guide means is a rigid member attached to' said body member.

9. For use in a well, apparatus which comprises a plurality of substantially parallel eccentric pipe strings insaid well extending through a plurality of subsurface earth intervals, at least one mandrel connected into one of said pipe strings adjacent one of said intervals and having a first passageway therethrough and formed with a recess extending around the internal periphery of the mandrel and having a diameter greater than the diameter of said one pipe string, said mandrel having a second pasisa geway adapted to receive another of said pipe strings, a plurality of opposing resilient means in said recess normally urged out of said recess to project into and restrict said first passageway, and a body member provided with means for perforating said one pipe string, said body member being provided with guide means, said guide means having two opposite fiat sides connected by curved surfaces, said mandrel and said recess being positioned in said pipe string such that said resilient means and guide means on cooperative engagement on the flat sides of the guide means orient said guide means and the perforating means to a position whereby the direction of said perforating means, when extended, avoids intersecting the periphery of said another pipe string, said flat sides and said resilient means forming cooperative surfaces dimensioned to maintain said guide means and perforating means in oriented position on said cooperative engagement, said perforating means being carried by and positioned in said body member to perforate said one pipe string only when said resilient means and guide means cooperatively engage on said flat sides to orient said guide means, said perforating means being positioned adjacent said one of the intervals when said guide means is in cooperative engagement with said resilient means such that the perforating means is directed away from said another pipe string.

10. For use in a well, apparatus which comprises a plurality of substantially parallel eccentric pipe strings in said well extending through a plurality of subsurface earth intervals, at least one mandrel connected into one of said pipe strings having a first passageway therethrough and formed with a recess having a diameter greater than the diameter of said one pipe string, said mandrel having a second passageway adapted to receive another of said pipe strings, a shoe means in said recess normally resiliently urged out of said recess to project into and restrict said first passageway, and a body member provided with means for perforating said one pipe string, said body member being provided with guide means, said guide means having two opposite flat sides connected by rounded surfaces, said mandrel and said recess being positioned in said pipe string such that said shoe means and guide means on cooperative engagement on one of the flat sides of the guide means orient said i guide member and the perforating means to a position whereby the direction of said perforating means, when extended, avoids intersecting the periphery of said an,- other pipe strings, said flat sides and said shoe means forming cooperative surfaces dimensioned to maintain said guide means and perforating means in oriented position on said cooperative engagement, said perforating means being canried by and positioned in said body member to perforate said one pipe string only when said shoe means and guide means cooperatively engage to orient said guide means, said perforating means being.

positionable adjacent said one of said intervals when said guide means is in cooperative engagement with said shoe means such that the perforating means is directed away from said another pipe string.

11. For use in a well, apparatus which comprises a plurality of substantially parallel eccentric pipe strings in said well extending through a plurality of subsurface earth intervals, at least one mandrel connected into one of said pipe strings having a first passageway therethrough and formed with a recess having a diameter greater than the diameter of said one pipe st-ring, said mandrel having a second passageway adapted to receive another of said pipe strings, a fiat-sided resilient means in said recess normally urged out of said recess to project into and restrict said passageway, and a body member provided with means for perforating said one pipe string, said body member being provided with a fiat-sided guide means attached thereto, said guide means having a fiat side, said mandrel and said recess being positioned in said pipe string such that said resilient means and guide means on cooperative engagement on said flat side orient said guide member and the perforating means to a position whereby the direction of said perforating means, when extended, avoids intersecting the periphery of said another pipe string, said fiat sides and said resilient means forming cooperative surfaces dimensioned to maintain said guide means and perforating means in oriented position on said cooperative engagement, said perforating means being carried by and positioned in said body member to perforate said one pipe string only when said resilient means and guide means cooperatively engage to orient said guide means, said perforating means being positionable adjacent said one of said intervals when said guide means is in cooperative engagement with said resilient means such that the perforating means is directed away from said another pipe string.

12. In combination: A plurality of mutually independent eccentrically disposed Well pipes; gun positioning means connected to a given one of said pipes for positioning a perforating gun therewithin; and coupling means mechanically connected to said gun positioning means slidingly fitted about a pipe other than said one pipe for independent movement of said other pipe freely through said coupling means, said coupling means being formed to space and position said one pipe relative to the other pipe so that the perforating gun when positioned by said gun positioning means fires in a direction away from said other pipe.

13. In combination: first and second mutually independent, eccentrically disposed well pipes; a section in said first pipe adapted to receive positioning means for 1a perforating gun to be lowered into said first pipe; and means affixed to said first pipe and loosely engaging said second pipe adapted to space said first pipe from said second pipe to maintain substantially constant the longitudinal taxes of said first and second well pipes, said spaciii ing and maintenance means allowing independent and free movement of said second pipe therethrough.

14. In combination: At least one first well pipe means; a second well pipe means including means for positioning pert-orienting means there within; a perforating means provided with guide means movlably arranged in said second well pipe means for operative engagement of said guide means with said positioning means, and coupling means adapted to slide freely along said first Well pipe means and to loosely embnacingly engage said first Well pipe means to hold said first well pipe means in a :given physical relationship to said second Well pipe means, so that said perforating means is oriented to fire away from said first well pipe means, said coupling means all-owing independent Iand free movement of said first well pipe means therethrough.

15. In combination: first and second mutually independent, eccenmieallly disposed Well pipes; a coupling section anranged in said first pipe adapted to receive positioning means for a perforating gun to be lowered into said first pipe; resilient positioning means in said section; said coupling section being afiixed to said first pipe and loosely engaging said second pipe adapted to space said first pipe from said second pipe to maintain substantially constant the longitudinal axes of said first and second well pipes, said coupling section allowing independent and free movement of said second pipe therethrough.

16. In combination: first and second mutually independent, eocentrically disposed well pipes; a coupling section arm-anged in said first pipe adapted to receive positioning means for an elongated body to be lowered into said first pipe; resilient positioning means in said section; said coupling section being aflixed to said first pipe and loosely engaging said second pipe adapted to space said first pipe from said second pipe to maintain substantially constant the longitudinal axes of said first and second well pipes, said coupling section allowing inde endent and [free movement of said second pipe therethrough.

References Cited in the file of this patent UNITED STATES PATENTS 2,408,419 Foster Oct. 1, 1946 2,785,754 True Mar. 19, 1957 2,791,277 Ilfirey et a1. May 7, 1957 2,858,107 Colmerauer Oct. 28, 1958 2,938,584 T ausch at al. May 31, 1960 2,939,533 Ooberly June 7, 1960 3,012,608 Mcbaren Dec. 12, 196 1