Switch means for actuating downhole devices

[57] 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.

Claims, 13 Drawing Figures

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PATENTED SEP 111973

SHEET 1 Of 2

3,758.731

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-3V MARCUS X..BATES

TH£//5 HtSEHT

PATENTEDSEP111973

SHEET 2 OF 2

3.758.731

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<img file="US3758731A_D0004.tif" />

^S'S MARCUS L.BATES

THEiK NGENT

3,758,731

SWITCH MEANS FOR ACTUATING DOWNHOLE DEVICES

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 crosssectional 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.

3,758,731

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 there4 through 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° 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 I, 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. Thia 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 con

3,758,731 tacts 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 LI 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.