US3757858A

US3757858A - Apparatus for moving pipe into and out of a well

Info

Publication number: US3757858A
Application number: US00206019A
Authority: US
Inventors: H Davis; R Robertson
Original assignee: SNUB R RIG CORP
Current assignee: SNUB R RIG CORP
Priority date: 1971-12-08
Filing date: 1971-12-08
Publication date: 1973-09-11
Anticipated expiration: 1990-09-11

Abstract

The apparatus includes a derrick and a base for supporting the derrick on the well head of a well. The derrick comprises two symmetrical legs that extend upwardly from the base on opposite sides of the centerline of the well head and equidistant therefrom so that the weight of the derrick imposes no unbalanced turning moment on the well head. Each leg supports a sprocket and sheave that move a chain and cable assembly vertically along the side of the leg adjacent the centerline of the well head. Elevators are attached to each chain for movement by the chains along the centerline of the well head to move pipe into and out of the well below the well head. The force imposed on the elevators is equally divided between the chains and the two legs of the derrick so that no unbalanced turning movements are imposed on the well head. When the fluid in the well is imposing an upward compressive force on the pipe greater than the weight of the pipe, members are spaced along the pipe above the well head that extend laterally to engage support members or brackets carried by the chains and limit the amount the pipe can bend due to the compressive force. The elevators hold the pipe against movement up or down relative to the elevators.

Description

United States Patent 1 Davis et a1.

[4 1 Sept. 11, 1973 1 APPARATUS FOR MOVING PIPE INTO AND OUT OF A WELL [73] Assignee: Snub-R-Rig Corporation, St. Mary Parish, La.

[22] Filed: Dec. 8, 1971 [21] Appl. No.: 206,019

[52] US. Cl. 166/77, 166/775, 173/147, 175/9 [51] Int. Cl E211) 33/03, E2lb 15/00 [58] Field of Search 166/75, 77, 77.5; 175/9; 173/147 [56] References Cited 1 UNITED STATES PATENTS 1,895,132 1/1933 Minor 166/77 2,272,835 2/1942 Geraghty 175/9 2,567,009 9/1951 Calhoun et al. 166/77 2,849,212 8/1958 Robbins.. 173/147 3,012,619 12/1961 173/147 Farque Primary Examiner-James A. Leppink Att0rneyW. F. Hyer et a1.

[57] ABSTRACT The apparatus includes a derrick and a base for supporting the derrick on the well head of a well. The derrick comprises two symmetrical legs that extend upwardly from the base on opposite sides of the centerline of the well head and equidistant therefrom so that the weight of the derrick imposes no unbalanced turning moment on the well head. Each leg supports a sprocket and sheave that move a chain and cable assembly vertically along the side of the leg adjacent the centerline of the well head. Elevators are attached to each chain for movement by the chains along the centerline of the well head to move pipe into and out of the well below the well head. The force imposed on the elevators is equally divided between the chains and the two legs of the derrick so that no unbalanced turning movements are imposed on the well head. When the fluid in the well is imposing an upward compressive force on the pipe greater than the weight of the pipe, members are spaced along the pipe above the well head that extend laterally to engage support members or brackets carried by the chains and limit the amount the pipe can bend due to the compressive force. The elevators hold the'pipe against movement up or down relative to the elevators.

10 Claims, 9 Drawing Figures United States Patent 1 [111 3,757,858

Davis et al. 1 Sept. 11, 1973 Pmmwsim 3.757.858 SHEH 2 0F 4 FIG. 3

' PAIENIEDSEH nan sum 3 or 4 PATENTED SEPI I I975 SHEET '4 OF 4 APPARATUS FOR MOVING PIPE INTO AND OUT OF A WELL This invention relates generally to apparatus for moving pipe into and out of a well, and in particular to such apparatus that is mounted on the well head of an existing well to run a pipe string into and out of the well to perform remedial work or the like on the well.

The apparatus of this invention can be used to service or perform remedial work on any well, but it has particular utility with wells that are located where a ground support for the conventional workover rig or service rig is not available, such as wells located in bodies of water, or in marshy or swampy locations. For example,

there are many oil and gas wells located in the Gulf of Mexico and most of them, periodically, need some type of service or remedial work. Where the work to be performed is not major, and can be done by running a small string of pipe into the well through the tubing that is in the well, or by simply pulling and rerunning the existing tubing in the well, the operator must make a decision as to what type of equipment he is going to use to do this work. Usually, the well will be producing. If the operator decides on using a conventional workover rig, it will usually be time saving to kill the well with mud so the workover rig can pull the pipe and run it back in the hole with the well dead. Saving time is important because operating conventional workover or service rigs offshore is very expensive. Another alternative for the operator, is to use what are known as hydraulic snubbing units that can run pipe into the well while the well is under pressure. This avoids the necessity of killing the well. Offsetting the advantage of not having to kill the well, however, is the substantially longer period of time required for these hydraulic pulling or snubbing units to-do the job. These units employ hydraulic cylinders with a maximum stroke at the present time of about 8 feet. This means that the pipe is run into the hole and pulled out of the hole in 8 foot strokes of the hydraulic cylinders. Obviously, this is a time consuming operation that requires four operations of the cylinders to raise or lower one 30 foot joint of pipe.

Also, the weight imposed on the well head should be kept to a minimum to reduce-the possibility of damaging the well head. The hydraulic cylinders described above are inherently heavy andthus impose a substantial load on the well head. In addition, the weight and bulk of the hydraulic cylinders complicates the rigging up and tearing down of. the equipment.

.It is an object of this invention to provide apparatus 7 for moving pipe into and out of a well for performing service and remedial work on a well that is light in weight, that can be mounted directly on and easily supcan run a joint of pipe into and out of the hole in one continuous operation, even when the well is under pressure and is imposing compressive forces on the pipe that would cause the pipe joint to bend laterally when extending above the well head.

It is another object of this invention to provide apparatus for running pipe into and out of a well under pressure and that will support the pipe extending above the ported by the well head of the well, and that can pull,

or run, as the case may be, an entire joint of pipe into and out of the well with one continuous upward or downward movement without imposing any significant unbalanced bending moment on the well head. The latter is an important feature of this invention since well heads can support a substantial axial load, but the well owners and operators do not want the well head to be subjected to an unbalanced bending moment of any consequence as this can damage the well head, such as by causing the elongation of the bolts holding the sections of the well head together resulting in leaking connections. v

It is another object of this invention to provide such apparatus for running pipe into and out of a well that in which:

well at spaced points along the pipe to hold the pipe from lateral movement or bending due to the compressive forces imposed on the pipe by the well pressure.

It is an additional object of this invention to provide such apparatus that can be mounted directly on the well head of the well and that can move pipe into and out of the well through the casing head a joint at a time as does a conventional workover or service rig, and yet not require the supporting platform necessary for such rig, nor the killing of the well which is required to make such rigs economically advantageous over the heretofore used hydraulic snubbing units.

It is another feature and object of this invention to provide elevators for use with such apparatus that will hold the pipe from movement relative to the elevators in either direction to allow the elevators to be used to handle pipe when the pipe is being moved into or out of thewell and subjected to an upward force from the pressure in the well that exceeds the weight of the pipe. These and other objects, advantages, and features of this invention will be apparent to those skilled in the art from a consideration of this specification including the attacheddrawings and appended claims.

The preferred embodiment of the invention will now be described in connection with the attached drawings,

FIG. 1 is a side view of the derrick, derrick base, and crown block of the preferred embodiment of this invention mounted on a well head;

FIG.- 2 is a view of the derrick of FIG. 1, looking in the direction indicated by thearrows 2-2 of FIG. 1;

FIG. 3 is a cross sectional view through one leg of the derrick of FIG. 1 taken along line 3-3 of FIG. 4;

FIG. 4 is a view on an enlarged scale of the lower portion of FIG. 1, showing the arrangement of the various components of the apparatus and how they are mounted on the well head;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is a top view showing the drive train from the two hydraulic motors used in the embodiment shown to drive the pipe hoisting chains; I

FIG. 7 is a verticalsectional view throughthe elevators employed with the apparatus: of this invention;

FIG. 8 is a view along line 8-8 of FIG. 7; and

FIG. 9 is a view taken along line 9--9 of FIG. 5.

The base, derrick, and crown block of the pipe handling apparatus of this invention is shown in FIG. I mounted on the well head of a well located in a body of water. As stated above, it is with this type well that the apparatus of this invention is most useful, particularly where the well is not associated with a platform of the type that will support conventional workover or service rigs. When these wells are drilled, the first operation is usually the driving of a string of conductor pipe into the ground below the water. This conductor pipe, indicated by the number 10 in FIG. 1, serves to conduct drilling mud back to the surface while the drilling rig is drilling the portion of the hole that is to receive the secnd string of casing, generally called surface pipe, and indicated by the number 11 in FIG. 1. When surface pipe 11 has been run into the hole, it is common practice to pump sufficient cement down the surface pipe and up into the annulus between the conductor pipe and the surface pipe to fill the annular space to the top of the conductor pipe. This forms a solid cement sheath 12 between the conductor pipe and the surface pipe, and also between the portion of the surface pipe below the conductor pipe and the hole that has been drilled to receive it.

Attached to the top of surface pipe 11 is casing head 13. The well shown has just one other string of casing, 14, which is run after the hole has been drilled to the desired depth. This string of pipe is usually called the oil string, and it is at least partially supported by a casing hanger (not shown) that engages the inside of casing head 13 and forms a seal between the upper end of oil string 14 and surface pipe 11. Tubing head 15 is then mounted on top of casing head 13, and tubing string 16 is run into the well to the desired depth. Tubing 16 is supported by a tubing hanger (not shown) that engages an appropriate seat inside tubing head 15 and provides a seal between the upper end of oil string 14 and the tubing. Wing valve 17 controls the flow of fluid into and out of the well through the annular space between oil string 14 and the tubing. Mounted on top of tubing head 15 is master valve 18 that controls the flow of fluid into and from the well through tubing string 16. Usually the well is produced throu h the tubing and the production flows laterally from the well head through wing valve 19 after passing through ma'ster valve 18.

In accordance with this invention, the pipe handling As shown in the drawings, guy wires 29 extend downwardly at an angle from the derrick. If the location is where anchorage can be obtained for such guy wires, then their use would be advantageous, particularly when the derrick is being erected. The derrick, however, is designed for use with or without guy wires. As can be seen from FIGS. 1, 2, 3, and 5, each leg of the derrick is generally triangular in cross section, having three vertical tubular members connected together by bracing extending between the vertical members. The adjoining ends of each section of each leg is provided with abutting plates that can be bolted together to connect the adjacent sections of each derrick leg. As stated above, the two legs of the derrick are symmetrically shaped and of identical construction so that the effective center of gravity of the derrick will lie substantially on the vertical axis of the well head, when the two legs are erected on the base, as shown in FIGS. 1 and 2, with apparatus is mounted directly on the well head and supported thereby. As shown in FIGS. 1 and 4, base 20 includes base plate 20a, beams 20b, and motor mounting plates 20c and 20d. Base plate 20a is attached to master valve 18 by bolts 21. Base 20 supports the derrick that extends upwardly from the base. The derrick in the embodiment shown includes two symmetrically shaped

legs

22 and 23 that extend vertically above base 20 on opposite sides of and equally spaced from the vertical centerline of the well head. Each leg of the derrick is made up of four sections,

22a

22d, and 23a 23d, respectively. The legs are broken into sections so that the derrick can be more conveniently moved to and from the location and erected on the base and dismantled therefrom. While being erected, cross braces 24 are used to tie the upper ends of the'sections together as they are assembled so that there will be a unity of structure between the two legs as the derrick-is being assembled upwardly above base 20. After crown block 25 is bolted to the top of the two legs of the derrick, as shown in FIG. 1, the assembly braces can be removed from one side to allow pipe joints to be moved into and out of position over the well bore between the legs. The derrick should be tall enough to allow the pipe handling equipment supported thereby to handle a full joint of pipe, say 40 feet is probably sufficient for a foot joint.

Crown block 25 includes crown block base 26 and

sheaves

27 and 28. Crown block base 26 is positioned on top of the two legs of the derrick so that

sheaves

27 and 28 are on opposite sides of and equidistant from the vertical axis of the well head. The sheaves are mounted on base 26 so that they rotate around parallel horizontal axes.

each leg parallel and equally spaced from the vertical axis of the well head.

In accordance with this invention, means supported by the derrick and movable vertically relative to the derrick are providedfor moving a pipe string, made up of a plurality of joints of pipe, through the well head into and out of the well bore a joint at a time. In other words, the pipe moving apparatus will move a pipe string, made up of a plurality of pipe joints, into and out of the well bore in steps substantially equal to the length of each joint of pipe so moved. Referring to FIGS. 3, 4, and 5, in the embodiment shown, such means'includeselevators 30 that engage the pipe and hold the "pipe against movement relative to the elevators. Theparticular construction of the elevators in the embodiment shown will be described in detail below. The elevators are supported by

elevator arms

30a and 30b that extend laterally from the elevators and are connected to vertically extending

roller chain sections

31 and 32. The roller chain sections move vertically along

derrick legs

22 and 23 on opposite sides of the centerline of the well head, and thus move elevators 30 vertically between the derrick legs along the centerline of the well head.

Derrick legs

22 and 23 are provided with chain guides 33 and 34, respectively. These guides comprise channel members that are attached to the derrick legs and provide vertical channels that guide the roller chains as they are moved vertically along the derrick legs. The chains are supported at the top of the derrick by cable sections (not shown) that extend upwardly from the upper end of the chains over

sheaves

27 and 28 of the crown block and down through the inside of the derrick legs where they are attached to the other end of the chain section.

Means are provided to move the chains vertically relative to the derrick legs, and in so doing to move elevators 30 vertically along the centerline of the well head. In the embodiment shown,

sprockets

34 and 35 are mounted on

shafts

36 and 37, respectively. The shafts are supported for rotation (bearings not shown) adja? cent the lower end of the derrick legs to position

sprockets

34 and 35 to engage

chain sections

31 and 32, respectively, and move the chain sections vertically as the sprockets are rotated. To rotate the sprockets,

hydraulic motors

38 and 39 are mounted on motor mounting plate 200 of base 20.

Sprockets

40 and 41 are mounted on the output shafts of the motors and rotate

sprockets

44 and 45 keyed on

shafts

36 and 37 through

drive chains

42 and 43, respectively.

Motors

38 and 39,

then, rotate

sprockets

34 and 35 and move

roller chain sections

31 and 32 vertically along the sides of

derrick legs

22 and 23. This in turn moves the elevators vertically along the centerline of the well head, and moves pipe supported by the elevators into and out of the well bore.

Motors

38 and 39 may be hydraulic motors or any convenient type motor for which power is readily available. These motors, as shown in FIG. 5, are positioned on base so that they impose no unbalanced turning moment on the well head.

Since one of the advantages of the use of the pipe handling apparatus of this invention is to be able to service a well without having to kill it, certain pressure control equipment will be required. As shown-in FIG. 4, blowout preventer stack 50 is bolted directly to the base plate 20a of base 20 and to the upper flange of master valve 18 by bolts 21. The base plate is grooved in the conventional manner to receive ring gaskets. The preventer stack usually consists of at least two ram type preventers, only lower flange 50a of which is shown in the drawings and stripper head 50b on top of the preventers. The stripper head includes a sealing element that engages the pipe extending through the head and prevents well pressure from escaping around the pipe. In one commonly used applicationof this apparatus, the tubing in the well bore remains in place, and a string of pipe of sufficiently small diameter to go inside the tubing is run into the tubing to perform certain functions, such as cleaning sand out of the tubing, retrieving gas lift valves, and opening slide valves. As shown in FIG. 4, the well tubing is still in place supported by the tubing hanger, and to service the well it only requires opening master valve 18 and running the small diameter tubing usually called macaroni, into the well tubing already in place. Back pressure or float type valves are positioned inside the'macaroni tubing to prevent well pressure from escaping from the well through the tubing when it is beingrun into the well.

If the servicing operationis to be performed with the well under pressure, pipe holding means must be provided to hold the tubing against its own weight, and also against the pressure of the well. In other words, when the amount of macaroni tubing in the well is such that its weight cannot-overcome the upward force of the well pressure acting on the tubing, then means must be provided that will hold the pipe against upward movement. Then, when the weight of themacaroni is such that it will overcome the upwardforce of the well pressure, means must be providedto support the weight of the macaroni. As shown-in FIG. 4, this is accomplished by using two conventional power type slips with one upside down. Thus, slip bow 51 is attached to the upper flange of stripper head 50b by bolts 52, with the slip bow upside down from its conventional position. Slip segments 53 must have room to move into and out of position to hold the pipe, therefore some space must be provided between the bottom of slip bow 51 and stripper head 50 so bolts 52 are arranged to support slip bow 51 at some preselected distance above the stripper head. Bolted directly to the upper end of upside down slip bow 51 is another slip bow 54. This slip bow is positioned in the conventional manner and slip segments 55 are moved into and out of engagement withthe upper pipe joint 56 in the conventional manner. Air or hydraulic cylinders located in

housings

57 and 58 attached to the slip bows move the slip segments into and out of pipe holding position.

As explained above, it is one of the features of this invention that the pipe can be moved into and out of the hole ajoint at a time. Macaroni tubing is, of course, inherently of relatively small diameter. A full joint of this pipe, then, say a joint about thirty feet long, is relatively limber and will bend laterally when subjected to relatively small compressive loads. This is one of the reasons for not using hydraulic jacks that have a stroke longer than 8 feet because 8 feet is about the longest length of macaroni that can be left unsupported laterally when the tubing is being moved into the well bore under pressure and is being subjected to a compressive load. Actually, if the well pressure is very high, the length of unsupported macaroni will probably be less than 8 feet.

In accordance with this invention, which can move a full section of macaroni tubing into the hole or pull a full joint of such pipe out of the hole in one operation, means are provided to laterally support the pipe extending above the well head when it is being run into and out of the hole and is subjected to a compressive force. In the embodiment shown, such means include lateral support plates 60 and lateral support plate brackets 61. A plurality of plates 60 are stacked on supporting table 62 (FIG. 4). This table is designed specifically to support plates 60 above the slips and provide enough room for the slips to operate. As best seen in FIG. 5, the lateral support plates have central opening 63 through which the pipe extends. This opening is large enough to pass the tool joints or collars on the pipe, but small enough to limit the lateral movement of the pipe in the opening sufficiently to keep the pipe from being bent excessively-due to this amount of lateral movement. In accordance with this invention, plate supporting brackets 61 are arranged in pairs on

chain portions

31 and 32 so that each supporting bracket will be opposite a similar supporting bracket on the other chain and at the same horizontal level. Then, as the brackets move upwardly with the chain as the pipe joint is being pulled out of the hole, one of the workers on the rig will position himself so that he can w r s th l lssppsrtp at on 1 221911. sst q 96 to the. dottedline position shown in FIG. 5, into engagement with the brackets as they move by sothat the plate will be carried upwardly with the chains by the two brackets.

The preferred structure of brackets 61 is best seen in FIG. 9. They are generally L-shaped with one leg 61a providing a mounting flange for attaching the bracket to one side of the roller chain. The other leg 61b has upwardly facing inclined surface 64 and notch 65 that provides an upwardly facing generally horizontal surface 66 and inclined surface 6?. Flange 33a of channel 33 is cut away to provide a window 68 through which the end of the lateral support plate can pass into and out of engagement with notch 65 of bracket 61. A simigagement with the back of notch 65, the outer ends of the tabs will just clear the inside of

adjacent flanges

33a and 34a of the channels. The length of the plates is such that there will be a minimum of clearance between the ends of the plates and the roller chain, and since the roller chain is riding very close to the bottom of the guide channels, movement of the plate along its longitudinal axis will be limited.

Thus, when the pipe is under a compressive force, a plurality of plates move upwardly with each joint of pipe as it is pulled from the hole to limit the lateral movement of the pipe joint sufficiently to prevent the pipe from being over stressed due to bending. The number of brackets and plates used will depend upon the strength of the pipe. Preferably, the brackets are spaced so that sufficient support will be provided for the smallest and weakest pipe it is contemplated to be used when operating the rig, and if stronger pipe is used, then it may be possible to skip every other pair of brackets, as the plates are moved into position.

As stated above, the plates are moved into engagement with the brackets as the brackets move past the stack of plates on top of table 62. In the embodiment shown, this is done manually. After the joint has been pulled from the hole, and slip segments 53 have been moved into engagement with the pipe to hold the pipe against further upward movement, the compressive load on the pipe will be transferred to the slips. This pipe section, then, can be unscrewed from the rest of the pipe string, and elevators 30 will be lowered back down to engage the next joint to be pulled from the hole. As the elevators are lowered, the lateral support plates will stack up on top of table 62. Preferably, one of the workmen will be in position to move the plates 90 and back into the orientation shown in FIG. 5. Should for some reason he fail to do so, inclined surface 67 will act as a camming surface and cause the plate to move laterally to the left as viewed in FIG. 9, and out of engagement with the bracket. Upper inclined camming surface 64 is of help when the brackets are picking up support plates. It allows the workman to move a plate into the path of the bracket before the bracket is in position to receive the plate. Then,-as the bracket moves upwardly, surface 64 will cam the plate to the left, again as viewed in FIG. 9, and if the workman will keep a light pressure urging the plate againt the bracket, as soon as the plate clears surface 64 it will move immediately into engagement with notch 65 and the worker will not have to worry about moving the plate into the notch on the fly, so to speak, just as it passes each time.

When running pipe into the hole, and it is being subjected to a compressive stress, after each joint of pipe is moved into the hole by the elevators, the holding operation will be transferred to slips 53 and the elevators released. Another joint of pipe is picked up and screwed into the top of the joint sticking up above table 62. This new joint is picked-up and supported for connecting into the string by separate hoisting equipment. At that time, elevators 30 will be adjacent the lower end of the new joint that has been picked up. As the elevators are raised to engagethe upper end of this new joint of pipe, the required number of plates 60 can be positioned at spaced points along the new joint of pipe in position to support it against lateral movement, when slip segments 53 release the pipe and allow the compressive force of the well pressure to be exerted on the new joint being run into the hole. This joint is then lowered into the hole during which operation plates 60 are stacked again on top of table 62 ready to be used to support the next joint.

In accordance with this invention, elevators are provided for holding the pipe from axial movement relative to the elevators so that the elevators can hold the pipe against an upward force from the well pressure or from a downward force due to the weight of the pipe itself. FIG. 7 is a cross sectional view through the elevators of this invention. Elevator body is attached to support

arms

30a and 30b which connect the elevators to

chain sections

31 and 32. Opening 71 extends through elevator body 70 and is of large enough diameter to allow the body to move freely over the pipe. Mounted on the upper side of the body are

elevator dogs

73 and 74. These dogs have inner configuration such that they will form an opening having a diameter less than the outside diameter of tool joint 72, when the dogs are in the position shown in solid lines in FIG. 7. The upper edge of the dogs are beveled to match the bevel on the tool joint and, thus, increase the area of the tool joint that is engaged by the dogs. When the elevators are being moved downwardly, when a tool joint is engaged the dogs will simply pivot upwardly to the dotted line position shown and allow the elevators to continue downwardly to a position below the tool joint. After the elevators have passed the tool joint, the dogs will fall back into position to engage the tool joint when the elevators move upwardly again.

Dogs

73 and 74, then, hold pipe joint 56 from downward movement relative to the elevators. The elevators include, however, means to hold the pipe against upward movement. In the embodiment shown, tubular latch housing 75 is attached to elevator body 70 by downwardly extending

arms

75a and 75b. Latch housing 75 has an inside cavity 76 of larger diameter than the opening through the housing to provide upwardly and downwardly facing annular shoulders 77 and 78. Three latch segments, 79a, 79b, and 790, are located in cavity 76. As shown in FIG. 8, these segments are segments of a tubular member that is provided with internal threads of the buttress type. The outer surface of the members are grooved to receive garter springs 80 that resiliently hold the segments with their edges in engagement, or at least resiliently urge the segments to that position. The internal buttress thread on the latch segments is designed to engage and mate with the buttress thread on the upper end of lifting sub 81. Tool joint thread 82 on the lower end of the sub allows the sub to be connected to the upper end of the pipe joint 56. When it is desired to connect a pipe joint to the elevators, the sub and pipe joint are lowered into engagement with

elevator dogs

73 and 74, or the elevators are raised. At the same time,

latch segments

79 a, 79b, and 790, will move laterally against the garter springs far enough to permit the lifting sub to reach the position shown in FIG. 7, at which time. they will move into engagement with the threads on the upper end of the sub and latch the sub into latch housing 75. Buttress threads provide a lateral force to expand the springs when the sub is moving into the latch, but provides no such force due to movement in the other direction. Thus, upward forces on the pipe will be resisted through the latch segments and shoulder 77, which will hold the pipe against upward movement relative to the elevators. To release the pipe from the elevators, it is rotated to screw the upper buttress threads of the lifting sub out of engagement with the latch elements and then the elevators can be moved downwardly relative to the pipe.

It is very important that the elevators move in a position to divide the weight of the pipe between the derrick legs as evenly as possible. This requires that the chains supporting and moving the elevators must move at the same speed. To insure that this occurs,

shafts

36 and 37 that drive

sprockets

34 and 35, are connected through

bevel gears

85 and 86 and jack shaft 87. This insures that the chains move at the same speed.

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 inherentto the apparatus.

lt 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 apparatus of this invention without departing from the scope thereof, it is to beunderstood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed 1. Pipe handling apparatus for mounting on a well head for moving pipe through the well head into and out of the well bore in the ground below the well head, comprising a derrick including two symmetrical vertical legs located on opposite sides of the vertical centerline of the well head and equally spaced therefrom, means for mounting the derrick on the well head to be supported thereby with the center of gravity of the derrick lying substantially on the vertical axis of the well head, means supported by the derrick and movable vertically relative to the derrick for moving a pipe string made up of a plurality of joints of pipe through the well head into and out of the well bore a joint at a time for each movement of the means in one direction and for transferring the force imposed by the pipe string on the pipe moving means to the derrick such that the resultant of such forces on the derrick is transmitted to the well head substantially along its vertical axis, the pipe string moving means including means movable vertically along each leg of the derrick on opposite sides of the vertical axis of the well head and equally spaced there-from and elevator means extending between and supported by said movable means to engage the pipe string and transfer the weight of the pipe string to the movable means and derrick legs, means for holding the pipe string from upward movement relative to the elevator means including a first member for connecting to the pipe string and a second member for connecting to the elevator means, one of said first and second members having a threaded section and the other of said first and second members having latch means engaging the threaded section on the other member upon downward movement of the first member relative to the second member to hold the first member and the pipe from direct upward movement relative to the second member and to release the first member for upward movement upon relative rotation of the members.

2. Pipe handling apparatus for mounting on a well head for moving pipe through the well head into and out of the well bore in the ground below the well head,

comprising a derrick having a plurality of vertical legs symmetrically positioned relative to the vertical center line of the well head, means for mounting the derrick on the well head to be supported thereby with the center of gravity of the derrick lying substantially on the vertical axis of the well head, means supported by the derrick and movable vertically relative to the derrick for moving a pipe string made up of a plurality of joints of pipe through the well head into and out of the well bore a joint at a time for each movement of the means in one direction and for transferring the force imposed by the pipe string on the pipe moving means to the derrick such that the resultant of such forces on the derrick is transmitted to the well head substantially along its vertical axis, the pipe moving means including a plurality of line means, each line means being positioned for vertical movement along one of the derrick legs, elevator means supported by the line means to engage a pipe string and move it vertically as the line means move the elevator means, and means for moving the line means at the same speed and including means for transferring the load imposed on the line means by the pipe string substantially equally to each derrick leg along'the centerline of the legs to balance the bending moment imposed on the well head by each leg.

3. Apparatus for mounting on a well head for moving pipe joints through the well head into and out of the well bore in the ground below the well head in steps substantially equal to the length of each joint of pipe so moved. comprising a base for mounting on the well head, a derrick including two symmetrically shaped legs of substantially the same size and weight for mounting on the base to extend vertically thereabove on opposite sides of the centerline of the well head and equidistant therefrom, line means extending along the side of each derrick leg adjacent the centerline of the well bore, an elevator extending between and connected to the line means for movement vertically along the centerline of the well head as the line means are moved vertically along the derrick legs, means for movmeans on each leg to rotate around an axis parallel to the axis of rotation of the wheel means onthe other leg so that the forces imposed on the wheel means by the line means is transmitted to the legs of the derrick along lines that are diametrically opposite the vertical centerline of the well head and equally spaced there from.

4. The apparatus of claim 1 in which the line means supported by each leg of the derrick includes a section of chain and a section of cable, and in which the wheel means for supporting the line means includes a sheave to engage the cable section and a sprocket to engage the chain section.

5. The apparatus of claim 4 in which the means for moving the line means supported by each leg includes two motors mounted on the base diametrically opposite each other and equidistant from the centerline of the well head; each motor having an output shaft for rotating one of the sprockets, and means for connecting the output shafts of the motors to cause the shafts to rotate the sprockets at the same speed to thereby move the line means at the same speed vertically along each leg of the derrick.

6. The apparatus of claim 1 further provided with means for moving with the line means to provide lateral support for the section of the pipe joint above the well head at vertically spaced positions along the joint to increase the ability of the joint to resist bending when subjected to a compressive force by the pressure of the fluid in the well bore.

7. The apparatus of claim 1 in which said lateral support means includes a plurality of support members having openings through which the pipe joint can extend and pg,22 a plurality of pick-up brackets along each spaced line means with each bracket on each line means having a bracket on the other line means on the same level to carry one of the support members along with the brackets and the pipe joint to support the pipe joint against lateral movement.

8. Apparatus for moving pipe through a well head into and out of the well bore in the ground below the well head, comprising a base mounted on the well head to support a derrick, a derrick mounted on the base, elevator means for engaging pipe to move the pipe through the well head, means for moving the elevator means to so move pipe, and means engaging the pipe at spaced locations and movable with the elevators to provide lateral support for pipe extending above the well head to limit the amount the pipe can bend due to compressive longitudinal forces imposed thereon by the pressure of fluid in the well bore.

9. The apparatus of claim 8 in which said lateral support means for pipe includes a plurality of lateral support members, each having an opening therein large enough to receive the pipe and to allow the pipe to move through the opening while limiting the lateral movement of the pipe relative to the support member sufficiently to keep the pipe from being over stressed when subjected to compressive forces by the fluids in the well bore, and means for moving the support members with the pipe in vertically spaced relationship and for holding the members from lateral movement to thereby limit the lateral movement of the pipe.

10. The apparatus of claim 9 in which the means for moving the lateral support members includes line means supported by the derrick and extending vertically along opposite sides of and spaced from the vertical axis of the well head along which the pipe is moved, means for moving the line means with the pipe, and means carried by the line means to move the lateral support members with the pipe and to limit the lateral movement of the support members as they are moved by the line means with the pipe.

Claims

1. Pipe handling apparatus for mounting on a well head for moving pipe through the well head intO and out of the well bore in the ground below the well head, comprising a derrick including two symmetrical vertical legs located on opposite sides of the vertical centerline of the well head and equally spaced therefrom, means for mounting the derrick on the well head to be supported thereby with the center of gravity of the derrick lying substantially on the vertical axis of the well head, means supported by the derrick and movable vertically relative to the derrick for moving a pipe string made up of a plurality of joints of pipe through the well head into and out of the well bore a joint at a time for each movement of the means in one direction and for transferring the force imposed by the pipe string on the pipe moving means to the derrick such that the resultant of such forces on the derrick is transmitted to the well head substantially along its vertical axis, the pipe string moving means including means movable vertically along each leg of the derrick on opposite sides of the vertical axis of the well head and equally spaced there-from and elevator means extending between and supported by said movable means to engage the pipe string and transfer the weight of the pipe string to the movable means and derrick legs, means for holding the pipe string from upward movement relative to the elevator means including a first member for connecting to the pipe string and a second member for connecting to the elevator means, one of said first and second members having a threaded section and the other of said first and second members having latch means engaging the threaded section on the other member upon downward movement of the first member relative to the second member to hold the first member and the pipe from direct upward movement relative to the second member and to release the first member for upward movement upon relative rotation of the members.

2. Pipe handling apparatus for mounting on a well head for moving pipe through the well head into and out of the well bore in the ground below the well head, comprising a derrick having a plurality of vertical legs symmetrically positioned relative to the vertical centerline of the well head, means for mounting the derrick on the well head to be supported thereby with the center of gravity of the derrick lying substantially on the vertical axis of the well head, means supported by the derrick and movable vertically relative to the derrick for moving a pipe string made up of a plurality of joints of pipe through the well head into and out of the well bore a joint at a time for each movement of the means in one direction and for transferring the force imposed by the pipe string on the pipe moving means to the derrick such that the resultant of such forces on the derrick is transmitted to the well head substantially along its vertical axis, the pipe moving means including a plurality of line means, each line means being positioned for vertical movement along one of the derrick legs, elevator means supported by the line means to engage a pipe string and move it vertically as the line means move the elevator means, and means for moving the line means at the same speed and including means for transferring the load imposed on the line means by the pipe string substantially equally to each derrick leg along the centerline of the legs to balance the bending moment imposed on the well head by each leg.

3. Apparatus for mounting on a well head for moving pipe joints through the well head into and out of the well bore in the ground below the well head in steps substantially equal to the length of each joint of pipe so moved comprising a base for mounting on the well head, a derrick including two symmetrically shaped legs of substantially the same size and weight for mounting on the base to extend vertically thereabove on opposite sides of the centerline of the well head and equidistant therefrom, line means extending along the side of each derrick leg adjacent the centerline of the well bore, an elevator extending between and connectEd to the line means for movement vertically along the centerline of the well head as the line means are moved vertically along the derrick legs, means for moving the line means at the same speed to move the elevators along the derrick legs far enough to move a pipe joint vertically along the centerline of the well bore a distance substantially equal to its length, and means for supporting the line means comprising wheel means mounted on each leg, means mounting the wheel means on each leg to rotate around an axis parallel to the axis of rotation of the wheel means on the other leg so that the forces imposed on the wheel means by the line means is transmitted to the legs of the derrick along lines that are diametrically opposite the vertical centerline of the well head and equally spaced therefrom.

5. The apparatus of claim 4 in which the means for moving the line means supported by each leg includes two motors mounted on the base diametrically opposite each other and equidistant from the centerline of the well head, each motor having an output shaft for rotating one of the sprockets, and means for connecting the output shafts of the motors to cause the shafts to rotate the sprockets at the same speed to thereby move the line means at the same speed vertically along each leg of the derrick.

7. The apparatus of claim 1 in which said lateral support means includes a plurality of support members having openings through which the pipe joint can extend and a plurality of pick-up brackets along each spaced line means with each bracket on each line means having a bracket on the other line means on the same level to carry one of the support members along with the brackets and the pipe joint to support the pipe joint against lateral movement.