Information
-
Patent Grant
-
6598679
-
Patent Number
6,598,679
-
Date Filed
Wednesday, September 19, 200122 years ago
-
Date Issued
Tuesday, July 29, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Bagnell; David
- Smith; Matthew
Agents
-
CPC
-
US Classifications
Field of Search
US
- 166 55
- 166 552
- 166 558
- 166 297
- 102 312
- 102 313
-
International Classifications
-
Abstract
An apparatus is provided which is adapted to be located in a conduit to be severed. The apparatus includes an upper ignition device, combustible material and a lower nozzle with a diverter. In operation the ignition device is actuated to ignite the combustible material to form a flame of hot gases for passage through apertures of the nozzle to the diverter which directs the hot gases radially outward and against the conduit to be severed. A uniform mixing cavity is provided above the nozzle in the flow path of the flame to the nozzle for mixing the hot gases prior to passages through the nozzle. A lower cavity is provided for the hot gases flowing out of the nozzle for pressurizing the hot gases at the outlet of the apparatus.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an apparatus for cutting pipe in a borehole extending into the earth from the surface.
2. Description of the Prior Art
U.S. Pat. Nos. 4,298,063, 4,598,769, 5,435,394, and 6,186,226B1 disclose apparatus for cutting pipe in a borehole. U.S. Pat. Nos. 4,598,769 and 5,435,394 are incorporated into the application by reference. In U.S. Pat. Nos. 4,598,769 and 5,435,394, the apparatus comprises an elongated body to be located in the pipe. The body has a central opening extending between an upper ignition device and a lower nozzle. Solid combustible material is located in the opening. The nozzle has a plurality of spaced apart apertures extending therethrough angularly around the axis leading to a diverter. The diverter has a flared surface which curves outward from a small circumference near the nozzle to an enlarged annular circumference. In operation, the ignition device is actuated to ignite the combustible material to form a flame of hot gases for passage through the apertures of the nozzle to the curved surface. The surface directs the flame and hot gases radially outward, which moves a sleeve down and the flame outward against the pipe for severing purposes.
Although the apparatus severs a pipe, sometimes problems occur in that the apertures of the nozzle become clogged and/or the severing procedure is not uniform due to the concentration of heat points of the flame radially outward from the exits of the apertures of the nozzle.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an apparatus which is an improvement to the apparatus of U.S. Pat. Nos. 4,598,769, and 5,435,394 in that it avoids the problems mentioned above.
The apparatus of this invention comprises a uniform mixing cavity above the nozzle in the flow path of the flame to the nozzle which allows the hot gases to mix and provides a more even distribution of the hot gases through the nozzle apertures to prevent the nozzle apertures from being plugged.
The invention also provides a lower mixing cavity for the hot gases flowing out of the nozzle which pressurizes the annular gap at the outlet of the curved surface of the diverter and more evenly distributes the outward flowing hot gases around the curved surface of the diverter to obtain a move even cutting of the pipe around its circumference.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
illustrates the apparatus or tool of the invention in pipe located in a borehole extending from the surface.
FIGS. 2A and 2B
are partial sectional views of the pipe cutting apparatus of the invention. The upper end of the section of
FIG. 2B
is connected to the lower end of the section of FIG.
2
A.
FIG. 3
is a cross-section of the lower end of the apparatus of
FIGS. 1 and 2A
and
2
B.
FIG. 4
is a view of
FIG. 3
as seen along lines
4
—
4
thereof.
FIG. 5
is a view of
FIG. 3
as seen along lines a
5
—
5
thereof.
FIG. 6
is a cross-section of the lower end of the apparatus of
FIGS. 1
,
2
A, and
2
B with the sleeve in an open position.
FIG. 7
is a view of
FIG. 6
as seen along lines
7
—
7
thereof.
FIG. 8
is a view of
FIG. 6
as seen along lines
8
—
8
thereof.
FIG. 9
is a cross-section of the thermal generator body of the apparatus.
FIG. 10
is a partial cross-section of the apparatus similar to that of a portion of FIGS.
3
and
6
.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to
FIGS. 1
,
2
A,
2
B, and
3
the apparatus or tool of the invention is identified at
21
. It comprises an elongated tubular body
23
having an upper ignition end
25
which carries an ignition device, an intermediate section
27
which carries fuel pellets and a nozzle end
29
. The tool
21
is adapted to be located in pipe
31
located in a borehole
33
extending into the earth from the surface
35
for severing the pipe. The pipe may be stuck in the borehole and it is desirable to sever the pipe above where it is stuck whereby the upper portion may be removed from the borehole. The pipe may be a drill pipe, production tubing, coiled tubing, casing, etc. The ignition device is actuated to ignite the fuel pellets to create a flame which is applied to a nozzle and diverter in the nozzle end
29
to direct the flame radially out of the tool against the pipe to sever or cut the pipe.
The body
23
comprises two hollow metal cylindrical members
41
and
43
having threads
41
T
1
and
43
T which are screwed together and an upper hollow metal cylindrical member
49
having threads
49
T which are screwed threads to
41
T
2
of member
41
. A cable head assembly
51
is coupled to member
49
and a wireline cable
53
is coupled to the upper end of assembly
51
and extends to the surface
35
to apparatus
55
which includes a reel employed for unwinding and winding the cable
53
to lower and raise the apparatus
23
. Also provided is an AC or DC source
61
of electrical power for applying electrical power to electrical leads
63
and
65
of the cable
53
when the switch
67
is closed.
The cylindrical members
41
and
43
have cylindrical openings
41
(O) and
43
(O) extending therethrough. Supported in the openings
41
(O) and
43
(O) are a plurality of stacked solid fuel pellets
71
. The pellets
71
are formed of combustible pyrotechnic material which is pressed together into a pellet of a generally donut or torroid configuration having a central hole
73
formed therethrough. The holes
73
of the pellets
71
are aligned when the pellets
71
are stacked in the openings
41
(O) and
43
(O). Loose combustible material
75
which may be of the same material as that of the pellets
71
is disposed in the holes
73
.
The pellets
71
are held between a lower support
81
and metal snap rings
91
A,
91
B, and
91
C located in grooves
43
A,
41
A,
41
B. The lower support
81
supports the pellets
71
when the tool is in a vertical position as shown in
FIGS. 1
,
2
A,
2
B and snap rings
91
A,
91
B, and
91
C prevents the pellets from falling out of the tool in the event the tool is in a horizontal position or its end
25
is lower than end
29
.
The member
49
has a central opening
49
(O) formed therethrough. A thermal generator
101
is located in the opening
49
(O) next to the upper pellet
71
. Referring also to
FIG. 9
, the generator
101
comprises an annular metal body
103
with an opening
103
(O) formed therethrough. An electrical contact
105
is supported at its upper end which is supported by a threaded insulator
107
and a threaded ring
109
both of which are screwed to threads
111
formed in the wall of the member
103
at its upper end. The contact
105
is electrically connected to a electrical resistive member
113
by an electrical lead
115
. The other end of the resistor
113
is connected to an electrical lead
117
which extends through the wall
103
. The contact
105
is connected to a contact located in annular member
119
. The contact in member
119
and lead
117
are connected to wires
63
and
67
by way of the assembly
51
. The body
103
has a threaded bottom port plug
121
having threads which are screwed to threads formed in the wall of member
103
at its lower end. The plug
121
has a central
123
opening formed therethrough for the passage of heat for igniting the material
75
and pellets
71
. Member
125
is an O-ring.
The support
81
is formed of carbon and has an annular shoulder
131
to support the pellets. The support
81
has a thin annular upper wall
133
that extends down to the annular shoulder
131
which has a central opening
135
formed therethrough. The lowest pellet
71
is supported by the shoulder
131
with the other pellets
71
stacked on top of each other. The lower edge of the shoulder
131
flares downward and outwards at
137
to a lower edge
139
which is supported by the upper end of a shield
161
. The support
81
acts as a spacer which spaces the pellets
71
from the lower components and defines a mixing cavity
153
between upper and lower planes
153
U and
153
L and which is in the form of a truncated cone having a cone shaped side wall
137
.
The lower components of the tool comprises a carbon shield
161
, a metal nozzle
201
, a carbon retainer
221
, and a carbon diverter
231
.
The shield
161
has an annular upper wall
183
with an upper end
185
that supports the lower edge
139
of the member
81
. It extends down to an annular flat upper wall
187
from which an upward extending cone
189
extends. The shield
161
has a flat lower end
191
. A plurality of spaced apart apertures
193
are formed through the wall portion
187
and end
191
around the axis of the cone
189
and the axis of the tool.
The nozzle
201
has a plurality of apertures
203
formed therethrough which are lined with carbon tubes
205
having a plurality of apertures
207
. Each apertures
207
is aligned with an aperture
193
. The nozzle
201
has a shaft
209
fixedly coupled thereto which extends downward from its lower surface
211
. The shaft
209
has threads
213
at its lower end.
A carbon retainer
221
has a central aperture
223
formed therethrough and a plurality of spaced apart apertures
225
formed therethrough with each aperture
223
aligned with an apertures
207
, such that a plurality of sets of aligned apertures
193
,
207
,
225
are formed. The retainer
221
has a lower outer annular wall
227
which extends downward to the lower level of the wall
43
such that the end
227
E of the wall
227
forms a plane with the lower end
43
E of the wall
43
.
The diverter
231
has a surface
233
which flares and curves downward and outward from a small annular circumference at
235
to a larger annular circumference at
237
defining half of a hyperboloid.
The wall
227
, the diverter surface
233
and the lower wall
227
of the retainer
221
form an annular chamber or cavity
241
into which hot gases from the nozzle apertures flow. The chamber
241
has an annular outlet gap
243
.
The diverter
231
also has a central aperture
245
. The nozzle shaft
209
extends through the diverter aperture
245
and is screwed to an anchor connector
247
having a wide annular shaped upper end
249
. The lower end
251
of the diverter
231
abuts against the upper end
253
of the anchor connector
247
. The shaft
209
is screwed into an aperture
251
of the anchor connector
247
and holds the diverter
231
in place.
Also provided is a metal sleeve
261
which is initially located in an upper closed position as shown in FIG.
3
and is movable by the hot gases to an open position as shown in FIG.
6
. The cylindrical wall
43
has an inward extending shoulder
263
which extends to a smaller cylindrical surface
43
C. The sleeve
261
comprises a cylindrical portion
261
C. In the closed position, the upper end of the cylindrical portion
261
C fits against the shoulder
263
and the surface
43
C. The lower end of the sleeve
261
has an inward extending portion
265
with a circular aperture
267
formed therethrough through which the anchor connector
247
extends. Members
271
and
273
are O-rings.
In the operation of the system, the uphole switch
67
is closed to apply an electrical output to the resistor
113
which generates enough heat to ignite the combustible material
75
and pellets
71
which generate a flame and hot gases which flow through the plurality of openings
135
of the support
81
into the chamber or cavity
153
which promotes mixing of the gases prior to flow through the aligned hole sets
193
,
207
,
225
. This prevents the hole sets
193
,
207
,
225
from becoming plugged. The flame and hot gases then flow out of the hole sets
193
,
207
,
225
into the annular cavity
241
formed between diverter surface
231
, the bottom side of the retainer
221
and the inside of wall
227
and then out of the gap
243
formed between the ends
227
E and
41
E of the walls
227
and
41
and the large circumferential edge
237
of the diverter. The flame and hot gases push the sleeve
261
downward to a lower open position allowing the flame and hot gases flow out of the gap
243
formed between the diverter edge
237
and the ends
227
E and
43
E of the walls
27
and
43
radially outward to cut the pipe or tubing in the borehole. In the cavity
241
, the pressure of the flame and hot gases builds up before leaving the gap
243
resulting in a more even distribution of the hot gases around the circumference of the diverter edge which results in a more even severing of the pipe or tubing in the borehole around its circumference.
Eight hole sets
193
,
207
,
225
are shown, however, the number of hole sets may vary from 6 to 24 or more. In one embodiment, for severing a pipe or tube having an inside diameter of 2⅜ inches, the outside diameter of the tool
21
may be 1½ inches. In this embodiment, and referring to
FIG. 10
, the diameters of D
1
, D
2
, D
3
, D
4
, D
6
, and D
7
, may be ⅝, 1, 1⅛, ⅝, 1, 1{fraction (7/16)} inches respectively, and the heights H
1
, H
2
, H
3
, and H
4
may be ⅜, ¼, ⅜, ⅛ inches respectively.
The height H
4
of the gap
243
may be increased or decreased by using diverter
231
having a different curved surface
233
.
Claims
- 1. An apparatus for cutting a conduit located in a borehole extending into the earth form the surface, comprising:an elongated body having an opening extending between an ignition end and a nozzle end with said body being adapted to be lowered into the conduit to be cut with said nozzle end located below said ignition end, said opening of said body comprises an opening having a central axis, combustible material located in said opening of said body, spacer means having a support surface and a lower end for supporting said combustible material in said opening of said body, said spacer means having an opening formed through said support surface, a nozzle and a diverter located at said nozzle end adjacent said spacer means with said nozzle located between said spacer means and said diverter and with said nozzle spaced from said spacer means, said spacer means having a surrounding surface formed between said opening of said support surface and said lower end forming an unobstructed mixing cavity within said surrounding surface above said nozzle, said cavity is defined at least by spaced apart planar boundaries and a surrounding wall located below said support surface and above a shield, said diverter comprising a surface which curves outward from a smaller circumference located near said nozzle to a larger circumference spaced away from said nozzle, ignition means located at said ignition end for igniting said combustible material to form a flame for passage toward said nozzle by way of said mixing cavity, said nozzle comprising a plurality of spaced apart apertures formed therethrough for directing the flame from said mixing cavity to said surface of said diverter for directing the flame radially outward of said body for cutting the conduit in the borehole, said apertures of said nozzle extend through said nozzle generally around and parallel to said central axis, said body at said nozzle end comprises a surrounding wall which extends to a position between said smaller circumference and said larger circumferences of said surface of said diverter such that said surrounding wall and said surface of said diverter within said surrounding wall form a second cavity for pressurizing the hot gases that flow from said apertures of said nozzle before leaving said body, said smaller circumference of said surface of said diverter is located radially inward of said apertures an amount greater than the radial distance of said apertures from said surrounding wall.
- 2. The apparatus of claim 1, wherein:said surrounding wall extends to a position greater than half of the axial distance between said smaller and larger circumferences.
- 3. An apparatus for cutting a conduit located in a borehole extending into the earth form the surface, comprising:an elongated body having an opening extending between an ignition end and a nozzle end with said body being adapted to be lowered into the conduit to be cut with said nozzle end located below said ignition end, said opening of said body comprises an opening having a central axis; combustible material located in said opening of said body, spacer means having a support surface and a lower end for supporting said combustible material in said opening of said body, said spacer means having an opening formed through said support surface, a nozzle and a diverter located at said nozzle end adjacent said spacer means with said nozzle located between said spacer means and said diverter and with said nozzle spaced from said spacer means, said spacer means having a surrounding surface formed between said opening of said support surface and said lower end forming an unobstructed mixing cavity within said surrounding surface above said nozzle, said diverter comprising a surface which curves outward from a smaller circumference located near said nozzle to a larger circumference spaced away from said nozzle, ignition means located at said ignition end for igniting said combustible material to form a flame for passage toward said nozzle by way of said mixing cavity, said nozzle comprising a plurality of spaced apart apertures formed therethrough for directing the flame from said mixing cavity to said surface of said diverter for directing the flame radially outward of said body for cutting the conduit in the borehole, said apertures of said nozzle extend through said nozzle generally around and parallel to said central axis, said body at said nozzle end comprises a surrounding wall which extends to a position between said smaller circumference and said larger circumferences of said surface of said diverter such that said surrounding wall and said surface of said diverter within said surrounding wall form a second cavity for pressurizing the hot gases that flow from said apertures of said nozzle before leaving said body, said surrounding wall extends to a position greater than half of the axial distance between said smaller and larger circumferences.
- 4. An apparatus for cutting a conduit located in a borehole extending into the earth from the surface, comprising:an elongated body having an opening extending between an ignition end and a nozzle end with said body being adapted to be lowered into the conduit to be cut with said nozzle end located below said ignition end, solid combustible material located in said opening of said body, a nozzle and a diverter located at said nozzle end with said nozzle located between said combustible material and said diverter, said diverter comprising a surface which curves outward from a smaller circumference located near said nozzle to a larger circumference spaced away from said nozzle, there being a cavity around said curved surface, ignition means located at said ignition end for igniting said combustible material to form a flame for passage toward said nozzle, said nozzle comprising a plurality of spaced apart apertures formed therethrough, the apertures opening into the cavity, wherein the flame is directed to said surface of said diverter and radially outward through an exit for cutting the conduit in the borehole, said body at said nozzle end comprises a surrounding wall which extends to a position between said smaller circumference and said larger circumferences of said surface of said diverter such that said surrounding wall constricts the exit of said cavity for pressurizing the hot gases that flow from said apertures of said nozzle before leaving said cavity.
- 5. The apparatus of claim 4, wherein:said smaller circumference of said surface of said diverter is located radially inward of said apertures an amount greater than the radial distance of said apertures from said surrounding wall.
- 6. The apparatus of claim 4, wherein:said surrounding wall extends to a position greater than half of the axial distance between said smaller and larger circumferences.
- 7. The apparatus of claim 5, wherein:said surrounding wall extends to a position greater than half of the axial distance between said smaller and larger circumferences.
- 8. An apparatus for cutting a conduit located in a borehole extending into the earth from the surface, comprising:an elongated body having an opening extending between an ignition end and a nozzle end with said body being adapted to be lowered into the conduit to be cut with said nozzle end located below said ignition end, combustible material located in said opening of said body, a nozzle and a diverter located at said nozzle end with said diverter located below said nozzle, said diverter comprising a surface which curves outward from a smaller circumference located near said nozzle to a larger circumference spaced away from said nozzle, an annular shield located above said nozzle, spacer means separate from said shield having a support surface with an opening formed therethrough for supporting said combustible material at a position spaced from said shield and forming a mixing cavity between said support surface and said shield, ignition means located at said ignition end for igniting said combustible material to form a flame for passage toward said nozzle by way of said mixing cavity, said nozzle comprising a plurality of spaced apart apertures formed therethrough for directing the flame from said mixing cavity to said surface of said diverter for directing the flame radially outward of said body for cutting the conduit in the borehole.
- 9. The apparatus of claim 8, wherein:said mixing cavity is defined at least by spaced apart planar boundaries and a surrounding wall located below said support surface and above said shield.
- 10. The apparatus of claim 8, wherein:said opening of said body comprises an opening having a central axis, said apertures of said nozzle extend through said nozzle generally around and parallel to said central axis, said body at said nozzle end comprises a surrounding wall which extends to a position between said smaller circumference and said larger circumferences of said surface of said diverter such that said surrounding wall and said surface of said diverter within said surrounding wall form a second cavity for pressurizing the hot gases that flow from said apertures of said nozzle before leaving said body.
- 11. An apparatus for cutting a conduit located in a borehole, comprising:an elongated body having a first end and a second end and an interior passage extending therebetween, the body being structured and arranged to be lowered into the conduit with the first end interposed between the second end and a surface of the earth, the first end being structured and arranged to receive an igniter, the second end comprising an outlet, combustible material located in the passage adjacent to the first end, a nozzle located in the passage, the nozzle comprising plural apertures that allow gases from the combustible material to pass into a cavity, each of the apertures having a first transverse cross-sectional area, the cavity being formed by a surface that directs the gases radially through the outlet, the cavity having a second transverse cross-sectional area where the apertures communicate with the cavity, the second transverse cross-sectional area being greater than the first transverse cross-sectional area, the outlet forming a restriction to the gases in the cavity flowing through the outlet.
- 12. The apparatus of claim 11, further comprising:a mixing chamber interposed between the nozzle and the combustible material.
- 13. A method of cutting a conduit located in a borehole in the earth, comprising the steps of:combusting a material to produce hot gases; flowing the gases through a plurality of nozzle passages that are oriented with the borehole and are located in a circumferential manner relative to the conduit; flowing the gases into a diverter cavity; pressurizing the gases in the diverter cavity to allow a more even circumferential distribution and then radially flowing the gases through a circumferential exit in the diverter cavity toward the conduit.
- 14. The method of claim 13 further comprising the step of mixing the gases in a chamber before the step of flowing the gases through a plurality of nozzle passages.
- 15. The method of claim 13 wherein the step of flowing the gases into a diverter cavity further comprises the step of flowing the gases from the nozzle passages into the larger diverter cavity.
- 16. The method of claim 15 wherein the step of pressurizing the gases in the diverter cavity to allow a more even circumferential distribution and then radially flowing the gases through a circumferential exit further comprises the step of flowing the gases in the diverter cavity through a constricting exit.
US Referenced Citations (8)