U.S. patent number 3,758,731 [Application Number 05/116,948] was granted by the patent office on 1973-09-11 for switch means for actuating downhole devices.
Invention is credited to Clyde R. Vann, Roy R. Vann.
United States Patent |
3,758,731 |
Vann , et al. |
September 11, 1973 |
SWITCH MEANS FOR ACTUATING DOWNHOLE DEVICES
Abstract
A switch means for electrically actuating a downhole device
wherein the switch means and downhole device are connected into a
tool string and run into the borehole on a slick line to provide a
source of electrical power at any given time. The switch means is
actuated by positively reciprocating the slick line to which the
tool string is attached a predetermined number of times. Provision
is made for resetting the apparatus at any time prior to closure of
the switch means.
Inventors: |
Vann; Roy R. (Midland, TX),
Vann; Clyde R. (Midland, TX) |
Family
ID: |
22370208 |
Appl.
No.: |
05/116,948 |
Filed: |
February 19, 1971 |
Current U.S.
Class: |
200/61.69;
166/65.1; 175/4.56 |
Current CPC
Class: |
E21B
41/00 (20130101); H01H 3/34 (20130101); E21B
43/11855 (20130101) |
Current International
Class: |
H01H
3/34 (20060101); H01H 3/32 (20060101); E21B
43/11 (20060101); E21B 43/1185 (20060101); E21B
41/00 (20060101); H01h 003/16 (); E21b
043/11 () |
Field of
Search: |
;200/61.69 ;335/140,138
;175/4.56 ;166/65 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Borchelt; Benjamin A.
Assistant Examiner: Birmiel; H. A.
Claims
I claim:
1. In combination with an electrically actuated downhole tool, a
switch assembly for providing a source of current to the tool,
comprising:
an elongated hollow body within which said switch assembly is
housed, said hollow body adapted to be suspended within a borehole
by a slick line;
spaced stop members formed on said hollow body; an actuator member,
said actuator member being slidably received on the exterior of
said hollow body and adapted to reciprocate between said stop
members; said actuator member having borehole wall engaging means
affixed thereto for causing said actuator member to be reciprocated
between said stop means in response to relative movement between
said body and a borehole wall;
a rack, means by which said rack is slidably journaled within said
hollow body and movable from a first to a second position;
means including a lever positioned to be engaged and moved by said
actuator member, to successively engage and move said rack towards
said second position when said lever is engaged and moved by said
actuator member;
means forming a ratchet positioned to releasably engage and hold
said rack against movement towards said first position;
means including a lower lever member connected for movement by said
actuator member for disengaging said ratchet from said rack so that
said actuator member, when moved against said lower lever member,
causes said ratchet to be released from said rack thereby enabling
said rack to return to the first position;
a source of electrical power, a switch arranged to be actuated into
a current flowing position, circuit means connecting said switch to
said source of power and adapted to energize an electrically
actuated downhole tool upon said switch being actuated; and
means connected to said rack for actuating said switch when said
rack is moved to said second position.
2. The combination of claim 1 wherein said switch includes spaced
apart electrical contacts;
said means connected to said rack for actuating said switch means
including a metallic plate member connected to a depending end of
said rack; means insulating said plate member from said rack, said
plate member adapted to form a current flow path across said spaced
apart contacts when said rack is moved to said second position.
3. The combination of claim 1, wherein said ratchet is in the form
of an arm, means by which said arm is pivotally mounted to said
body, means by which said arm is normally biased into a rack
engaging position;
said lower lever member being disposed between one said stop member
and said lever means; linkage connecting said lower lever member to
said ratchet for moving said ratchet when said actuator engages
said lower member, to thereby cause said ratchet to release said
rack.
4. The combination of claim 1 wherein said actuator includes spaced
apart ring members circumferentially disposed about said body and
further including bow members radially spaced apart from one
another and connected to said ring members, with one depending end
of each bow being connected to one ring member; said bow having an
outwardly disposed marginal portion thereof for engaging the
borehole wall.
5. The combination of claim 1, wherein said circuit means includes
a heating element, a bimetal switch having normally open contacts
thereon, where said bimetal switch is moved to the closed position
when said heating element is electrically energized;
said power source having two electrical conductors with one
conductor being connected to one contact of said bimetal switch and
to said heating element;
said heating element and the first recited switch being series
connected with the remaining terminal of the last said switch being
connected to the remaining terminal of said power source; and
the remaining contact of said bimetal switch and the remaining
electrical conductor of said power source adapted to be connected
to the downhole tool.
6. The combination of claim 3 wherein said switch includes spaced
apart electrical contacts;
said means connected to said rack for actuating said switch means
including a metallic plate member connected to a depending end of
said rack; means insulating said plate member from said rack, said
plate member adapted to form a current flow path across said spaced
apart contacts when said rack is moved to said second position.
7. The combination of claim 1 wherein said rack has a marginal
longitudinally extending portion thereof formed into spaced apart
circumferentially extending teeth, each of said teeth adapted to be
individually engaged by a portion of said ratchet and a portion of
said lever so that said lever can engage one of said teeth and move
said rack towards said second position while said ratchet engages
another of said teeth and holds said rack while said lever is being
actuated by said actuator member.
8. The combination of claim 1 wherein said circuit means includes a
normally open switch for connecting said power source to a downhole
tool; a time delay means for moving said normally open switch to
the closed position upon the first switch being moved to the closed
position.
9. Apparatus for electrically actuating downhole tools, said
apparatus including a housing in the form of an elongated hollow
body;
spaced stop members formed on said hollow body; an actuator member,
said actuator member being slidably received on the exterior of
said hollow body and adapted to reciprocate between said stop
members; said actuator member having borehole wall engaging means
affixed thereto for causing said actuator member to be reciprocated
between said stop members in response to relative movement between
said body and a borehole wall;
a rack, a lever, a ratchet; said rack being slidably received
within said hollow body and movable between a first and second
position;
said lever positioned to successively engage and move said rack
towards said second position;
said actuator member being arranged relative to said lever so as to
engage and move said lever to thereby cause the before recited
movement of said rack;
said ratchet positioned to releasably engage and hold said rack
against movement towards said first position;
a source of electrical power, a switch arranged to be actuated into
a current flowing position, circuit means connecting said switch
means to said source of power and adapted to energize an
electrically actuated downhole tool upon said switch being
actuated; and
means connected to said rack for actuating said switch when said
rack is moved to said second position.
10. The apparatus of claim 9 wherein said ratchet is in the form of
an arm, means by which said arm is pivotally mounted to said body,
means by which said arm is normally biased into a rack engaging
position;
a lower lever member being disposed between one said stop member
and said lever; linkage connecting said lower lever member to said
ratchet for moving said ratchet when said actuator engages said
lower member, to thereby cause said ratchet to release said
rack.
11. The apparatus of claim 9 wherein said circuit means includes a
heating element, a bimetal switch having normally open contacts
thereon, where said bimetal switch is moved to the closed position
when said heating element is electrically energized;
said power source having two electrical conductors with one
conductor being connected to one contact of said bimetal switch and
to said heating element;
said heating element and the first recited switch being series
connected with the remaining terminal of the bi-mettalic switch
being connected to the remaining terminal of said power source;
and
the remaining contact of said bimetal switch and the remaining
electrical conductor of said power source adapted to be connected
to the downhole tool.
12. The apparatus of claim 9 wherein said rack has a marginal
longitudinally extending portion thereof formed into spaced apart
circumferentially extending teeth, each of said teeth adapted to be
individually engaged by a portion of said ratchet and a portion of
said lever so that lever can engage one of said teeth and move said
rack towards said second position while said ratchet engages
another of said teeth and holds said rack while said lever is being
actuated by said actuator member.
Description
BACKGROUND OF THE DISCLOSURE
There are many different downhole tools which are lowered into a
borehole and subsequently actuated by a source of electrical
current at a prescribed depth. Examples are perforating tools,
packers, and downhole recorder devices.
Heretofore, many downhole tools have been actuated by a wire line
wherein the power source is located near the well head and above
the surface of the earth. The wireline cable must support the tool
and at the same time provide the electric current flow path. The
extreme length and weight of a wire line necessarily requires
employment of an expensive insulated double conductor cable, with
the exterior of the wire line usually forming one of the electrical
conductors. Moreover, the requirement of an extreme length of wire
line causes a large voltage drop therein. When running a jet
perforating gun into a borehole on a wire line, the wire line is
subject to an electrical current being inducted therein because of
radio waves and the like, thereby causing premature detonation of
the gun. Accordingly, it is desired to provide a source of power
which can be attached to a tool string and lowered into the
borehole on a slick line, thereby obviating the necessity of
employing an expensive wire line. It is furthermore desirable that
such a tool string be supported by an inexpensive slick line, and
that a predetermined simple manipulation of the slick line actuate
the switch means, thereby providing electrical current to actuate
the tool.
SUMMARY OF THE INVENTION
The present invention encompases an electrically actuated downhole
tool combination wherein an electrical power supply and a switch
means therefore are included in the tool string, with the tool
string being supported by a slick line, and with the switch means
being actuated in response to a reciprocal motion of the slick
line.
When the tool is properly positioned downhole in a bore-hole,
reciprocal motion of the slick line causes a slidable member to
move a lever which in turn engages a rack to thereby jack the rack
into a first position which closes the contacts of an electrical
circuit. Should it be decided to locate the tool string elsewhere,
the tool can be reset by merely lifting the slick line a specified
amount whereupon a ratchet is released from the rack to thereby
reset the switch assembly.
There is further provided a time delay circuitry associated with
the switch means which enables the tool to be finally positioned
immediately following the reciprocation step.
Therefore a primary object of this invention is to provide a power
package for actuating downhole tools in response to relative
movement between the power package and the borehole.
Another object of this invention is to provide a downhole tool,
having circuitry including a switch means, which is actuated upon
reciprocation of the tool.
A still further object of this invention is the provision of a
switch mechanism having a rack actuated by reciprocal motion of the
apparatus, and further including a ratchet which enables the rack
to be reset at any time before closure of the switch.
Another object of this invention is the provision of an improved
downhole switch means which is selectively actuated by manipulation
of its support means.
The above objects are attained in accordance with the present
invention by the provision of a combination of elements which are
fabricated in a manner substantially as described in the above
abstract and summary.
These and various other objects and advantages of this invention
will become readily apparent to those skilled in the art upon
reading the following detailed description and by referring to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary, part cross-sectional, side view of a
borehole formed within a portion of the earth, with the tool of the
present invention being schematically illustrated therein;
FIG. 2 is an enlarged, fragmentary longitudinal cross-sectional
view of the present invention;
FIG. 3 is a cross-sectional view taken along line 3--3 of FIG.
2;
FIG. 4A is a cross-sectional view taken along line 4A--4A of FIG.
2;
FIG. 4B is a cross-sectional view taken along line 4B--4B of FIG.
4A;
FIGS. 5 and 6, respectively, are cross-sectional views taken along
lines 5--5 and 6--6, respectively, of FIG. 2;
FIG. 7 is an enlarged, disasembled, perspective view of part of the
apparatus disclosed in the foregoing figures;
FIG. 8 is a fragmentary, part-cross-sectional view of part of the
apparatus disclosed in the foregoing figures;
FIGS. 9, 10, and 11, respectively, set forth the details of a
modification of the apparatus of FIG. 7; and
FIG. 12 is a schematical diagram of one electrical circuitry which
can be used in conjunction with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Illustrated in FIG. 1 is a borehole 10 which has been formed in the
ground 11 in order to gain access to a hydrocarbon bearing
formation 12.
Cement 13 surrounds at least a marginal portion of casing 14. A
slick line 15 is adapted to support the elongated hollow body 16
which is suspended within the casing of the borehole. A swivel 17
is usually employed for connecting the slick line to the tool
string.
For purpose of illustration, the tool string includes a jet
perforating gun 18 which is connected to the tool or switch
assembly of the instant invention by the illustrated sub 19. A bull
plug 20 forms the lower depending end of the tool.
The switch assembly is housed within an elongated hollow body,
preferably round in cross-sectional area, and includes a polished
portion 21 which is limited in longitudinal length by the
illustrated spaced apart stop members 22 and 23. An actuator member
24 is circumferentially disposed and slidably captured about the
polished section. Relative movement between the tool and the
borehole reciprocates the actuator between the two stop members. A
lever 25 and a similar lower lever member 26 are seen protruding
outwardly from the polished portion of the body.
Looking to the details of FIG. 2, in conjunction with the remaining
figures, it is seen that the actuator member includes spaced apart
rings 27, 28 which are connected together by the elongated
resilient bows 29 with the marginal terminal ends of the bows being
affixed to each of the spaced apart ring members.
The inside peripheral wall surface 30 is enlarged at the
illustrated threaded area so as to threadedly receive insulated
bulk-head 31 therein. The bulkhead forms a part of the power
section, within which there is included a source of stored
electrical power in the form of a storage battery 32. Spring 33
engages a limited portion of the interior side walls of the body
and urges the battery into its illustrated position. Conductors 34
lead from the series connected battery and switch means 35.
The switch means is comprised of spaced apart copper conductors 35'
having insulation therebetween with the insulation also forming the
before mentioned bulkhead 31 for hermetically sealing the battery
compartment from the remainder of the tool string. Electrodes 235
form a current flow path to and from the switch means.
The upper chamber 30 enlarges into chamber 36, and provides a
shoulder therebetween against which bulkhead 37 is retained by
means of snap ring 38. Inspection port 39 enables the position of
the rack 40 to be visually observed.
The rack 40 includes an upper constant diameter portion which is
reciprocatingly received within bulkhead 37, and further includes a
multiplicity of longitudinally spaced apart circumferentially
extending teeth having a circumferentially disposed horizontal
surface 42 formed by a frusto conical portion 43, and an opposite
marginal end portion 44 which terminates as a free end at 45.
Keeper 46 is pinned to the free end portion so as to maintain
biasing means 47 compressed between bulkhead 48 and the keeper.
The last named bulkhead is maintained in anchored relationship with
respect to the wall of the body by the radially spaced apart screws
49. Aperture 50 provides a passageway for linkage 51. The linkage
is attached to a lower lever member 52. The lever member is
pivotally attached to the body at 53, and has a marginal end
portion depending through longitudinal slot 54.
The remaining end portion of the linkage is affixed to aperture 51'
of ratchet assembly 55. The ratchet is biased into the illustrated
position by a leaf spring 56, with the leaf spring having a
marginal portion thereof attached to the inside peripheral wall of
the body by fastener means 56'. Spaced apart mounts 57 maintain the
ratchet in the illustrated position of FIG. 2 and 8.
Lever 25 further includes a body portion 59 which is milled in a
manner to form chamber 60 for receiving the illustrated articulated
member 61 therein. Apertures 62, 63, 64, and 65 are formed in the
members, with apertures 65 receiving pin 65' therethrough, while
apertures 63 and 64 are pinned together by a common pin type
fastener. Aperture 62 receives an end portion of spring 66 thereon
so as to bias the lever against stop member 124.
FIGS. 9-11 set forth a modification of the lever seen in FIG. 2,
and includes an elongated member 159 having stop member 67 in the
form of a laterally arranged pin, and a hinge 165 which is received
through aperture 165'. Base plate 168 supports the hinge and the
stop means, with slot 166 receiving member 159 therethrough in a
manner which allows the member 161 to pivot about a journal formed
at 165.
FIG. 12 shows a time delay circuitry for use in conjunction with
the apparatus of the present invention, wherein storage battery 32
has one electrical terminal thereof electrically connected to
heating element H and to one electrical contact of switch S. The
heater is series connected with respect to the before mentioned
switch 35, with the remaining electrical terminal of the switch
being connected to the remaining battery post. The two illustrated
leads at 34 are adapted to be connected to provide a source of
current to an electrically actuated tool, such as the previously
discussed jet perforating gun seen at 18, for example.
OPERATION
In operation, the switch means 16 is attached into a tool string
which includes an electrically actuated tool, such as the jet
perforating gun 18. Those skilled in the art will understand that
the tool 18 could be situated in underlying relationship with
respect to the instant invention, or for that matter, the entire
tool of FIG. 2 could be inverted so as to enable the relationship
of the tool string seen in FIG. 1 to be turned 180.degree. from the
illustration. The toll is run into the hole on the slick line, and
generally positioned relative to the production formation by using
a depthometer which measures the length which the slick line has
been run downhole. When it is desired to perforate the casing, the
cable drum is actuated in a manner to impart reciprocal motion into
the slick line, which in turn causes the actuator member to
reciprocate with respect to the body an amount indicated by l.sub.1
in FIG. 1. Each reciprocation of the body causes the actuator
member to pivot lever 25 an amount which lifts the rack in an
upward direction a distance equal to the spacing between two
adjacent teeth 42.
The ratchet continues to successively engage each of the teeth as
the lever is pivotally moved in response to the action of the slick
line. After making the required number of strokes to move the
bridge member into electrical contact with the electrodes of the
switch means, the operator has 30 seconds in which to make final
vertical adjustments of the tool string so as to perforate the
casing at the exact required length.
As soon as the switch 35 has been moved from the normally opened to
the closed position, current flow occurs from the battery, through
the heater, thereby heating the element of the bi-metal switch and
causing the time delay period to commence as the contacts thereof
begin to move to the closed position. Upon closure of the second
switch, current is supplied at conductors 34. This action explodes
the detonator which in turn detonates the shaped charges of the
perforating gun, whereupon the entire tool string is then usually
removed from the borehole.
Any time, prior to closure of switch S, should it be deemed
desirable to discontinue the perforation operation, the slick line
is lifted a distance "L2" so as to bring ring member 28 into
contact with lower member 26. This action causes linkage 51 to be
pivotally moved counterclockwise so as to release the rack. As the
rack is released, compressed spring 47 forces lever 25 in a
counterclockwise direction so that as the lever abuts stop means
124, is also clears the teeth of the rack, thereby enabling the
rack to return to a lowermost position. Since the metallic face 45
no longer bridges contacts 35', heater H cools down, thereby
permitting switch S to remain in the opened position. Hence,
anytime prior to the expiration of the 30 second time delay, the
apparatus can be reset by merely lifting the slick line a
sufficient amount.
The distance between bulkhead 37 and 31, as well as the length L1
and L2, or the length of the rack 40, can be different from that
disclosed in the drawings. It is usually desirable to have at least
12 teeth on the rack so as to require one dozen strokes in order to
actuate the device. It is quite obvious when the gun fires for the
reason that it is felt at the well head.
In the embodiment of FIGS. 9-11, mounting plate 168 is attached to
the inside peripheral wall of the body so as to dispose the free
end of member 161 in proper alignment so as to permit engagement
with the teeth of the rack. Each time lever 159 is pivotally
actuated by the ring, pin 67 engages finger 161, thereby lifting
one tooth of the rack past the ratchet so as to enable the ratchet
to engage and hold the rack while the lever 25 is again cycled so
as to lift the rack another increment equal to the distance between
adjacent teeth.
* * * * *