US 3426850 A
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Description (OCR text may contain errors)
Feb. 11, W69 J. c. M DUFFIE, JR 3,426,850
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United States Patent 3,426,850 METHOD AND APPARATUS FOR PERFORATING IN WELLS John C. McDuflie, Jr., Houston, Tex., assignor to Esso Production Research Company Continuation of abandoned application Ser. No. 780,387, Dec. 15, 1958. This application June 20, 1966, Ser. No. 567,794 U.S. Cl. 166-255 13 Claims Int. Cl. E21b 47/00, 43/119, 43/116 ABSTRACT OF THE DISCLOSURE A method for perforating in a well bore which contains at least two spaced-apart pipe strings. In one of the pipe strings a directional perforator is arranged together with a radiation detector capable of detecting radiation from a radiation source located in another of the pipe strings to provide, upon rotation of the perforator and radiation detector, indications of the angular position of the radiation source, and thereby the other pipe string, relative to the direction of perforation.
This application is a continuation of Ser. No. 780,387, now abandoned, entitled, Method and Apparatus for Perforating in Wells, filed Dec. 15, 1958, by John C. McDuflie, Jr.
This invention generally concerns multiple zone rwell operations. More particularly, the invention concerns locating pipe strings arranged in a borehole relative to the position of a well tool. In its more particular aspects, the invention concerns locating pipe strings arranged in a borehole relative to the direction of fire of a gun perforator and orienting the gun perforator to direct the fire thereof in a direction away from one or more of the pipe strings to avoid perforation thereof or toward one or more of the pipe strings to cause perforation thereof.
In multiple zone well operations a plurality of pipe strings are arranged in a borehole which penetrates a plurality of vertically spaced productive zones and production fluids from each zone are conducted independently to the earths surface through these pipe strings. In order to perforate a particular interval, a gun perforator is run in the borehole and fired in a direction to cause penetration of the productive formation. However, when at least two pipe strings are positioned adjacent the intenval to be perforated it is necessary to direct the fire of the gun perforator to avoid striking and perforating one or more of the pipe strings other than the pipe string through which the gun perforator is run. Also, in well openations wherein the borehole contains a plurality of pipe strings it may be desired to direct the fire of the gun perforator to perforate one or more of the pipe strings, as for example, when it is necessary to establish subsurface communication between pipe strings during blowouts, workovers, etc.
These desired results are achieved by the present invention which provides method and apparatus for locating pipe strings in a borehole relative to the direction of fire of a gun perforator, for orienting the gun perforator to direct the fire thereof in any desired circumferential direction; and for firing the gun perforator to avoid perforating a particular pipe or pipes or for perforating a particular pipe or pipes as may be desired. Radioactivity detection techinques are employed to locate the pipe and particularly the techinque of detecting radiation emitted by radioactive material.
The invention is advantageous in many ways. For example, it avoids the use of gun guides; it avoids the pos- ICC sibility of an incorrect orientation should a pipe string rotate or slip in a clamp clamping pipe strings together or should the original alignment of the pipe strings be in error; it permits running pipe strings in the Well separately; and it permits full and constant openings through all of the pipe strings.
These purposes and other purposes of the invention will be apparent from a description thereof taken in conjunction with the drawing wherein:
FIG. 1 is a cross-sectional view of the earths subsurface showing a borehole having arranged therein two pipe strings, one of which contains a tool for perforating and for locating pipe; also shown is a schematic illustration of the surface equipment for rotating the tool, for registering detection of pipe, and for firing the perforator;
FIG. 2 is a vertical, partly sectional view of the tool of FIG. 1;
FIG. 3 is a plan view of a borehole containing two pipe strings and illustrating one manner of arranging the apparatus according to the invention; and
FIG. 4 is a plan view of a borehole containing three pipe strings and illustrating one manner of arranging the apparatus according to the invention.
Referring to the drawing in greater detail, in FIG. 1 is shown a borehole 10 penetrating a subsurface productive formation 11. Two eccentric, spaced apart pipe strings 12 and 13 are arranged in borehole 10 and cemented therein by means of cement 14.
A perforator tool, designated 15, is suspended in pipe string 12 by means of a m'ulti-electrical conductor cable 16. Tool 15 includes a tool positioner and pipe locator section 17 and a perforator section 18 connected together by means of flexible joints 19 and extension 33.
As seen in greater detail in FIG. 2, section 17 includes a housing 20 in which is arranged a reversible motor 21 to which is connected a gear box 22, which in turn is connected to a rotatable shaft 23, to which is connected a radiation detector 24 and a selsyn motor transmitter 26. Shaft 23 extends through the lower end of housing 20 and connects with the upper flexible joint 19. Housing 20 is provided with bearings 27 which permit shaft 23 to rotate relative to housing 20 and sealing means such as O-ring 29, which is adapted to prevent fluid from entering housing 20. Drag springs 28 are arranged on the exterior of housing 20 and function to prevent rotation of housing 20 and to centralize the housing. The latter function is desired in order to maintain consistent radiation detection readings in any direction. Shaft 23 may be provided with a slip-ring assembly 30 for conducting electrical signals transmitted through a conductor 31 which is connected to cable 16 to conductors 32' which connect to the gun elements 34 arranged on gun perforator 18, and for conducting electrical signals from detector 24 to conductor 31. A conductor 32 connects cable 16 to motor 21.
Detector 24 is provided with a shield 25 configured so as to col'limate the detected radiation to confine the area of detection to a limited arc, as, for example, an arc of 45 of the well bore. This limited arc of investigation is more clearly seen in FIGS. 3 and 4.
As seen in FIGS. 3 and 4, the direction of fire 35 of gun elements 34 is away from the direction of the arc of detection 36 of the pipes 13 and 50 as determined by shield 25.
The surface equipment which electrically connects with cable 16 includes a power supply 40, a selsyn motor receiver 41, a radiation detector indicator 42, a motor switch 43, and a gun switch 44.
Naturally radioactive or artificially produced radioactive substances are arranged adjacent to, such as outside of, Within, on, etc., pipe string 13. The radioactive substance may be arranged in any desired manner. For example, the interior or exterior of pipe string 13 may be coated with the radioactive substance; or the radioactive substance may be mixed in the thread-sealing compound used in making up the joint or joints of pipe string 13; or a fluid or a container containing the radioactive material may be placed or located within pipe string 13. In FIG. 2, the interior of pipe string 13 is provided with a coating of radioactive material 45.
When it is desired to perforate formation 11, tool 15 is lowered on cable 16 through pipe string 12 until the tool is positioned adjacent formation 11. Motor 21 then is actuated to rotate in one circumferential direction by means of motor switch 43. Through reduction gear box 22, shaft 23 rotates slowly, thereby rotating shielded detector 24 and selsyn transmitter 26 mounted thereon. Through extension member 33 and flexible joints 19 connection, gun section 18 is rotated also. Drag springs 28 maintain housing stationary both vertically and horizontally during rotation of these elements. As detector 24 rotates, shield permits detector 24 to detect radiation only in a limited are. When radiation particles emitted by radioactive material 45 coated on pipe string 13 are detected by detector 24 as evidenced at the detection indicator 42 on the surface of the earth, the direction of the arc of detection 36 may be recorded and observed relative to any rotative position of tool 18 established by means of selsyn receiver and transmitter 41 and 26, respectively. The direction of fire of gun elements 34 is fixed relative to the direction of detection 36. Therefore, locating the pipe string relativeto the direction of detection locates the pipe string relative to the direction of fire. Tool 18 then may be rotated by means of motor 21 or, through the selsyn motors, or through separate electrical controls if desired to a position wherein the direction of fire avoids pipe string 13. Gun elements 34 are fired by means of gun switch 44 once the desired rotational position of the gun perforator is obtained. In this case which is illustrated in FIG. 3 wherein only two pipe strings are arranged in the borehole and it is necessary to avoid only the one pipe string 13, the use of selsyn motors may be omitted because since the direction of detection and the direction of fire are fixed relative to each other once pipe string 13 is detected, perforator 18 may be oriented by rotation thereof to direct the gun elements 34 for safe firing. However, in the case illustrated in FIG. 4 wherein an additional pipe string 50 also is positioned in the borehole the positions of each of the pipe strings 13 and 50 may be registered by the selsyn indicator 41 relative to the rotative position of tool 18 established by selsyn transmitter 26, and tool 18 may be rotated to position the direction of fire 35 of gun elements 34 to avoid the pipe strings. One manner of operation may be to orient the tool so that when the direction of detection is positioned between the pipe strings the direction of fire is away from both pipe strings as illustrated in FIG. 4.
If desired, instead of having tool 15 centralized in pipe string 12, biasing means may be employed to bias tool 15 against the wall of pipe string 12. Also, if desired, other retaining means may be employed in conjunction with or in place of drag springs 28.
Any desired radioactive substance may be employed as the radioactive material. Examples of such substances are: radon, radium bromide, radium chloride, uranium bromide, uranium tetrabromide, etc. These are naturally radioactive substances, however, known artificially radioactive substances also may be employed.
Detector 24 may be any device responsive to radiation produced by the radioactive material, for example, it may be a Geiger-Mueller counter, an ionization chamher, or a proportional counter.
Shield 25 is formed of radiation absorbing or moderating material, such as lead, tungsten, parafiin, boron, cadmium, etc., which material is capable of absorbing or moderating the radiation being detected.
The invention is applicable to so-called tubingless completions, that is, wells completed with small diameter pipe called tubing, being empoyed as borehole casings. This is the type operation illustrated in FIG. 1. However, the invention may also be used in cased and tubed wells, that is, in wells where a casing is run and cemented in place and tubing strings are arranged in the casing. Although the particular type positioning apparatus, including the reversible motor and the selsyn motors, is a preferred form of apparatus in performing the method of the invention, other types of apparatus are within the scope of the invention, for example, a hydraulic type positioning device such as disclosed and claimed in US. patent application Ser. No. 780,524, entitled, Method and Apparatus for Operating in Wells, filed Dec. 15, 1958, by H. S. Arendt, may be employed instead.
The description of the invention is directed to well completion operations wherein when perforating subsurface intervals it is desired to avoid pipe strings in the borehole other than the pipe string in which the gun perforator is run. However, as mentioned previously herein, it may be desired to perforate one or more of the pipe strings in the borehole other than the pipe string in which the perforator is run. In this instance, the procedure is similar to the procedure described; however, the gun perforator will be positioned to perforate the pipe strings rather than to avoid perforation thereof.
The term direction or line of fire is intended to mean, as used herein, one or more directions of fire.
Having fully described the method, apparatus, objects and operation of my invention, I claim:
1. A method for perforating in a well bore penetrating a subsurface formation, said well bore having arranged therein at least two eccentric spaced-apart pipe strings comprising:
arranging in one pipe string a tool provided with a perforator having a selected direction of perforation and with a detector of radiation having a selected direction of radiation detection relative to said perforator, and with a means capable of causing rotation of said tool;
arranging in at least one other pipe string a source of radiation;
actuating said rotating causing means to rotate said tool to determine an angular position of said radiation source relative to the position of said radiation detector;
further rotating said tool until said direction of perforation thereof relative to said detector is in a selected direction; and
then actuating said perforator.
2. A method as recited in claim 1 including positioning the direction of perforation away from the position of said source of radiation.
3. A method as recited in claim 1 including positioning the direction of perforation toward the position of said source of radiation.
4. A method for perforating in a well bore having arranged therein a plurality of pipe strings comprising the steps of:
arranging in one pipe string a rotatable tool provided with a perforator having a selected direction of perforation and provided with a collimated detector of radiation having a selected direction of radiation detection fixed relative to said direction of perforation; arranging in at least one other of said pipe strings a source of radiation capable of emitting radiation detectable by said detector of radiation;
rotating said tool to a selected angular position thereof as determined by radiation emitted by said radiation source and detected by said detector in order to orient said perforator relative to the position of said other pipe string in which said source of radiation is arranged; and
then actuating said perforator when said tool is in said selected angular position.
5. A method as recited in claim 4 in which perforation of said pipe string in which said source of radiation is arranged is avoided.
6. A method as recited in claim 4 in which said pipe string in which said source of radiation is arranged is perforated.
7. A method for perforating in a well bore having at least one pipe string arranged therein comprising the steps of:
positioning a source of radiation in one pipe string at a depth in said well bore at which it is desired to perforate;
positioning in said well bore external of said pipe string in which said source of radiation is positioned a rotatable perforator having a selected direction of perforation and provided with a collimated detector of radiation capable of detecting radiation emitted by said radiation source which is indicative of the angular position of said source of radiation relative to said direction of perforation;
rotating said perforator to a selected angular position thereof as determined by radiation emitted by said source and detected by said detector in order to orient said perforator relative to the position of said pipe string in which said source of radiation is arranged; and
then actuating said perforator when said tool is in said selected angular position.
8. A method as recited in claim 7 in which perforation of said pipe string in which said source of radiation is positioned is avoided.
9. A method as recited in claim 7 in which said pipe string in which said source of radiation is positioned is perforated.
10. A method for perforating in a well bore employing a perforator having perforating axes lying in longitudinally extending planes wherein the angular disposition of the planes defines a Zone in which perforations are not produced in one of a plurality of tubing strings in said well bore comprising the steps of:
disposing a detector of radiation in one of said tubing strings with said perforator attached to said detector of radiation;
disposing a radiation source in another of said tubing strings;
obtaining signals from said detector which are representative of energy transmitted between said source and detector and which are indicative of the angular position of said source of radiation relative to the direction of perforation;
simultaneously rotating said perforator and said detector of radiation while obtaining said signals to derive an indication of the rotative positions of said perforator with respect to said other tubing string in which said source of radiation is disposed in accordance with which said perforator may be selectively oriented so that said perforator, when actuated, avoids perforation of said other tubing string;
selectively orienting said perforator; and
then actuating said perforator.
11. Apparatus for perforating in a well bore having arranged therein a plurality of pipe strings comprising:
a rotatable tool provided wtih a perforator having a selected direction of perforation and with a collimated detector of radiation having a selected direction of radiation detection and with means capable of causing rotation of said tool arranged in one of said pipe strings, said direction of perforation and said direction of detection being fixed relative to each other;
a source of radiation arranged in at least one other of said pipe strings;
means at the surface of the earth for indicating the position of said other pipe string containing said source of radiation relative to angular positions of said rotatable tool; and
means for actuating said perforator.
12. Apparatus as recited in claim 11 in which said means capable of causing rotation of said tool includes an electrically operated reversible motor.
13. Apparatus as recited in claim 11 in which said means for indicating the position of said other pipe string relative to angular positions of said rotatable tool includes surface and subsurface arranged selsyn motors.
References Cited UNITED STATES PATENTS 2,781,098 2/1957 Bielstein 16645 2,785,754 3/1957 True 166-45 3,104,709 9/1963 Kenneday et a1 -451 3,154,147 10/1964 Lanmon l66-240 3,165,153 1/1965 Lanmon 1754.51 3,288,210 11/1966 Bryant 166-35 X 3,294,163 12/1966 Lebourg 175-451 X DAVID H. BROWN, Primary Examiner.
U.S. Cl. X.R. 166297, 313; 175-4.51