GB2105767A - Well jack supported on rotary table mounting structure - Google Patents

Abstract

A jack 27a for lowering a string of casing 26a into a well after a drilling operation, is adapted to be supported on the beams 15a which normally support the rotary table during drilling. The jack 27a preferably includes piston and cylinder units 33a, 34a supported from first structure 32a by flanges 59a, the first structure 32a resting on beams 15a and carrying frst pipe gripping unit 35a. A second structure 36a is mounted on the piston rods 75a of units 33a, 34a and carries a second pipe gripping unit 37a. In an alternative arrangement of the same apparatus the units 33a, 34a are supported by the ground and the first structure 32a is supported by the upper surfaces 84 of flanges 59a. <IMAGE>

Description

SPECIFICATION Well jack supported on rotary table mounting structure This invention relates to jacks for moving a string of pipe vertically within a well, preferably for the purpose of lowering into a well a string of casing which is heavier than can be supported by the drawworks, traveling block and related equipment of a rig.

In order to facilitate mounting of the jacking mechanism under some circumstances, a jack embodying the invention is supported on the same structure which supports the rotary table and its load during drilling. After the well has been drilled to a desired depth, the rotary table may be removing from its supporting beams, and the jack may then be placed on the same beams or other support structure to transmit load forces directly thereto.

In the drawings: Fig. 1 shows a rig during drilling; Fig. 2 is an enlarged view of the rig with a casing jack positioned therein; Fig. 3 is a side view on line 3-3 of Fig. 2; Fig. 4 is an enlarged vertical section on line 4--4 of Fig. 2; Fig. 5 shows a variational arrangement; Fig. 6 is a side view on line 6-6 of Fig. 5; Fig. 7 shows the jack of Figs. 5 and 6 supported from the ground; Fig. 8 shows another variation; Fig. 9 shows the jack of Fig. 8 supported from the ground; Fig. 10 is an enlarged vertical section on line 10-10ofFig. 9; and Fig. 11 is a horizontal section on line 11-11 of Fig. 10.

The rig 10 in Fig. I includes the usual mast or derrick 11 projecting upwardly above the rig floor 12 containing an opening 13 within which rotary table 14 is supported on two parallel horizontal "I" beams 1 5 secured at opposite ends to rig substructure 1 6. Kelly 1 7 is rotated by the rotary table to drive drill string 18 to drill a well bore 19.

Substructure 1 6 is supported on the ground and supports the rig floor, beams 15, rotary table 14 and all loads applied thereto. The convention rotary table includes an outer body 20 and an inner part 21 mounted by bearings 22 for rotation by the engine of drawworks 24 about vertical axis 23. Part 21 contains a master bushing and kelly bushing assembly 25 for driving kelly 1 7 while permitting its vertical movement.

After the hole has been drilled to a desired depth, the rotary table is removed from opening 13, and a jack 27 for lowering a casing string 26 is supported on beams 1 5. The jack is actuated by pressurized fluid (desirably hydraulic) supplied by a power unit 28 which may be located on the earth beneath the rig floor and may include an engine driving a pump and controlled by a unit 29 on the rig floor through hydraulic lines 30 to regulate the delivery of fluid to the jacking mechanism through lines 31 and 131. Jack 27 includes a first support structure 32 mounted on "I" beams 25, two piston and cylinder mechanisms 33 and 34, a first gripping unit 35 supported by member 32, a second support structure 36, and a second gripping unit 37.

Member 32 may be a rigid unit formed of several metal parts welded together, including upper and lower horizontal plates 38 and 39 containing openings 40 centered about axis 23, two vertically aligned circular openings 41 centered about a vertical axis 42, and a second pair of aligned circular openings 43 centered about a diametrically opposite vertical axis 44. Plates 38 and 39 may be secured together by vertical connecting members, including two "I" beams 45 and 46 and additional elements 47 welded to plates 38 and 39. The horizontal undersurface 48 of plate 39 engages and is supported by the horizontal top surfaces 49 of beams 1 5 to effectively support structure 32 from beams 1 5.

Structure 32 may be connected to elements 50 and 51 of the substructure by turnbuckles 52, adjustable to center structure 32 relative to axis 23 and to take up all looseness in the connection.

Each mechanism 33 and 34 includes a hollow vertical cylinder 53 closely confined within the corresponding openings 41 or 43 of member 32 and containing a piston 54 reciprocable along axis 42 or 43 and having a lower head 55 and a reduced shank 56 projecting through an opening 57 at the top of the cylinder in sealed relation to an upper extremity 58. Pressurized hydraulic fluid is supplied to and exhausted from the lower and upper ends of the cylinders through lines 31 and 1 31. An enlarged circular upper portion 59 of each cylinder forms a downwardly facing horizontal annular shoulder 60 engageable with the upper horizontal surface of plate 38 to support mechanisms 33 and 34.Gripping unit 35 supported on plate 38 may be of known construction, including slips 61 power actuable to support or release a casing within a downwardly tapering slip bowl opening 62 in a body 63 of unit 35. The horizontal undersurface 64 of body 63 rests on plate 38. Body 63 is centered about axis 23 by locating elements 65 which are welded to plate 38 and curve arcuately in correspondence with the outer surface of body 63. Slips 61 are movably suspended by links 68 from a ring 67 which is power actuable upwardly and downwardly with the slips by hydraulic piston and cylinder mechanism 66 between a lower active casing supporting position (full lines in Fig. 4) and an upper retracted position (broken lines) in which the casing is free for downward movement relative to unit 35.

Structure 36 includes upper and lower horizontal plates 69 and 70 secured rigidly together by "I" beams 71 and other connector members containing central openings 72 and vertically aligned circular openings 73 and 74 through which upper reduced portions 75 of the piston rods project, with annular horizontal shoulder 76 on the rods engaging the horizontal undersurface of plate 70 about openings 73 and 74 to support structure 36 from the piston rods.

The piston rods are detachably retained within openings 73 and 74 by retaining plates 77 secured to the rods by screw fasteners 1 77. Unit 37 may be constructed the same as unit 35 and be centered by arcuate locating elements 78 welded to plate 69. A railing 79 may enclose an area within which a person may walk on structure 36. The body 63 of each of the gripping units 35 and 37 may be a one piece rigid annular element containing the slips, or may be formed of two halves detachably connected together by pins at diametrically opposite locations, or by a hinge pin and latch at such locations, to facilitate placement of the unit 35 or 47 about a casing.

After a well has been drilled with the rotary table in its Fig. 1 position, the rotary table is removed and member 32 is lowered onto beams 1 5. Piston and cylinder mechanisms 33 and 34 are then lowered downwardly through openings 41 and 43 for support by structure 32. Unit 35 is next lowered onto structure 32, and member 36 is lowered onto and connected to the piston rods, after which unit 37 is placed on member 36. The jacking mechanism can then lower casing 26 into the well.

Piston and cylinder mechanisms 33 and 34 are desirably received at opposite sides of one or more blowout preventors 80 or 81 connected to the upper end of the well and located beneath the rig floor level and beneath beams 1 5. The casing is lowered by supplying pressure fluid to the upper ends of the cylinders and discharging it from their lower ends to move pistons 54, structure 36 and unit 37 downwardly while the slips of unit 37 are gripping the casing and while the slips of unit 35 are released.When structure 36 reaches the lower full line position in Fig. 3 the slips of unit 35 are actuated to grip and support the casing, while the slips of unit 37 are released, following which pressure fluid is supplied to the lower ends of cylinders and discharged from their upper ends to cause upward movement of the pistons and structure 36 and unit 37 to the upper ends of their range of travel (broken lines in Fig.

3). Unit 37 is then actuated to again grip the casing, while the slips of unit 35 are released, and another downward stroke of the pistons is induced to lower the casing through another step.

This process is repeated until the desired length of casing has been lowered into the well. Added joints of casing can be connected to the upper end of the string as necessary by a conventional single joint elevator suspended from a traveling block in the customary manner. If desired, the casing or another pipe can be moved upwardly by reciprocating the upper gripping unit 37 as discussed but with its slips in active gripping condition during upward movement, and with the string being suspended by the lower gripping unit during downward retraction of unit 37.

The two units 35 and 37 may be of very heavy construction capable of supporting very heavy lengths of casing, say for example up to a 1,000 ton load, which may be substantially greater than that which the mast of the rig and the drawworks, traveling block, crown block and related equipment would be capable of handling without provision of the jacking mechanism. As an example, the load capacity of the mast, drawworks, etc. might be limited to 500 tons. in that event, during the initial portion of the casing lowering operation, and until the weight of the installed casing reaches the 500 ton limit, the first part of the casing may be lowered without powered actuation of the jacking mechanism, and utilizing unit 35 as a spider in conjunction with traveling block.When the suspended casing load nears the capacity of the traveling block and drawworks, etc., the remainder of the jacking mechanism can be positioned in the rig, to permit continuation of the lowering process by the jacking mechanism.

After the casing has been completely installed in the well, the entire jacking mechanism can be removed from the rig by a process which is the reverse of the discussed installation process.

More particularly, unit 37 can first be withdrawn upwardly from structure 36, following which elements 1 77 can be detached and structure 36 can be removed upwardly from the upper ends of the piston rods, after which units 35 can be moved upwardly from its position of support on structure 32, the piston and cylinder units 33 and 34 can be pulled upwardly from within member 32, and that member can then be withdrawn upwardly from beams 1 5.

The form of jack shown at 27a in Figs. 5 to 7 is adapted for support either entirely from the rotary table supporting beams 1 5a in the manner of the first form of the invention or alternatively by direct support of the piston and cylinder mechanisms from the ground independently of the rig framework structure. Mechanism 27a includes a lower horizontal member 32a, an upper member 36a, two piston and cylinder mechanisms 33a and 34a and two pipe gripping units 35a and 37a which may be identical with units 35 and 37 of the first form of the invention. Members 32a and 36a may be formed sectionally of a number of metal parts as in Figs. 2 and 3, but for simplicity of illustration are typically represented as unitary one-piece structures. Member 32a contains a central opening 40a through which a casing 26a can be lowered along vertical axis 23a of the well.

The ends of members 32a contain openings 41 a and 43a within which the cylinders 53a of mechanisms 33a and 34a are received in closely confined and accurately located relation.

Cylinders 53a may be of externally straight cylindrical configuration corresponding to the diameters of openings 41 a and 43a except at the provision of an annular flange 59a formed on and integral with each of the cylinders at a location intermediate its upper and lower ends 82 and 83.

These flanges have horizontal upper and lower surfaces 84 and 85 engageable in different conditions with the lower horizontal surface 87 or the upper horizontal surface 86 of member 32a.

In the condition of Figs. 5 and 6, flanges 59a engage the upper surface of member 32a to suspend the piston and cylinder mechanisms from member 32a, and thus from beams 1 5a, with the lower ends 83 of the cylinders being spaced above ground level and free of any direct support from the ground. Pistons 54a in cylinders 53a have rod portions 56a which project upwardly through seals 84 at the tops of the cylinders, and have reduced diameter upper portions 75a fitting closely within openings 74a in member 36a and secured thereto by snap rings or other fasteners 77a. Annular upwardly facing shoulders 76a formed on the piston rods engage horizontal undersurface 187 of member 27a to support that member from the pistons for actuation thereby.

The casing extends through a central opening 72a in member 36a.

In using this jack in the manner shown in Figs.

5 and 6, the well is first drilled with the rotary table in its Fig. 1 position, after which the rotary table is removed from beams 1 5a and the jack is supported therein. The mechanism is assembled by first lowering member 32a to its Fig. 5 position on beams 15a, following which mechanisms 33a and 34a are inserted through openings 41 a and 43a in member 32a to the Fig. 5 position in which flanges 59a engage member 32a and suspend the piston and cylinder mechanisms and any load applied thereto from member 32a and beams 15a. Gripping unit 35a may then be placed on member 32a, and member 36a can be moved downwardly onto the upper ends of the piston rods and secured thereto, with unit 37a then being placed on member 27a.Pressure fluid supplied to the lower ends of the cylinders causes pistons 54a to move member 36a and unit 37a upwardly while pressure fluid applied to the upper ends of the cylinders moves the pistons and members 36a and unit 37a downwardly. The slips of units 35a and 37a are actuated between gripping and released condition as discussed in connection with the arrangement of Figs. 1 to 5, to jack the casing downwardly into the well or move it upwardly if desired. This is all accomplished without the necessity for providing any direct support of piston and cylinder mechanisms 33a and 34a from the ground, since the entire jacking mechanism and all loads applied to it are supported directly from the rotary table support beams 15a.

If conditions are encountered in which it is preferable to support the jacking mechanism of Figs. 5 and 6 from the ground rather than from the rotary table support beams 1 5a, this is accomplished in the manner illustrated in Fig. 7, by providing base structure 88 beneath the cylinders resting on the ground 89 and supporting the cylinders therefrom. These base structures 88 may typically be of concrete, or of any other suitable material.In Fig. 7, the member 32a does not contact beams 15a, but is spaced thereabove, so that none of the load of the jacking mechanism is applied to beams 15a. Member 32 is received about piston and cylinder mechanisms 33a and 34a above flanges 59a, with the undersurface 87 of member 32a resting downwardly against the upper surfaces of flanges 59a to support member 32a from the ground through the cylinders 53 of units 33a and 34a. Mechanisms 33a and 34a may be located by a horizontal template 90, which may be a rigid metal part containing a central casing passing opening 91 and two openings 92 within which cylinders 53 are close fits.Template 90 may be retained against lateral movement relative to beams 1 5a by attachment thereto, as by J-bolts 92 having their lower turned ends engaging the upper flanges of beams 1 5a and having their shanks projecting upwardly through openings in template 90 and threadedly connected to nuts 93 at their upper ends for clamping the bolts 92 against the flanges of beams 15a.

The jack is assembled in the Fig. 7 condition by first securing template 90 to beams 15a as shown and then lowering piston and cylinder mechanism 33a and 34a through openings 92 in the template onto the base structures 88, with the lower ends of the cylinders preferably being secured in appropriate manner to those bases.

Members 32a can then be lowered downwardly about the piston and cylinder mechanisms 33a and 34a to positions of support on flanges 59a, with the gripping unit 35a then being placed on member 32a, member 36a being connected to the pistons as discussed in connection with Fig. 5, and unit 37a being placed on member 36a. In this Fig. 7 condition, the entire load of the jacking mechanism and all casing loads applied thereto are supported from the ground through base structures 88.

The arrangement of Figs. 8 through 11 can also be utilized in two different ways. Referring first to Fig. 8, the piston and cylinder mechanisms 33b and 34b may be identical with the mechanisms 33 and 34 of Figs. 1 to 5 except for omission of the upper enlargement on the cylinders and the substitution on each of the cylinders 53b of a lower flange 59b integral with and fixed relative to the cylinder and an upper flange assembly 95. Member 32b corresponding to members 32 and 32a of the arrangements of Figs. 1 to 4 and 5 to 7 is confined vertically between shoulders 59b and 95 to transmit both upward and downward forces from member 32b to the cylinders.The top flange assembly 95 may be detachable, and for that purpose may be formed sectionally as illustrated in Fig. 10 to include a ring 96 receivable within a groove 97 formed in the outer surface of the corresponding cylinder 53b in a relation locking ring 96 against either upward or downward movement. The ring 96 may be formed of arcuate semicircular sections typically hinged together at 98 (Fig. 11) and having free ends engageable at 198, to enable the ring to be moved onto and off of the cylinder. The ring is retained in its interlocking position of reception within groove 97 by confinement between two rigid outer rings 99 and 100, which are clamped together by bolts 101.When rings 99 and 100 are thus secured together, an inner cylindrical surface of ring 100 engages an outer surface 1 96 of ring 96 to prevent opening movement thereof.

In Fig. 8, the jacking mechanism is supported on rotary table beams 15b, by engagement of member 32b with those beams. The piston and cylinder mechanisms are supported by member 32b through upper flange assemblies 95, with the lower ends of the piston and cylinder mechanisms being suspended above ground level without the necessity for any type of ground supported base structures. The apparatus is assembled in this Fig.

8 condition by first moving member 32b downwardly about the upper portions of cylinders 53b (with flange assemblies 95 removed from the cylinders), and by then attaching flange assemblies 95 to the cylinders to clamp member 32b rigidly to the cylinders. The entire assembly consisting of member 34b and the piston and cylinder mechanisms 33b and 34b is then lowered into the rotary table recess in the rig and to the Fig. 8 position in which member 32b is supported on beams 15b and acts to suspend the piston and cylinder mechanisms 33b and 34b also from those beams. Gripping unit 35b and upper member 36b and top gripping unit 37b may then be sequentially moved into position as illustrated in Fig. 8 to complete the jacking mechanism.This apparatus may be employed for lowing or raising casing or other pipe in the same manner discussed in connection with the other forms of the invention, with the entire weight of the jacking mechanism and the casing load being supported from beams 15b.

If it is desired to utilize the apparatus of Figs. 8 through 11 in a ground supported condition, this may be accomplished in the manner illustrated in Fig. 9, by providing base structure 88b resting on the ground and on which the lower ends of the piston and cylinder mechanisms 33b and 34b are supported, so that the flanges 59b on the cylinders then support member 32b from the ground through the side walls of the cylinders, with member 32b being spaced above the rotary table supporting beams 15b to transmit all loads to the ground and not to those beams. A template 90b corresponding to template 90 of Fig. 7 can locate the piston and cylinder mechanisms relative to beams 15b by engagement with the cylinders at a location beneath the level of flanges 59b. The portions of the jacking mechanism above member 32b may be the same as in Fig. 8 and may function to lower or raise a casing in the same manner.

Claims (11)

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

1. Jacking mechanism for use with a well drilling rig having a removable rotary table and having a structure which supports the rotary table during drilling, said jacking mechanism comprising a first member receivable above said structure, two fluid actuated units extending downwardly from said first member at different sides of said axis, a second member supported by said fluid actuated units and actuable upwardly and downwardly thereby, and first and second pipe holding means supported by said first and second members for releasably supporting a casing; characterized by said jacking mechanism being convertible between a first condition in which said first member is supported by said rotary table supporting structure of the rig and said fluid actuated units are supported by said first member, and a second condition in which said fluid actuated units are supported from the ground and said first member is supported by said fluid actuated units.

2. Jacking mechanism as claimed in claim 1, in which said fluid actuated units have external shoulder structures which in said first condition are engageable downwardly with said first member to suspend said fluid actuated units therefrom and in said second condition are engageable upwardly with said first member to support said first member from said fluid actuated units.

3. Jacking mechanism as claimed in claim 1, including shoulders on said fluid actuated units which in said first condition are received above said first member and suspend said fluid actuated units from said first member, and in said second condition are beneath said first member and support it from said units.

4. Jacking mechanism as claimed in claim 1, including two vertically spaced shoulders on each of said fluid actuated units engageable with upper and lower sides of said first member to transmit both upward and downward forces from said first member to each of said units.

5. Jacking mechanism as claimed in claim 4, in which one of said shoulders on each of said units is detachable to enable vertical separation of said first member from said units.

6. Jacking mechanism as claimed in claim 5, in which said detachable shoulder of each unit includes a ring received within a groove in said unit and openable for removal from said groove, and a retainer structure for holding said ring in the groove.

7. Jacking mechanism as claimed in any of the preceding claims, in which each of said fluid actuated units includes a cylinder extending through an opening in said first member and a piston movable vertically relative to the cylinder and connected to said second member to actuate it vertically.

8. Jacking mechanism as claimed in any of the preceding claims in which said first and second pipe holding means comprise releasable slip type casing gripping units supported on said two members respectively.

9. Jacking mechanism as claimed in any of the preceding claims, including template means fixed against laterai movement and containing openings receiving and locating said units.

10. Jacking mechanism as claimed in any of claims 1 through 8, including template means beneath said first member fixed to said rotary table supporting structure and containing openings receiving and locating said units.

11. Jacking mechanism substantially as hereinbefore particularly described and as illustrated in the accompanying drawings.