US3901330A

US3901330A - Electric power drive assembly

Info

Publication number: US3901330A
Application number: US418065A
Authority: US
Inventors: Damon T Slator; Cicero C Brown
Original assignee: Brown Oil Tools Inc
Current assignee: Hughes Tool Co
Priority date: 1973-11-21
Filing date: 1973-11-21
Publication date: 1975-08-26
Anticipated expiration: 1992-08-26

Abstract

Disclosed is a reversible, electric motor drive assembly pivotally supported from the traveling block in a derrick employed to rotate, raise, lower or otherwise handle tubular members used in the drilling and production of oil and gas wells. Hydraulic cushioning means support the assembly from the traveling block. A tubular mandrel extending through a bore in the motor shaft provides a conduit for introducing drilling fluid to a drill string connected to the rotating output drive stem of the assembly. The assembly is equipped with a pneumatically operated friction brake to permit precise and rapid alignment of equipment carried by the stem with tubular members to be handled. A locking means is employed to prevent loosening of the mandrel during reverse rotation of the stem. The reduction gearing in the assembly is immersed in oil and functions as a pumping mechanism to provide improved oil cooling and lubrication while magnetic drain plugs in the gear housing remove metal debris from the circulating oil.

Description

United States Patent Slator et a1.

1 Aug. 26, 1975 1 ELECTRIC POWER DRIVE ASSEMBLY [75] Inventors: Damon T. Slator; Cicero C. Brown,

both of Houston, Tex.

[73] Assignee: Brown Oil Tools, Inc., Houston,

Tex.

[22] Filed: 4 Nov. 21, 1973 [211 App]. No.: 4l8,065

[52] US. Cl. 173/57; 74/411.5; 74/467; 173/164; 285/89 [51] Int. Cl. E21B 19/16 [58] Field of Search 173/57, 164; 175/170, 85;

[56] References Cited UNITED STATES PATENTS 2,032,732 3/1936 Zcrbe 74/467 2,677,440 5/1954 Willis 184/625 X 3,214,198 10/1965 Pcuchmaur 285/355 X 3,312,294 4/1967 Wilson 175/85 X 3,623 558 11/1971 Brown 173/57 3,696,872 10/1972 Jonsson 173/164 X 5 7 ABSTRACT Disclosed is a reversible, electric motor drive assembly pivotally supported from the traveling block in a derrick employed to rotate, raise, lower or otherwise handle tubular members used in the drilling and production of oil and gas wells. Hydraulic cushioning means support the assembly from the traveling block. A tubular mandrel extending through a bore in the motor shaft provides a conduit for introducing drilling fluid to a drill string connected to the rotating output drive stem of the assembly. The assembly is equipped with a pneumatically operated friction brake to permit precise and rapid alignment of equipment carried by the stem with tubular members to be handled. A locking means is employed to prevent loosening of the mandrel during reverse rotation of the stem. The reduction gearing in the assembly is immersed in oil and functions as a pumping mechanism to provide improved oil cooling and lubrication while magnetic drain plugs in the gear housing remove metal debris from the circulating oil.

PATENTED 2 1975 WN V/Z I I, w 7 ill! I l z ELECTRIC POWER DRIVE ASSEMBLY RELATED APPLICATIONS AND PATENTS This application is related to the inventions described in US. Pat. application Ser. No. 130,597 filed Apr. 2, 1971 and now U.S. Pat. No. 3,766,991 entitled Electric Power Swivel and System for Use in Rotary Well Dril' ling, and in US. Pat. application Ser. No. 206,325 filed Dec. 9, 1971 and now US. Pat. No. 3,774,697 entitled Rotary Drive Assembly for Handling Tubular Members, both of said inventions as well as the present invention being assigned to a common assignee.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to means for handling tubular fluid conducting members. In the specific application to be described, the present invention relates to vertically movable powered drive means for imparting rotary, vertical and pivotal motion to drill pipe and other tubular well members employed in the drilling and production of petroleum wells.

2. Brief Description of the Prior Art In the conventional method of drilling wells, large internal combustion engines or other power sources are employed to rotate a rotary table set in the floor of a drilling derrick. Rotary motion of the rotary table is conveyed to a square kelly which is free to slide vertically through the rotary table while it is rotated by the table. The lower end of the kelly is threadedly engaged to the upper end of a string of drill pipe and the rotary motion is carried to a bit located at the lower end of the string.

As lengths of pipe are added to or removed from the drill string, it is necessary to employ auxiliary equipment such as wrenches, tongs, ropes and chains to threadedly engage and disengage the pipe members employed in the string. The technique, which is well known, is slow and extremely dangerous.

Other operations conventionally employed during the drilling ofa well may require cocking the kelly over to connect into or release a short length of drill pipe. The cocking and threading or unthreading requires manual movement of the heavy equipment away from its normal vertical position which again necessitates the use of cumbersome, dangerous equipment.

As described in the prior related patent applications, a power swivel of the type referred to herein may be used to raise, lower, rotate and pivot pipe members, and any other equipment employed in drilling and completing a well. The ease with which such a swivel may be raised, lowered or pivoted, as well as the operators ability to manipulate the device automatically from a control panel, makes the task of making or breaking strings, or handling other equipment, faster and safer. While the apparatus of the related applications have substantially reduced many of the foregoing problems, there has been a need for improved control over the angular positioning of the power drive stem in the power swivel. Such a need arises for example when elevators are carried by the drive stem and it is desired to align the access opening in the elevators with a length of pipe .which is to be moved. Simple reversal of the polarity of the electrical power supplied to the motor functions to brake the stem rotation but does not operate to hold the stern stationary. Moreover, several repeated turns of the stem may be required before the stern comes to rest at the desired angular position.

During the process of working a well, and in particular when a pipe string is being broken, there are times when the swivel stem must be operated in reverse rotation. The fluid conducting mandrel that passes through the center of the swivel and of the motor, and which is used to conduct drilling mud and other fluid to the well, as described in US. Pat. application Ser. No. 130,597 may tend to loosen, due to fluid drag, where conventional right-hand threads are used to secure the mandrel to the stem.

SUMMARY OF THE INVENTION The assembly of the present invention provides vertical, rotary and angular movement in tubular well pipes as required in the drilling and completion of petroleum wells. These needs are provided without the use of cumbersome rotary tables and slow, dangerous auxiliary equipment. In the present invention, a reversible electric motor with reduction gearing is mounted as a vertically and pivotally movable rotary drive or power swivel assembly in a well derrick, and is employed to handle the tubular members used in the drilling and production of a well.

An annular brake drum is rigidly attached, concentrically, to the output drive stem of the assembly to assist in precisely orienting the stem. Pneumatically activated annular brake shoes, rigidly mounted ultimately to the assembly housing, are selectively operable to engage the brake drum to prevent or stop rotation of the swivel stem and whatever equipment is attached thereto. With this latter improvement, the operator need no longer rely on a hit-or-miss approach in orienting the drive stem and the equipment attached thereto in order to make a union with other equipment.

Extensive hollow regions within the gear housing permit increased circulation of lubricating and cooling fluid around the bearings supporting and aligning the swivel stem. In addition, a pumping action is provided by the mating of gear teeth to further enhance the circulation of the lubricant-coolant. One or more magnetic drain plugs in the lower portion of the swivel housing collect metal shavings that result from wear. Draining and replacement of the lubricating oil, as well as removal of the collected metal shavings are effected by merely removing the drain plugs.

The mandrel passing through the motor and drive stem, and used to communicate drilling fluid to the drill string, is threadedly connected to the inside of the stem at a point below the swivel. This connection is secured by a lock nut which is threadedly joined to the interior of the stem by threads having a thread lead which is less than that in the mandrel connection. The lock nut functions to tighten against the base of the mandrel when the assembly is undergoing reverse rotation and prevents the mand rel from loosening from the stem.

These and other features and advantages of the present invention will be better understood from the following specification, the related drawings and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical elevation in partial section illustrating a preferred form of the swivel and brake system of the present invention; and

FIG. 2 is an enlarged scale insert from FIG. 1 showing details in the construction of the lubricant-coolant pumping means of the present invention.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT The assembly of the invention is indicated generally at in FIG. 1. The assembly includes a main housing 17 in the form of a substantially annular, hollow body which encases the upper end of a rotatable output drive or swivel stem 18 and reduction gears connected between a motor shaft and the stem. A flow path 11 extends through the housing l7 to supply lubricant to the various internal components. The upper end of the housing 17, which is closed over by a circular, centrally apertured plate 12, includes two radially extending diametrically

opposed suspension ears

13 and 33 used to suspend the assembly 10 from the derrick (not shown).

A tubular sleeve 37, having an axial throughbore 38, is screwed into the lower end of a vertical bore 34 formed through the suspension ear 33, which is similar in construction to the ear 13. A bore 36 through the ear 35 of plate 12 registers with the bore 34. The bore 38 defines a pressure cylinder 38a adapted to receive a piston 39 formed with a lower head 40 fitted with

seal rings

41 and 42 for slidable sealing engagement with the wall of bore 38. Piston 39 extends upwardly through

bores

34 and 36 which are provided with

packings

43 and 44 respectively, sealing with the piston to close the upper end of the cylinder. A nut 43a screws into the bore 34 in the suspension ear 33, keeping the seal 43 under pressure, and providing a smooth base, flush with the top of the ear 33, upon which the seal 44 may be seated. The upper end portion of piston 39 which projects above plate 12 is provided with an externally threaded pin 45 which is screwed into a hanger cap 46. The latter has an upwardly extending lug 47 which is received in a clevis 48 and pivotally secured thereto by means of a transversely extending pivot pin 49. The clevises on both sides are secured to the opposite ends of a bail 50 by means of which the entire device is swung (in a manner not illustrated) from a hook or like connection of a travelling block employed in conventional rotary drilling and suspended from drilling cables in a conventional drilling derrick.

Each of the cylinders 38a is in communication with a port 51 which is connected to a conduit 52 leading to a closed reservoir of an inert pneumatic fluid (not shown) such as nitrogen gas, which is kept continuously pressurized.

The outer ends of ears 33 are fitted with trunions 72 journalled in the ends of guide arms 73 which connect to guide sleeves (not shown) disposed for sliding movement on vertically positioned guide bars (not shown) suitably mounted in the drilling derrick in which the power swivel is suspended. The trunions thus provide a pivoting connection between the power swivel and the guide sleeves so as to permit the power swivel to be tilted at an angle to the vertical when required.

In order to effect tilting of the power swivel when desired, a fluid pressure actuated tilting jack (not shown) is connected between the travelling block supporting the power swivel and housing 17 of the power swivel. Such a tilting jack is disclosed in US. Pat. application Ser. No. 130,579, and further information regarding the mounting and use of the assembly 10 may be derived from the said patent application as well as US Pat. application Ser. No. 206,325.

A reversible electric motor encased within a motor housing M is employed to provide power in the form of rotary motion in a hollow drive shaft 16 having an axial bore 16a. Bolts 15 secure the motor housing M to the top plate 12. The lower end of the drive shaft 16 is locked to a central spur or pinion gear 27 equipped with gear teeth 27a (FIG. 2). An annular bearing mount 53 encircles the gear 27 and supports an inner race member 54 on inclined roller bearings 55. An outer race 56 for the bearings 55 is mounted concentrically within the circular plate 12. The roller bearings 55 are employed for preloading the rotatable drive assembly and provide both axial and radial friction reducing support.

Three planetary gears, one shown generally at 57, are mounted for rotary motion about shafts secured to a circular mounting head formed at the upper end of the stem 18. The lower end of the stem 18, which extends downwardly through bore 14 in the housing 17 and below the brake system 90, is internally threaded to receive other equipment. The centers of the gears 57 are positioned on the same radius and are circumferentially spaced 120 from each other. The three gears 57, which are the same, will be described with specific reference only to the one gear shown. This gear 57 includes a central shaft 29 which is mounted in a receiving recess 18a formed in the top surface of the mounting head on the stem 18. Socket head bolts 30 hold the shaft 29 in firm engagement with the stem 18 and ball bearings 58 mount an annular gear ring 26 about the shaft 29. The ring 26 is equipped with external gear teeth 28 which mesh with the gear teeth 27a on the pinion gear 27 and also mesh with gear teeth 31a formed internally of a large ring gear 31. The ring gear 31 is rigidly secured to the plate 12 by suitable socket head bolts 32.

Rotary and axial support for the large weight which is to be suspended from the stem 18 is provided by tapered roller bearings 59 supported between lower and

upper races

19 and 19a, respectively. The lower race 19a is supported on an annular H-beam collar 20 which in turn is supported on an internal shoulder 21 formed in the housing 17. A conventional strain gauge is attached to the upstanding web 20a connecting the upper and lower portions of the collar 20 and suitable electrical leads 70a extend to an external control panel (not shown) to provide an input signal to a transducer which forms a visible indication of the weight being supported by the stem 18.

At the lower end of the housing 17, the stem 18 is supported radially by roller bearings 22. An annular fitting 23 secured to the base of the housing 17 by bolts 25 mounts a resilient seal 24.

Magnetic drain plugs (one shown) are threadedly inserted in vertical holes 81 (one shown) located in an annular arrangement about the lowest portion of the passage 11 in the housing 17. Passageways 11a (one shown), forming a portion ofthe flow passage 11 in the housing 17, are radially aligned with corresponding holes 23a in the annular fitting 23, just below each roller bearing 22. An enlarged spacing 71 (FIG. 2) in the passage 11 forms a passageway above

gear teeth

27a and 28, between the bearing mount 53 and the pinion gear 27, and up to the bearings 55.

The mating of the pinion gear with the planar gear displaces the oil located between the teeth of each gear, causing this oil to flow parallel to the cylindrical axes of the gears. The open space 71 above the region of the meshing of the gear teeth is greater than that below the gears, permitting a greater amount of the moving oil to flow into the upper space 71 as compared with that flowing in the opposite direction. In this way, as the gears turn in either direction, oil is circulated upwardly to flow over and around the bearings 55, while more oil is drawn into the region of the meshing teeth from below, and a continuous pumping action is established to keep the oil circulating.

A tubular mandrel 60 extends upwardly through the bore of the stem 18, being threadedly connected to the stem at a point at the bottom of a brake system 90 by a threaded connection 61. The mandrel extends upwardly through the bore of pinion gear 27 and the bore 16a of the motor shaft 16 and thence through a swivel housing 62. The mandrel 60 continues externally to appropriate fittings (not shown) required for the conduc' tion of drilling mud or other fluid to the drill string through the bore of the mandrel 60.

Viscous drag between the interior surface of the mandrel 60 and the fluid it contains tends to unthread the mandrel during reverse rotation of the stem 18. A lock nut 63 is threadedly connected to the interior of the stem 18 just beyond the mandrel-to-stem connection 61. The thread lead of the lock nut connection is made smaller than that of the mandrel connection. The lock nut 63, having a smaller surface area exposed to the fluid within than does the mandrel 60, will experience smaller viscous drag than will the mandrel. Furthermore, with a smaller thread lead, the lock nuts axial movement will be less than that of the mandrel for one turn. Since the mandrel, upon loosening, must move in the direction of the lock nut, any loosening of the mandrel induced by reverse rotation of the swivel stem will be blocked by the slower moving lock nut. This locking force increases as the forces tending to rotate the lock nut and mandrel increase.

The brake system 90 is enclosed by a hollow, annular housing 91, the upper portion of which is composed of a flange 91a welded to a ring 91b which is welded to a second, smaller flange 910. The housing 91 is thus suspended by flange 9lc which is connected, through an annular fitting 82, to the annular fitting 23 by bolts 25. The lower portion of the housing 91 is formed by a flanged ring 91d which is welded to the flange 91a.

An annular sleeve 92 is locked to and thereby rotates with swivel stem 18. An annular brake drum 93 is bolted to the sleeve 92 by bolts 94. The outer annular surface 93a of the brake drum 93 provides the braking means when contacted by brake shoes 95 (only one shown).

A pneumatic connector 96, suspended from the housing 91 by a bolt 96a, leads from a pneumatic supply line (not shown) to a flexible member 96b, which is designed to inflate with pressurized air supplied from the pneumatic line. Inflation of the member causes the member to press against an enclosing flexible member 96c. This in turn causes the brake shoes 95 carried on the member 960 to be forced inwardly against the brake drum 93a. The brake shoes comprise a plurality of plates of any suitable material suspended annularly about the inner surface of the flexible member 96c. The

flexible member 96c is resilient and causes retraction of the brake shoes 95 and collapse of the flexible member 96b when the pressure within the flexible member 96b is relieved through the pneumatic supply line.

The sleeve 92 is equipped with a vertical, cylindrical bore 92a plugged at the'top end to form a flow passage rotating with the swivel stem 18. The bottom of the passage 92a is threaded to receive a hose fitting (not shown). A circumferential recess 92b in the sleeve 92 communicates between the passage 92a and a passageway 82a in the vertical wall of the annular fitting 82. The passageway 82a is aligned with an opening in the ring 91b of the housing 91 to permit access, via a conduit (not shown), to the passageway 82a, which is threaded to receive a hose fitting (not shown). Double resilient seals 83 above and below the region of the passageway 82a preserve the integrity of the communication from the passage 92a to the passageway 82a to the conduit.

OPERATION OF THE ASSEMBLY ln operations such as making or breaking a pipe string, attaching orienting equipment for directional drilling, etc., the operator is periodically required to stop and hold the swivel stem 18 steady in some particular angular orientation. When this need arises, the operator actuates the brake system by increasing the pneumatic pressure via the conduit (not shown) connected to the pneumatic connector 96. The flexible member 96b is thereby inflated, pressing against the flexible member 960, causing the brake shoe to be forced against the brake drum 93. Friction between the brake shoe 95 and the outer surface 93a of the brake drum 93 supplies the braking action, which prevents the brake drum 93 from rotating with respect to the brake shoe 95. Since the brake shoe is held fixed to the brake system housing 91, which is rigidly connected to the swivel housing 17, and since the brake drum 93 is rigidly connected to the stem 18, activation of the brake system in this manner prevents rotation of the stem 18 with respect to the housing 17. The operator may thus align the stem, including whatever equipment may be attached thereto, and selectively lock'the stem against rotation about its axis.

Once the activity necessitating the locking of the stem in position is completed, the operator need only reduce the pneumatic pressure via the conduit to the connector 96. The resilient member 960 will collapse, causing the retraction of the brake shoe 95 from the brake drum surface 93a. The stem is then released, and the operator may continue with rotational motion, if desired.

Once the mandrel 60 is installed and screwed into place within the stem 18, the lock nut 63 is fastened below the mandrel, tightly against the bottom face of the mandrel. Any viscous drag or other retarding force exerted on the mandrel during forward rotation of the stem 18 only serves to tighten both the mandrel 60 and the lock nut 63 in their respective threaded connections to the stem 18. In reverse rotation, however, the retarding forces tend to unthread the mandrel 60 and the lock nut 63. The mandrel attempts to overrun the slower moving lock nut, which in turn jams the two members together to prevent further movement. Thus, if the mandrel tends to loosen, it will be blocked by the lock nut, with the result that the mandrel is effectively locked in place in its attachment to the swivel stem 18.

The housing 17 is filled with an appropriate lubricating and cooling fluid such as a light weight motor oil. As the assembly is driven rotationally by the motor M, the meshing of the pinion gear 27 with the planatary gears 57, combined with the increased volume above the region of the mating of the teeth of these gears, pro duces a circulating pumping action. Oil is thus forced over the roller bearings 55, and then through the rest of the expanded cavity 11 within the housing 17.

The passageway formed at 11a and 23a through the housing 17 and the annular fitting 23 respectively allows circulation of the oil to the roller bearings 22. The roller bearings 59 giving vertical support to swivel stem 18 are also open to the oil circulation due to the shape of the passageway 11 within the housing 17. The described oil circulation serves to keep all exposed parts within the housing 17 lubricated, to cool parts that tend to heat up during operation of the swivel, and to flush all metal fillings and chips and other metallic debris produced during operation. In the process of circulating around the flow path 11, the oil moves this debris past the magnetic drain plugs 80. These plugs magnetically attract and hold the metallic debris, removing it from the circulating oil. The debris can then be periodically removed by removing and cleaning the magnetic drain plugs 80.

The flow passage 92a in the sleeve 92 which rotates with the swivel stem 18 permits a pneumatic, hydraulic, or other type connection between any equipment attached to and rotating with the swivel stem 18 and an external source (not shown). A hose connection is made from said rotating equipment via the threaded bottom of the passage 92a. Communication of the fluid to or from the external source is then made via the groove 92b, the passageway 82a, threaded for an external hose fitting, and thence to the source via said hose (not shown).

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials as well as in the details of the illustrated construction may be made within the scope of the appended claims without departing from the spirit of the invention.

We claim:

1. A rotary drive assembly for rotating tubular members comprising:

a. motor means for developing rotary power in said assembly;

b. an axially extending rotatable stem means rotatably powered by said motor means; and

c. friction braking means included in said assembly for selectively stopping and/or retaining said stem means at a fixed angular position about its axis.

2. A rotary drive assembly for rotating tubular members as defined in claim 1 further including fluid powering means for selective activation of said friction braking means.

3. A rotary drive assembly for rotating tubular members as defined in claim 1 further including:

a. a tubular mandrel means extending axially through said stem means; and

b. locking means, movable relative to said mandrel means, for retaining said mandrel means within said stem means, said locking means including means for providing increasing locking forces in response to increasing rotational forces tending to displace said mandrel means within said stem means.

4. A rotary drive assembly for rotating tubular members as defined in claim 3 further including fluid powering means for selective activation of said friction braking means.

5. A rotary drive assembly for rotating tubular members comprising:

a. motor means for developing rotary power in said assembly;

b. an axially extending rotatable stem means rotatably powered by said motor means;

c. gear reduction means disposed between said motor means and said stem means;

(1. housing means enclosing said gear reduction means;

e. fluid means contained within said housing means;

f. pumping means for preferential circulation of said fluid means through flow passage means provided within said housing means, said pumping means including differential volume regions provided adjacent the axial ends of meshing gear means in said reduction means to induce a circulatory flow of fluid; and

g. magnetic means for removing metallic debris from said circulating fluid means.

6. A rotary drive assembly for rotating tubular members as defined in claim 5 further including friction braking means for selectively stopping and/or retaining said stem means at a fixed angular position about its axis.

7. A rotary drive assembly for rotating tubular members as defined in claim 6 further including fluid powering means for selective activation of said friction braking means.

8. A rotary drive assembly for rotating tubular members as defined in claim 5 further including:

a. tubular mandrel means extending axially through said stem means; and

9. A rotary drive assembly for rotating tubular members as defined in claim 8 further including friction braking means for selectively stopping and/or retaining said stern means at a fixed angular position about its axis.

10. A rotary drive assembly for rotating tubular members as defined in claim 9 further including fluid powering means for selective activation of said friction braking means.

Claims

1. A rotary drive assembly for rotating tubular members comprising: a. motor means for developing rotary power in said assembly; b. an axially extending rotatable stem means rotatably powered by said motor means; and c. friction braking means included in said assembly for selectively stopping and/or retaining said stem means at a fixed angular position about its axis.

3. A rotary drive assembly for rotating tubular members as defined in claim 1 further including: a. a tubular mandrel means extending axially through said stem means; and b. locking means, movable relative to said mandrel means, for retaining said mandrel means within said stem means, said locking means including means for providing increasing locking forces in response to increasing rotational forces tending to displace said mandrel means within said stem means.

5. A rotary drive assembly for rotating tubular members comprising: a. motor means for developing rotary power in said assembly; b. an axially extending rotatable stem means rotatably powered by said motor means; c. gear reduction means disposed between said motor means and said stem means; d. housing means enclosing said gear reduction means; e. fluid means contained within said housing means; f. pumping means for preferential circulation of said fluid means through flow passage means provided within said housing means, said pumping means including differential volume regions provided adjacent the axial ends of meshing gear means in said reduction means to induce a circulatory flow of fluid; and g. magnetic means for removing metallic debris from said circulating fluid means.

8. A rotary drive assembly for rotating tubular members as defined in claim 5 further including: a. tubular mandrel means extending axially through said stem means; and b. locking means, movable relative to said mandrel means, for retaining said mandrel means within said stem means, said locking means including means for providing increasing locking forces in response to increasing rotational forces tending to displace said mandrel means within said stem means.

9. A rotary drive assembly for rotating tubular members as defined in claim 8 further including friction braking means for selectively stopping and/or retaining said stem means at a fixed angular position about its axis.