US2349041A - Signaling device for gun perforators - Google Patents

Description

May 16, 194.44 D. G. c. HARE 2,349,041

SIGNALING DEVICE FOR GUN PERFORATORS Filed Aug. 29, 1941 E lIE -K ZB 30 n D. G. C. HARE INVENTOR STATES attach stoisaamo newton son ops mesne assignments, to The Tems Donald G. (2. Rare, Houston, Tex, assignor. by

Comlmnv.

3 Claims.

This invention relates to signaling systems and devices and more particularly to a device for providing an indication at the surface when a tool such as gun performator is raised or lowered in a bore hole. The principal object of the invention is the provision of a simple device of this had which will furnish a positive indication that a device such as a gun perforate! is moved upwardly or downwardly from a provious position in a bore hole.

In the perforating of a well casing or of the formations around a bore hole by means of a gun perforator, it is frequently dimcult to determine the exact position of the perforatin device in the hole. These devices are comparativeLv heavy and as they are usually run into and out of the hole by means of a wire cable, the weight of the device often causes considerable elongation of the cable. it is quite common in gun perforating practice to lower the perforating toolto the bottom of the hole or to a cement plu which may have been placed at an elevation above the bottom of the hole, and then to -raise the tool to the point at which it is intended to perforate; Because of the stretch of the cable the operator is not always certain that the tool has been raised oil. the bottom, even though he may have pulled vup some distance on the suspending cable.

In accordance with this invention, c device is provided either within or attached to the periorating tool for closing. an electric circuit to provide a signal at the surface when the, tool is raised from its bottom position.- A signal will also be given in case the perforating tool should become stuck during the .lowering operation.

For a better understanding'of the invention reference may be had to the accompanying drawing in which.

P18. 1 is a vertical elevation, partly in section, of a gun perforating tool at rest on a cement plug in a bore hole, while a Fig. 2 is a diagram of the electrical connecons.

Referring to the drawing, a bore hoIeJd-Vprovldcd with a casing 02 has been plugged as by means of the cement plug it, and it may be assumed that it is desired to perforate the casing I! at a point somewhat above the plug it. A gun perforating tool it which, as is generally known, usually comprises a plurality of barrels II and charges of explosive adapted when tired to project bullets 28 throu'gh the casing and into the formation, is lowered into the hole by means of a cable 22, which usually includes a erator or buzzer 62.

pair of wires shown at it in Fig. 2, for connect ing a sourw of electricity it at the surface to one or more firing caps 28 in the tool. When a switch it is closed, the cap 29 will be fired to cause the explosive, not shown, to discharge the bullets through the casing,

An inertia member 82 is resiliently supported within the housing of the tool it as by means of a spring disc 3t secured to the housing by lugs 86. A pair of contact members 3d are rigidly secured to the perforating tool housing in vertical alignment with the inertia member t2 and separated from the inertia element by a distance such that on a predetermined raisin or lowering acceleration of the perforating tool the inertia member will strike one of the contacts 88 to complete an electric signal circuit which will be described. As' shown in Fig. 2. the inertia member 32 is connected electrically with a source of current which inturn is connected to a signal generator 62 which may be a high frequencybuzzer having a frequency of about 1,00! cycles. The buzzer 62 is connected through one 0011 of a transformer M to the two contacts 38. The firing circuit, which has already been partially described, also includes the other coil of the transformer 5t and preferably a choke coil 46 and a pair of condense 68 connected acroutheline, In operation, acceleration of the perforating tool in either an upward or downward directioncauses the inertia member 32 to engage the lower or upper contact 38 respectively to close the signal circuit, thus energizing the signal gen-- High frequency'curre'nt. from the buzzer circuit is coupled into the tiring circuit-by means of transformer it and the choke coll M and condensers It. tend to prevent currents from the buzzer circuit from flowing through the firing cap 28. As a further safe-guard condensers 50 may be placed in the signalor'buzzer circuit to prevent any direct current from enter ing the firing circuit. The signal current coupled into the firing circuit will pass through the signal receiver 52 which may comprise a pair of position. to be in the. position shown in Fig. l, the operator pulls upward-1y on the cable 22' until he hears the signal in the receiver 52 caused by the upward motion of the tool closing the signal circuit through the inertia contactor t2, and he then has a positive indication that the perforate ing tool has been raised above the cement plug it, The operator thenmoves the switch it to its lower position, thus connecting the sour ce or current 26 into the firing circuit 26 and the firing of the cap 28 will discharge the explosive to cause the bullets to be projected through the casing l2.

If the perforator should become stuck during the lowering operation and then dislodged so as'to move downwardly again, the downward acceleration will cause the inertia member 82 to strike the upper contact 33 to close the signal circuit and provide a signal at the receivers 52, as before described.

It willthus be seen that a simple arrangement has been provided to furnish a positive in dication of movement of the perforating tool and that no additional electric circuit is needed from the tool to the, surface, the signal current being impressed on the already existing firing circuit to energize the signal receiver.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof and, therefore, only such limits" tions should be imposed as are indicated in the appended claims.

I claim: 7 4

1. In combination with a gun perforator adapted to be lowered to the bottom of a bore hole on a wire cable, a signalingdevice, a source of electrical current and a vertically movable inertia contactor in said perforator, a signal cir'-,

cuit in which said signaling device, current source and inertia contactor are connected electrically in series,,a firing circuit for said perforator and a transformer connecting. said signal circuit with said firing circuit, the arrangement being such that on upward or downward accelerating movement of said perforator said inertia contactor aeeaoci will close said signal circuit through said transformerto couple a signal current into said firing circuit, and a. signal receiver connected in said firing circuit. I

2. In combination with a gun perforator adapted to be lowered to the bottom of a bore hole on a wire cable, a signaling device, a source of electrical current and an inertia contactor connected in a series signal circuit incsaid perforator, said contactor comprising a pair of vertically separated fixed contacts and a vertically movable inertia member disposed between said contacts so that upward or downward accelerating movement of said perforatori will cause said inertia members to engage one ofsaid contacts to close said signal circuit, a firing circuit for said periorator including a second source of electrical current, a firing cap, a normally open switch, a signal receiving device and said cable connected electrically in series, and a transformer connecting said signal circuit with said firing circuit, the arrangement being such that when said signal circuit is closed a signal will be impressed on said firing circuit and indicated by said receiving, device.

3, In combination with a gun perforator suspended in a well from a cable and connected in a firing circuit including said cable to a'source of electricity at the surface, meansfor indicating when said perforator is moved vertically from astationary position comprising a signaling device, asource of electricity and an inertia con-- tactor connected in a signal circuit in said percircuit.-

forator, means for inductively coupling said signal circuit to said firing circuit, and a signal receiver at the surface connected in said firing DONALD G. c'.

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