US3022729A

US3022729A - Apparatus for drilling boreholes with explosive charges

Info

Publication number: US3022729A
Application number: US855616A
Authority: US
Inventors: Jr Leon Haynsworth Robinson
Original assignee: Jersey Production Research Co
Current assignee: Jersey Production Research Co
Priority date: 1959-11-27
Filing date: 1959-11-27
Publication date: 1962-02-27
Anticipated expiration: 1979-02-27

Description

Feb. 27, 1962 L. H. ROBINSON, JR 3,022,729

APPARATUS FOR DRILLING BOREHOLES WITH EXPLOSIVE CHARGES Filed Nov. 27, 1959 2 Sheets$heet 1 .Z JJMLM ATTORNEY.

Feb. 27, 1962 L. H. ROBINSON, JR

APPARATUS FOR DRILLING BOREHOLES WITH EXPLOSIVE CHARGES 2 Sheets-Sheet 2 FIG.?

Filed Nov. 27, 1959,

FIG.3.

FIG.4.

ATTORNEY- INVENTOR. L EON H. ROBINSON JR t I I I I I I I I I i I static pressure of at least 1000 p.s.i.

United States Patent 3,022,729 APPARATUS FOR DRILLING BOREHOLES WITH EXPLOSIVE CHARGES Leon Haynsworth Robinson, In, Houston, Tex., assignor, by mesne assignments, to Jersey Production Research Company, Tulsa, 01th., a corporation of Delaware Filed Nov. 27, 1959, Ser. No. 855,616 4 Claims. (Cl. 102-20) This invention relates to the drilling of boreholes, and more particularly to drilling boreholes utilizing a succession of explosive charges including shaped jet charges.

In connection with drilling boreholes for the purpose of exploiting possible hydrocarbon deposits in the earth, it has been known to utilize explosive charges for the purpose of expediting drilling operations. It has also been known to use shaped jet charges in combination with nondirectional'blasting charges. Examples of the prior art use of explosive charges for drilling operations may be found in US. Patent No. 2,897,756 to L. Borins et al. and U.S. Patent No. 2,587,243 to W. Sweetman.

Previous attempts to use explosive charges for earth drilling have been characterized by very slow penetration rates, great expense, and the necessity for using more or less cumbersome equipment. While the development of shaped jet charges has made the use of explosives for drilling more attractive because of the directional characteristics of the shaped charge, it has not proved to be a cure-all for the deficiencies of explosive drilling. A prime reason is that, while the shaped charge is capaable of penetrating further into the earth than can a nondirectional explosive charge, it blasts a hole that is quite wide at its mouth but which narrows rapidly and terminates in an elongated cavity that is far too narrow to accommodate a well or drill pipe. The use of blasting charges in the manner taught by the aforecited Borins et al. patent has not particularly helped the situation because the blasting charges do not deepen orwiden the hole drilled by the shaped charge to any great extent.

The present invention makes use of a well pipe having a landing seat or nipple at or near its lower end. The well pipe is connected to conventional mud circulating equipment at the surface so that drilling fluid is pumped down the well pipe and up the annulus around the well pipe. Use is made of elongated shaped jet charges and elongated non-directional gauging charges adapted to be pumped down the well pipe, and further adapted to seat on the landing nipple or seat so that a differential pressure is built up thereacross.

The jet charges and gauging charges are injected into the stream of drilling fluid going down the well pipe, according to a predetermined sequence. First, a shaped charge is pumped down the well pipe. After it seats on the landing seat, the explosive portion of the jet charge is spaced from the bottom of the borehole a predetermined distance, and a pressure of predetermined magnitude is built up across the shaped charge. Responsive to differential pressure, the charge is detonated so as to blast a hole in the earth at the bottom of the well bore. A gauging charge is then landed on the seat so as to extend into the hole produced by the preceding shaped jet charge. Preferably, the gauging charge is long enough to penetrate substantially the entire length of the hole blasted by the shaped charge. The gauging charge, which may be of a brisant or unbrisant explosive material or a combination thereof, is detonated while tamped with drilling fluid and preferably while under a hydro- Drilling fluid is circulated after each detonation of a shaped charge and a gauging charge so as to remove earth fragments and fragments of the explosive charge housing. Preferably,

3,022,729 Patented Feb. 27, 1962 "ice '2 so as to be spaced apart substantially 100 to 4000 feet, and the drilling fluid is circulated so that particles therein are traveling at the rate of between 100 and 400 feet per minute so that the successive explosive charges are detonated between 1 and 10 minutes apart.

The invention will be more completely understood, and the various objects and features of the invention will become apparent upon consideration of the following description thereof when taken in connection with the accompanying drawings, wherein:

FIG. 1 is a perspective diagram of a portion of equipment that may be used at the earths surface in connection with the practice of the invention;

FIG. 2 is a view of a shaped jet charge being pumped I down a well pipe, showing a preferred construction of the lower end of the well pipe;

FIG. 3 is a side view, partially in cross-section, of a preferred jet charge capsule to be used in connection with the invention;

FIG. 4 shows certain details of the firing collar shown in FIG. 3;

FIG. 5 is a side view of a portion of the firing collar of FIG. 3;

FIG. 6 is a cross-sectional view showing the differential pressure responsive firing mechanism shown in FIG. 3;

FIG. 7 is a side view, partially in crossectic; of a gauging charge to be used in connection with the present invention.

In FIG. 1 there is shown surface equipment for use in connection with the present invention. The usual drilling rig 1 is provided with an explosive charge loader's platform 3 at a distance above the drilling floor 20 determined by the length of well or drill pipe to be run into the hole to be drilled with the apparatus. An explosive charge housing 5 for storing explosive charges is located on the loaders platform 3.

The usual traveling block 9 is suspended from a crown block (not shown) by cables in the usual manner. Lo-

- cated between the swivel 19 and book 10 is an explosive the explosive charges are injected into the drilling stream charge magazine housing 17. Connected to swivel 19 is a Kelly joint 18 which extends through the rotary table 21 into the surface casing 25. The function of the magazine housing is to provide remotely controlled apparatus for injecting a plurality of explosive charges into the well according to a predetermined sequence. Drilling fluid is circulated through the magazine housing 17 into the swivel l9 and Kelly joint 18 from the usual standpipe 15 and hose connection 13. A mud pump (not shown) supplies pressurized drilling fluid to the standpipe. Below the drilling floor 20 is located the usual mud return line 27 which may be controlled by a valve 29. The mud control line is hydraulically coupled to the annular space around the drill pipe in the usual manner.

As shown most perspicuously in FIG. 2, the drill or well pipe 28 is provided with a landing seat 31 at or near its lower end. The purpose of this landing seat is to receive a collar 45 fitted around an explosive charge 33 which is pumped down the well. When the collar 45 lands on the seat 31, flow of drilling fluid down through and out the lower end of the well pipe will be either stopped or substantially reduced so that a diflerential pressure will be built up across the explosive charge. As will be described in detail below, difierential pressure is used for the purpose of firing the explosive charge.

The details of the explosive charge magazine housing 17 are described in copending application Serial No. 855,681 of L. H. Robinson and R. H. Friedman, filed concurrently herewith.

FIGS. 3, 4, 5, and 6 illustrate a preferred embodiment for the shaped jet charge, its container, and the firing collar illustrated'in FIG. 2. As shown in FIG. 3, the brisant explosive charge material 43 is encapsulated in a housing or container 33 along with the usual booster charge 41 and detonator 39. In addition, there is provided a firing mechanism 37 for the purpose of firing the detonator 39 responsive to a predetermined differential pressure across the opposed ends of the explosive charge container. The details of the firing mechanism will be described below with reference to FIG. 6. Inasmuch as the use of a shaped jet charge is contemplated, the usual conical liner 47 is provided. At the upper and lower ends of the container 33 there are provided

stop members

35 and 49. The purpose of the stop members is to hold a seating ring or firing collar 45 on the charge container. The firing collar is longitudinally slidable along housing 33 and has a tapered lower surface for the purpose of seating on the seat 31 at the bottom of the drill pipe so that a differential pressure can be produced across the charge. A frangible sleeve 46 is attached to the upper end of collar 45 by a suitable adhesive, the sleeve 46 serving to keep the collar 45 properly aligned on the housing 33. The details of the firing collar are best illustrated in FIGS. 4 and 5. The firing collar is formed of

members

53 and 55 and locking

members

57 and 59. The purpose of the locking members is to prevent the firing collar from coming apart before the charge is fired and to permit the firing collar to collapse inwardly when the container is destroyed by firing the charge. As shown in FIG. 5, the outer edges of the locking members have a V shape so that they will not drop away from the

members

53 and 55 when in locking engagement therewith.

The details of the firing mechanism are shown in FIG. 6. The firing mechanism includes a housing 63 having an inlet tube 64 open to borehole pressure, and an outlet tube 73 opening into a low pressure tube 77. The low pressure tube 77 extends the length of the shaped charge container to the bottom of the container so that it is exposed to the pressure outside of the drill pipe when the firing collar 45 is seated on seat 31. The outlet tube 73 extends into the interior of the housing 63. A flexible, resilient diaphragm 61 of rubber-like material such as neoprene seals the inlet tube 64. A similar diaphragm 75 seals the outlet tube 73. The interior of the housing 63 thus is fluid-tight and is filled with water, glycerin, or other suitable, substantially incompressible liquid. A release collar 65 is in sliding fit over the tube 73. A spring 71 normally biases the release collar 65 away from the tube 73 so that it engages the tube 64 of the inlet port. A firing pin 67 is pivoted about a pivot member 69 and is springbiased by means of spring 68 to rotate counterclockwise as shown in FIG. 6. The firing pin will be released when release collar 71 is moved to the right so as to strike detonator 39 at one end of its are of movement. The release collar is moved to the right when a sufficiently large differential pressure exists between the inlet tube 64 and the low pressure tube 77. The differential pressure will cause diaphragm 61 to bulge downwardly into the housing 63 so as to force the release collar to the right and release the firing pin 67 so that it will strike the detonator 39.

The

diaphragms

61 and 75 are not absolutely necessary, but serve to keep clean fluid around the working parts of the firing mechanism. This is desirable to insure that the firing mechanism will function properly.

FIG. 7 illustrates a gauging charge particularly adapted for use with the present invention. The gauging charge comprises a housing 78 similar to the housing used with the shaped charge. A firing collar 45a is provided that is similar to firing collar 45. A frangible sleeve 46a is also attached to the collar 45a. The firing mechanism 37a may be substantially the same as firing mechanism 37. A low pressure tube 77a extends from the firing mechanism 37a to the lower end of the charge container in the same manner as described above with respect to low pressure tube 77. A substantial section of the lower portion of the container is filled with a brisant or unbrisant explosive material or a mixture of brisant and unbrisant explosives. There is no conical liner provided with the device so that the explosive effects of the gauging charge are substantially nondirectional. A stop is provided above the topmost level of the explosive so that firing collar 45a will land on seat 31 in such a manner that the topmost level of the explosive charge will be spaced from the bottom of the well pipe. The housing 78 is also provided with an upper stop 84. This construction is for the purpose of preventing damage to the well pipe when the explosive charge is detonated. The container may be formed of a frangible material so as to be destroyed easily. The blasting cap 79, when struck by firing pin 67, will be detonated and will ignite a length of primacord 81. To facilitate destruction of the container, the primacord may be wound in a spiral around the inner surface of the container. Also, an auxiliary disintegrating charge 83a of tetryl or like material may be used to complete the destruction of the container. The container may be formed of a plastic material. A particularly suitable explosive for use in connection with the gauging charge is PETN or composition B (RDX and TNT). Other suitable explosives may be found on page 4 of the text The Science of High Explosives by M. A. Cook (Reinhold Publishing Company, 1958). The length of the lower end of the container 78 containing the explosive preferably is long enough to extend substantially the length of the hole blasted by the shaped charge.

The operation of the apparatus described in FIGS. 1 through 7 is as follows. Before the apparatus described above is used, a borehole may be drilled in the earth through the relatively soft earth formations near the earths surfaces by means of conventional rotary drilling equipment. Alternatively, the apparatus described above may be utilized from the time that the well is spudded. However, it usually will be found to be more economical to use a rotary drilling procedure for the initial stages of drilling the borehole until relatively hard earth formations are encountered.

When a hole has been drilled to a desired depth in the conventional manner, the rotary drill pipe may be pulled out of the hole and a thinner walled pipe 28 such as shown in FIG. 2 may be substituted therefor. An advantage associated with utilizing thinner walled pipe is that larger explosive charges can be run down the pipe. The lower stand of the pipe may be provided with reamer blades 28a for the purpose of reaming the hole should such become necessary. Likewise, the lowermost edge of the pipe may be studded with diamonds to rotary-drill for short time intervals should relatively soft earth formations be encountered.

Initially, a shaped charge 33 from magazine housing 17 is injected into the drilling fluid stream. At intervals of approximately 1 to 10 minutes, the driller may inject the other charges from the magazine housing 17 into the fluid stream. When a shaped charge is seated at the bottom of the well pipe, manifestly the differential pressure across the shaped charge will detonate the charge as described above. An elongated tapered hole will be produced. Drilling fluid circulation will continue so that detritus including earth fragments, fragments of the shaped charge container, and fragments of the firing collar 45 will be circulated up the annulus around the well pipe.

One or more gauging charges are landed in succession at the bottom of the pipe after each shaped charge. It will be found that one gauging charge is sufficient to enlarge the entire hole to a desired diameter. As mentioned above, the gauging charges should extend substantially to the bottom of the hole formed by the jet charge. Collar 45a, inasmuch as it is slidable along at least a portion of the gauging charge container, will readily seat on the seat 31 so that a differential pressure will build up to detonate the gauging charge. Manifestly, the gauging charge will be tamped; a hydrostatic pressure of at least 1000 psi. will be exerted thereon. When a gauging charge is detonated, it will be found that an almost perfect cylindrical hole will be blasted into the earth formations by the gauging charge. The hole will be amazingly uniform in diameter and will be of a sulficiently large diameter so that the well pipe 28 may be lowered to the depth of the hole blasted by the shaped charge 33. It will be found that. by virtue of the fact that the gauging charge is tamped and under hydrostatic pressure, the volume of earth that is spalled by the gauging charge will be between 50 and 100 percent greater than when the explosive charge is not tamped and is not under hydrostatic pressure. A hydrostatic pressure of at least 1000 pounds has been found to be satisfactory. Much higher hydrostatic pressures may be utilized with the effectiveness of the gauging charge increasing as the hydrostatic pressure is increased. Detritus produced by the gauging charge may be circulated out of the hole formed as described above, as the well pipe is lowered.

The invention is not to be restricted to the specific structural details, arrangement of parts, or circuit connections herein set forth, as various modifications thereof may be efl'ected without departing from the spirit and scope of this invention.

What is claimed is:

1. An explosive charge capsule for injection into a well pipe having a seating surface at the lower end thereof, comprising: an elongated housing having a compartment for an explosive charge material; an annular seating ring slidably afiixed to the elongated housing and longitudinally slidable along the housing, adapted to seat on the seating surface of the well pipe to substantially seal the well pipe against fluid flow downwardly therethrough; a firing apparatus enclosure in said capsule; an inlet line hydraulically coupling the exterior of the upper portion of the capsule to the interior of the enclosure; an outlet line extending into said enclosure hydraulically coupling the interior of said enclosure to the exterior of the lower portion of said capsule; a sleeve in said enclosure slidably fitting over the end of said outlet line, and having a closed end; a coil spring within said sleeve biasing the closed end of said sleeve away from the end of said outlet line within said enclosure, yieldable under differential pressure between said outlet line and said inlet line so that the closed end of said sleeve slides toward said end of said outlet line; first and second resilient diaphragms respectively sealing the interior of said inlet line and the interior of said outlet line so that said enclosure is fluidtight; a substantially incompressible fluid within said enclosure; a detonating charge extending into said enclosure and into said compartment for detonating explosive material within said compartment; a firing pin pivotally supported within said enclosure positioned to strike said detonating charge at one end of its arc of movement, said firing pin being positioned relative to said sleeve so that said sleeve prevents rotationof said firing pin toward said one end of its are of movement from the other end of its arc of movement until a predetermined difierential pressure between said inlet line and said outlet line moves said sleeve a predetermined distance toward said end of said outlet line; and spring means biasing said firing pin for pivotal movement to engage said sleeve and strike said firing pin.

2. An explosive charge capsule for injection into a well pipe having a seating surface at the lower end thereof, comprising: an elongated housing having a compartment for an explosive charge material; an annular seating ring slidably afiixed to the elongated housing and longitudinally slidable along the housing, adapted to seat on the seating surface of the well pipe to substantially seal the well pipe against fluid flow downwardly therethrough; a firing apparatus enclosure in said capsule; an inlet line hydraulically coupling the exterior of the upper portion of the capsule to the interior of the enclosure; an outlet line extending into said enclosure hydraulically coupling the interior of said enclosure to the exterior of the lower portron of said capsule; a sleeve in said enclosure slidably fitting over the end of said outlet line, and having a closed end; a coil spring within said sleeve biasing the closed end of said sleeve away from the end of said outlet line within said enclosure, yieldable under difierential pressure between said outlet line and said inlet line so that the closed end of said sleeve slides toward said end of said outlet line; a detonating charge extending into said enclosure and into said compartment for detonating explosive material within said compartment; a firing pin pivotally supported within said enclosure positioned to strike said detonating charge at one end of its are of movement, said firing pin being positioned relative to said sleeve so that said sleeve prevents rotation of said firing pin toward said one end of its arc of movement from the other end of its are of movement until a predetermined differential pressure between said inlet line and said outlet line moves said sleeve a predetermined distance toward said end of said outlet line; and spring means biasing said firing pin for pivotal movement to engage said sleeve and strike said firing pin.

3. An explosive charge capsule for injection into a well pipe having a seating surface at the lower end thereof, comprising: an elongated housing having a compartment for an explosive charge material; an annular seating ring slidably afiixed to the elongated housing and longitudinally slidable along the housing, adapted to seat on the seating surface of the well pipe to substantially seal the well pipe against fluid flow downwardly therethrough; a firing apparatus enclosure in said capsule; an inlet line hydraulically coupling the exterior of the upper portion of the capsule to the interior of the enclosure; an outlet line extending into said enclosure hydraulically coupling the interior of said enclosure to the exterior of the lower portion of said capsule; a sleeve in said enclosure slidably fitting over the end of said outlet line, and having a closed end; a coil spring within said sleeve biasing the closed end of said sleeve away from the end of said outlet line within said enclosure, yieldable under differential pressure between said outlet line and said inlet line so that the closed end of said sleeve slides toward said end of said outlet line; a detonating charge extending into said enclosure and into said compartment for deto nating explosive material within said compartment; and a spring-biased firing pin biased so as to strike said explosive charge at one extremity of its path of movement, and positioned relative to said sleeve so that said sleeve holds said firing pin away from said detonating charge until a predetermined differential pressure exists between said inlet line and said outlet line whereby said firing pin will be released to strike said detonating charge.

4. An explosive charge capsule for injection into a well pipe having a seating surface at the lower end thereof, comprising: an elongated housing having a compartment for an explosive charge material; an annular seating ring operatively associated with said elongated housing adapted to seat on the seating surface of the well pipe to substantially seal the well pipe against fluid flow downwardly therethrough; a firing apparatus enclosure in said capsule; an inlet port hydraulically coupling the exterior of the upper portion of the capsule to the interior of the enclosure; an outlet port extending into said enclosure hydraulically coupling the interior of said enclosure to the exterior of the lower portion of said capsule; a sleeve in said enclosure slidably fitting over the end of said outlet port, and having a closed end; a coil spring within said sleeve biasing the closed end of said sleeve away from the end of said outlet port within said enclosure, yieldable under difierential pressure between said outlet port and said inlet port so that the closed end of said sleeve slides toward said end of said outlet port; a detonating charge extending into said enclosure and into said compartment for detonating explosive material within said compartment; and a spring-biased firing pin biased so as to References Cited in the file of this patent strike said explosive charge at one extremity of its path UNITED STATES PATENTS of movement, and positioned relative to said sleeve so that said sleeve holds said firing pin away from said detonating 448902 Yorke 1891 charge until a predetermined differential pressure exists 5 2555993 Spencer 1953 between said inlet port and said outlet port whereby said 2'749'840 Babcock June 121 1956 firing pin will be released to strike said detonating charge. 2'911'909 Fuchs 1959