US 2998068 A
Description (OCR text may contain errors)
Aug. 29, 1961 M. E. TRUE APPARATUS FOR USE IN WELLS 2 Sheets-Sheet 1 Filed Dec. 15, 1958 POWER SOURCE CAM FOLLOWER CAM SURFACE F I G. 4.
FIRING /26 LINE OF FIRE F I G. 6.
DETECTOR INDICATOR Fl G. 2.
INVENTOR. MARTIN E. TRUE DETZECTOR 22 SHlELD--" 23 SOURCE" E Aug. 29, 1961 M. E. TRUE 2,998,068
APPARATUS FOR USE IN WELLS Filed Dec. 15, 1958 2 Sheets-Sheet 2 sums spnme CAM FOLLOWE PATH 0F CAM FOLLOWER GUIDE SPRING POSITION 40 FIG. 5.
INVENTOR. MARTIN E.TRUE,
United States Patent M 2,998,068 APPARATUS FOR USE IN WELLS Martin E. True, Houston, Tex., assignor, by mesne assignments, to Jersey Production Research Company, Tulsa, Okla., a corporation of Delaware Filed Dec. 15, 1958, Ser. No. 780,343 1 Claim. (Cl. 16655) This invention generally concerns multiple zone well operations. More particularly, the invention concerns apparatus for orienting a gun perforator in order to direct the fire thereof in a selected direction.
In multiple Zone well operations, a plurality of pipe strings are arranged in a borehole which penetrates a plurality of productive intervals and production fluids from each interval 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 formation. However, when at least two pipe strings are positioned adjacent the interval to be perforated, it is necessary to direct the fire of the gun perforator in order to avoid striking any one of the pipe strings other than the pipe string through which the gun perforator is run. Also, in well operations whereinthe 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 in certain instances as, for example, when it is necessary to establish subsurface communication between pipe strings during blowouts, workovers, etc.
These purposes are achieved by the present invention which, briefly, provides apparatus for perforating in a well bore penetrating a subsurface formation, said well bore having at least two eccentric, spaced-apart pipe strings arranged therein comprising a gun perforator having a selected direction of fire arranged in one of said pipe strings; means for rotatably positioning said gun perforator to direct the direction of fire thereof in any selected direction in a 360 arc and means for detecting the location of at least one other pipe string relative to the direction of fire in order to avoid perforation of said other pipe string or to perforate said other pipe string which ever procedure is desired.
The invention is advantageous over known devices for positioning the direction of fire of a gun perforator in that the use of gun guides is avoided; it permits maintaining full openings throughout the pipe strings; it eliminates the possibility of incorrect orientation should a pipe string rotate or slip in a clamp or should it be misaligned by error; and it permits running pipe strings in the well bore separately.
These purposes and other purposes of the invention will be apparent from a description thereof taken in conjunction with the drawings 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 the gun perforator, the positioning assembly, and the pipe locator apparatus; also shown schematically is surface equipment for 10- cating pipe and for firing the gun perforator;
FIG. 2 is a vertical, partly sectional, view of the gun perforator positioning assembly of FIG. 1;
FIG. 3 is a plan view taken on lines 3-3 of FIG. 2;
FIG. 4 is a plan view taken on lines 44 of FIG. 2;
FIG. 5 is an enlarged fragmentary view of the gun perforator positioner assembly of FIG. 2;
FIG. 6 is a plan view illustrating one manner of orientation according to the invention when the borehole contains two pipe strings; and
FIG. 7 is a plan view illustrating one manner of lfatented Aug. 29,1961
orientation when the borehole contains more than two pipe strings.
Referring to the drawings in greater detail, in FIG. 1 is shown a borehole 10 penetrating a subsurface formation 11. Two spaced-apart pipe strings 1'2 and 13 are arranged in borehole 10 and are cemented therein by means of cement 14. A perforator tool, generally designated 15, is suspended in pipe string 12 on a multi electrically conductive cable 16. Tool 15 includes a pipe detector section 17, a gun positioner section 18, and a gun perforator section 19. Section '17 includes a source of radiation 20, a radiation detector 21 provided with a collimating shield 22 and a shield 23 positioned therebetween. Section 19 includes gun elements 24 which may be any desired type of gun perforator, such as the jet type or the bullet type. Cable 16 extends to the surface of the earth where it electrically connects to a detector indicator 25, a firing device 26, and a source of power 27.
Details of section 18, shown more clearly in FIG. 2, include a mandrel 28 provided with a cam follower 29; a cage 30 provided with a cam surface 31 and arranged on mandrel 18 in a manner such that cam follower 29 rides on cam surface 31; and drag springs 32 adapted to frictionally engage the interior wall of pipe string 12 to restrain movement of cage 30. As seen more clearly in FIG. 5, the cam surface 31 is configured generally in the form of alternately inverted Ys which extend fully about cage 30 to form a continuous path. For purposes of illustration, the width of each Y is shown to be 60; however, any desired increment of degrees may be employed. Leaf spring guides as, for example, guides 33 to 37 are positioned at various junctures of the path as shown.
FIGS. 3 and 4 illustrate, also, the spacing of the cam surface Ys.
When it is desired to position the direction of fire of gun elements 24 in any desired direction as, for example, to direct the fire thereof to avoid striking pipe string 13, tool 15 is lowered through pipe string 12 until it is positioned adjacent formation 11. Cable 16 then is raised and lowered thereby causing cam follower 29 to travel on cam surface 31. Referring to FIG. 5, starting with cam follower 29 at the position designated 40 raising of cable 16 raises mandrel 28 and attached cam follower 29 and causes the cam follower 29 to travel upwardly in path 41. It is guided past the juncture of paths 41 and 42 by means of leaf spring 34 which is biased against path 42. When cam follower 29 reaches the juncture of paths 41 and 43, it moves past leaf spring 35 against the bias thereof into the upper portion of path 43 until it reaches the upper end thereof. Then, cable 16 is lowered thereby lowering mandrel 28 and attached cam follower 29 and in its downward travel through path 43, leaf spring 35 guides the cam follower by path 41. Cam follower 29 in its downward travel at the juncture of paths 43 and 44 forces leaf spring 36 open against the bias thereof and cam follower 29 is lowered to the lower end of path 44. This manner of raising and lowering of cam follower 29 is continued and a complete 360 revolution or many revolutions may be made. While mandrel 28 is rotated, section 17 and section 19 are also rotated. At any point during the 360 traverse, the collimated detector may be employed to detect induced radiation resulting from the bombardment of the surrounding area by radiation source 20. Shield 22 is designed to restrict the arc of detection to a selected are as, for example, 45. Shield 23 insures that only induced radiation is detected by detector 21. Detector indicator 25 indicates the presence of pipe string 13 when detector 21 is focused thereon. If desired, the bombardment and detection of radiation may be continuously made during the 360 traverse by camfollower 29 to establish the location of pipe string 13 relative to the direction of detection. The direction of detection relative to the direction of fire of gun elements 24 is known. Consequently, the direction of fire of gun elements 24 relative to the position of pipe string 13 is established. The gun perforator may be then rotated by raising and lowering cable 16 until the gun penforator 'is positioned so as to direct the fire of the gun elements 24 away from pipe string 13. A situation of this nature is illustrated in FIG. 6 wherein the direction of fire 50 of gun elements 24 is directed away from pipe string '13.
In a similar manner, other pipe strings may be avoided. This situation is illustrated in FIG. 7 wherein the direction of fire 50 of gun elements 24 is positioned to fire away from both pipe strings 39 and 13.
The particular technique for detecting pipe strings shown and describedwith regard to the operation of the invention may be substituted by other arrangements; for example, the radiation source may be focused instead of or in conjunction with focusing of the detector; the detector may be arranged in the pipe string to be detected; the source may be arranged in the pipe string to be detected; and soforth.
The source of radiation 20 may be fast neutrons or gamma rays. Thus, the source maybe an alpha-neutron, deuteron-neutron, or proton-neutron reaction wherein the alpha particle, deuteron, or proton is accelerated by an electric field and thereby caused to interact with selected target materials in order to produce neutrons of various energies within the confines of source 20; or the radiation may be neutrons originating from a radiumberylliurn or prolonium-beryllium source. Sources of high energy gamma radiation which may be employed are radioactive Na La Sb Co, or high energy gamma rays produced by various reactions in high energy parti-cle machines in a manner well known to the art of nuclear physics. For example, the bombardment of lithium by protons produces high energy 17 mev. gammas.
Detector '20 detects slow neutrons or gamma rays or fast neutrons and for the detection of this radiation ionization chambers, Geiger-Mueller tubes, and scintillation counters may be used.
Shields 22 and 23 are formed ofradiation absorbing materials such as lead, tungsten, paraflim-boron, cadmium, etc., which materials are capable of absorbing the induced radiation to be detected. The invention'is applicable to so-called tubingless completions; that is, wells completed without setting casing. This method, which is illustrated in FIG. 1, includes running the required pipe strings and i cementing the pipe strings in place. The invention may be also employed in cased wells; that is, in wells where a casing is run and cemented in place and pipe strings are arranged Within the casing.
In the instances wherein a plurality of pipe strings are arranged in the borehole to insure that the direction of fire of the gun perforator is away from all of the pipe strings except the one in which the gun perforator is arnanged, it is preferable to direct the fire in only one direction. In instances of this nature, also, instead of having the direction of detection opposite to or other than the direction of fire, it may be preferable to have the direction of detection coincide with the direction of fire.
Although the description of the invention relates to perforating the formation and avoiding striking other pipe strings arranged in the well bore, the invention is not to be so limited; that is, as mentioned previously herein, the invention may be employed for perforating selected pipe strings in the well bore. 7
Having fully described the operation, objects, and apparatus of my invention, I claim:
Apparatus for perforating in a well bore penetrating subsurface formations, said well bore having at least two spaced-apart pipe strings arranged therein comprising a gun perforator having a selected direction of fire arranged in one of said pipe strings; gun perforator positioning means adapted to position said gun perforator to direct the direction of fire thereof in any selected direction in a 360 are including cage means provided with a cam surface configured in the shape of alternately inverted Ys and also provided with means for engaging the interior wall of said one pipe string to restrain movement of said cage means; means connected to said gun perforator and provided with a cam follower adapted to ride on said cam surface; guide means arranged on said cam surface adapted to guide said cam follower to move in only one circumferential direction; and means for detecting the location of at least one other pipe string relative to said direction of fire.
References Cited in the file of this patent- UNITED STATES PATENTS 2,178,540 McNeese et a1 Nov. 7, 1939 2,316,361 Piety Apr. 13, 1943 2,400,970 Baker May 28, 1946 2,429,910 Anderson et al Oct. 28, 1947 2,781,098 Bielstein Feb. 12, 1957 2,785,754 True Mar. 19, 1957