US2975601A

US2975601A - Handling of equipment laterally of a well location

Info

Publication number: US2975601A
Application number: US554765A
Authority: US
Inventors: Warren K Thorson
Original assignee: Dresser Industries Inc
Current assignee: Dresser Industries Inc
Priority date: 1955-12-22
Filing date: 1955-12-22
Publication date: 1961-03-21
Anticipated expiration: 1978-03-21

Description

March 21, 1961 w. K. THORSON HANDLING OF EQUIPMENT LATERALLY OF A WELL LOCATION 6 Sheets-Sheet 1 Filed Dec. 22, 1955 W /1. Tho/Jon March 21, 1961 w, THQRSON 2,975,601

HANDLING OF EQUIPMENT LATERALLY OF A WELL LOCATION Filed Dec. 22, 1955 6 Sheets-Sheet 2- W A. Tho/"Jon INVENTOR.

ATTO/F/VEVJ March 21, 1961 w, THQRSQN 2,975,601

HANDLING OF EQUIPMENT ELATERALLY .OF :A WELL LOCATIQN Filed Dec. 22, 1955 6 Sheets-Sh'et 3 INVENTOR ATTOH/VEYJ March 21, 1961 w. K. THORSON 2,975,601

HANDLING OF EQUIPMENT LATERALLYOF A WELL LOCATION Filed Dec. 22, 1955 6. Sheets-i-Sheet 4- ATTORNEY March 21, 1961 w THQRSQN 2,975,601

HANDLING OF EQUIPMENT LATERALLY OF A WELL LOCATION Filed Dec. 22, 1955 6 Sheets-Sheet 5 INVENTOR March 21, 1961 w, THQRSQN 2,975,601

HANDLING OF EQUIPMENT LATERALLY. OF A WELL LOCATION Filed Dec. 22, 1955 6 Sheets-Sheet 6 1% INVENTOR.

United States Pate HANDLING OF EQUIPMENT LATERALLY OF A WELL LOCATION Warren K. Thorson, Dallas, Tex., assignor, by mesne assignments, to Dresser Industries, .Iuc., Dallas County, Tex a corporation of Delaware Filed Dec. 22, 1955, Ser. No. 554,765.

13 Claims. (Cl. 6146.5)

This invention relates to improvements in the handling of equipment laterally of a well location during the drilling of and performance of other operations on a well, particularly at an offshore or other water location. In one of its aspects, it relates to a mast for suspending equipment above a well in connection with the drilling thereof and performance of other operations thereon, and

a method of using same which obviates the need for barge-mounted cranes conventionally. employed at offshore locations for handling wellhead equipment and the like laterally of the well. In another of its aspects, it relates to apparatus so constructed and arranged as to be especially well adapted for use over a drilling slot in a floatable barge-mounted type support commonly employed in offshore well operations.

In the drilling of offshore wells, it is common practice to convey a mast to the well location upo'na floatable barge-mounted support. At the desired location, the barge is submerged or the support otherwise fixedly located with respect to the subsurface level to provide a firm foundation for the mast. The mast is then properly positioned over'an open space inwardly of a side of the support and above the well location, which space is known as a drilling slot. When sopositioned, the mast may be used for suspending equipment above the well location to drillsame and to perform other operations thereon, such as the completion of the well. In connecto $10,000 a day, and the well may be so located as to require up to two Weeks in travel time from the home port. Also, the floating barges are at the mercy of weather conditions and cannot operate in rough weather.

It is, therefore, an object of this invention to provide such equipment handling apparatus on the fixed off-shore mast support and, more particularly, to employ for this purpose the same mast or derrick used in the drilling of and performance ofotheroperations on the well.

Another object is to provide an improved mast of this type which is so constructed as to be usable as a crane boom for handling equipment laterally of the well location and, in the case of offshore wells, laterally of the fixed support for the mast.

. Still another object is to, provide a novel method of converting a mast of. the character. describedfrom its position for use in suspending equipment above the well location to one in which 'it performs asa crane boom for handling equipment laterally of the well location in a .manner suchthat there is substantially no eccentric loading on the boom due to combined bending and compression forces.

The techniques employed in rigging up to drill two or more wells from the fixed support at the offshore loca tion are generally cumbersome and time-consuming. More particularly, the transfer or shifting of the necessary drilling equipment from one well location on the support to another has required several separate operations. It is a broad object of this invention to simplify this procedure.

A more particular object is to provide apparatus in which a mast as well as means for suspending and hoisting equipment therefrom are mounted on a platform for movement as a unit over the deck of the offshore support between different positions at the offshore location.

Still a further object is to provide, in apparatus of the character described in the foregoing object, a mast and drawworks which are fixedly mounted on the platform in such a manner that the mast may be used in both drilling and performing other operations upon a well and in handling equipment to one side of the support.

During conveyance to the well location, the mast should be in a lowered, substantially horizontal position so as to reduce the possibility of damage thereto due to high winds and the danger of overturning by lowering the center of gravity of the support. Also, the: weight of such apparatus should be concentrated toward the center of the structure and the slot should be as short as possible. This latter construction not only further increases the stability of the support, but also materially lessens its cost.

A further object of this invention is to provide apparatus including a mast which may be lowered during conveyance and raised at the well locations, and which is so arranged as to reduce to a minimum the length requirements of the slot. d A still further object is to provide apparatus of the type above-described in which the mast is also usable as a crane boom for handling equipment laterally of the.support and wherein the hoisting means of the mast used in drilling and performing other operations upon the well is also used in the equipment handling operations.

Yet another object is to provide apparatus for use in drilling and performing other operations upon an'offshore well and handling equipment about the location thereof, which apparatus is so arranged as to concentrate the weight thereof inboard rather than outboard of the mouth of the slot.

Still a further object is to provide, in apparatus of the character described, a mast which may in certain instances be moved to a plumb position upon an uneven settling of the mast support.

Other objects, advantages and features of this invention will be apparent to one skilled in the art upon a consideration of the written specification, "the attached claims and the annexed drawings.

In 'theldrawings, wherein like reference used throghout to designate like parts:

Fig. l is a side elevation of a mast embodying the features of the present invention and mounted uponaplatcharacters are form supported at an offshore location, such mast being adjusted into a plumb position despite the uneven settling of" its support;

Fig. 3 is an end elevation of the mast and supportiof hoisting equipment suspended therefrom;

Fig. 1, and showing inconnection therewith apparatus for Fig. 4 is a fragmentary view similar to the upper end of Fig. 3, but with the crown block at the upper end thereof carried in a manner to accommodate a fast line extending up an opposite side of the mast from that shown in Fig. 3;

Fig. 5 is a plan view of the mast and apparatus of Fig. 3, and illustrating the disposition of the platform relative to the drilling slot of the support structure;

Fig. 6 is a view somewhat similar to Fig. 5, but in which the crown block is carried by the mast as shown in -Fig. 4 and-the raising and lowering apparatus is positioned for cooperation therewith;

Fig. 7 is an enlarged elevational side view of the crown block of Fig. 3, viewed from the left thereof, as indicated by broken line 77 of Fig. 8;

Fig. 8 is a top plan view of the crown block;

Fig. 9 is an elevational frontview of the crown block, taken substantially along broken line 99 of Fig. 8;

Fig. 10 is an elevational view of a spooling device shown schematically in Figs. 3, 5, and 6 for use in guiding the fast line onto the drum of the drawworks substantially uniformly of the length thereof;

Fig. 11 is another elevational view of the device of Fig. 10 taken from the right thereof, and showing in phantom the fast line operatively engaged therewith;

Fig. 12 is an enlarged detailed view, partly in section and partly in elevation, of a means for extending the length of the stiff raising leg which supports the mast in the upright position of Fig. l, which leg has been extended to tilt the mast to the position shown in broken lines in Fig. l to the left of the upright position in which it may operate as a crane boom;

Fig. 12A is a detailed view of an alternative construction for the means for extending the length of the stiff Fig. 13 is a cross-sectional view of the leg extending means, taken substantially along broken line 13-13 of Fig. 12; and

Fig. 14 is an enlarged view, partly in section and partly in elevation, of another means for extending the length of the stiff leg which supports the mast in an upright position.

In accordance with the present invention, and with particular reference to the embodiment shown in Figs. 1 to 6, inclusive, there is provided a mast having an open face (Fig. 3) and mounted upon a platform 21 at itslower end for swinging movement in a vertical plane transversely to said open face between a lowered horizontal position,. in which the mast is supported by a head rest 42a as shown in broken lines, and an upright position, as shown in solid lines. More particularly, the lower end of the mast 20 is pivotally connected at 22 to the platform 21 and is laterally supported in its upright position byone or more stiff legs 23 pivotally connected at their upper ends'to the mast intermediate the upper and lower ends thereof as at 24 and similarly connected to the platform at their lower ends, in a manner to'be described more fully hereinafter. As shown inthis embodiment'of the invention, the mast 20 is provided with a track or guide 25 over which the upper ends of legs 23 are movable, during raising of the mast, from the broken line to the solid line position. That is, each leg 23 is cooperable with block and tackle means 26 and drawworks 27, connected to the block and tackle means by fast line 28, for forcing the raising legs 23 along the track 25 in .a manner to raise or lower the mast. In the upright position of the mast, the upper end of each leg 23 is latched at its pivotal connection 24 in a manner to laterally support the mast in the upright position.

The details of the mast and the above-mentioned means for raising and lowering same are not described in detail 160,044, filed May 4, 1950, now matured into Patent No.

2,781,108. Referenceis made to such copending application, as well as pages 2480-2484 of the 1954-55 edition of the Composite Catalog of Oil Field and Pipeline Equipment, for a fuller disclosure of the operation of that portion of the mast which has thus far been described. It should be understood, however, that many of the novel features of the present invention are not limited in use to such a mast construction, but, for example, may be employed in connection with similar structures having an open face transverse to the direction of swinging of the mast.

The platform 21 and the apparatus which includes the mast and drawworks are supported above a slot 29 in a barge-mounted support structure 30 which is adapted to be fixedly located with respect to the subsurface level 32 at an offshore well location. Thus, as shown in Fig. 2, the support structure 30 may be provided with a plurality of supporting columns of piles 31 adapted to be driven into the subsurface beneath the water level 33. Alternatively, the support may be any one of the other well known mobile type structures employing, inthe place of the piles 31, a submergible hull or such a hull in combination with suitable piling. Although many of the details of such a support structure 30 are not particularly important in connection with the present invention, it should be noted that this structure includes a transverse support 34 having bearing surfaces on its deck over which bearing surfaces on the platform 21 may be skidded. That is, as illustrated in Fig. 5, the platform 21 and apparatus mounted thereon may be skidded as a unit from the position shown in broken lines, in which a well may have been drilled and completed at position 35, into the position shown in solid lines, wherein a well may be drilled and completed at position 35a,

The block and tackle means 26 conventionally includes a traveling block 36, to which a book 37 is attached, and a crown block 38 carried on the upper end of the mast or derrick. As distinguished from the conventional arrangement wherein the fast line 28 is extended downwardly from the crown block to the drawworks in substantially the plane of swinging movement of the mast, according to the present invention the crown block 38 is so constructed and arranged that the fast line 28 connected to the tackle of the means 26 may extend down the outer side of the mast, as shown in Figs. 3 and 4. Thus, the fast line is connected with drawworks 27 disposed to one side of the vertical plane in which the mast is swingable and, as shown in the drawings, substantially laterally to one side of the mast in its upright position. By means of this construction, the traveling block 36 may swing, in a plane substantially parallel to the swinging movement of the mast without the tackle between it and the crown block being misaligned withthe sheaves of 'the crown block. Still further, with the drum'of the drawworks shown in Fig. 1 in solid lines, to the tilted position, shown I 'inbroken lines in Fig. 1. As can be readily seen from Fig. 3, the open construction of the mast 20 enables the traveling block 36 to be swung from a position within the mast above the well location outwardly thereof to a position to one side of the well location. More particularly, the traveling block 36 is swingable about the crown block 38 to a position outboard ofthe mouth of the drilling slot of support structure 30, in which position it may handle equipment for the purposes previously mentioned. That is, the block and tackle means .26 may (in I the tilted position'of the mast) be used either prior to or after the well is drilled for setting wellhead protective jackets and production platforms at such locations. Thus,

with such equipment suspended from the traveling block when the mast is in itsbroken line position of Fig. 1, another line (not shown) having one end attached, for example, to block 36 and the other to a winch on the platform, may be used to swing the equipment laterally into the position desired. Obviously, in the drilling of the well and performance of other operations thereon the mast may be used in its upright position in a manner well known in the art so that a description thereof is not required.

It will be noted, however, that Fig. 2 illustrates another use for the extendable stiff raising leg 23, this additional use being in connection with adjusting the upright position of the mast 20 so that it is plumb with the water level or earths surface even though the support structure 30 may have settled into the subsurface unevenly, or, on the other hand, in a case in which said subsurface is inclined. Thus, although the piles or columns 31, of the support structure 30 have settled into the underwater earth formation at the offshore location in such a manner that the upper deck of the structure is not parallel to the earths surface, the leg 23 is shown in Fig. 2 as having been extended to plumb the mast 20 so that the crown block will be disposed above the well.

In addition to being extendable in length and pivotally connected at its lower end to the platform 21, the stiff raising and tilting leg 23 is also releasable from its forcetransmitting connection with the platform 21. referring to Figs. 12 and 13, the pin 40 is removable to release the leg 23 from its fixed connection with the platform 21. Also, with respect to the hydraulic type extending means of Fig. 14, it can be seen, particularly in connection with the detailed description to follow, that opening of the hydraulic system will release the otherwise positive fiuid connection between the leg 23 and platform 21. This releasable connection between the stiff leg and platform makes possible a novel method of converting the mast 20 from use in drilling and other operations to use as a crane boom in handling equipment laterallyof the well location. In connection with this method, a pair of guy lines. are extended between opposite sides of crown block 38 at the upper end of the mast 20 divergently outwardlyand downwardly to points 42 fixed with respect to the platform 21 which, as shown in Fig. l, are spaced from the mast on the deck of the then released so as to transfer the lateral support for the mast from the stiff legs to the guy lines.

Upon such release of the aforementioned connection, the mast will be positively connected to the platform 21 only at the pivotal connection 22 at its lower end. Thus, the legs no longer provide a force-transmitting connection and any,

load suspended from the traveling block will be transmitted through thepivotal connection 22 so that the mast in the tilted position will: be loaded in compression as a column only.

To explain this aspectffurther, if the lateral support provided by the positive connection of leg 23 with the platform were not rendered ineffective ,by the abovedescribed release, the mast, acting in its tilted position as a crane boom, would also be loaded eccentricallyas a cantilever beam. By transferring or shifting this lateral I support to a point nearer the upper end or point of loading of the mast, the method of this invention reduces these undesirable loading characteristics and, in fact, in shifting such supportto the point of loading of the mast, this method-enables a minimum .ofeccentric loading.

Thus,

It will be appreciated also that this novel method lessens the cost of the over-all construction as it requires a leg 23 of only such length as is necessary in raising the mast. Furthermore, by transferring the lateral support of the mast from a stiff or rigid member such as leg 23 to a flexible one such as guy lines 41, this method provides the tilted mast with the necessary flexibility for functioning as a crane boom.

When the well is drilled prior to the placing of the equipment which ordinarily requires a separate crane, the method merely involves the steps above-described in which the mast is swung from its upright toits tilted position. However, when such equipment is to be handled prior to drilling of the well, it is necessary to first raise the mast from its lowered horizontal position to the upright position, and then to further move it in the manner described to its tilted position. As described in the aforementioned patent application and publication, the block and tackle means 26 is employed in the raising of the mast from its substantially horizontal to its upright position. As the mast is further moved from its upright to its tilted position, the traveling block 36 is moved upwardly toward the crown block 38 so as not to swing against any transverse members across the otherwise open face of the mast.

Obviously, winches at points 42 may be so inter-connected or synchronized in operation, in a manner well known in the art, that the mast be returned to a position in which its positive connection with the platform maybe remade, as by insertion of pin 40. Then, upon retraction of legs 23, in a manner to be described hereinafter, the mast may be returned from its tilted toits upright position. Still further, the synchronized winches provide a means for extending or retracting the guy lines 41 to adjust the tilted position of the mast.

The aforementioned construction of the crown block 38 and arrangement of the drawworks 27 to one side of the mast permits the length of the slot 29 to be reduced to a minimum. This construction and arrangement also permits the drawworks to be located in a position out of the way of the swinging mast so that it may be fixedly mounted on the platform, and at the same time inboard of the outer end of the slot so that the platform is not loaded in a manner which would tend to tilt the support structure. More particularly, the drawworks 27 is mounted upon a machinery deck 43 laterally of the main portion of platform 21 upon which the mast and stiff legs 23 are disposed as distinguished from forwardly or rearwardly thereof. Of course, suitable machinery (not shown) is provided in connection with the rotatable drum 43a of the drawworks for rotating same in the desireddirection for raising or lowering the traveling outer side of the mast, opposite from that of Figs. 3 and. 5 for'connection with the drawworks mounted as shown in Fig. 6. In either case, it can be seen that inextending downwardly and outwardly of the mast 2t) and substantially parallel thereto, the fast line 2 8 will not interfere, with any of the swinging movements of the mast during the raising and lowering as well as tilting thereof. Furthermore, the varying forces necessarily applied to the fast line will not cause extreme variations in the tension of the guy line 4 1 as would be the case if the drawworks werelloc'ated to the rear of the mast toward theguy line anchor or to the front of the mast and the fast line extended directly from the crown block to the drawworks, as is customary.

. It should be understood, however, that although the i foregoing constitutes a novel and desired arrangement of the drawworks with respect to the mast, it may be possible to locate the drawworks intermediate the mast and end of the support during raising of the mast and drilling of the well, and then to skid the drawworks to the other side of the mast for tilting purposes.

The detailed construction'of crown block 38 per se is more fully described and claimed in a patent application copending herewith. However, this construction is shown and described herein in Figs. 7 to 9 as one which, while not essential to the practice of the present invention, is at least especially well suited to obtain the greatest benefit thereof. In the crown block construction as shown, the upper end of mast 20 is provided with a deck 44 comprising longitudinal and transverse support members upon which is secured a bracket 45 for supporting fast line sheave 46 for rotation about an axis substantially parallel to that of the drawworks drum, and a watertable 47 for supporting additional sheaves including a deadline sheave 48 for rotation about an axis disposed substantially transversely to the rotational axis of fast line sheave 46. Thus, in a manner more fully described in the aforementioned copending application, the fast line 28 is received from the side of the mast and over sheave 46 for extension to a sheave of the traveling block 36. The re turn line from this sheaveof the traveling block will then extend upwardly and about sheave 49b of those disposed transversely to the fast line sheave 46. As is customary, the line is then extended in turn between the additional sheaves to the left of sheave 49b and those of traveling block 36 until the tackle reaches sheave 4&5 from which it extends downwardly as deadline 49 to an anchor 49a at the base of the mast to which the deadline is secured. a

The upper ends of the guy lines 41 may be connected to opposite sides of the mast at their upper ends by means of eye bolts 490 secured to opposite ends of the shaft 47a for sheave 48 and those aligned therewith. These bolts may be turned so as to be substantially in line with the guy lines., 7

The foregoing description is sufiicient to illustrate that this crown block construction permits traveling block 36 to swing in a plane substantially parallel to the plane of movement of mast 20 as the mast is tilted, while at the same time permitting the fast line 28 to extend downwardlyalong the outer side of the mast to drawworks disposed to one side of the plane of movement of the mast without misalignment with its sheave on the crown block, and for this to take place with the axis of rotatable drum 43a of the drawworks disposed substantially parallel to said planes of movement.

As the mast 20 is swung about itshlower end, the

angular relation between the fast line 28 and the axis of rotatable drum 43a of drawworks 27 is. constantly changing. In fact, due to the degree of angularity and the heavy loads which are to be suspended from the block and tackle means with the mast tilted, it has been found that conventional methods of guiding the line onto the rotatable drum substantially uniformly of the length thereof are not satisfactory.- There is shown in Figs. and 11 a device 56) for so guiding the line, which device is disclosed in more detail and claimed in the aforementioned copending application disclosing the details of crown block 38.

As indicated diagrammatically in a number of the fig- I dies of the drawings, the device. 50 is disposed between hydraulic actuator forthe member 52 includes a piston 56 slidable within a cylinder 57 secured to part of the guide. The piston rod 55 of the actuator is secured at one end to member 52,"?111dfii16 opposite sides of piston 56 at the other end of the rod are exposed to

ports

58 and 59 in cylinder 57. Thus, fluid may be introduced to either side of the piston 56 for moving the member 52 carrying the snatch block in the desired direction.

More particularly, the lines leading from

ports

58 and 59 connect with a four-way valve 60 to alternately expose one side of the piston to a source of fluid pressure and to exhaust the opposite side. It is desired that the movement of guide 53 be synchronized with the speed at which the line is wound about rotatable drum 43a, and this may be done by manual operation of valve 60 or by suitable automatic means. Obviously, equivalent mechanical means may be employed in lieu of the hydraulic actuator shown and described.

The fast line 28 has not been shown in the solid line illustration-s of Figs. 10 and 11, so that the pulley 51 merely depends from member 52 in an inactive position. The active position of the pulley 51 as the fast line 28 is guided in tension thereover onto the drawworks drum 43a is shown, however, in phantom in Fig, 11.

Turning now to adetailed description of the mechanical means shown in Figs. 12 and 13 for extending and retracting the length of stiff leg 23, it can be seenthat such means comprises a block 61 to which the stiff leg 23 is pivotally connected by universal joint 62. As shown in Fig. 12, a screw part 63'of jackscrew means carried within a housing or case 64 is secured to and extends downwardly from the lower end of block 61. The block 61 is provided with flanges 65 slidably movable within guide members 66 secured to a laterally extending member 67 of the platform 21, and limited in upward movement by a stop part 66a. Also, the housing 64 is so mounted upon a support 68 of the platform as to mount the screw part for movement along an axis parallel to the guided path of block 61. More particularly, acme threads on the screw part 63 provide a drive connection with a nut 69 of the jackscrew means which is, in turn, rotated within within housing 64 by means of a right angle worm and gear drive 70. v

It'will be understod that equivalent means, such .as the ball bearing screw shown in Fig- 12A, may be substituted for the jackscrew of Fig. 12. in converting the rotary movement of drive 70' to linear. movement. As'well known in the art, and as shown inFig. 12A, this equivalent means includes a. nut 7011, a screw part 70b received within the nut, and oppositely disposed, spiral grooves formed in both the nut and screw part to receive balls 70c therebetween. As the housing is rotated tomove the screw part linearly, the balls are caused'to move continuously .within the grooves and a return conduit 7061.

when the stiff leg 23 is extended so as to tilt the mast and the .pin 40 is removed to disconnect the leg from the platform, it can be seenthat lower part 72 of block 61 provides a stop against which part 71 will abut upon return .of the leg to its retracted position so that pin 4tlmay be reinserted. This-construction may also prove important as a safety feature, for example, should the block and tackle means 26- break or' should a load suddenly he dropped from the hook37 so that the reaction therefrom causes the leg to'be abruptlyretracted. That is, the stop provided by the part 72 woulclprevent the. mast from swinging back over beyond the vertical and toward its horizontal position. H

The hydraulically actuated means for extending the length of leg 23, shown in Fig.14, includes a piston 73 A slidable within a cylinder74 telescopically received in the lower hollow end of stiff leg 23. At its end opposite the piston 73, the piston'rod 75 is pivotally connected to the platform 21 by means of a ioint which includes a part 76a on the rod having a pin 76b journaled in 'U-shaped bracket 76c secured to the platform.

The lower flanged ends of cylinder 74 and stiff leg 23 are connected together so that upon application of fluid pressure to opposite sides of the piston 73, the leg 23 may be extended or retracted as desired. For example, the leg 23 may be extended in length from its retracted position, as shown in Fig. 14, by the application of fluid pressure to the upper end of piston 73 through line 77. For this purpose, there may be provided a four-way valve 78 connected to the line 77 as well as a line 79 communicating with the lower end of piston 73 so that fluid pressure may be applied to the upper end of the piston, as mentioned, and exhausted from the opposite sides thereof through a return line. On the other hand, the stiff leg may be retracted from an extended position by manipulation of the valve 78 in such a manner as to apply fluid pressure to the lower end of the piston and to permit exhaustion of such fluid pressure from the upper end thereof. As can be seen from Fig. 14, in the retracted position of the stiff leg 23, the flanged lower end of cylinder 74 engages and rests upon the upper shouldered surface of joint part 76a so that the latter provides a stop therefor.

Similarly to the extending means described in connection with Figs. 12 and 13, the fluid pressure actuated means of Fig. 14 may also be actuated or operated in such a manner as to release the force-transmitting connection between the leg 23 and the platform 21. That is, as shown in Fig. 14, the leg and platform are in effect positively connected by the pressure fluid acting within the piston and cylinder arrangement. Thus, upon opening of the fluid system, this positive connection between said two parts is released and the leg 23 is relieved of any fixed force-transmitting connection with respect to the platform 21 which would result in an eccentric loading of the mast upon tilting thereof. Furthermore, a clamp 80 may be used for securing the cylinder and lower end of the stiff leg to the pivotal joint 76 when the mast is in an upright position. i

It will be understood that while specific reference is made to the actuation of the device of Fig. 14 by hydraulic pressure, other types of fluid pressure may be adapted to this purpose.

With the mast in an upright position, it is also desirable to relieve the stiff leg extending means from loads transmitted from the leg to the platform. Thus, in each of the structures above-described in connection with Figs. 12 and 13 as well as Fig. 14, there are provided oppositely facing abutting surfaces for receiving shims or the like which serve to transmit the load on the leg directly to the platform. In connection with Fig. 12, it can be seen that such abutting surfaces are provided by the lower end of part 72 of block 6-1 and the upper end of housing 64, which parts will be relatively near one another when the mast is in upright position. in the extending means of Fig. 14, such abutting surfaces are provided by the lower flanged end of cylinder 74 and the upper shoulder upon the joint part 76a secured to piston rod 75.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the method and apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the :invention without departing fro'mthe scope thereof, it is 'to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense. V

The invention having been described, what is claimed is: l. A method of. using a mast in drilling and'perform- If) ing other operations on a well and also in handling equipment offset from a well location comprising the steps of locating the mast with its lower end at a predetermined location and then swinging the mast in one direction about its lower end and in a vertical plane from a reclining position at one side of the well location to an upright drilling position in which equipment can be suspended directly above the well for the purpose of drilling and performing said other operations, supporting the mast at a point intermediate its ends against further swinging movement in said vertical plane while the mast is in said upright drilling position, vertically moving a load with a block and tackle carried by the mast while the latter is in said upright position, applying a controlled force to the mast while its lower end remains at said predetermined location to further swing the mast in said one direction from said upright drilling position to a tilted position on the opposite side of the well location from said reclining position while shifting the support of the mast against further swinging movement from said inter; mediate point to a point nearer the upper end thereof, and vertically moving a load with a block and tackle carried by the mast while the latter is in said tilted position.

2. In the method of using a mast as a crane boom for handling equipment at one side of a well location, wherein the mast is of the type which is mounted on a platform for swinging movement in a vertical plane and supported in a substantially upright drilling position above a well location by a leg connected between the mast and platform, the steps of locating the mast with its lower end at a predetermined location and then raising the mast by swinging it in one direction from a substantially horizontal position to said substantially upright drilling posi-.

tion, vertically moving a load with a block and tackle carried by the mast while the latter is in said upright position, connecting a guy line between the mast adjacent its upper end and a point fixed with respect to the platform for limiting tilting of the mast to a predetermined amount, applying a force through the leg while the lower end of the mast is still in said predetermined location to controllably move the mast in said one direction from said substantially upright drilling position toward its predetermined tilted position, releasing the connection of the leg between the mast and platform and employing the guy line to limit tilting of the mast so that lifting loads upon the mast in its tilted position are prevented from being transmitted to the platform through the leg, and then employing a block and tackle carried by the mast to vertically move a load while the mast is in tilted position.

3. In a method of using a mast as a crane boom for handling equipment at one side of a well location, wherein the mast is of the type which is mounted on a platform for swinging movement in a vertical plane 'and wherein a leg is connected between the mast and platform to support the mast in an upright position; the steps of vertically lifting a load with a block and tackle while the mast is insaid upright position, connecting a guy line between the upper end of the mast and a point fixed with respect to the .platformfor limiting tilting of the mast to a predetermined amount, extending the length of the leg in a manner to swing the mast from its upright to approximately its predetermined tilted position and during movement of the mast to its tilted position employing the leg to apply a force thereto controlling swinging movement of the mast, then releasing the connection of the leg between the mast and platform to permit the mast to extend the guy line and prevent-loads upon'the mast in its'tilted position from being transmitted to the platform through the leg, and then employinga block and tackle carried by the mast to vertically move a load while mounting the mast on the platform toward one edge thereof for swinging movement in one direction in a vertical plane from a substantially horizontal drilling position through an upright position in which the upper end of the mast is above the platform to a tilted position in which said upper end is to one side of the platform and the mast is at a substantial angle with the vertical, a leg connected between the mast intermediate its ends and the platform and supporting the mast in its upright drilling position, means for causing the leg to apply a force to the mast to swing the mast toward its tilted position, means for releasing the connection of said leg between the mast and platform when the mast is tilted, and means connected to the mast adjacent its upper end when the mast is in tilted position and limiting swinging movement of the mast beyond said tilted position.

5, Apparatus for use in drilling and performing other operations on a well and for handling equipment at one side thereof, comprising a platform, a mast, means mounting the mast on [the platform for swinging movement in one direction in a vertical plane from a substantially horizontal position through an upright drilling position to a tilted position, block and tackle means carried by the mast for suspending equipment above the well location in the upright drilling position of the mast and to one side of the well location in the tilted position of the mast, a stiff leg connected between the mast intermediate its ends and the platform for supporting the mast in its upright position, a guy line connecting between the mast adjacent its upper end and a point fixed with respect to the platform and of a length to support the mast in a predetermined tilted position in which the mast leans at a substantial angle with the vertical, means for extending the length of said leg to swing the mast to the tilted position thereof while the leg provides lateral support for the mast during its movement to tilted position, and means for releasing the connection of said leg between the mast and platform when so extended, whereby lateral support for the mast can be absorbed by the guy line and the load of the suspended equipment will not be transmitted to the platform through the stiff leg.

6. Apparatus of the character defined in claim including means for extending and retracting the length of the guy line for moving the mast from its predetermined to another tilted position.

7. Apparatus for use in drilling and performing other operations on a well as well as in handling equipment about the location thereof, comprising a platform, a mast, means mounting the mast on the platform for swinging movement in one direction in a vertical plane from a substantially horizontal position through an upright drilling position in which equipment may be suspended therefrom above the well to a tilted position in which the upper end of the mast lies laterally to one side of the well location and in which the mast leans at a substantial angle with the vertical, means providing lateral support for the mast in its upright drilling position, a pair of guy lines connected to the mast adjacent its up per end and extending downwardly therefrom to a point fixed with respect to the platform, said lines being of a length to support the mast in a predetermined tilted position, means for swinging the mast from its horizontal to its upright drilling position and then toward its tilted position, means for releasing the lateral support for the 'mast so that it is supported by the guy lines in the predetermined tilted position thereof, and means for extending or retracting the length of the guy lines for moving the mast from said predetermined tilted position.

equipment, means including a stiff raising leg connected between the mast intermediate its ends and the platform and cooperable with the block and tackle means to lift the mast in one direction from "a substantially horizontal to a substantially vertical drilling position in which the mast 'is supported by the leg, means extending the length of said leg in a manner to tilt the mast inrsaid one direction and away from its substantially vertical position to a tilted position in which the mast leans at a substantial angle with the vertical so that the block and tackle means can vertically lift loads situated at one side of the wall, means for releasing the connection of the leg between the mast and platform when the mast is in its tilted position, and means connected to the mast adjacent its upper end when the mast is in tilted position and limiting swinging movement of the mast beyond said tilted position.

9. Apparatus for use in' drilling and performing other operations on a well and handling equipment at one side thereof, comprising a platform, a mast, means mounting the mast on the platform for swinging movement in a vertical plane about a single pivot axis at the lower end of the mast, a leg extendable for retractable in length and pivotally connected at opposite ends to the mast intermediate its ends and the platform for supporting the mast in an upright position when retracted, means for extend- 1 ing the length of said leg to move the upper end of the 8. Apparatus for use in drilling and performing other operations on a well and for handling equipment at one side thereof, comprising a platform, a mast mounted on the platform for swinging movement in a vertical plane, block and tackle means carried by the mast for suspending equipment therefrom, drawworks connected to the 'block andtackle means for raising and lowering said mast to one side of a vertical plane, containing said pivot axis and to swing the mast to a tilted position, means for releasing the pivotal connection of the leg with the platform when the mast is in its tilted position and means connected to the mast adjacent its upper end when the mast is in tilted position and limiting swinging movement to the mast bey'ond said tilted position.

10. Apparatus of the character defined in claim 9, wherein the mean for extending the length of the leg includes a fluid pressure powered actuator.

11. Apparatus for use in drilling and performing other operations on a well and handling equipment at one side thereof, comprising a platform, a mast mounted on the platform for swinging movement in a vertical plane, an elongate guide on the platform, a member having a sliding connection with and slidable longitudinally along the guide toward and away from the mast, a stilf leg pivotally connected at its upper end to the mast intermediate the ends of the mast and at its lower to said member, means for moving the member along the guide to swing the mast in said vertical plane, said member being formed of two separable parts, means pivotally connecting one of said parts to the leg, means connecting the other part to the moving 'means, and means releasably connecting said parts.

12. Apparatus for use in drilling and performing other operations on a well and handling equipment at one side thereof, comprising a platform, a mast mounted on the platform for swinging movement ina vertical plane, a housing mounted on the platform, jackscrew means carried in the housing, and a stiff leg pivotally connected at its upper end to the mast intermediate the ends of the mast and at its lower end to the jackscrew means, the screw of said jackscrew means being formed of separate parts, means pivotally connecting the upper of said screw parts to the leg, a flange on the lower of said screw parts facing oppositely to the upper portion of the housing to receive shims therebetween, means releasably connecting said screw parts together, and a guy line connected between the upper end of the mast and a point fixed with respect to the platform.

13. Apparatus for use in drilling and performing other housing mounted on the platform, ball bearing screw means carried in the housing, and a stiff leg pivotally connected at its upper end to the mast intermediate'the ends of the mast and at its lower end to the ball bearing screw means, the screw of said ball bearing screw means being formed of separable parts, means pivotally connecting the upper screw part to the leg, a flange on the lower of said screw parts facing oppositely to the upper portion of the housing to receive shims therebetween, means releasably connecting said screw parts together, and a guy line connected between the upper end of the mast and a point fixed with respect to the platform.

References Cited in the file of this patent UNITED STATES PATENTS 14 Thompson Aug. 17, Woolslayer et. al. July 12, Moon Ian. 30, Troche et a1 Sept. 23, Cardwell et al Nov. 11, Wilson Nov. 24, Patterson Apr. 17, Hall July 3, Selberg et a1 Feb. 12, Balogh Mar. 26, Braun May 14, Jenkins et a1. June 24,

FOREIGN PATENTS Germany June 20, France Nov. 9, Great Britain Dec. 19,