CA1223247A

CA1223247A - Well drilling assembly

Info

Publication number: CA1223247A
Application number: CA000453802A
Authority: CA
Inventors: Bjarne Skeie
Original assignee: Maritime Hydraulics AS
Current assignee: Mhwirth AS
Priority date: 1984-01-25
Filing date: 1984-05-08
Publication date: 1987-06-23
Also published as: ATE54480T1; KR850005546A; US4791999A; EP0150695A3; NO154578B; EP0150695B1; JPS60159295A; ATE39969T1; AU2805984A; DE3476096D1; DK244584A; EP0196284A1; AU569740B2; DK244584D0; EP0150695A2; KR900006634B1; EP0196284B1; DE3482708D1; NO840285L; NO154578C

Abstract

WELL DRILLING ASSEMBLY

Abstract of the Disclosure.

A well drilling assembly of the type in which a rotary device is attached to a drawworks, for example to the hoisting hook on a derrick, to which rotary device a hollow shaft is coupled, having a threaded end which is adapted for connection to a complementary threaded end on the drill string, and wherein a clamping/lifting means known as an elevator is suspended below the rotary device by two hanger struts. The shaft connected to the rotary device is telescopic. Outside the shaft a lifting means is provided for the lower part of the telescopic shaft. The two hanger struts which carry the elevator for one end of the pipe are means of a sliding holder known as a link hanger. The link hanger is axially mov-able by means of hydraulic cylinders.

The lifting means for the lower part of the tele-scopic shaft consists of hydraulic cylinders which are constructed as a unit together with the hydrau-lic cylinders, the cylinders constituting piston rods for the hydraulic cylinders.

Description

1 ~L2Z3~

The present invention relates to a well drilling apparatus of the type in which a motor-driven rotary device is attached to the traveling block of a derrick draw-works, wherein a shaft is connected to the rotary device, one end of the shaft havillg threads adapted for connectioll to an end of the drip string havillg completllentary mating treads and wherein a c~amping/liftincJ device or an elevator is suspended from the rotary device by two links.

On the type of drilling equipment utilized most frequently today, a rotatable, polygonal pipe, known as a kelly, is suspended from the hoist hook above a mud swivel. The kelly is threaded at the lower end and attached by means of the latter to the complementary threading in the upper end of the drill string, The kelly is rotated by means of a rotary table and gradually moves axially in relation to the rotary table as the drill bit descends. One of the drawbacks of this system is that it can handle only a single, 30-foot section of drill pipe at a time. During a tripping operation ire, when the drill string is pulled up or lowered down into the well, the drill string is admittedly divided into stands, each stand consisting of three lengths of pipe. These are stored in racks as they are hoisted up from the well and disconnected from the rest of the drill string. The drill pipe is thus stored in stands of three pipe sections in the pipe racks.
However, when new drill pipe needs to be added to the string during drilling, only a single length of 30-foot-long drill pipe may be entered and rotated into the last pipe on the drill string, and the upper end of the new pipe attached to the kelly. This is a relatively time-consuming procedure. Considering that new drill pipe must be added to the string several times an hour, it can be easily understood that substantial savings of time and money could be achieved if this procedure can reduce the number of operations to one-third by adding whole stands during the drilling, each stand consisting of Tory single sections On a more modern, prior art apparatus, the rotary device itself is attached to the traveling block of the draw-works on the derrick. The rotary device turns a shaft which is rotatable I,

2 ~2~3~D~7 suspended from the mud swivel. loath this equipment, an entire pipe stand consisting of three sections of` pipe of 90 feet total length can be connected to the upper en of the drill string. This obviously saves both time an]
o'er;. A disadvantage of this apparatus is that it is no possible, at least not Without special, time consuming moclificat:Lons, to carry out a tripping operation. The tllaill reason is that some twisting builds up in the drill string during drilling. The twisting may in fact constitute several turns of the string when the upper and lower end of the drill string are seen in relation to each other. This hoist causes powerful torque to be applied to the drill string and, in turn, to the drilling apparatus, When drilling is finished and tripping is to be performed, the upper end of the drill string is enclosed by an elevator. When the drill string is lifted, it is suspended in the elevator.
The lower part of the drill string will often during the lifting operation be prevented from rotating freely, whereby twisting isle still be present in the string, to be transferred to tile elevator and, in turn, to a link-hanger.
The powerful torque, and the rather rough handling of the drill string during lifting may, in extreme cases when the string is still in a twisted state, cause the individual drill pipes to unscrew from each other, which leads to operations requiring considerable resources, a situation to be avoided at all costs. This is remedied through the present construction, in that a stewing ring bearing and an auxiliary motor have been provided above the link-hanger, as well as an air/fluid transfer apparatus in order to alloy retwisting and relieving of the drill string during tripping.

The lower part of the known apparatus is, admittedly, mounted so as to be rotatable to a certain degree, however, here the transfer of hydraulic fluid and air from the fixed part of the apparatus to the rotatable part occurs through a number of hoses, which means that if tripping is to be performed, ~3;2~7 these hoses would have to be disconnected. Other disadvantages are also present if the known apparatus were to be used for tripping with the drill string, because the apparatus has not been constructed Whitehall this function in mind. Therefore, r! -tripping is perrorlllecl in the conventional manner.

Another disadvantage is that entering of the conical threaded joints between the pipes and the shaft of the well drilling apparatus has to be effected by moving the entire 10 drilling apparatus with the draw-~.orks in the vertical direction, which involves large and unruly masses, resulting in a risk of impacts and bumps during the alignment of the connections, with a great danger of damaging the threads of the joints.

15 The object of the present invention is to provide a drilling apparatus of the type recited above which does not have the above-mentioned disadvantages, and which is construct Lo performing the tripping function and thus is admirably suited for this, as well as having a number of other advantages.
This is obtained according to the invention by a well drilling apparatus of the type recited in the introduction, a type which is characterized in that the shaft connected to the rotary device is telescopic, that outside the shaft a lifting 25 means is provided for the lower part of the telescopic shaft, and that the two links which carry the elevator are axially movable in relation to the telescopic shaft for one length of pipe, being attached to the shaft by means of a slide able link-hanger.
Jo Other features of the invention are disclosed in the subsidiary claims.

The invention will be described more detailed in the 35 following with reference to the accompanying drawings, Welch show a preferred embodiment of the invention.

I

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Lo Figure 1 shows a portion of a derrick provided with the well drilling apparatus O r the invention.

Figure 2 is an isometric drywall of the apparatus Or it illV~llt toil .

Figure 3 shows a simplified sketch of the well drilling apparatus of the invention, suspended from the hoist hook within the derrick.
Figure 4 shows a part of the drilling apparatus of the invention in partial cross section.

figure 5 shows a detail of the drilling apparatus of the invention in vertical section.

Figure 6 is a more detailed illustration of the hydraulic lifting devices.

Figure 7 shows another detail of the drilling apparatus of the invention in partial cross section.

Figure 8 is a cross section along the line VIII - VIII in fugue, and Figure 9 is a cross section along the line IX-IX in Figure I

On an oil derrick 1, a traveling block is provided in a manner allowing lifting, to which is attached a crane hook 2, which crane hook can be moved vertically by means of a draw-works, which is not illustrated in the drawing. With the aid of parallel arms 3, the hook can also be moved in the lateral direction, and be guided approximately vertically along the rails 5.
Via a tint; 6, a mud swivel 7 is suspended from the crane Hoyle, through Welch mud is supplied to the drill string 39. Inside the derrick frame, an upper grab tool S Whitehall a grab head 9 _ together with a lower grab arm 10 with a rotatable grab need11 can move a stand from an operative position to a rack an the derrick, and vice versa, during tripping. Down on the rig floor a roughneck 12 is provided, comprising a Turk-wrench and a spinner which rotate a length of pipe in Swahili a way that a joint is screwed together and correct torque is applied, and, conversely, releases the joints and rotates the upper section out of the drill string.

On the apparatus according to the invention, a hollow shaft assembly 13 (see Figure 4) is provided below the swivel 7, which freely rotates in the swivel. Conveniently, the shaft is divided into a plurality of detachable parts, known as subs.
The shaft 13 is rotatable mounted within a support means 14 to which a gear box 15 is rigidly attached. A powerful rotary motor 16 is mounted on the gear box, driving the shaft 13 via a transmission gear 17. The gear box can be blocked by a paw (not shown). The above-recited parts are included in the upper fixed section of the drilling apparatus.

The well drilling apparatus comprises, apart from the above-mentioned components, a compressed air/hydraulic fluid swivel 28 for the transfer, with no need of hoses, of compressed air/hydraulic fluid from the fixed section to a rotatable section including a linl~-hanger 35 with suspended links 37 which hotel an elevator 38, a bearing cage 40, hydraulic cylinders 24,25, 45,46 and a torque wrench 54 for adding and releasing the joints between drill pipes.

The shaft 13 has an expanded section 18 with a central ventilated cavity 19 within which a shaft head 20 can move freely. Around the periphery of the inner surface of the head 20, are seals 60 provided, which coats with a eon-tally disposed pipe 61, which extends inside the shaft 13 from its upper section and a distance into the move-able shaft head 20. A downward-extending shaft pin 21 , I, Jo is sealingly attached to the shaft heed 20, ensuring llquid-tlght communication for mud in the central regions of the shaft 13, the pipe 61, and the shaft pin 21. carrier part 41 is attached in the lower en ox r1 tile e~pan(le(l section lo of` Lowe shaft 13. The carrier Par hats interrlal, longitudinal splints, while? a section 21' Or the shaft pin 21 has external, longitudinal splints for slideal~le guide, interaction, and the -transfer Or torque from the expended section 18 to the shaft pin 21 during drilling. At the same time, the carrier part 41 has an upper shoulder, against which the shaft head 20 rests during drilling (the drill string in tension). According to the above, the shaft head 20 can move telescopically along the pipe 61 in the cavity 19, restricted by the upper end wall of the cavity and the shoulder of the carrier part Lo Outside the expanded section 18 of the shaft 13, an annular flange 23 is provided , with lugs connected for the attachment of hydraulic cylinders 24,25, Hydraulic cylinders 42,43 are provided outside the hydraulic cylinders 24, 25, so that they are constructed as two hydraulic cylinders inside one another, where the cylinders 24, 25 constitute the piston rods for the hydraulic cylinders 42, 43, said piston rods being provided with stationary pistons 44. See Fig. 6, which shows the cylinder 42 in its upper position.

The internal or lower parts of the hydraulic cylinders 24, 25 are connected to a bearing cage 40 with centra~ypositioned sliding bearing surfaces for interaction with a slowed bearing 56, which together constitute a thrust bearing Lo, 56. The bearing 40, 56 is shown in Fig 7 and Fig. 9. The sliding bearing 56 is attached to the shaft pin 21 both non-rotatably and so as to prevent the bearing Tom owe axially in relation to the shaft pin. On activation of the internal or lower hydraulic cylinders 24, 25, these actuates the bearing cage 40, which in turn acts on the sliding bearing 56. The bearing 56, which is permanently fixed to the shaft pin 21, thus operates Jo " `

2~7 the shaft pin 21 and the shaft head 20. This operation can be performed with the shaft pin 21 rotating.
Tile abreast function Jill ivy a significant advantage over prior art e~1uiplllent for smooth enteril1q of the Cowlick thr(!acled joints bottle the upper end of a drill pipe end tile outwardly extending pin 21 when supplying pipe for the extension of the drill string during drilling.

Outside the expanded section 18 of the shaft 13, a rotatable sleeve 22 is provided (see jig, 5), which is mounted via a support means 26. The support means 26 is attached to a skirt 27, which in turn is attached under the gear box 15. In order to allow the performance of all functions on the well drilling apparatus, such as operating the hydraulic cylinders 24 J 25, the cylinders 45, 46, the elevator 38 and the torque wrench I
compressed air and/or hydraulic fluid is supplied, controlled from a control panel. As previously mentioned, twisting will occur in the drill string during drilling, and the drill string must be untwisted during tripping. In order to maintain 20 the above-recited functions during the untwisting of the string, when the complete lower section, including the elevator 38, the torque wrench 54, the bearing cage Lo, the hydraulic cylinders I 25, 45, 46, the link-hanger 35, the links 37, and the sleeve 22 are moving with the string, it must be possible 25 to transfer compressed air/hydraulic fluid from the upper, fixed section of the well drilling apparatus to the lower, - rotatable section of the apparatus. This is enabled by cooperation of the upper part of the sleeve 22 and the skirt 27 which forms an air/hydraulic fluid swivel 28, provided for the 30 air/fluid transfer1from the stationary part 27 to the rotatable part 22, Compressed air/hydraulic fluid is supplied via hoses (not shown) to a number of separate grooves 29 running along the inner circumference of the slit 27 . Between each groove, seals are provide. The grooves 29 correspond to a similar 35 number of axial passages 30 via a similar number of transverse passages 31, so that air/fluid may be transferred from the groove 29 to tile -transverse passage 31 and the

3;24~

_ passages 30, irrespective of the relative position between the rotatable part 22 and the stationary part 27. The pass-ages 30 are in turn connected to hoses which extends to the individual components (elevator, torte wrench, etc.). In this way, compressed air/hydraulic fluid is transferred without need of hoses from the upper, stationary section of the well drill-in apparatus to the lower, rotatable section.

The external wall of the hydraulic cylinders 42,43 supports lo the link-hanger 35 (see Figure 4 and 6). When fluid is supplied to the outer cylinders 42,43 above the stationary pistons 44, the link-hanger 35 will be raised, and may be lowered again on the return of the fluid, optionally supplying fluid under the stationary pistons 44. (See broken-line passages, Figure 6). Moreover, the link-hanger 35 is in-rotatably connected to the sleeve 22, said sleeve being provided with a massive external glide key 65, and the internal bore of the link-hanger 35 is provided with corresponding key grooves, in order to rigidly transfer a considerable torque. From the lugs 36 provided on the link-hanger 35 the links 37 are suspended,supp-outing the elevator 38. The elevator 38 is a device having a central bore of a shape complementary to the upper expanded end of a drill pipe 39. The elevator may be divided so that it may be inserted over the upper, expanded end of the drill pipe.

The elevator 38 and the link-hanger 35 follow each other and will normally adopt one of three positions. The upper position is adopted during drilling when the drilling equipment approaches the rig floor in order to get as close as possible to this with the drilling equipment itself. During normal drilling, the link-hanger 35 rests freely on Belleville springs (not shown), which springs rest against the lower collars of the hydraulic cylinders 24,25 (or the piston rods). During the tripping operation, the Belleville springs are compressed until the link-hanger 35 stops against an external shoulder (Fig. 4) on the lower part 55 of the expanded section 18 of the shaft 13, thus resulting in the load being transferred from the elevator 38 via the links 37 to the link-han~er 35 end on to the shaft 13 via the shaft-sections 55 and 18.

During untwisting of the drill string) the twisting nay he relieved by a motor 33 (Fig. 5), the pinion I of which el-lt~c1ge-wow h Q gear wheel I which is connected to the support means 26 and permanently connected to the annular flange 23. The motor 33 may also be used for rotating the elevator into the correct position when said elevator is to open/close for, respectively, the insertion/fetching of stands of drill pipe into/from the pipe racks.

Two hydraulic cylinders 45 and 46 are provided under the bearing cage JO. The piston rods I and JO cooperate with an axially slid ale sleeve 47, having a guide channel 48, which operates a handle 49 of an internal blow-out preventer, known as an IMP JO, which is clearly seen in Fig. 8. This consists of a turn ale spherical body 52 having a contrary 51, iamb sort of a ball valve. On operation of the handle I
the ball may be rotated for opening, respectively closing, of the through passage in the drill string, in the same way as a conventional Tao cock. To the lower side of the bearing cage 40 the torque wrench 51~ is attached via a strut member 53.

The invention works in the following manner during drilling.
Through the action of the rotary motor 33 via the pinion 34, gear wheel 32, sleeve 22, link-hanger 35 and links 37, the elevator 38 is set in the correct angular position for receiving a stand of drill pipe. The traveling bloc with the entire JO drilling apparatus is guided into an upper position, as shown in inure 1. By means of the pipe handling equipment 8, 9, 10, 11, a pipe is guided into operative position and into the open elevator, while simultaneously the hand in system lowers the pipe into the upper joint on the last pipe of the drill string, which is held in a fixed position at the rig floor in wedge slips. or the connection of a new stand of pipe, and for the application of` sufficient Turk to the joints, the iron roughneck I which is provided on the rig floor, is employed.

Thereafter, the entire drilling apparatus is lowered, so that the upper joint ox -the drill pipe is entered by the telescopic shaft pin 21~ Lyle the drill string remains held fixedly h!
tile wedge slips, tulle shaft 13 is rotated by means or` the rotary motor 16, end the threads are screwed in. The twirl French I which comprises two jaws arranged one above the other, the jaws being to some extent turntable in relation to each other, adds the joint between the drill pipe and the shaft pin 21 with sufficient torque.
During tripping, when the drill bit is to be pulled out of the well, a stand of pipe is hoisted up from the well, and the upper end of the next stand is fastened by means of the wedge slips. The stand, consisting of three lengths of pipe is then detached from the rest of the drill string at the rig floor level by means of the torque wrench on the iron roughneck. The spinner on the iron roughneck 12 then rotates the stand so that the entire threaded connection is released. During this operation, the elevator 38 has been moved a short distance downwardly, so that the upper end of the stand of pipe can rotate freely in relation to the elevator. The stand, which is now detached, is clamped by the grab tools 8 and 10 and transported to the pipe rack, while ultaneously the elevator is opened and rotated in the correct direction for removing the pipe. Lyon the pipe is being hoisted up, the entire drill string is suspended from the shaft 13, as mentioned above. In addition, the hydraulic cylinders 42 and 43 may act like springs. The hydraulic oil then flows over a circuit with an adjustable valve, so that at a predetermined load on the links 37, oil will bleed out from the upper chamber in the hydraulic cylinders above the piston 44, and thus the link-hanger 35 will be pulled down so that their lower edge rests against a substantial shoulder on the part 55 on the ex~ancled section lo of rho showoff lo.
In this way, the weight of the entire drill string may be transferred to the traveling block.

As mentioned above, a rather high degree of twist may be imparted to the drill pipe owing to the nature Or the jell itself. This torque can be taken up without problems by the apparatus during tripping, because the link-hanger 35 I
rotate controllable in relation to the upper section ox the drilling apparatus. II` the drill pipe stickles during the pulling operation, the pipe must be rotated and mud urged clown into the well. This is done by coupling the outwardly extending shaft pin 21 to the upper part of` the drill string, so that the entire shut of the drill string Noah hangs in the normal manner from the apparatus as it does during drilling, except that the drill string is now being hoisted up Chile being rotated instead of being Laredo Dylan into the well.

The apparatus of the invention comprises three separate, independently movable systems, The cylinders 24 and 25 can move the pin 21 in and out, and thus shorten or extend the shaft length 13. By means of the external hydraulic cylinders 42 and 43, the linh-hanger 35 can be moved independently up and down on the sleeve 22, ire. in relation to the shaft 13, and thus the elevator 38 is movable up and down independently of the shaft 13. In addition, the link-hanger 35 with associated parts may be rotated in relation to the upper section of the well drilling apparatus.

The thrust bearing JO, 56 comprises, as previously mentioned, of a sliding bearing 56 and a bearing cage 40 with sliding surfaces as can be seen in jig. 7 and jig. 9. The sliding bearing 56 is attached to the shaft in such a manner that it has high inertial resistance both to rotation and to axial JO movement in relation to the shaft As seen in Fig. 9, the the bearing ring 57 is divided diametrically at 58. The two bearing ring members are held together by bolts 59, indicated by broken lines in Fig, 9. The object of a supportably bearing lo to enable toe piston rods on the hydraulic cylinders 24 and 25 to be move upwardly without opt eratincl the shaft pin 21. To enable this, the handle 49 for operating the valve body 51 in the IBOP 50 must be removed, The sleeve 47 with the guide channel - ~L223Z4~

_ 48 can then slide outside the IBOP. The purpose for this is to permit maintenance work on the IBOP or to allow a check valve to be introduced into the drill string. The hydraulic cylinders 24, 25 are drawn up high enough that the torque wrench 54 can break loose the upper joint for the IBOP. Try_.
provides sufficient access for overhauling or replacing the IBOP.

If the driller, during a tripping operation, notices that the well is out of balance, the shaft 13 can at any time be entered into the drill pipe and the IBOP can be closed by remote con-trot. A check valve with barbs is then inserted into the drill string through the opening 52 in the valve body 51 in the IBOP
after this has been opened just long enough to allow the valve to be guided down into the drill string. The IBOP is then reconnected to the pin 21. When mud is subsequently pumped, the check valve will be forced downwardly in the pipe. Trip-in to get the drill bit down to the bottom of the well can then commence.

Claims

The embodiments of the invention in which an exclusive property of privilege is claimed, are defined as follows:

1. A well drilling assembly comprising a rotary device suspendable by a hook of a derrick hoisting means to which a hollow shaft assembly is connected the hollow shaft having a threaded end which is adapted to be coupled to the end of a drill string which has complementary threads, a drill pipe elevator suspended below the rotary device by two links, the hollow shaft assembly including an expanded section and a shaft pin which is telescopic relative to the expanded section, and lifting means externally of the hollow shaft assembly for moving the shaft pin telescopically relative to the expanded section, the elevator being axially movable in relation to the hollow shaft assembly by means of a slideable link hanger.

2. A well drilling assembly according to claim 1 including hydraulic cylinders for moving the link hanger.

3. A well drilling assembly according to claim 2 wherein the lifting means for the shaft pin of the telescopic hollow shaft assembly includes hydraulic cylinders.

4. A well drilling assembly according to claim 3 wherein the hydraulic cylinders are constructed as a unit having internal cylinders constituting piston rods for outer hydraulic cylinders.

5. A well drilling assembly according to claim 4 wherein the piston rods of the hydraulic cylinders are attached by a bearing cage of a thrust bearing to the shaft pin of the hollow shaft assembly, and two hydraulic cylinders are attached to the underside of the bearing cage, the two hydraulic cylinders being connected to a slidable sleeve for moving said sleeve axially on the shaft pin, said sleeve having a guide channel engaging with a handle connected to an internal blow-out preventer.

6. A well drilling assembly according to claim 1, wherein the expanded section of the shaft assembly defines a central internal cavity in which a shaft head moves said shaft head supporting the outwardly projecting shaft pin in such a manner that the shaft pin is non-rotatable in relation to the expanded section, the shaft pin being provided with splints.

7. A well drilling assembly according to claim 3 wherein the hydraulic cylinders are suspended in articulated fashion from an annular flange which is fastened non-rotatable in relation to a sleeve to which it is attached, the annular flange being attached by a bearing to a skirt which is rigidly attached to a stationary part of the rotary device, and a gear wheel is provided in connection with the annular flange and engaging with a pinion that is turned by a motor.

8. A well drilling assembly according to claim 5 wherein a torque wrench is fastened by strut members below the bearing cage.

9. A well drilling assembly according to claim 5 wherein the link hanger is attached non-rotatable to the outside of the sleeve by means of a key groove and spline.

10. A well drilling assembly according to claim 1 including means for transferring compressed air and hydraulic fluid from a stationary section of the assembly to the rotatable section by means of an air/hydraulic fluid swivel, thereby avoiding the use of hoses.

11. A well drilling assembly according to claim 8 wherein the thrust bearing is a sliding bearing which is fastened with high inertial resistance to rotation and to axial movement to the shaft pin, said bearing cage being freely movable relative to the shaft pin, and that the bearing is diametrically dividable so that it can be disengaged from the pin in order that the piston rods can thereby move the bearing cage and thus the sleeve freely on the pin after the handle has been removed, for the purpose of bringing the torque wrench up to the upper joint of the internal blow-out preventer.