US1925012A

US1925012A - Well drilling system

Info

Publication number: US1925012A
Application number: US629005A
Authority: US
Inventors: William G Taylor
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1932-08-16
Filing date: 1932-08-16
Publication date: 1933-08-29
Anticipated expiration: 1950-08-29

Description

Aug. 29, 1933. w, TAYLOR 1,925,012

WELL DRILLING sYs'r'El Filed. Aug. 16. 19:32

Inventor:

William G Tc loh.

:25 motor becomes greater than a predetermined Patented Aug. 29, 1933 UNITED STATES WELL DRILLING SYSTEM William G. Taylor, Schenectady, N. Y., aalignor to General Electric Company, a corporation of New York Application August 1:, 1932. Serial No. czaoos 3Claims.

My invention relates to well drilling apparatus, more particularly to a control system for oil well drilling apparatus, and has for its object a simple and reliable system for controlling the pres- 5 sure of the drill on the earth's formation in response to the load on the main driving motor for the drill, together with means for maintaining normally a predetermined constant pressure of the drill on the earths formation.

My invention is more particularly an improvement on oil well drilling systems wherein the drill is automatically fed so as to maintain a predetermined weight of the drill, i. e., pressure of the drill, on the earths formation, such as described 16 and claimed in the Loomis Patent No. 1,779,480,

dated October 28, 1930.

In carrying out my invention, I control the feeding of the drill in accordance with the suspended weight on the drill string in such a manner as to maintain a predetermined constant weight of the drill on the earth's formation and I also provide means for retrieving the drill string irrespective of the other conditions of operation in the event that the load on the main driving amount. For a more complete understanding of my invention, reference should be had to the accom- P 8 8 drawing the single figure of which shows in diagrammatic form a well drilling system embodying my invention.

Referring to the drawing, I have shown my invention in one form as applied to a well drilling system of the type adapted to feed the drill to maintain a predetermined substantially constant v pressure of the drill on the earths formation such as described and claimed in the aforesaid Loomis patent. As shown the drill string 10 of the rotary type provided with a bit 11 is suitably suspended from a derrick by blocks and tackle (not fully shown) comprising a cable 12 passing through the blocks and having its ends secured respectively to the winding drums 13 and 14. The winding drum 14, it will be understood, is provided with suitable driving means (not shown) .whereby it may be'rotated to raise the drill string out of the well. Duringnormai drilling operations, however, the drum 14 is secured against rotation and acts as a dead end for that end of the cable. The drill is rotated by means of a suitable electric driving motor 15, shown as of the three phase type, which is connected through a suitable chain drive 16 and rotary driving mechanism 17 to the drill 10. The driving mechanism 17, for example, may consist of bevel gears of suitable ratio.

As described and claimed in the aforesaid Loomis patent, the-drum 13 is controlled to gradually lower the drill string as the hole is ,60 bored. As shown, the drum can be rotated in either, direction by means of an electric driving motor 20 which is connected to the drum through a suitable reduction gearing 21, a worm 22, a

.worm gear 23 and a chain andsprocket drive 24.

The worm 22 is suitably mounted for endwise movement, i. e., in the direction of its axis of rotation, in response to the weight of the drill string which is applied to the worm, it will be ob-= served, through the driving connections with the drum l3.

This endwise movement of the worm 22 which, it will be observed, is responsive to the weight of the drill suspended on the cable 12, is utilized to control the electric motor 20 and thereby control the feeding of the drill. To accomplish this the endwise movement of the worm is utilized to actuate an electrical contact arm 25 which is movable between spaced adjustable upper and lower contacts to control the opening and closing of reversing switches 26 and 27 in the motor circuit so as to control the starting and stopping of the motor and its direction of rotation. As shown, the end 0! the worm bears against a flexible diaphragm 28 forming a wallof a sealed fluid systemrincluding a pipe 29 and a second flexible diaphragm 30. This movement of the worm in an endwise direction is thus transmitted and applied, at the point desired, to the diaphragm 30. The diaphragm 30 is in turn connected by a rod 31 to a pivoted arm 32, the movable end of which is connected by a link to an operating arm 33 secured to the switch arm 25. Preferably, the switch arm 25 and the arm 32 are mounted in a sealed casing 34 which communicates through a duct loosely surrounding the rod 31 with a casing enclosing the outer or right-hand side of the diaphragm 30. By means of a suitable air pump 35 the air pressure can be varied in the chamber 34 and on the right-hand'side of diaphragm 30,

as indicated by the pressure indicator 36, to adjust the response of the arm 25 to the tension in the cable 12. This arrangement of the pressure responsive control for the switching means forms we no part of my present invention, however, it being described and claimed in a copending application of Caius E. Weaver, Serial No. 612,012, iiled May 18, 1932, and assignedto the same assignee as this invention. no

I have also provided a relay switch 40 which is operated in response to the load on the electric driving motor 15 so as to cause the motor 20 to retrieve or raise the drill in case the torque exerted on the drill, and therefore the load on the motor 15, becomes too great. As shown, this switch comprises an electrically conducting bridging member 41 adapted to be moved to bridge the upper contacts 42 or the lower contacts 43. The bridging member is operated by a coil 44 which is energized from a suitable current transformer 45 connected in one of the supply lines of the motor 15. When the load on the motor and the current in the motor circuit is less than a predetermined maximum the current supplied to the coil 44 is not great enough to lift the bridging member and consequently it remains in its lowermost position,

as shown, bridging the contacts 43. Upon an increase in motor load, and hence current, above the predetermined maximum, the bridging member is lifted to bridge the upper contacts 42.

The relay'40 controls a switch comprising a bridging member 46 which may be moved from one position to another to bridge the contacts 4'? or 48. This bridging member 46 is operated by means of two coils 49 and 50, the coil 49 moving it to the position shown in the drawing to bridge the contacts 47 while the coil 50 moves it to its opposite position to bridge the contact 48. The circuit to the coils 49 and 50 is controlled by the relay switch 40 and is further controlled by a pivoted contact arm 51 connected to the, common armature member 52 of the coils 49-50 so as to be moved to engage either the contact 53 or the contact 54. In the position shown in the drawing the, arm 51 is in engagement with the contact 53 and consequently when the bridging member 41 is moved to engage the contacts 42, a circuit will be closed from the supply main 55- through the conductor 56, the bridging member 41, coil 50, the contact arm 51 to the conductor 57. This energizes the coil 50 which moves the bridging member 46 in engagement with the contacts 48, and also moves the contact arm 51 into engagement with the contact 54. This movement of contact arm 51 away from contact 53 opens the energizing circuit of coil 50. Thereupon when the bridging member 41 drops to the position shown, a circuit is closed for the coil 49 through the contact arm 51 whereby bridging member 46 is moved back to the position shown in the drawing.

The position of the bridging member 46 determines whether the motor 20 shall be controlled by the contact arm 25, or whether the motor 20 shall be energized in a direction to raise the drill independently of the position of the contact arm 25. In the position shown it will be observed that the bridging member 46 is in the circuit of the operating coil 60 for the reversing switch 27 so that this coil as well as the operating coil 61 for the reversing switch 26 can be controlled-by the contact arm 25. With the contact arm25 in its uppermost position as shown, a circuit is closed from the conductor 56 through the conductor 62, the contact arm 25 to the upper contact and thence through conductor 63 and operating coil 61 to the supply main 57 whereby the coil 61 picks up the switch 26 and closes a circuit for the motor 20 in a direction to raise the drill. As the drill is raised its weight suspended .on the cable 12 increases thus moving the worm 22 towards the right as seen in the drawing. Consequently the arm 32 and projection 33 are correspondingly moved towards the right and contact arm 25 is moved downward. The motor continues to operate until the contact arm 25 moves to a position between its two contacts thus breaking the circuit for the coil 61 whereupon the switch 26 is dropped open and the motor 20 is brought to rest. When the weight of the drill string on the cable becomes greater than the value for which the control is adjusted, the contactarm 25 is forced downward into engagement with its lower contact whereby a circuit is closed from the contact arm through the conductor 65, the bridging contact 46, conductor 67, and coil 60 to the supply main 5'7. This closes the switch 2'7 to start the motor 20 in opposite direction to lower the drill whereby more weight is applied to the earths formation and the tension in the cable 20 is corerspondingly decreased until finally the I contact arm 25 disengages its lower contact to stop the motor.

In the event that the load on the motor 15, however, becomes'greater than a predetermined amount, the bridging member 41 of relay 40 is raised to its uppermost position whereby the coil 50 is energized and the bridging contact 46 is moved into engagement with the contacts 48. This closes a circuit from the conductor 56 through the conductor 68, the bridging contact 46, conductor 69, conductor 63 and the coil 61 to the supply main 57 whereby the switch 26 is closed and the motor started in a direction to raise the drill. This operation continues until the load on the driving motor 15 has been decreased to a predetermined amount for which the relay 40 is set, when the relay drops down to the position shown and the bridging member 46 is thereby moved back to the position shown to deenergize the coil 61 and stop the motor. This retrieving action of the drill in response to the load on the motor 15, it will be observed, takes place entirely independently of the weight control by the contact arm 25.

An alternative arrangement may be provided by removing or breaking a section 70 of the conductor 69 which section joins the upper contact of switch arm 25 to the junction of

conductors

63 and 69. It will be readily seen that this eliminates the retrieving action produced by excessive pressure of the bit on the earth's formation which causes switch arm 25 to be moved upward until it engages the upper contact, and will therefore leave only the retrieving action produced by excessive torque which increases the motor current, thereby causing relay 40 to move bridging member 41 upward, as previously described. In other words, the equipment now feeds the drill downward in response to the weight of the drill, but retrieves the drill in response only to the torque applied to the drill as evidenced by the load on the motor.

What I claim as new and desire to secure by Letters Patent of the United States is:

1 The combination in well drilling apparatus, of a drill, hoisting means for raising and lowering the drill, an electric motor, a driving connection including a worm and a worm gear between said motor and said hoisting means said worm being mounted for axial movement in response to the suspended weight of the drill, control means for said motor, means responsive to movement of said worm for operating said control means to cause the motor to lower the drill when the pressure of the drill on the earth's formation becomes less than a predetermined value, a second electric mo or connected to rotate said drill and means responsive to the current supplied to said second motor for operating said control means to raise said drill in the event that the load on said second motor exceeds a predetermined value.

2. The combination in well drillir g apparatus of a drill, a driving motor for raising and lower-- ing said drill, means for controlling said motor for each direction of rotation, a control contact device movable to one position to close a raising circuit for said motor control means whereby said motor is caused to operate in a direction to raise the drill and movable to another position to close a lowering circuit for said motor control means whereby the motor is caused to operate in a direction to lower the drill, means responsive to the suspended weight of the drill for controlling said contact device so as to cause said motor to lower said drill when the pressure of the drill on the earth's formation becomes less than a predetermined amount, a second switching device movable to one closed circuit position to close a portion of said lowering circuit and to a second closed I circuit position to disable said lowering circuit 3. The combination in well drilling apparatus, of a drill, a driving motor for raising and lowering said drill, means for controlling said motor for each direction of rotation, a control contact device movable to one position to close a circuit for said motor control means to raise the drill and to another position to close a circuit for said motor control means to lower the drill, means responsive to the suspended weight of the drill for controlling said contact device so as to cause said motor to lower said drill when the pressure of the drill on the earth's formation becomes less than a predetermined amount, a second switching device movable to one closed circuit position to close a portion of said lowering circuit and to another closed circuit position to disable said lowering circuit and complete said raising circuit independently of said contact device, separate windings for moving said second switching device respectively to said first and second position, means responsive to load current in said motor for closing the circuit of one of said windings to operate said second switching device to said second position to raise said drill upon the occurrence of a predetermined maximum load on said motor and for closing the circuit of the other of said windings to return said second switching device to said first position upon the reestablishment of a motor load below said predetermined maximum, and means operated by said second switching device for controlling the connections to said windings.

WILLIAM G. TAYLOR.