US1967111A - Rotary well drilling apparatus - Google Patents

Description

19mm R July 17, @3 21, L, J. BLACK ROTARY WELL DRILLING APPARATUS 2 SheecQs-Sheet 1 Filed Dec. 29, 1928 ditoznn:

Jufly 17, 19341. Q]... .J. BLACK ROTARY WELL DRILLING APPARATUS Filed Dec. 29, 1928 2 Sheets-Sheet 2 Patented July 17, 1934 UNITED STATES PATENT OFFICE This invention relates to rotary well drilling apparatus and more particularly to a means for controlling the weight imposed upon the bits of rotary well drilling apparatus.

As is well known to those familiar with the art, considerable difficulty is met with when drilling to great depths with rotary well drilling ap paratus in keeping the well bore straight. This difficulty arises principally from the fact that so much weight is imposed upon the drill pipe or string that the lower portions thereof buckle until they are supported by the walls of the bore which are usually of considerably greater diameter than the bit. An important object of the present invention is the provision of means for maintaining a substantially constant pressure on the bit and reducing the total pressure which would normally be supplied to a desired maximum.

A further object of the invention is to produce an apparatus of this character which will involve no change in the present drilling organization other than the addition or" a small hoist which is connected with the drilling line.

A still further object of the invention is to provide a device of this character which will be effective in operation throughout the entire drilling period in which the well is cored through a distance equal to a drill stem length which may be twenty or thirty feet.

A still further object of the invention is to provide in combination with apparatus or" this character, safety mechanism preventing accidental destruction or severing oi the drilling line, due to paying out or" the entire cable content of the auxiliary hoist.

ihese and other objects I attain by the construction shown in the accompanying drawings, wherein for the purpose of illustration is shown a preferred embodiment of my invention and wherein:-

Figure 1 is a front elevation of a rotary drilling rig embodying a drilling weight control constructed in accordance with my invention;

Figure 2 is a front elevation of the auxiliary hoist;

Figure 3 is a side elevation partially in section thereof;

Figure 4 is a detail view showing the pawl releasing position of the toggle mechanism;

Figure 5 is a section on the line 55 of Figure 2.

Referring now more particularly to the drawings, the numeral generally designates a rotary drilling table, 11 a drill stem directed therethrough for rotation thereby and 12 and 13 the fixed and movable blocks of hoisting mechanism, the movable block. being connected to the upper end of the drill stem to support the same.

The drilling line 14, which is reeved through these blocks, is secured at one end to a drum 15 forming a part of the usual rotary drilling draw works structure. Such draw works include, in addition to the drum, a drive sprocket 16 or some other suitable means through which the draw works may be connected to the table to rotate the same. The drum has associated therewith brakes 17 operated through a lever 18 to hold the drum in fixed position or to release this drum to permit the drilling line to pay out and the drill stem to lower. Operation of the draw works is obtained by a driving engine 19, which is usually a steam engine supplied from a main 20.

The usual procedure in handling such apparatus during a drilling period is for an attendant to manipulate the brake lever 18 to release the stem and allow it to lower in order to compensate for the drilling. Obviously, this provides no indication of the pressure placed upon the bit except that afforded when the drilling line it slackens. When this occurs, it is necessary to connect the drum 1'? with power and rewind a portion of the drilling line thereon.

In accordance with my invention, 1 provide an auxiliary hoisting drum 21, to which the opposite end oi the drilling line is attached instead of being attached to some fixed point or to the eye 22 of the traveling block. An operating motor 23 is provided to drive this drum constantly in one direction. This motor is at present disclosed as a steam engine, receiving its steam supply through a branch 24 of the main and this branch has arranged therein an adjustable regulating valve 25, by means or" which the steam pressure admitted to the engine may be controlled. This regulating valve may be of any suitable character.

It will be obvious that if the drilling line in its connections to the drum 15 and drum 21 and through the blocks 12 and 13 to the drill stem 11 has five runs and the total weight of the drill stem is thirty-five tons, each of these runs will normally be subjected to a strain of seven tons, if the entire weight is to be counterbalanced. Assuming that of the total weight of thirty-five tons, ten tons is to be imposed upon the drill during the drilling operation, then each of these runs must support a strain of five tons in order that the weight applied to the bit shall remain at the desired total.

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Under these circumstances, the regulating valve will be so set that the engine 23 through its internally developed power and its gearing connections 26 with the drum 21 will exert a pulling strain of five tons through the drum 21 upon the drilling line 14. If the weight imposed upon this line exceeds five tons, then the engine and drum will be reversely operated and the drilling line will unwind therefrom, permitting the drill stem to lower. If, on the other hand, the weight imposed upon this line is less than five tons, the engine will operate in its normal manner and will wind the drilling cable upon the drum 21 until a total five ton strain is imposed thereagainst, at which time a state of balance will be reached. It will also be obvious that in drilling with say a thirty foot drill stem, in order to drill down through the full thirty feet of the drill stem with a five run hoisting block connection, one hundred and fifty feet of drilling line must be paid out during this operation. Bearing this in mind, it will be obvious that if, at the time the dril is lowered into the well, through the manipulation of the drum 15, the attendant permits the drilling cable to slack off from the drum 15, the drill stem will be lowered until the bit too forcibly engages the bottom of the bore and the weight upon the separate runs will fall below the desired total. The drum 21 will then be operated to wind the cable thereon. By continuing this operation until one hundred and fifty feet of the cable has been wound upon the drum 21, the brakes 15 can be locked and until the drill stem has lowered through its full length, the drum 21 will continue to pay out the cable to feed the drill as the operation of the drill cuts away material from the bottom of the bore.

In order to prevent complete withdrawal of cable from the drum 21 with the resultant tendency to shearing of the cable, I provide, in combination with this drum, a safety mechanism, more clearly disclosed in Figures 2 to 5. In the production of this safety mechanism, the drum flanges 27 are formed with ratchet teeth 28 and adjacent these flanges, a shaft 29 is extended bearing pawls 30 for engagement with these ratchet teeth. Upon suitable supports 31 adjacent the shaft, I mount toggle link mechanisms 32. Each toggle link mechanism comprises an upper link 33 pivoted to swing longitudinally of the drum and a lower link 34 pivoted to the lower end of the link 33 at its upper end and to an arm 35 secured to the shaft 29. Pivotal movement of the links about the connection therebetween is limited in one direction when the links are approximately aligned with one another by abutting shoulders 36 formed upon the links and in the opposite direction by abutting shoulders 37 when the links have assumed a predetermined angle to one another. The connection between the links and the shaft is sufficiently loose to accommodate the necessary movement of the shaft during passage of the ratchet teeth beneath the pawls. When the links are positioned with their shoulders 36 engaged, the pawls are in operative engagement with the ratchets and when the links are positioned with their jaws 37 engaged, these pawls are held out of engagement with the ratchets.

The links are preferably provided in two sets and the links of at least one of these sets are connected by a spring 38, the opposite ends of which are so connected that when the shoulders 36 are in engagement with one another, the pivotal connection 39 of the links lies to one side of the axis of the spring and when the shoulders 37 are engaged with one another, the pivotal center lies to the opposite side of the axis of the spring.

It will thus be obvious that the spring 38 serves to maintain the links in either of the positions above described and to shift the links from one position to another when they have been given an impulse moving them from the first position toward the second position a distance sufiicient to cause the pivotal connection 39 to move past the axis of the spring.

Each set of links is equipped with a guide 40 preferably in the form of an apertured car on one of the links of the set. Through the aperture 41 of this ear, a bar 42 is directed having applied thereto over the drum a pair of grooved pulleys 43 through which the drilling cable 14 is passed. It will be obvious that this bar will shift longitudinally of the drum as the cable is spooled thereon. Mounted upon this bar at opposite sides of the toggle link sets are adjustable stops 44 which, when the bar has been shifted a predetermined distance, come into contact with the link mechanisms adjacent the pivotal connections thereof and shift these pivotal connections against the action of the spring from one position to another. One set of stops is so positioned that the shifting movement of the toggle links to the position in which the jaws 36 engage is completed at a time when the drum is operating reversely and paying out cable while there are still several turns left upon the drum. The other set of stops is adapted to engage and shift the toggle links at the time when the cable has been wound to its fullest extent upon the drum, that is to say, the maximum extent to which it is intended that it shall be wound hereon.

If the amount of cable to be wound upon the drum will result in spooling upon the drum of more than one layer so that the cable will move first from one end toward another and then start a reverse winding movement, the last named set of stops are so positioned that they trip the toggle links just as the winding of the first layer is completed. It will be obvious that starting from a .point where a minimum amount of cable is wound upon the drum, the winding operation will first cause the bar to move to the left in Figure 2, and this movement will cause the right hand set of stops to come in engagement with the toggle links and shift them from a position where they permit engagement of the ratchets by the pawls to a position where they withdraw the ratchets therefrom. The winding movement having been completed and the drilling operation started, the drum 21 starts paying out its cable, with the result that as this cable is nearly depleted, the left hand set of stops comes into engagement with the toggles and moves them to a position where the pawls are permitted to reengage the ratchets. This prevents any further cable being withdrawn from the drum and, therefore, prevents shearing of the cable which would very possibly result if the unwinding were continued to the end thereof.

It will be obvious that in employing a structure of this character, the constant close attention of an operator at the ordinary draw works is eliminated and that accordingly he may give his attention at other points where it may be necessary. The regulation of pressure of the drill is not only rendered automatic but this regulation is extended through the entire stage of the drilling operation during which the drill em is being sunk.

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reearrr There will be no necessity for many adjustments of the regulating valve, as the drilling pressures are not critical but must merely be kept approximately at the highest point of eficiency, which is that point at which the weight imposed upon the drill bit is the greatest, which can be imposed with safety and without danger of buckling of the stem. It will, of course, be understood that employing the principle hereinbefore set forth, the invention, as illustrated, is capable of a very considerable range of change and modification. For example, by modifying the present arrangement to the extent of driving the rotary from an independent engine, the engine of the main hoist could be equipped with a regulating valve alternatively usable with the ordinary throttle valve, thus permitting the single drum hoist to accomplish the functions which, in the arrrangement above described, are accomplished by main and auxiliary hoists.

Other changes being possible without in any manner departing from the spirit of the invention, I do not limit myself to the structure hereinbefore set forth except as hereinafter claimed.

i. In rotary well drilling apparatus, a support for a drilling string including a drilling line, a hoist connected to one end of the drilling line, an operating motor for said hoist acting through said drilling line and hoist to exert a continuous predetermined lifting efiect upon the string less than the total weight of the string for the purpose of preventing excessive torque, said operating motor being reversible against the motive force employed therein when the effective weight of the drilling string exceeds the lifting effect exerted thereon to thereby permit the string to lower, means operated by the cable positively engaging with and locking the hoist aga nst reverse motion when a predetermined amount of drilling line has been withdrawn therefrom, and a second hoist connected to the opposite end of the drilling line.

2. In rotary well drilling apparatus, a draw works including the usual drum, fixed and travelng blocks, a second hoisting drum, means for holding the drum of the draw works against rotation, a drilling cable secured at one end to the drum of the draw works and reeved through said blocks and. connected at its opposite end to said second drum, a fluid pressure motor for said second drum permitting reverse rotation of the second drum when a predetermined gravity pull is exerted on the hoisting line greater than the pressure of the motive fluid on said motor for the purpose of preventing excessive torque, means for regulating the mean efiective pressure of said motor to thereby determine the weight which may be suspended from the traveling block without reverse rotation of said second drum, means engageable with the drum to prevent reverse rotation thereof and means for placing said preventing means in action automatically when a predetermined amount of cable has been unwound therefrom.

3. In rotary well drilling apparatus, a draw works including the usual drum, fixed and traveling blocks, a second hoisting drum, means for holding the drum of the draw works against rotation, a drilling cable secured at one end to the drum of the draw works and reeved through said blocks and connected at its opposite end to said second drum, a fluid pressure motor for said second drum permitting reverse rotation of the second drum when a predetermined gravity pull is exerted on the hoisting line greater than the pressure acting on said motor for the purpose of preventing excessive torque, means for regulating the mean effective pressure acting on said operating motor to thereby determine the weight which may be suspended from the traveling block without reverse rotation of said second drum, pawl and ratchet mechanism for preventing rotation of said second drum in a direction permitting cable to be withdrawn therefrom, and means controlled by the cable rendering said pawl and ratchet mechanism inoperative after a predetermined amount of cable has been wound thereon until such amount of cable has been again withdrawn therefrom.

i. In a rotary well drilling apparatus, a draw works including the usual drum and traveling blocks, a second independently operable hoisting drum, manually operable means for controlling the operation of the first named drum, including means for holding it against rotation, a drilling cable secured at one end to the first named drum and reeved through said blocks and connected at its opposite end to said second named drum, a fluid pressure operated motor for said second drum permitting reverse rotation of the second drum when a predetermined gravity pull is exerted on the hoisting line greater than the pressure acting on said motor, and constantly adjustable, manually operable means for regulating the mean effective pressure acting on said operating motor to thereby predetermine the weight which may be sustained from the traveling block without reverse rotation of said second drum.

LEE J. BLACK.

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