US 3589453 A
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Description (OCR text may contain errors)
United States Patent 2,649,046 8/1953 Davis i.
Inventor Alexis A. Venghlattis Weston. Conn. Appl. No. 755,489 Filed July 26. 1968 Division of Ser. 50. 578.36. Sept. 1966. Pat. No. 3.0532]. Patented June 29. I971 Assignee Dresser Industries Inc. Dallas, Tex.
SHAPED CHARGE PERFORATING APPARATUS AND METHOD 2 Claims, 7 Drawing Figs.
Int. Cl r Field of Search References Cited UNITED STATES PATENTS 2.821,]36 l/l958 Castel l75/455 2,873,676 2/l959 Caldwell... l75/4.6 2,968,243 1/l96l Turechek .v l75/4.6 3,327,792 6/1967 Boop r. l75/4,55 X
Primary Examiner--David H. Brown Atlorneys- Robert W. Mayer. Russell E. Schlorff. Daniel Rubin, Peter J. Murphy, Roy L. Van Winkle and William E. Johnson, Jr.
detonating the charge to simultaneously form the perforation and place the inert particles in the perforation to form a permeable bridge therein.
sum 1 or 2 fll'Em-4 SHAPED CHARGE PERFORATING APPARATUS AND METHOD This is a division of application Ser. No. 578,216, filed Sept. 9, I966 now Pat. No. 3,4l5,32 I.
This invention relates generally to improved methods and apparatus useful in perforating oil and gas wells and the like. More particularly, but not by way of limitation, this invention relates to improved perforating apparatus and methods for completing a well in an unconsolidated formation.
Generally, in the completion of oil and gas wells and the like, an elongated metal casing is positioned in the well bore. Due to the irregularity of the well bore and due to the difference in diameter between the well bore and the metal cas ing, a cementitious material is usually pumped into the annular space. The cementitious material serves to permanently fix the metal casing in the well bore and to prevent migration of well fluids through the annular space. It is obvious that the metal casing and the cementitious material disposed adjacent a productive formation will prevent the flow of fluids from the formation into the interior of the casing. Therefore, the prac tice has been to perforate the casing, cementitious material, and the formation by the use of either shaped charge or bullet perforators. The perforators are lowered into the casing to a position adjacent the productive formation and then fired from the surface through an appropriate electrical circuit.
The aforesaid procedure has been very successful, but a great deal of difficulty has been encountered when the productive formation consists of an unconsolidated sand or similar substance. The particle size of unconsolidated sands will vary between two one-thousandths of an inch and twenty one-thousandths of an inch while the diameter of the perforalion made with the usual perforators will be somewhere between one-fourth and three-fourths of an inch. As is obvious from the foregoing, even the largest sand particles are very small as compared to the smallest diameter of perforation made by conventional perforating apparatus. Thus, as well Fluids are produced through the perforation into the interior of the casing, said particles will, more than likely, be produced therewith. If a sufficient quantity of sand is produced into the :asing, the sand may accumulate therein and completely alock the production of well fluids or if pumping or valve apaaratus is disposed in the well, the sand may have a serious :rosive effect thereon.
One attempt made to solve the foregoing problem utilizes in array of very small bullet perforators fired simultaneously n a prearranged pattern. Although the perforations made are no large in diameter to be useful in preventing the migration )f sand into the casing, the bullets will, when fired into friable :ementitious material, shatter the cementitious material formng a permeable bridge in the perforations to inhibit the migraion of the unconsolidated sand.
Another attempted solution involves the use of shaped :harges constructed to provide small diameter perforations. lowever, the diameter of the perforations are still sufficiently arge so that they do not effectively inhibit the flow of sand nto the casing. Unlike the bullet perforators, the shaped :harges form a clean hole or perforation and do not shatter he cementitious material even when the material is friable. :herefore, small perforations formed by shaped charges have lot been effective to inhibit the flow of sand into the casing.
Very often in the completion of wells, a relatively small liameter production tubing will be run within the casing. 'ackers, of a type well known in the well tool art, or other imilar apparatus, are usually utilized to hold the tubing in the asing and to prevent the flow of fluid through the annular pace between the tubing and casing. In such instances, the erforating apparatus must be run through the tubing prior to caching the zone to be perforated. Usually, the tubing terrinates above the producing formation so that the perforating pparatus is disposed within the relatively large diameter of he casing when the perforator is tired.
To make the most efficient use of perforators, it is highly desirable to be able to control the distance from the shaped charge or bullet to the casing, that is, to control the standoff. Manifestly, perforating apparatus small enough to be run through the tubing will have a considerable standoff when located in the casing and will not provide the optimum conditions for firing the bullets or shaped charges to perform the perforating operation in the most efficient manner.
SUMMARY OF THE INVENTION Generally, this invention provides improved perforating apparatus including a carrier arranged to be moved through the well bore; a plurality of shaped charges carried by the carrier, each charge being oriented in a direction whereby the detonation thereof forms an explosive jet that perforates the formation, each charge including a plurality of inert particles arranged to be carried into the perforations forming a permea ble bridge therein; and, ignition means for detonating the charges.
In another aspect, this invention contemplates the construc tion of a shaped charge that includes a plurality of inert particles that are carried into the perforation and that are sized and shaped to form a permeable bridge therein.
Also, this invention provides a collapsible carrier whereby shaped charges may be lowered through relatively small diameter tubing and positioned in relatively larger diameter casing for efficiently performing the perforating operation. Additionally, this invention contemplates the construction of another carrier for the shaped charges that includes a member constructed from sheet explosive that holds an array of charges and provides for their simultaneous detonation.
One object of the invention is to provide an improved method of completing a well in an unconsolidated formation wherein permeable bridges are formed in the perforations to inhibit the migration of sand therethrough.
Another object of the invention is to provide an improved perforating apparatus wherein a selected array of shaped charges may be simultaneously detonated from a plurality of such arrays.
Still another object of the invention is to provide an improved perforating apparatus arranged to form relatively small diameter perforations and to form permeable bridges therein.
The foregoing and additional objects and advantages of the invention will become more apparent as the following detailed description is read in conjunction with the accompanying drawings wherein like reference characters denote like parts in all views and wherein:
FIG. l is a cross-sectional view of a shaped charge constructed in accordance with the invention;
FIG. 2 is a cross-sectional view similar to FIG. 1, but illustrating another embodiment of shaped charge also constructed in accordance with the invention;
FIG. 3 is a vertical cross-sectional view illustrating perforating apparatus constructed in accordance with the invention disposed in a cased well bore;
FIG. 4 is a cross-sectional view taken substantially along the line 4-4 of FIG. 3;
FIG. 5 is an elevational view of another embodiment of perforating apparatus also constructed in accordance with the in- SHAPED CHARGE Referring to the drawing and to FIG. 1 in particular, shown therein and generally designated by the reference character 10 is a shaped charge constructed in accordance with the invention. The shaped charge it] includes a hollow body l2, an
explosive material l4 partly filling the interior of the hollow body l2, and a cap 16 closing one end of the hollow body l2.
The explosive material l4 has a conical cavity 18 in the end thereof adjacent the cap l6. A liner 20, which is also of conical configuration, is located in the hollow body 12 in jux taposition with the surface of the explosive material 14 forming the cavity 18. The liner 20 may be constructed from rela tively thin sheet metal, but is preferably constructed from a granular metal as disclosed in U.S. Pat. No. 3,255,659 issued on June I4, 1966 to Alexis A. Venghiattis.
A plurality of particles 21 are located between the surface of the explosive material l4 and the liner 20. The particles 2] are preferably formed from an inert material and preferably have at least one dimension that is not less than one-half the diameter of the perforation that is formed upon detonation of the shaped charge [0.
FIG. 2 illustrates another embodiment of shaped charge generally designated by the reference character 22. The shaped charge 22 includes the previously described hollow body 12 and explosive material 14. One end of the hollow body 12 is closed by a cap 24, which is constructed similarly to the cap 16 but, as is apparent from a comparison of P165 I and 2, is more elongated to provide additional standoff for thrshaped charge 22 for reasons that will he explained more full; hereinafter.
The opposite end of the hollow body 12 is closed by a seal ing cover 26. The sealing cover 26 is optional, but its use is preferred when the shaped charge 22 is used in open or capsule type carriers wherein the explosive material 14 would otherwise be exposed to well fluids.
As illustrated in FIG. 2, the shaped charge 22 also includes the conically shaped cavity 18 that is formed in the explosive material 14 and a conical liner 28 disposed in juxtaposition therewith. A plurality of particles 30 are disposed in the liner 28. As previously mentionedwith respect to the liner 20, the liner 28 is preferably formed as taught in U.S. Pat. No. 3,255,659.
As will be understood by those skilled in the art of shaped charges, the conical cavity 18 in the charges 10 and 22 produces the so-called Munroe effect upon detonation that results in a high energy jet of sufficient energy magnitude to form perforations. Preferably, the shaped charges 10 and 22 are of a size that will result in the formation of a perforation having an average diameter of 0.050 inches. The particles 2] and 30 in the shaped charges 10 and 22, respectively, are ar ranged to be carried into the perforation formed by the charges and are of such size and shape that they will form a permeable bridge therein for reasons that will be discussed.
PERFORATING APPARATUS OF FIG. 3
FIG. 3 illustrates perforating apparatus generally designated by the reference character 32 and disposed in a casing 34. As shOwn therein, the casing 34 is located in a well bore 36 and is retained therein by cementitious material 38 disposed in the annular space between the wall of the well bore 36 and the exterior ofthe casing 34.
The lower end of a relatively small diameter tubing 40 is il lustratcd as bein disposed within the casing 34. The tubing 40 is retained in a central position in the casing 34 by a packer 42 that also serves to prevent the flow of fluid through the annu- In space between the tubing 40 and the casing 34.
The perforating apparatus 32 is suspended in the casing 34 on a wire line or cable 44 that extends upwardly through the tubing 40 to the surface (not shown) of the well bore 36. The cable 44 has sufficient mechanical strength to support the perforating apparatus 32 and also contains the necessary electrical conductors (not shown). The lower end of the cable 44 is connected to an adapter 46 that forms the upper end of the perforating apparatus 32.
The perforating apparatus 32 also includes a pair of shaped charge holding members 48 that are disposed in generally parallel spaced relationship and extend substantially parallel to the longitudinal axis of the casing 34. The upper end of each of the shaped charge holding members 48 is connected by a hinge 50 with a linkage member 52. The opposite end of each of the linkage members 52 is connected by a hinge 54 with the adapter 46.
The lower end of each of the shaped charge holding members 48 is connected by a hinge 56 with a linkage member 58. The lower ends of the linkage members 58 are pivotally joined by a hinge 60. The hinged connecting structure joining the shaped charge holding members 48 provides an articulated linkage wherein the shaped charge holding members 48 can move relatively together and relatively apart in substantially parallel relationship.
A spring 62 is illustrated as being connected with the adapter 46 and having its free end portions in engagement with the linkage members 52. The spring 62 constantly biases the linkage members 52 and the holding members 48 relatively apart.
Similarly, a spring 64 encircles the hinge 60 and has its free end portions in engagement with the linkages 58. The spring 64 serves to bias the linkages 58 and the holding members 48 relatively apart thus maintaining the shaped charge holding members 48 in substantially spaced, parallel relationship As illustrated in HQ. 3 and also n FIG. 4 the shaped charge holding members 48 each includes a plurality of he shaped charges 22 Manifestly, the shaped charge 10 could be utilized in lieu of shaped charge 22 as could any of the well-known constructions of shaped charge. Preferably, the shaped charges used include a sealing cover, such as the cover 26 shown in FIG. 2, so that the explosive material 14 will not come into contact with fluids in the well bore 36.
The shaped charges 22 are each connected with some means for detonating the shaped charges. For example, FIGS, 3 and 4 illustrate a primacord 66 connecting each of the charges 22 with a respective one of a pair of boosters 68 and detonators 70. The detonators 70 are connected with wires 72 that extend upwardly through the adapter 46 and the cable 44 to a source of electrical energy (not shown) located on the surface (not shown) adjacent the upper end of the well bore 36, As is well known, electric current passing through the conductors 72 ignites the detonators 70, boosters t8 and the in terconnected primacord 66. Manifestly, the ignition of thc primacord 66 detonates the shaped charges 22 essentially simultaneously due to the high explosive nature of the prim :icorrt 66 OPERATION OF THE EMBODIMENT OF FIG. 3
To utilize the perforating apparatus 32, the shaped charges 22 are disposed in the shaped charge holding members 48 in accordance with the desired perforation pattern and number of perforations to be formed. The adapter 46 is connected with the cable 44 and the perforating apparatus 32 is then extended into the tubing 40. As will be apparent from viewing FIG. 3, the holding members 48 are moved relatively together, compressing the springs 62 and 64 to permit the insertion of the apparatus 32 into the relatively srnal. diameter tubing 40.
The apparatus 32 is then lowered through the tubing -1-6. passing through the open end thereof into the relatively larger diameter casing 34. When the apparatus 32 is disposed adjacent the formation to be perforated, its downward movement is arrested and the apparatus 32 is suspended on the cable 44 in the well bore 36. The conductors 72 are then energized igniting the detonators 70, boosters 68 and the primacord 66. When the primacord 66 dctonates, the shaped charges 22 are simultaneously detonated to form a plurality of perforations 74 as illustrated in F168. 3 and 4.
As the shaped charges 22 detonate, the perforations 74 are formed through the casing 34, the cementitious material 38, and extend into the formation surrounding the well bore 36. Simultaneously, the inert particles 30 are carried into the perforations 74 as illustrated in FIG. 4, forming permeable bridges therein to prevent or at least to inhibit the migration of unconsolidated materials from the formation through the perforations 74 into the interior of the casing 34.
Generally, detonation of the shaped charges 22 disintegrates a large portion of the shaped charge holding members 48 dropping the linkages 58 into the lower portion of the well bore 36. For this reason, the linkage members 52 and 58 and the shaped charge holding members 48 are preferably constructed from a material that is easily drillable, such as alu minum, or one of the plastics. After the detonation of the shaped charges 22, the portion of the apparatus 32 remaining intact can be retrieved from the well bore 36 by withdrawing the cable 44 therefrom as is well known in the art.
it should be evident from the foregoing that utilizing the relatively small shaped charges 22 permits their close spacing in the holding members 48 whereby the formation is perforated by a large number of relatively small perforations 74, that is, the formation is saturated with small diameter perforations 74 whereby a flow area of relatively large size is obtained. it will also be noted, that the shaped charges 22 are properly positioned relative to the casing 34, that is, they will have the desired standofi to perform the perforating operation in the most efficient manner due to the preselected length of the cap 24 (see FIG. 2)v Thus, while the shaped charges 22 form relatively clean perforations 74, the perforating apparatus 32 is effective in unconsolidated formations to form the desired perforations while inhibiting the flow of sand from such formations due to the permeable bridge formed by the inert particles 30,
PERFORATING APPARATUS OF FIG. 5
FIG. 5 illustrates another embodiment of perforating apparatus generally designated by the reference character 100. As shown therein, the perforating apparatus 100 is suspended in a well bore 102 on a cable 104. The cable 104 includes members of sufficient structuralstrength to support the per forating apparatus 100 as well as including the necessary electrical conductors for detonating the perforating apparatus 100 as will be described.
The perforating apparatus 100 also includes an adapter 106 that is connected with the cable 104 and a selective ignition control device 108 that is constructed as described in U.S, Pat. No. 3,221,655 issued Dec. 7, 1965 to Alexis A. Venghiattis. Connected with the lower end of the selective ignition control means 108 is a plurality of identically constructed shaped charge carriers 110.
As is evident from viewing HO. 5, the shaped charge carriers 110 are arranged in end-to-end relationship. The number of shaped charge carriers 110 utilized depends upon the number and concentration of perforations desired. Manifestly, and although not illustrated, spacers can be utilized between the shaped charge carriers 110 to provide any desired spacing.
FIG. 6 illustrates in more detail the construction of the shaped charge carriers 110. As shown therein, each of the shaped charge carriers 110 includes a tubular housing 112 having a closed upper end 114 and a threaded lower end 116. A plug 118 is threaded into the lower end 116 of the housing 112 thereby closing the lower end 116 thereof. The upper end 114 of the tubular housing 112 is partially threaded as shown at 120 to receive the plug 118 forming a portion of the adjacent shaped charge carrier 110.
The tubular housing 112 is provided with a plurality of apertures 122 that extend through the wall thereof. Closure members 124 are pressed into the apertures 122 to close the apertures 122 against the entrance of well fluids. The tubular housing 112 is constructed to withstand the pressures encountered within the well bore 102.
A cylindrical shaped charge holding member 126 is disposed substantially coaxially within the tubular housing 112 with its upper end abutting the end 114 of the housing 112 and is lower end abutting the plug 118. The cylindrical holding member 126 is provided with a slot 128 for receiving one end of a partially threaded pin 130 to align the chai'ge holding member 126 in the housing 112 for reasons that will be described. The partially threaded pin extends through the wall ofthe tubular housing 112 and into the slot 128 as shown.
A plurality of shaped charges 10 are located in the holding member 126 and each is aligned with a respective one of the apertures 122. The alignment of the shaped charges 10 with the apertures 122 is assured by the relationship of the slot 128 and the partially threaded pin 130.
As illustrated in the upper portion of FIG. 6, electrical conductors 132 and 134 extend through an opening 136 formed in the sidewall of the tubular housing 112. The opening 136 is provided to protect the electrical conductors from damage as the perforating tool 100 passes through the well bore 1027 The conductor 132 extends through the wall of the tubular housing 112 and is connected with a detonator and boaster 138 which is in turn connected with a primacord 140, The primacord 140 is connected with each of the shaped charges 10 within a single carrier 110 whereby all the shaped charges 10 contained therein will be simultaneously detonated.
As shown in the lower portion of FIG. 6, the conductor 134 extends through the tubular housing 112 of the subjacent carrier 110 and, although not shown, will be connected to the shaped charges therein as previously described. It will of course to be understood that the electrical conductors 132 and 134 are electrically interconnected with the electrical conductors (not shown) contained in the cable 104 and extend to the surface (not shown) adjacent the well bore 102 wherein they will be connected to a source of electrical poten tial (not shown).
OPERATION OF THE PERFORATINO APPARATUS OF FIG. 5
The perforating apparatus 100 is lowered into the well bore 102 on the cable 104 until it is adjacent the formation or zone to be perforated. When the zone to be perforated is reached, the perforating apparatus 100 is suspended by the cable 104 and the downward movement thereof terminated,
One of the conductors, conductor 132 for example, is energized through the selective ignition control 108 as described in the previously mentioned Venghiattis U.S. Pat. No. 3,22 l ,655 to detonate the shaped charges 10 contained in the interconnected shaped charge carrier 110. It should be emphasized that only the shaped charges 10 in the selected carrier 110 will be detonated.
When the shaped charges 10 detonate, the explosive jet formed thereby perforates the cover 124 and extends into the formation forming the number and arrangement of perforations therein as predetermined by the number and distribution of charges in the carrier 110. Manifestly, the perforating apparatus 100 may also be used in cased and cemented wells as previously described in connection with the perforating apparatus 32.
After the shaped charges 10 have been detonated in a selected one of the carriers 110, the remaining carriers 110 may be actuated to detonate the shaped charges 10 contained therein or the perforating apparatus 100 may be raised or lowered to a different formation prior to the detonation of the shaped charges in each of the carriers 110.
As will be understood from the foregoing detailed description of the shaped charges 10, they are very small and are capable of forming relatively small perforations whereby a large number of the shaped charges 10 may be contained within a single carrier 110. Thus, the formation adjacent the shaped charge carrier 110 will be saturated with relatively small perforations formed by the shaped charges 10.
FIG. 7 illustrates a modification of the shaped charge apparatus 100. More specifically, FIG. 7 illustrates a shaped charge holding member, designated by the reference character 150, that can be utilized in lieu of the shaped charge holding member 126.
Although only a portion of the cylindrical charge holding member is illustrated it will be understood that it will extend the full length of the tubular housing 112 as did the holding member 120. The shaped charge holding member 150 is constructed from a sheet explosive and thereby eliminates the necessity for the primacord 140 illustrated in FIG. 6.
It will be noted in FIG. 7 that the conductor I32 and the detonator and booster 138 are connected directly to the holding member 150. The shaped charges 10 are planted directly in the holding member [50 and are arranged to be simultaneously detonated thereby upon detonation of the detonator and booster I38.
Manifestly, the operation of the perforating apparatus with the shaped charge holding member 150 therein will be substantially the same as with the shaped charge holding member [26 therein. The charge holding member 150 has the advantage of eliminating the necessity for interconnecting the shaped charges 10 with the primacord 140. Thus, there is less chance of detonation failure when using the holding member 150.
It will also be understood that the perforating apparatus 100 utilizing either the shaped charge holding member 126 or the shaped charge holding member 150 can be effectively utilized to perforate unconsolidated sands as previously described in connection with the perforating apparatus 32. The shaped charges 10 also include the inert particles 21 (see FIG 1) so that the perforation formed thereby will also include a permeable bridge to inhibit the flow of sand through the perforations it will be understood that the embodiments described in detail hereinbefore are presented by way of example only and many changes and modifications can be made thereto without departing from the spirit of the invention or from the scope of the annexed claims.
What I claim is:
l. Perforating apparatus for use in completing a well com prising:
a tubular housing having an upper closed end, a lower closed end. and a plurality of apertures extending transversely through the wall of said housing;
closure means closing each of said apertures;
a plurality of shaped charges located in said housing;
generally cylindrical-shaped charge holding means located substantially coaxially in said housing and holding each said shaped charge in alignment with a respective one of said apertures; and
ignition means extending into said housing for detonating said charges;
said holding means being constructed from a sheet explosive; and
said ignition means extending into said housing and being connected with said sheet explosive.
2. Perforating apparatus for use in completing a well comprising:
a plurality of tubular housings, each said housing having upper and lower closed ends and a plurality of apertures extending through the wall thereof, said housings being connected in end-to-end relationship;
closure means closing each said aperture;
a plurality of shaped charges disposed in each said housing;
a generally cylindrical-shaped charge holding member located substantially coaxially in each said housing holding each said charge in alignment with a respective aperture;
selective ignition control means connected with one of said housings; and,
ignition means connecting said control means with said charges, whereby the shaped charges located in a selected housing are simultaneously detonated,
said holding means being constructed from a sheet explosive and being operably connected with said ignition means.