US 20060185854 A1
A U-shaped elevator having no doors is provided with first and second latching mechanisms which when contacted by the tubular to be entrapped within the elevator move from a closed position to an open position and which then return to a closed position as soon as the tubular is entrapped within the elevator. The latching mechanisms have a safety catch which prevents the tubular from being inadvertently removed from the elevator. The safety latch mechanism can only be activated by a handle which is manipulated by hand by personnel working on the derrick utilizing the elevator. The elevator has an open throat to receive tubulars that have couplers or other features with a lower flange surface for lifting a pipe string. The throat access has blocking members that are movable to allow tubulars to move out of the gap unless the blocking members are locked to prevent such movement. The blocking members have latches biased toward a position to immobilize the members. To allow tubulars to exit the throat, an unlocking mechanism is actuated manually or by motorized means under remote control.
1. An elevator for lifting and lowering an oilfield tubular joint, the elevator comprising:
a) a body having adjacent arms separated by a throat arranged to accept said oilfield tubular joint;
b) a throat access blocking member arranged to allow said oilfield tubular joint to enter said throat; and
c) said throat access blocking member capable of being held in the closed state, but is non-responsive to force applied by said tubular joint tending to move out of said throat.
2. The elevator according to
3. The elevator according to
4. A method for entrapping and releasing a joint of tubular within an elevator, comprising the steps of:
Positioning said elevator, carrying a latching member, above a joint of oilfield tubular; lowering said elevator over said tubular to thereby entrap said tubular within said elevator using said latching member; and releasing the entrapment of said tubular.
5. A method for entrapping and releasing an oilfield tubular joint within an elevator, comprising the steps of:
a) positioning an elevator, carrying a latching member; beside an oilfield tubular joint;
b) entrapping said tubular joint within said elevator by pushing the elevator and the tubular joint into latching engagement with each other; and
c) releasing the entrapment of said tubular joint.
6. An elevator for lifting and lowering a joint of oilfield tubular, casing, the elevator comprising:
a) a body having adjacent arms separated by a throat arranged to accept said joint of oilfield tubular; and
b) one of said arms provided with a throat access blocking member that is arranged such that the blocking member responds to force delivered to said blocking member by said joint of oilfield tubular to allow said oilfield tubular to enter and/or exit said throat.
This application is a continuation of U.S. application Ser. No. 10/444,425, filed on May 23, 2003, which is a Continuation-in-Part of U.S. application Ser. No. 9/999,344, filed on Nov. 15, 2001, now U.S. Pat. No. 6,568,478, which was a Continuation-in-Part of U.S. application Ser. No. 9/410,706, filed on Oct. 1, 1999, now abandoned.
The invention relates, generally, to pipe handling elevators used for lifting and lowering oilfield tubulars, usually as strings of pipe being tripped into or out of an oil or gas well.
It is well known in the art of drilling, completion and workover of earth boreholes in the oil, gas and geothermal industries to run strings of oilfield tubulars into and out of such boreholes, sometimes referred to as “tripping in” or “tripping out”. Such tubulars can be, for example, drill pipe, drill collars, casing and tubing. It is also well known to use elevators in such tripping in or out operations to lift or lower such tubulars out of, or into the wells. The handling gear for such tubulars is oftentimes much alike in principle for all sizes but the difference in scale is impressive. Well casing with a diameter of six feet, with a two inch wall thickness, is not uncommon.
Elevators in the prior art typically are hinged, heavy clamps attached to a hook and traveling block by bail-like arms, sometimes referred to simply as “bails”. Such elevators oftentimes use one or more doors which are themselves quite heavy, and which may require two or three strong men to close or hinge the one or two doors around the tubular. Doors are a common feature but there are single door and split door types. One type simply hinges to open to admit or eject pipe. In hoisting a joint of drill pipe, the elevators are latched onto the pipe just below the tool joint (coupling) which prevents the drill pipe from slipping through the elevators. Similarly, in lifting casing or tubing, the sections of such tubulars have either an upset end, i.e., one in which the O.D. is larger than the primary diameter of the casing or tubing, or they are joined together with a collar having an enlarged O.D. In all of these type of operations, the elevator when hinged to the closed position, i.e., when the one or two doors are closed shut, the internal diameter of the elevator is less than the O.D. of the end of the enlarged tool joint, upset, or collar to prevent the tubular from slipping through the elevator.
Handling practices differ between small and rather large diameter pipe. Each section of very large pipe will typically be picked up from the horizontal position and swung to the vertical for stabbing into the connection of the assembled tubular string. Such large pipe, for example, large diameter steel casing, presents special problems. When elevators are placed on the horizontal pipe they have to pivot to orient the elevator throat opening downward. That leaves the doors, on door-type elevators, swinging on hinges. The doors on a large elevator may weigh several hundred pounds. To close such doors, drilling crew men place themselves in hazardous situations. The rigging devised to get the doors closed often is creative, but risky.
An elevator with doors needs clearance for the doors to swing in the closing arc under the pipe being engaged. The pipe has to be elevated, or clearance otherwise provided, for the swinging door.
The elevators discussed above are of the so-called“non-slip” variety. There are other elevators which grasp the tubular and can be used to then hoist or lower the tubular, but the grasping elevators are typically used with the light weight tubulars.
The elevators of the “non-slip” variety have generally been constructed with doors (generally, one or two) which open to allow the insertion or removal of the tubulars. These doors have traditionally been heavy, slow in operation, difficult to handle and present a considerable safety hazard to the operator. Also, the balance point of the elevator will change dramatically when the doors are opened, thus exacerbating handling problems and adding danger to the operator.
Especially with very heavy tubulars, for example, 20″-30″ casing, the tubular is initially in a horizontal position, laying in place, for example, on or near the floor beneath a derrick, and the hinged door elevator is lowered near the point of attachment to the tubular. The derrick hands then are required to open the very heavy door or doors, which may weigh several hundred pounds, to allow the elevator to be placed over the tubular. Moreover, because the door or doors must close around the tubular, the tubular end around which the elevator is placed must be above the derrick floor.
The present invention avoids the above mentioned shortcomings by eliminating the troublesome door members. Retention of the pipe is then accomplished by a system of multiple pipe catches, which are automatically deployed after the insertion of the pipe joint and which automatically retract during insertion of a pipe joint. Importantly, since this elevator lacks swinging doors, the element of the greatest safety concern is eliminated and, the equilibrium of the elevator is undisturbed during insertion or removal of pipe.
When a tubular approaches the elevator, according to the present invention, the tubular first contacts the disconnector arms. As insertion continues, the disconnector arms are swung away in an arc-like path and this motion actuates the disconnector links which disengage the safety latches, allowing the pipe catches freedom to move. The continuing movement of the pipe into the elevator next causes the pipe to contact the pipe catches directly and pushes them out of the way against a nominal spring force. After the pipe is fully seated into the elevator, the pipe catches (no longer restrained by the pipe body) will automatically deploy by means of spring power. The pipe is now mechanically entrapped and cannot fall out of the elevator. As a function of the mechanism's geometry, the greater the force from the pipe resting against the catches, the greater will be the resistance to opening. The pipe catches, in effect, become self-energizing. In fact, it will not be possible to manually open the elevator if a side force against the catches is present. This feature is an additional safety benefit.
In practicing the methods according to the present invention, elevators can be dropped or lowered onto a horizontal tubular, or swung against a vertical tubular to latch around the tubular, thus by avoiding all or most of the problems associated with using hinged door elevators.
The present invention comprises a horseshoe, or “U” shaped body having first and second extending arms separated by a throat to accept a pipe or other tubular. On each arm a blocking member imposes into the passage to and from the throat and either blocking member will prevent pipe (within the elevator rating size) from moving out of the throat of the elevator. The blocking member is spring biased to the blocking, or closed state. In the closed state, a spring biased security lock goes to the locked state, and the blocking member is immobilized in the closed state. There are two ways to free the blocking member. One way is for pipe to be urged toward the throat where it engages an enabling lever which lifts the security lock and frees the blocking member to move to admit pipe to the throat. The second way to manipulate the blocking member is to activate a dumping lever which lifts the security lock and moves further to move the blocking member away from the throat to permit pipe to move out of the throat.
The elevator has no structure that prevents the elevator from engaging pipe lying on a rig floor. The elevator freely pivots within the loops of bails which engage ears, one on each side of the body.
Not all elevators are suspended from the traveling blocks by bails, the term used herein represents any of the many contrivances serving the equivalent function in suspending elevators from traveling blocks or the equivalent hoisting apparatus.
In the preferred embodiment, and as a special feature of the invention, the ears are positioned such that the lift vector, originating at the transverse line about which the ears rotate within the bail loops, passes some distance from the centerline of pipe, when positioned for lifting, within the throat. With an open throat, the periphery of the ledge that engages the lifting surface of the pipe, normally the lower surface of a connector, represents an area that has a geometric center shifted toward the back of the throat. Ideally, but not in a limiting sense, the extended lift vector passes through, or near that geometric center.
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 attached claims and appended drawings.
For a further understanding of the nature and objects of the present invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein:
FIGS. 12(a) and 12(b) are top plan views of yet another alternative embodiment of an elevator in accordance with the present invention;
FIGS. 15(a) and 15(b) are top plan view of yet another embodiment of the invention.
Referring now to the drawings in more detail,
In the operation of using the prior art elevator illustrated in
It should be appreciated that although
Referring now to
The light weight tubular 62 of
Referring now to
Referring now to
The latch mechanism 102 in
A disconnector link 134 has a first end connected to the disconnector arm 130 and a second end connected to a safety latch plate 120. The plate 120 has a recess 126 sized to receive a rod 124, which as illustrated in
The tubular catch 131 is configured from a hard metal, for example, steel, and is thick enough and strong enough to withstand any forces exerted by the entrapped tubular, and has an arcuate lower surface 133 closely approximating the curvature of the entrapped tubular, for example, as illustrated in step 10 of
In the operation of the latch mechanism 102 of
As insertion continues, the disconnector arms are swung away in an arc-like path and this motion actuates the disconnector links which disengage the safety latches, e.g., plate 120, allowing the pipe catches, e.g. catch 131, freedom to move. The continuing movement of the pipe into the elevator next causes the pipe to contact the pipe catches directly and pushes them out of the way against a nominal spring force. After the pipe is fully seated into the elevator, the pipe catches (no longer restrained by the pipe body) will automatically deploy by means of spring power. The pipe is now mechanically trapped and cannot fall out of the elevator. As a function of the mechanism's geometry, the greater the force from the pipe resting against the catches, the greater will be the resistance to opening. The pipe catches, in effect, become self-energizing. In fact, it will not be possible to manually open the elevator if a side force against the catches is present. This feature is an additional safety benefit.
It should be appreciated that as the tubular to be trapped within the elevator touches the disconnector arm such as arm 130 in
When the tubular which is entrapped within the elevator 100 is in a position which no longer requires the elevator 100 to be used, the handle 170 illustrated in
Thus, it should be appreciated that in utilizing the apparatus and method herein disclosed, whenever it is desired to attach the elevator according to the invention around a tubular, whenever the tubular is in a horizontal or near horizontal position, the only step required to attach the elevator to the tubular is to drop the elevator, or lower the elevator onto the tubular and the latching mechanisms herein described will entrap the tubular with no additional steps required. Such a method is illustrated by means of the sequential steps of
Ears 1 d and 1 c of the elevator 1 are situated such that their centerline passes some distance d toward the throat from the pipe centerline, identified as PCL in
The access to the throat can be cleared by pulling handle 12 toward the free end of the arm. That action rotates member 10 about secondary post 9 and all elements mounted on member 5 rotate counterclockwise to pull blocking member 5 out of the throat access, to free pipe to move from the throat of the elevator.
Springs 15 and 16 bias the blocking member to the closed state and bias the security lock, element 10 on post 11, to the locked state.
Hand grip 14 is used for manually moving the elevator and glove shield 13 to keep gloves out of the mechanism.
Alternatively, a powered version of the latch mechanism leaves the option of manual manipulation of the latches unencumbered. A motor 20 rotates (see
The mounting and configuration of driving motor 20 accommodates either fluid powered or electric drive systems. Open center valving serves motor 20, if fluid is used, to facilitate free wheeling of the motor for manual latch operation. The motor 20 can be mounted on either plate 1 a or plate 1 aa to project either above or below the elevator.
Referring now to
In the current, preferred embodiment, the A.C.E. consists of a body 200 that, functions as the basic platform to which, the lifting ears 202 and the cradles 204 are affixed. The body 200 structure is a beam, fabricated or otherwise, resembling a rectangular hollow tube—other shapes may be appropriate depending on tool size, capacity or other economic factors—formed into a three-sided “U” shape, as illustrated in
The ability of the cradles 204 to wrap around the tubular 206 to such a great degree is a function of their being able to pivot to open and closed positions. In the open position the cradles 204 swing out of the throat 201 of the body 200 so that, a tubular 206 may move unhindered into or out of the body 200 and in the closed position, the cradles 204 swing into the throat 201 of the body 200 and encircle the now trapped tubular 206 centrally over the lifting ears 202. The cradles 204 are attached to the body 200 by means of pivot pins 207 and are urged to the normally open position by the cradle-open springs 209. Whenever a tubular 206 enters the open A.C.E. it pushes against the back of the cradles 204 moving them to the closed position. When the closed position is attained, the sliding lock blocks 211 are freed from the open position and are urged backward to the lock position by the lock springs 213. The unlocking handles 215 are now in the extreme back of their respective slots and this provides reliable visual indication of lock status. The tubular 206 is now securely trapped within the closed cradles 204. To remove the tubular 206, the sliding lock blocks 211 must be moved to the forward position either manually or by a motor. Unlocking handles 215 are provided for manual operation. As soon as the sliding lock blocks 211 are moved out of the way, the cradle-open springs 209 articulate the cradles 204 pivotally to the open position, ejecting the tubular 206 from the A.C.E. and trapping the sliding lock block 211 in the forward or open position.
The improvements are: (1) Greater shoulder bearing area via the cradles more generous wrap around and centralized location, insuring less stress on the collar of the tubular and providing greater lifting capacity; (2) Centralizing the tubular over the lifting ears for a perfectly straight lift which, aids stabbing into the previous joint; (3) Superior lock strength by means of a solid lock block rather than numerous pins and linkages, to assure the tubular remains securely within the A.C.E.; (4) Simplified operation by means of a straight pull, single motion handle; (5) Increased operator safety due to the operating handles being far removed from the lift bails to preclude pinching injuries; (6) Simple, accurate, reliable visual indication of lock status, thus eliminating the need for operator intervention to ensure lock-up.
Referring now to
In operation, of the device as illustrated in
Referring now to
With this system the lift pin 306 is located on the center of the tubular 314 so that the weight of the tubular 314 is carried symmetrically on the axis of the tubular 314 and the tubular 314 hangs straight.
It should be appreciated that in using the apparatus illustrated in
Referring now to
As seen further in
As illustrated in
Referring now to
It should be appreciated that the pumps 512 and 513 can be individual pumps or can be the same pump to drive the actuators 510 and 511, and can be either pneumatic or hydraulic as desired.
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 elevator described and illustrated herein.
It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims.
As many possible embodiments may be made of the elevator of this invention without departing from the 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.
While one or more of the preferred embodiments of the present invention contemplates the use of an elevator having a U-shape with parallel arms, the arms can either be parallel, or inclined slightly towards each other or even inclined slightly away from each other. Moreover, while the present invention contemplates that a given elevator will have a single pair of latching mechanisms, the elevator according to the present invention could also include two or more pairs of latching mechanisms which could be used to entrap a tubular within the elevator.