Pipe handling apparatus

Abstract

An arbor arranged for attachment to overhead support, such as a top drive or main rig hoist, is arranged to resiliently support a main body. The main body is arranged to support a wedge-lock type pipe gripper assembly on a second arbor that is resiliently supported by the main body. The two arbors are rotationally connected but only indirectly connected axially and, to a limited extent, can move independently. The actuator, or linear motor, that actuates the wedge-lock system has the ability to force release of the wedge-lock system when it has been set by massive pipe loads. The forced release actuation is independent of the load supporting features of the main body. Full range actuation of the main body and main arbor assembly length will not actuate the wedge-lock release system. The length of the overall assembly can be oscillated to vibrate a supported pipe string.

Description

BACKGROUND OF THE INVENTION

During drilling and casing of wells, a pipe string is assembled by adding stands of pipe, consisting of one or a plurality of pipe sections, to pipe strings. The pipe strings extend through the drilling floor rotary opening and continue downward into existing well bores. The pipe string being assembled may be drill strings or casing strings, and occasionally other tubular strings.

The rate of the pipe string assembly is part of the well drilling time involvement and can amount to many hours of total well producing time involved. Cost reduction, involves time reduction in pipe string assembly.

Well production time, in terms of drilling rate, has been addressed with great earnest for many years. Pipe string assembly rate has about the same cost effectiveness as drilling rate. This invention addresses the reduction of costs, and does so within the safety concerns common to well bore production and production expected of completed wells.

For safety reasons, the use of personnel in contact with tubulars during pipe string assembly on the drilling floor is being minimized. Full mechanization of such activities on the drilling floor is not always possible but every effort to limit the contact between the more dangerous activities and people is worthwhile.

Offshore drilling rigs are usually massively complex and costly and the addition of machinery approaching automatic functions is not an expense that is a large percentage of the overall costs. On smaller on-shore rigs, the complex machinery is not readily adaptable and the reduction of contact between men and machinery is approached with simpler apparatus such as the present invention.

Pipe being assembled by adding threaded sections is rotated at the upper end during the thread run. At times, during the lowering of the pipe string into the well, the pipe string is rotated to facilitate installation in the well and that is done from the top of the string.

In economic interest, the feed rate during the lowering of the string into the well is maximized, within the limits of safety considerations. The downwardly moving string occasionally encounters cause for brief stoppage, usually called ledging. The massive hoisting machinery that supports the moving pipe string is hard to stop and the result is usually a jarring experience in many respects. There is a need for some form of shock minimizing apparatus between the pipe string and the hoisting machinery. The cushioning effect is often called float and one feature of the present invention is to provide that enhancement.

Machines carrying heavy and dangerous loads normally have a design safety margin that seems adequate unless shock is encountered. Shock that is inherent to function, such as ordnance, has been defined through tests but such tests are not possible in oil field hoisting situations. Any potentially dangerous shock load needs a cushioning factor if it is not well defined and considered during design. The expression “wedge lock gripper” usually refers to the inclusion of a self-locking taper that will not “un-do” if the actuating load is removed. To make the wedge lock feature “fail safe” the supported load needs to urge the wedge part engaging the load in the grip actuating direction. Increasing load then increases the grip. The gripping dies and the activating wedge is often called a grapple.

Once a maximum load is realized, and the fail safe feature has increased the grip on the load, the force needed to disengage the wedge lock could well exceed the force used to actuate the fail safe system. Reserve force may be needed to unlock the pipe gripper when appropriate. The wedge-lock feature of fail-safe apparatus is seldom, if ever, released during the time that the pipe string is supported by the main hoist apparatus.

A forceful release feature related to the wedge-lock assembly is suitable if it can release only one stand, or joint, of pipe. The forceful release, however, needs to release the wedge-lock assembly that has been set by the massive load of a pipe string. The feature providing the float quality to the pipe string, if not arranged to force the release, needs to be augmented by structure that can provide the force needed to release a heavily engaged wedge-lock assembly. The present invention is, in part, directed toward the certainty of wedge-lock release ability.

The ability to float the pipe string load between the travel limits of the first linear motor invites the use of the system as a vibrator of a pipe string.

If there were no viscous damping to consider, a suspended pipe string would have a natural frequency axially. Shaking the pipe string at that frequency would yield vertical displacement, at any selected point along the pipe string, rather large in light of the power needed to sustain the oscillation. A pipe string suspended in a mud filled well bore introduces viscous damping that eliminates full length response to vibration at the natural frequency. A short length of the longer pipe string can be expected to respond to a frequency that would be about impossible to calculate. Further, any favorable frequency would constantly change in sympathy with the constantly changing factors common to the operation.

A vibrator capable of freely changing frequency would allow experimental tuning of the frequency in search of a frequency delivering the most favorable response. A favorable response would be the movement of a previously stuck pipe string. A stuck pipe string, such as casing, can be considered to be one that will no longer advance into the well under the force of its own weight.

Natural frequencies are normally expressed in sine waves whatever may be the form of the exciting energy. Shock activates all natural frequencies in a system. The travel limits of the float produced by variable volume chambers introduces a natural source of shock output to a supported load. During the vibration of the pipe string, a change in float pressure may cause a fluid powered cylinder form of linear motor to hit at least one of the limit stops. A shock wave will result and will add to the ability to select a favorable output from the novel apparatus.

During the installation of casing, a stuck string occasionally occurs when only a few more pipe sections remain to be installed. If a vibrator eases the movement of just a few joints of casing many casing jobs can advance to planned depth with little or no sticking problems. The present invention embodies, in one aspect, the ability to vibrate the string being supported.

SUMMARY OF THE INVENTION

An arbor arranged for attachment to overhead support, such as a top drive or main rig hoist, is arranged to resiliently support a main body. The main body is arranged to support a pipe grapple assembly on a second arbor that is resiliently supported by the main body. The two arbors are rotationally connected but only indirectly connected axially and, to a limited extent, can move independently. The actuator, or linear motor, that actuates the wedge-lock system has the ability to force release of the wedge-lock system when it has been set by massive pipe loads. The forced release actuation is independent of the load supporting features of the main body. Full range actuation of the main body linear motor will not actuate the wedge-lock release system.

The apparatus has alternate provisions to function as a vibrator of a supported load. The frequency involved is variable.

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.

BRIEF DESCRIPTION OF DRAWINGS

The exemplary drawings illustrate the preferred configuration of the apparatus. They are not intended to represent the only configuration usable in practicing the claimed points of novelty.

FIGS. 1 and 2 are mutually continuous. FIG. 2 continues from the lower end of FIG. 1.

FIG. 1 shows the upper end of the apparatus, mostly in cut-away.

FIG. 2 shows the lower end of the apparatus, mostly in cut-away.

FIG. 3 shows the structure of FIG. 1 after actuation of the wedge-lock feature.

FIG. 4 shows the structure of FIG. 2 after the wedge-lock feature is actuated to grip pipe.

FIG. 5 is a section taken along line 5-5 of FIG. 2.

FIG. 6 is a section taken along line 6-6 of FIG. 4,

FIG. 7 is a section taken at the location of FIG. 5 but of an alternate configuration.

FIG. 8 is identical to FIG. 7 but after expanding grippers against pipe.

FIG. 9 is a top view of part of the apparatus.

FIG. 9A shows a fragment of FIGS. 1 and 3 for detail.

FIG. 10 is a side view, rather enlarged, of a selected area of the apparatus.

FIG. 11 is a side view, in cutaway, of a part of the apparatus, with options.

FIG. 12 is a sectional view taken along line 12-12.

FIGS. 13 and 14, are fragmented side views, rather enlarged, of selected areas of FIGS. 2 and 4, respectively.

FIG. 15 is a partial top view of an alternate embodiment of the invention.

FIG. 16 is a partial side view of the embodiment of FIG. 15.

FIG. 17 is a top view, mostly symbolic, of an alternate form of the invention.

DETAILED DESCRIPTION OF DRAWINGS

In the formal drawings, details that do not bear upon points of novelty, are not of value in understanding descriptive matter, and are within the capability of those skilled in the art, are omitted in the interest of descriptive clarity. Such omitted details may include weld lines, pins and threaded fasteners, seal details and the like.

Linear motors use power to produce linear movement. There are many forms of such motors. Most prevalent are fluid powered cylinders. They are simple to design, use, and explain. They are used in the current descriptive matter, but they should not be construed in a limiting sense.

The pipe handling apparatus is shown in FIGS. 1-4. FIGS. 1 and 2 are mutually continuous, FIG. 2 being the bottom portion. Similarly, FIG. 3 and FIG. 4 are mutually continuous with FIG. 4 being the bottom portion of the apparatus.

FIGS. 1-2 and FIGS. 3-4 show the apparatus before and after actuation (respectively) to grip pipe P. The apparatus as depicted consists mainly of three parts, main body 1, main arbor 2, and active arbor 3. The active arbor is spline connected to the main arbor by mating splines 2c and 3d. The main arbor 2 is provided with an attachment point 2a such as a threaded tool joint for overhead support. Such overhead support may be a top drive or main rig hoist.

The main arbor 2 defines a piston 2b. Similarly, the active arbor 3 defines a piston 3a. Cylinder cap 4 defines fluid chamber 1a between piston 2b and cylinder cap 4. Bulkhead 6 defines fluid chamber 1b between bulkhead 6 and piston 2b and fluid chamber 1c between bulkhead 6 and piston 3a. The base of main body 1 and piston 3a define fluid chamber 1d.

The main body 1 provides a sleeve through which the main arbor 2 and active arbor 3 may reciprocate axially along main body 1, independently of each other, by means of fluid pressure selectively directed to chambers 1a, 1b, 1c and 1d.

Secondary parts include swivel 5 and baffle plate 7. The apparatus also has a sealed bore or channel 3c that allows mud to flow vertically along its length. The channel 3c extends from the attachment point 2a to the bottom of the extended active arbor at ports 11a.

Swivel 5 is bearingly supported on cap 4 and carries the working fluid flow into and out of the apparatus. The swivel does not rotate and is connected to rig related fluid lines (not shown). The cylinder cap may be retained on the main body by a ring of cap screws (also not shown).

Baffle 7 is mounted on main body 1 at its base with cap screws 7b and is spring loaded away from main body 1 by springs 7a. The springs 7a create a space or gap between the main body 1 and the baffle 7. The body-to-baffle gap is a position indicator for pipe being engaged during operation of the apparatus.

The active arbor 3 extends below the baffle 7 through baffle hole 7c to define three arbor wedges 3e. Grippers or dies 8 show a three phase wedge arrangement, to be activated by the three wedges 3e on the active arbor to create a wedge-lock system. Low quality pipe may justify distribution of the grippers along a plurality of wedges. In a uniform bore, in heavy wall pipe, a one phase gripper-wedge arrangement is usually adequate.

The swivel 5 conducts working fluid from ports such as 5a and 5c to peripheral galleries such as 5b and 5d which vent to ducts such as 4a, 4b, 1e, and 1f to chambers such as 1c and 1d. Movement of piston 3a opens and closes the wedge-lock system. Pressure in chamber 1d closes the grip lock system onto pipe and pressure in chamber 1c, if adequate, forces the grip lock system to release pipe.

Chamber 1b could vent to atmosphere but venting may be captured through an available gallery and vent circuit, at least partly to maintain particulate control. Plate 6 is a bulkhead to separate chambers 1b and 1c.

The stroke of piston 2b can be any length that available operation space admits. The usual stroke may be in the order of one foot.

Working fluid used to power piston 2b maybe compressible, non-compressible or the variant of both, usually called air over oil. In the air over oil version, the oil may provide power and the air (or gas) may provide cushion. The oil may be used for velocity control of linear motor parts. Alternatively the air may provide power and the oil may provide control.

Pressure delivered to chamber 1a lifts body 1 and all supported weight. The action of piston 2b, however, has no influence upon the action of piston 3a.

FIG. 2 and FIG. 4 show the extended portion of active arbor 3 of the apparatus that is inserted into a pipe to be handled. Nose piece 11 helps guide the apparatus into pipe. Ports 11a pass fluid moving down channel 3c. Drift 10 is just under the inside diameter of pipe to be handled and protects packing 9 from pipe edges and consequent damage.

Packing 9 is mounted in a ring on arbor extension 3f. The leak inducing differential pressure actuates the packing toward closure with the pipe bore. An alternate packing form is inflated by pressure in duct 3c and resembles a fat car tire. It is not shown.

The grippers 8 are retained on the active arbor 3 by spring loaded axially extending straps 8a that reside in grooves in the active arbor. To perform the wedge-lock function of the apparatus, the grippers 8 are urged toward the small end of the wedges 3e, by spring 12 acting between flange 3g and ferrule 8b. When grippers 8 are not urged to engage pipe P, ferrule 8b rests against abutment 3h on the arbor 3. When the grippers 8 need to be deployed to grip pipe P, the extending active arbor 3 is shortened by piston 3a and limiter flange 8d engages ferrule 8b, urging the grippers to extend radially outward to engage the interior surface of pipe P.

FIG. 3 is identical to FIG. 1 but has been actuated to grip pipe and to lift a pipe string load.

Piston 3a has closed the grippers 8 onto pipe P and pressure above piston 2b, in chamber 1a, acting on cylinder cap 4 has lifted the main body 1 and all supported load.

FIG. 4 is identical to FIG. 2 but the arbor 3 has been moved upward by piston 3a, moving arbor wedges 3e upward, shortening the extending portion of arbor 3. The upward movement of grippers 8 is stopped by the engagement of ferrule 8b against the limiter flange 8d.

After the grippers 8 contact the pipe P, the wedges 3e slide on the gripper surfaces easier than the grippers slide on pipe. The grippers 8 do not greatly compress links 8a after the grippers make contact with the pipe P.

FIG. 5 shows pipe grippers 8 and arbor 3 joined by dovetail fittings 3j. On small pipe handling gear, arbor 3 can be highly stressed. To avoid stress a raising configuration, the strap 8a may be, instead, confined to the surface of arbor 3, by bands, or the like, retaining the grippers 8. In such case the dovetail fittings 3j are not needed.

FIG. 6 is identical to FIG. 5 but has been actuated to set grippers 8 against pipe P.

FIGS. 7 and 8 represent an alternate to the gripper and arbor arrangement shown by FIGS. 5 and 6. In this alternate arrangement, the active arbor, now shown as 20, has 3 tapered dovetail grooves 20c. Grippers, now shown as 20a, can have a near, total peripheral coverage. Ramp 20b has to be of uniform shape and is slanted toward the arbor axis in the upward direction. To achieve rotation of pipe P, the grippers 20a are dragged peripherally and no gripper tilting in a dovetail slot occurs.

FIG. 9 is a top view of the baffle plate 7 of FIG. 1.

FIG. 9A shows the thrust device 7A used to manipulate baffle 7. This is a simplification of a complex fluid power cylinder. Only one is shown, four are planned, distributed peripherally about the apparatus centerline. Significant is the point that, by duct and piston arrangements, baffle 7 is urged in the opposite direction form that delivered by piston 3a. Duct 1g is open to the top of piston 3 and duct 1h is open to the bottom of piston 3a. Piston 7q delivers thrust to baffle 7 by way of rod 7r.

FIG. 10 is a side view showing the configuration of the gripper drag link 8a. Spring 12 urges the grippers 8 to move on the active arbor toward the pipe releasing position.

FIG. 11 is a side view, fragmented, of an alternate configuration of the apparatus of the invention. Essentially, the alternate configuration is that shown in FIG. 1 with the main body 1 now captioned as 30. The body 30 is provided with peripheral accumulator chambers 30a and 30b and enlarged fluid conducting galleries 36.

In the upper accumulator chamber 30a annular piston 33 separates gas 34 and liquid 35. Liquid passes through port 31 and gas is charged through port 32. Ballast is provided by the upper accumulator chamber 30a to chamber 1a, and float is provided for the main body 30.

The lower accumulator chamber 30b, with piston 39 separating air, or gas, 38 from oil 40 provides ballast, by way of duct 40a, to chamber 1d, and float to the active arbor. Gas 38 is charged through port 37 and any oil or liquid may be supplied or drained through port 41.

By designer preference, either accumulator chamber, or both, may be omitted. Either accumulator, as shown, can be replaced by integral accumulators readily available in the market place.

Piston 3a can be biased upward, causing active arbor 3 to activate slips to engage pipe. To release the pipe, pressure is applied to chamber 1c, enough to overcome pressure in chamber 1d. If the apparatus is being taken from service and transported, pressure in chamber 1d will expand the slips. If pressure is removed from chamber 1d, spring 12 will pull the grippers 8 to their minimum diameter.

Vent 41 is available for removing pressure from chamber 1d if the apparatus is not rotating. If it is to be drained during apparatus rotation a duct to swivel 5, in the nature of duct 36, can be arranged.

FIG. 12 is a section taken along line 12-12 of FIG. 11. Note that piston 33 is a peripheral ring. The peripheral accumulator can be replaced by one or more integral accumulators opening to duct 40a.

FIGS. 13-14 are fragmented side views, rather enlarged, of the gripper region of the active arbor 3 of FIG. 1-FIG. 4. FIG. 13 shows the retracted state of the grippers 8.

FIG. 14 shows the grippers 8 on the active arbor deployed to engage the inner surface of pipe P. This drawing admits the illustration of the optional capture features that secure the grippers to the active arbor for safer handling. Annular recess 3h in the active arbor receives the mating nose 8c of the grippers 8 when the grippers are not deployed as in FIG. 13.

FIG. 15 is a top view of the apparatus when fitted for use as a vibrator. Main body 30 is shown devoid of any feature not related to the vibrator purpose. Spool valve 31 is actuated by solenoids 32 and 33 to alternately connect the sump circuit S and the fluid power circuit P to chamber 1a above piston 2b. Power to the solenoids is externally supplied and controlled by rig equipment. The vibrator, in some cases, may require fluid channel of such capacity that the power circuits, by designer choice, may not come through the swivel. It may be supplied, short term, by supplemental routes employed only briefly.

The apparatus, if not optimized as a vibrator, will have power source and sump connections, valve controlled, and can be vibrated with the valves commonly used.

FIG. 16 is a side view of the arrangement of FIG. 15. In long term use, when the vibrator is not used, the ports for P and S circuits may be plugged.

FIG. 17 shows a vibrator pump arrangement that would likely require flow capacities that are maximized. If block 36 is a quick coupler with automatic shut-off, the system could be brought on line to get out of a stuck string situation. Pump 34 can be considered symbolic but no valves are shown or intended. Pump 34, with motor 35 is a surge generator directly connected to chamber 1a. Conduit 35 will likely be flexible. The valving and control circuitry that positions piston 2b can situate the piston such that the surge generator brings the piston 2b into either travel limit to deliver shock to the suspended pipe string.

Introduction of oscillation of pipe load support forces causes a variation in the axial velocity of the top of the pipe string, or vibration, whether or not there is average downward movement of the pipe string. That is anticipated by and is within the scope of the claims.

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 apparatus.

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 apparatus 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.

Claims

1. A pipe handling apparatus for assembling and dismantling pipe strings used in wells, the apparatus comprising: a) a main arbor arranged for attachment to an overhead support;b) a main body situated on said main arbor for axial movement thereon;c) an active arbor supported by said main body, extending therefrom, arranged for axial movement relative thereto, and rotationally connected to said main arbor;d) a first fluid powered linear motor arranged to vary the assembled length of said main arbor and said main body in response to fluid power selectively supplied by a separate source;e) a second fluid powered linear motor arranged to adjust the assembled length of said main body and said active arbor in response to fluid power selectively supplied by a separate source;f) a wedge-lock pipe gripper situated on said active arbor for gripping pipe by contact with said pipe's inner surface when said assembled length of said main body and said active arbor is selectively said adjusted; andg) fluid conducting galleries, at least partly in said main body, arranged conduct fluid to enable said separate source of fluid power to selectively actuate said first and said second fluid powered linear motors.

2. The apparatus according to claim 1, wherein said fluid conducting galleries, at least in part, are in a swivel bearingly and sealingly mounted on said main body, to allow said main body to rotate relative thereto to enable a stationary said separate source of fluid power to selectively control said linear motors.

3. The apparatus according to claim 1 wherein said attachment to an overhead support is accomplished by a tool joint on said main arbor.

4. The apparatus according to claim 1 wherein said main body is free to rotate relative to said main arbor.

5. The apparatus according to claim 1 wherein a baffle plate is provided and supported on said main body and arranged to engage the top end of pipe to be handled by said gripper, said baffle is biased in a direction opposite force applied to said active arbor to change said assembled length of said main body and said active arbor.

6. The apparatus according to claim 1 wherein at least one accumulator is arranged to exchange fluid flow surges with said galleries that supply fluid to move said first linear motor.

7. The apparatus according to claim 1 wherein at least one accumulator arranged to exchange fluid flow surges with said galleries that supply fluid to move said second linear motor.

8. The apparatus according to claim 1 wherein valving is provided to cause pressure changes delivered to said first linear motor to cause oscillatory cycling of said length of said assembled main arbor and said main body.

9. The apparatus according to claim 1 wherein said first linear motor is in the form of a hydraulic cylinder and a pulse generator is arranged to deliver fluid volume pulses to said first linear motor to cause vertical oscillation to a pipe string supported by the apparatus.

10. A pipe handling apparatus for assembling and dismantling pipe strings being installed in or removed from wells, the apparatus comprising: a) a main arbor and a main body having a telescoping relationship, said main arbor extending from said main body and having a connector for attachment to an overhead support;b) an active arbor telescopingly received in said main body, and extending some variable distance therefrom;c) a first fluid powered linear motor, responsive to fluid power manipulation at a separate location, to vary the extension of said main arbor from said main body;d) a second fluid powered linear motor, responsive to fluid power manipulation at a separate location, to vary the extension of said active arbor from said main body;e) a pipe gripping arrangement on said active arbor for insertion into a pipe bore to grip or release pipe in response to change in the distance said active arbor extends from said main body;f) a fluid conducting conduit situated to receive drilling fluid from said drilling rig, conduct it along said main and active arbors and to inject said drilling fluid into said pipe bore;g) a fluid handling gallery arrangement, at least partly situated in said main body, to deliver said fluid power and control to said first and said second motors when said main arbor is rotating and said fluid power manipulation is provided from a stationary installation; andh) a telescoping relationship between said main arbor and said active arbor comprising mating non-circular surfaces to conduct torque between the two arbors.

11. A pipe handling apparatus according to claim 10 wherein said fluid handling gallery arrangement includes a swivel bearingly and sealingly situated on said main body.

12. A pipe handling apparatus according to claim 10 wherein said pipe gripping arrangement comprises pipe grippers that extend a variable radial distance from said active arbor and change said radial distance when said active arbor is moved relative to said body.

13. A pipe handling apparatus according to claim 10 wherein said first fluid powered motor varies the length of the apparatus to compensate for run of threads when pipe is being connected or disconnected by threads.

14. A pipe handling apparatus according to claim 10 wherein said non-circular surfaces are splines.

15. A pipe handling apparatus according to claim 10 wherein said main arbor is terminated at an upper end by a tool joint.

16. The apparatus according to claim 10 wherein valving is provided to cause pressure changes delivered to said first linear motor to cause oscillatory cycling of said length of said assembled main arbor and said main body.

17. The apparatus according to claim 10 wherein said first linear motor is in the form of a hydraulic cylinder and a pulse generator is arranged to deliver fluid volume pulses to said first linear motor to cause vertical oscillation to a pipe string supported by the apparatus.

18. A method for the installation of pipe strings in wells wherein at least one linear motor used between the rigs pipe string load support gear and the pipe string is subjected to input power variations to cause the upper end of the pipe string to experience axial vibration.