CA1239634A

CA1239634A - Weight compensating elevator

Info

Publication number: CA1239634A
Application number: CA000478177A
Authority: CA
Inventors: William D. Stringfellow; Melvin C. Hawke
Original assignee: Weatherford Holding US Inc
Current assignee: Weatherford Holding US Inc
Priority date: 1984-07-27
Filing date: 1985-04-02
Publication date: 1988-07-26
Also published as: NO176287B; NO176287C; EP0171144A1; JPS6138089A; EP0171144B1; DE3573820D1; NO852336L

Abstract

WEIGHT COMPENSATING ELEVATOR
ABSTRACT
A method and device for connecting threaded tubular drill string members with a weight compensating elevator or device for use in handling casing in a rotary drilling rig configuration or for handling heavy materials in similar operations. First and second members, connected respectively to a lifting block and a threaded drill string member, have compressed gas directly or indirectly acting between them. The preferred embodiments incorporate a housing with bellows therein so that inflation of the bellows permits both the vertical suspension of the drill string member, casing or other material in a seemingly weightless state above the desired position and the movement of the drill string member vertically over a limited distance by the compression and expansion of the bellows induced by manual force exerted upon the drill string member as well as permitting the movement of the drill string member vertically over a limited distance by the increase or decrease of air pressure within the bellows.

Description

1 239~34 MET~OD AND ~EVIC~ FO~ ~ONNECTING THR~ADED ~U~ULAR D~ILL
~RIN~ M~MBERS
-Bsc~ro~nd o~ the ~nvention ~ he pr~sent lnvention relates to ~ method and devlce ~or connectin~ thre~ded tubular drill ~trlng membex~, for ex~mple c~ing members.

In meny ~r~lllng ~ppl~oation~, ~nd especl~lly ln deep hlgh pree~re wells, one or more cas~ng strings are Bet to protect the well bore and/or the for~atlon.
Wheth~r the crew member~ are runnlng surface, lntermedl~te~ or prod~ctlon cesing, the ~andling of theso heavy t ndlvidu~l oaslng memberg pre~ent~ ~pecl~l problem~. ~or ~n~tanae, in a typlc~l oper~tlon the rig .. 18 configured to hundle the hea~y welght of the aseembled caslng skrlng by u3lng mult~ple Wrap~ o~ csble ~ ~round the travelllng block. Whllc thls accommodate8 the holstln~ and QUgpengion of heavy c~glng ~trlngs, lt rod~ce~ the ablllty Of the ri~ crew to precisely positlon in cloge proxlml~y to the a~gembled ca~lng strlng tha next caslng mem~er to be connected.
Aa 2 consequence ~f t~ls tmpreclsion~ the make-up of casing strings is made more difficult, and dam~ge to c~slng thre~dg oCCUr~ All too o~ten. For inst~nce, lf the slngle Jo1nt pin connectlon i~

posltloned too hlgh above the su~pended box end of the ae~ombled utrlng, the threadY ~o not engaye. On the oth~r hand, lf the pln is lowered too Par, the full ~O weight of the gingle c~ lng member may resk on the first thre~d of the aggembled strlng and t~read aamage may occur. This may require removal of the damaged member ana coetly aelays ln the a~sembly proces3. And, even lf no thre~d damage lnlt~ y occurs ~ a re~uLt of lowerlng the caslng pln too far, lf lt re~t~ on the lZ39~34 QRaemble~ ~trln~, th~ wor~r ~th~ ~tabber") m~y have dl~lcuity ln m~noeuvring the oa~ing to ~lign lt 80 as - to make ~ proper threaded connection. In the event o~
~uch ~ m~sal~gn~nt, croeg ~hreading or other thread dam~e ~ llkely to occur.
The present lnventlon i8 dlrected to sn ~mprov~ method an~ devlce for connecting c~lng and other thre~ded tubular ~rlll atring memb~r~. Preferred embodlme~ts pxovld0 an elev~tor-llke device whloh provide~ ~he ri~ h~nd8 greater control ov~r the vertlcal mo~ment of caglng to be ~ttached to us~emble~ caslng strlnge .
Accordlng to one ~pect of the pre~ent inventlon there 18 provided a methon o~ oonnecting threa~ed tubular ~ trlng member~, for a~mple caslng member~, whloh method oomprisss the step~ of:
a) providlng 8 dev~ce whloh comprlses~a f ~r~t member u~t~ohed o ~ lng block, ~ econd m~mbes to which a first threaded tubular drill s~ring member can be attached, and mean~ responelve, dlrectly or lndlr~ctly, to compraa~ed gag aotlng be~ween sald ~lrst member and ~ald ~econ~ member;
b) ~ttaching Q ~lr~t threaded tubular drlll strlng member to 8a~ ~ secon~ member;
25 c ) ralslng sald ll~tlng block to lif~ aald ~ir~t threaded tubular drlll strlng member vla sald devioe, d) arr~nging for the pregsure of sald compres~ed gaq to m~lntain ~ald fir~t member an~ ~al~ ~econd member apast whllst pexmitting downwara manual force to lower s~ld flr~t tubular drlll strlng member wlth re~pect to eald liftlng block;
e) mano~uvrlng sald flr~t threa~ed tubular drlll ~trlng member into a po~tlon ab~e a ~econd tubular ~rlll ~trlng member;
~) applylng manual downward pre~ure to ~ald ~i .

lZ3'3~;3~

flrst t~bular drlll ~trlng memb3r to brlng the thresds o~ 6ald flrst ~nd ~econd threaded tubular drlll string - membera lnto cont~ct; and g) rot~tlng sa~d first tubul~r drill string member wlth re8pac~ to 8~1d ~econd tubular ~rlll strlng member to connect ~ald threaded tubular drlll ~trlng member~.
Aecordlng to enother a3pect of ths pre~snt inventlon there ls provide~ a device for use ln carryln~
o~t a method ~ocordlng to the inventlon, which devlca comprl~e~:
8 ) a flr~t ~mber att~chable to ~ llftlng block;
b) a ssoond member to whlch a threaded tub~l~r drlll strlng member can be connected, ~nd 15 t~ ) re~lllent meQnel whloh, $n ~1~, act betwe~3n s~ld flrst membcr ~na ~econd member and whic~ permlt sala threadod tubula~ drlll ~trlng member to move - do~wardly with regpect to gal~ fi~t member when downwara pre~ure 1~ spplled to sa~d load oh~racterl~ed ln that:
~ ald re~lllent mean8 comprl~e~, dlrectly or lndlrectly, compres~ed ga~.
For R better under~tandlng of the pre~ent inventlon reerence wlll no~ be made, by way of exam~le, to the accomp~nylng druwlngs, ln whlch:-,, ~- ,q,., _4_ 1~3~3~

Figure 1 is a per~pective view of a portion of a typical rotary drilling rig configuration utilizing an embodiment of the present invention connected to a single joint ~levator in preparation for lifting a ca~ing joint into the mast.
Figure 2 iB a perspective view of a portion of a typical rotary drilling rig configuration utilizing an embodiment of the present invention in the process of lifting a casing joint into the mast Figure 3 is a perspective view of a portion of a typical drilling rig configuration utilizing an embodiment of the present invention in which the bellows is expanded and the casing joint is suspended over the assembled casing string.
Figure 4 is a perspective view of the assembly illustrated in Figure 3, illustrating the compression of the bellows and the lowering of the casing joint.
Figure 5 is a perspective, sectional view Of a preferred embodiment of the present invention.
Figure 6 is a sectional view taken along line 6-6 in Figure 5.
Figure 7 is a sectional view taken along line 7-7 in Figure 6.
The above general description and the following detailed description are merely illustra-tive of the generic invention, and additional modes, advantages, and particulars of this invention will be readily suggested to those skilled in the art without departing from the spirit and scope of the invention.
Description of__he Preferred Embodiment References ~ill now be made in detail to the presently preferred embodiment of the invention, as -5- 1~3~3~

described in the accompanying dra~ings, and to particular alternative embodiments. Figures 1-4 generally depict a typical rotary drilling rig configuration in the process of connecting the next 5- casing member (or ~joint~) to an assembled casing string.
When casing is being ~run~, or connected in an asse~bled string and lo~ered into a hole that has already been drilled, the rig is typically configured to handle the very heavy ~eight of the assembled ca~ing string by suspending the traveling block 10 from the cro~n block (not sho~n) using multiple ~raps of the drilling line 11 around the sheaves of the traveling block 10. On heavy strings, a large number of ~raps, up to sixteen or more, may be required. From bails 12a and 12b on the traveling block is suspended an elevator 13, normally a slip elevator, sized to hoist and lower the entire ~eight of the casing string, ~hich ~eight may exceed 2,000,000 pOUnds.
Belo~ the primary elevator 13 is normally suspended by cables 14 and a s~ivel (not illustrated), a smaller elevator 15, often called the single joint elevator so named because it is sized to hoist and lower a single ~joint~ or length of casing 20. The single joint elevator 15 is typically required to hoist and lower only approximately 100 to 20,000 pounds of ~eight.
That portion of the casing string 21 ~hich has already been assembled and lo~ered into the hole is suspended in the spider 16 mounted on the rig floor 17.
The slips of ~he spider 16 grasp the upper most member of the assembled casing string 21 below it~
box 22 (or female threaded end), leaving the box 22 exposed for connection ~ith the pin 23 (or male -6- ~3~3~

threaded end) of the next length 20 to be added to the string.
As illustrated in Figures 1 and 2, the single joint elevator 15 is pivoted to the area of the next 5- length of casing 20 to be added and attached thereto ju~t below its box 24. By operating the draw~orks (not sho~n), the driller dra~s up some of the drilling line 11 so as to hoist into the mast the single joint elevator 15 and casing length 20. Hoisting continues until the casing length 20 is positioned vertically above the spider 16 and the expo3ed box 22, as depicted in Figure 3. This process requires the driller to then lower the casing length 20 so that the rig hand (called a ~floor hand") can stab the pin 23 into the box 22 and rotate it to "make-up" the connection. Rotation and make-up is typically accomplished via use of po~er tongs 18, sho~n in Figure 4. Then the single joint elevator 15 is disengaged and the primary elevator 13 is then similarly engaged on the casing length 20, the spider slips 16 released, and the assembled string 21 is lo~ered into the ~ell bore the length of the single joint 20. At this point, the spider slips 16 are reset and the entire process is repeated until all of the casing lengths have been made-up.
The particular difficulty addressed by thi~
invention arises in positioning the casing length 20 above the box 22 so that the stabber can make the threaded connection~ When a large number of drilling line ~raps are used on the traveling block 10, the driller's ability to precisely control vertical movement of the casing 20 is hindered. Also~ of courxe, ~ith inexperienced drillers and stabbers, the proper positioning of casing 20 is at times difficult to obtain. As a consequence, if the pin -7- ~39~

23 is not lo~ered far enough, the threads do not engase. And, if the pin 23 i lo~ered too far, the ~eight of the casing 20 may ~ell rest on the first thread, causing damage to either or both members being connected. Similarly, if the pin 23 is lowered onto the box 22, because of the ~eight of the casing length 20, the stabber may find it difficult to align the pin 23 in the box 22 to permit proper make-up. This, too, may result in cross threading or other thread damage.
This problem is presently addressed, if at all, in the industry by use of a spring in the tra~eling block mechanism. Ho~ever, this spring is often in effective ~hen heavy strings are to be hoisted.
15 Further, the spring block~ do not provide enough flex ~hen single joints are being handled to solve the problems met by the present invention.
The preferred embodiment of the present invention provides for an elevator-like ~eight compensating device 1 to be positioned bet~een the primary elevator 13 and the single joint elevator 15. In the preferred configuration, this device 1 is suspended by cable 14a from the bell 13a of primary elevator 13 and has suspended belo~ it a cable 14 to ~hich is attached a single joint elevator 15. It ~ill be readily appreciated by those familiar ~ith the art, ho~ever, that the invention readily admits of numerous other configurations.
For example, and ~ithout limitation, a s~ivel (not sho~n~ may be positioned above or belo~ the compensation device 1 of this invention, and the appropriate means of connection may be provided to its housing.
Similarly, the device readily admits to applications in other materials handling operations, 3uch as ~here heavy equipment i3 being suspended from the 1~3~ 39~

boom of a crane and it is desireable to be able to easily adjust its vertical position, so a~ to be able to lo~er the equipment to the ground ~ithout harm. Further, in drilling rig operations, other S memberR of the assembly, such as a swivel or a single joint elevator, may be incorpora-ted into the body of the present invention to provide a single useful tool.
In the primary preferred embodiment illustrated in Figures 1 through 7, and shown in more particular detail in Figures 5 through 7, the housing of this invention 1 is generally comprised of a lo~er housing member 30 and an upper housing member 31. Upper housing member 31 has an upper face 31a and a substantially vertical and cylindrical side wall 31b extending therebelo~. Provided in side wall 3lb are one or more wall openings 31c oriented to accomodate the lo~er housing member 30 therein and to permit vertical movement of the lo~er housing member 30 ~ithin the upper housing member 31. In the preferred embodiment, lo-wer housing member 30 is comprised of connected support members 30a and 30b. In this particular configuration, separate side ~all openings 31c is provided for the extension of each support member 3Oa and 3Ob therethrough.
Attached to and positioned bet~een the lo~er housing member 30 and the underside of the upper face 31a of upper housing member 31 is a bellows 40.
The bellows 40 may consist of commercially available air springs or air actuators. Upon inflating the bellows 40 (as via an air supply (not shown) connected to air line 41), the upper housing member 31 i5 lifted up~ard and away from lo~er housing member 30 by the expansion of the bello~s 40, as illustrated in Figure 3. When deflated, the bellows 40 contracts, ~2~

_g_ .

causing the upper housing member 31 to lo~er, as illustrated in Figure 4. This expansion and contraction permits the vertical position of the suspended casing joint 20 to be altered selectively by manually pulling do~n~ard on the suspended casing joint 20 until the pin 23 is properly positioned, as indicated in the description of the operation of the invention herein.
A second preferred embodiment (not illustrated) utilizes a housing also generally comprised of a lo~er housing member and an upper housing member.
In this alternative embodiment, the upper housing member has both an upper face and a lo~er face and a substantially vertical side ~all therebet~een.
Preferentially, the upper and lower housing members are generally cylindrical in shape, although this embodiment does lend itself to other constructions as ~ell.
This alternative embodiment provides openings in the lo~er face of the lower housing sv as to accomodate the side wall of the upper housing and the vertical movement of the upper face of the upper housing ~ithin the interior of the lo~er housing.
Attached to and positioned bet~een the upper face of the upper housing and the lo~er face of the lo~er housing i~ a bellows. ~pon inflating the bello~s, the upper face of the upper housing is lifted up~ard by the expansion of the bellows until it reaches a level ~ithin the lower housing at or near the underside of its upper face. When deflated, the bello~s contracts, causing the lo~er face of the upper housing to lo~er. Like the operativn of the first preferred embodiment, the contraction and expansion of the bello~s of this alternative device also permits the vertical position of the suspended casing joint 20 to be manually varied over a limited -lo- 1~3~3~

range by pulling do~n~ard on the suspended joint 20 until proper alignment of the pin 23 in the box 22 occurs. In this alternative embodiment, a mechanical stop may be incorporated in the interior of the lo~er housing to provide a minimum bello~s height upon deflation.
In either of the described embodiments, connectors are provided on the housing members 30 and 31 for attaching the ~eight compensator 1 to other members of the rig assembly in conventional manners. Also, a conventional pneumatic connection provides a source of air for the bello~s 40 and may be operated from the rig's compressed air supply (not sho~n).
Similarly, conventional control circuitry (also not sho~n) provides a means to manually apply and bleed off air pressure ~ithin the bello~s. A pressure relief valve is also preferably provided, the limit for ~hich is determined by the characteristics of the particular bello~s employed and the desired handling characteristics described belo~.
In operation, a single length of casing 20 is hoisted into the mast. The bello~s 40 is pressurized until the maximum pressure permitted by the relief valve (not sho~n) is attained. The rig hand may then manually adjust the pressure do~n~ard until the preferred pressure is reached. Because of the a lift~ provided by the bello~s 40, that preferred pressure ~ill be characterized by the seemingly ~eightless suspension of the casing length 20 above the box 22 and the relative ease ~ith ~hich the casing 20 may be manually lowered by the rig hand under the increased control provided by this invention, so that the threads of the pin 23 and box 22 may be properly aligned and connected ~ith damage to neither. Because the ~eight of each casing length 39~3~

20 is substantially the same ~eight as the prior casing members, it ~ill not ordinarily be necessary for the rig hand to readjust the bello~s' pneumatic controls ~ith each ne~ joint. Instead, once the 5- ~eight compensation has been adjusted to his liking for the particular ~eight of the casing being handled, it need not be reset. However, the rig hand may also lower or raise the casing joint 20 by decreasing or increasing the air pressure ~ithin the bello~s 40.
The present invention provides a method for handling heavy materials, of ~hich casing is merely one variety. The method comprises hoisting the casing or other material above its desired position 1~ and in close vertical proximity thereto. An up~ardly vertical force is applied to a vertical suspansion apparatus, the force being of such magnitude as to balance the material in vertical equilibrium, ~ith the vertical suspension apparatus having ~ithin its housing a bello~s or similar device so as to permit the limited adjustment of the housing's vertical height by manually applying a do~n~ardly vertical force to the casing and, consequently, to the vertical suspension apparatus.
The present invention, therefore, is ~ell adapted to carry out the objects and attain the ends and advantages mentioned as ~ell as others inherent therein. Further, it is apparent to one skilled in the art that other embodiments readily suggest themselves ~ithin the scope of this invention. For example, a plurality of bello~s, arranged in series or parallel and mounted in singular or multiple housings, may be utilized. Also, a conventional ~eight sensing automatic adjusting device may be connected to the pneumatic supply to adjust the -12- 1239~3~

pressure ~ithin the bello~s in accordance ~ith the detected ~eight of the casing member. Further, although the presently preferred embodiment incorporates bello~s, to the extent that other embodiments incorporate mechanical springs and pneumatic or hydraulic cylinders for the same purpose, in the same ~ay, and to accomplish the same result, they are also encompassed ~ithin the scope and spirit of this invention. When used in this invention, such mechanical springs may be adjustable or non-adjustable. And, ~hen used in this invention, the pneumatic or hydraulic cylinder may be of such constructions as to not require separate housings therefor.
What is claimed is:

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for connecting threaded tubular drill string members, for example casing members, which method comprises the steps of:
a) providing a device which comprises, a first member attached to a lifting block, a second member to which a first threaded tubular drill string member can be attached, and means responsive, directly or indirectly, to compressed gas acting between said first member and said second member;
b) attaching a first threaded tubular drill string member to said second member;
c) raising said lifting block to lift said first threaded tubular drill string member via said device;
d) arranging for the pressure of said compressed gas to maintain said first member and said second member apart whilst permitting downward manual force to lower said first tubular drill string member with respect to said lifting block;
e) manoeuvring said first threaded tubular drill string member into a position above a second tubular drill string member;
f) applying manual downward pressure to said first tubular drill string member to bring the threads of said first and second threaded tubular drill string members into contact; and g) rotating said first tubular drill string member with respect to said second tubular drill string member to connect said threaded tubular drill string members.

2. A device for use in carrying out a method according to Claim 1, which device comprises:
a) a first member attachable to a lifting block;
b) a second member to which a threaded tubular drill string member can be connected; and c) resilient means which, in use, act between said first member and second member and which permit said threaded tubular drill string member to move downwardly with respect to said first member when downward pressure is applied to said load characterized in that:
said resilient means comprises, directly or indirectly, compressed gas.

3. A device according to Claim 2, wherein one of said first and second members has an end wall and a side wall having at least two elongate slots therein disposed to opposite sides slots and the ends of which extends through said slots and the ends of which provide attachment points for connecting said other member to said lifting block.

4. A device according to Claim 2, wherein said first member comprised an enclosure having a top wall, a bottom wall and a side wall extending therebetween, wherein said second member comprised a top wall mounted in said first member and provided with lifting straps which extend though the bottom wall of said first member, and wherein said resilient means acts between the bottom wall of said first member and the top wall of said second member.

5. A device according Claim 4, including a stop arranged to limit the minimum distance between said first and second members.

6. A device according to Claim 2, wherein said resilient means comprises a spring.

7. A device according to Claim 6, including means to adjust the stiffness of said spring.

8. A device according to Claim 2, wherein said resilient means acts between said first member and said second member via hydraulic fluid.

9. A device according to Claim 3, including an adjustable pressure relief valve.

10. A device according to Claim 2, including means to adjust the pressure of said compressed gas to a desired setting.

11. A device according to Claim 10, including means to automatically adjust the pressure of said compressed gas to maintain said first member and said second member space apart by a given distance when said load is lifted, said means being capable of being rendered inoperative to allow manual downward pressure on said load to displace said load downwardly with respect to said first member.

12. A device according to Claim 2, including a bellows actuable by said resilient means and disposed between said first member and said second member.

13. A device according to Claim 2, including a piston and cylinder actuable by said resilient means and disposed between said first member and said second member.

14. A device according to Claim 2, wherein a joint elevator is connected to said second member.

15. A drilling rig provided with a device as claimed Claim 2.