CA2311464C - Apparatus for dropping articles downhole - Google Patents

Apparatus for dropping articles downhole Download PDF

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Publication number
CA2311464C
CA2311464C CA002311464A CA2311464A CA2311464C CA 2311464 C CA2311464 C CA 2311464C CA 002311464 A CA002311464 A CA 002311464A CA 2311464 A CA2311464 A CA 2311464A CA 2311464 C CA2311464 C CA 2311464C
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CA
Canada
Prior art keywords
housing
passage
outlet member
outlet
passages
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA002311464A
Other languages
French (fr)
Other versions
CA2311464A1 (en
Inventor
John L. Baugh
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Baker Hughes Holdings LLC
Original Assignee
Baker Hughes Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Baker Hughes Inc filed Critical Baker Hughes Inc
Publication of CA2311464A1 publication Critical patent/CA2311464A1/en
Application granted granted Critical
Publication of CA2311464C publication Critical patent/CA2311464C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21BEARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B33/00Sealing or packing boreholes or wells
    • E21B33/02Surface sealing or packing
    • E21B33/03Well heads; Setting-up thereof
    • E21B33/04Casing heads; Suspending casings or tubings in well heads
    • E21B33/05Cementing-heads, e.g. having provision for introducing cementing plugs

Abstract

A plug-dropping head is disclosed in which the objects to be dropped are placed in individual discrete passages. A motor-driven or hand-operated rotating member orients an entrance to a passage going through it to, in series, individual passages in the housing for sequential dropping of objects downhole. A relief port is provided so that as the rotating outlet member moves from one passage in the housing to the next, the relief passage prevents deadheading of the surface pump.

Description

TITLE: APPARATUS F'OR DROPPING ARTICLES DOWNHOLE
INVENTORS: JOHN L. BAUGH
FIELD OF THE INVENTION
The field of this invention relates to surface-mounted equipment which can be used for dropping articles of various sizes and shapes downhole to facilitate downhole operations.
BACKGROUND OF THE INVENTION
Many downhole operations require sequential dropping of various objects downhole to facilitate a downhole operation. The sequence may involve dropping a ball on a ball seat to close off the wellbore to allow pres-sure to be built ~p to actuate tools such as packers or hangers or downhole valves. Cementing operations typically involve dropping one or more wiper plugs in a specific order to, for example, wipe the wellbore clean of the cement. These objects to be dropped downhole are frequently assembled in surface equipment referred to as a plug-dropping head. In the past, plug-dropping heads have been stacked vertically to accommodate the sequential dropping of objects downhole. Thus, the lowermost object would be dropped first and so forth up until the topmost plug-dropping head has released the object stored therein. The problem with this arrangement is that it gets to be quite tall and in most applications, the plug-dropping heads are inaccessible.
One way the prior designs have compensated for this inaccessibility problem is to actuate the plug-dropping heads by remote control. Such techniques are described in U.S. Patents 5,435,390 and 5,590,713.

One of the objects of an aspect of the present invention is to provide a compact design which can be operable to insert a plurality of objects downhole within fairly confined vertical space limits at the surface. The device presents a compact design which can efficiently deliver a series of objects downhole.
Another object of an aspect of the present invention is to allow circulation to continue as the device operates to sequentially drop objects downhole. These and other advantages of the present invention will become more apparent to those skilled in the art from a review of the description of the preferred embodiment below.
SUMMARY OF THE INVENTION
A plug-dropping head is disclosed in which the objects to be dropped are placed in individual discrete passages. A motor-driven or hand-operated rotating member orients an entrance to a passage going through it to, in series, individual passages in the housing for sequential dropping of objects downhole. A relief port is provided so that as the rotating outlet member moves from one passage in the housing to the next, the relief passage prevents deadheading of the surface pump.
Accordingly, in one aspect of the present invention there is provided an apparatus for dropping at least one object downhole, comprising:
at least one housing defining a plurality of passages; and at least one rotatably mounted outlet member having a passage thereon selectively movable into alignment with said passages in said housing so as to allow an object in any one of said passages in said housing to drop.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the present invention will now be described more fully with reference to the accompanying drawings in which:
Figure 1 is a sectional elevational view showing the apparatus in a position where one of the objects is being dropped downhole.
Figure 2 is a section view along lines 2-2 of Figure 1.
Figure 3 is the view of Figure 2, with the outlet member rotated approx-imately 80° from the position shown in Figure 2, showing the outlet member arriving close to the position where the next object will be dropped downhole.
Figure 4 is a sectional elevational view showing a stackable configura-tion.
Figure 5 is a topmost unit for a stackable configuration showing a spider 73 to stop reverse movement in an upflow situation.
Figure 6 is a section view along line 6-fi of Figure 4.
Figure 7 is a section view along line 7-7 of Figure 5.
Figure 8 is a section view through guide 70.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Figure 1, the apparatus A has a top sub 10 connected to a body 12. Body 12 is connected to bottom sub 14. These components together comprise the housing. Thread 16 is used to connect the surface pumping equipment (not shown) to the apparatus A. Thread 18 connects the apparatus A to the wellbore. A passage 20 extends through the top sub 10 and ultimately continues as passage 22 in the bottom sub 14. A rotatably mounted outlet device 22 is secured in the bottom sub 14. It has a gear 24 which is driven by a drive schematically shown as 26. Operation of the drive 26 rotates the entrance 28 of a passage 30 which extends through the outlet device 22. Entrance 28 is off-center from the longitudinal axis of body 12.
Within body 12 there is a tubular component 32 which defines a series of passages 34, 36, 38 and 40. Those skilled in the art will appreciate that varying the amount or size of these passages is within the spirit of the inven-tion. These passages are illustrated in Figure 3. Each passage has, inter-nally to it, a flapper or other retaining device 42 which is preferably pivotally mounted on a rod 44. When the entrance 28 of the passage 30 on the outlet device 22 is not in alignment with, for example, passage 36, a solid portion of the outlet device 22 is presented at the base of passage 36, thus preventing the flapper 42 from pivoting about its pivot rod 44. The same is true for the other passages except that the initial passage, which is shown in Figure 3 as passage 34, does not have a flapper. The apparatus A is configured for the start of operations with the passage 34 in alignment with the entrance 28 to the outlet device 22 with the objects to be dropped downhole positioned in passages 36, 38, and 40, as an example.
Another feature of the tubular component 32 is relief passage 46.
Figure 3 illustrates that passage 46 still overlaps passage 34 as the entrance 28 approaches alignment with passage 40. Thus, the flow from the surface pumping equipment can still go through passage 46, through passage 34, until the flapper 48 can swing open when entrance 28 is fully in alignment with passage 40, as shown in Figure 2. The object in passage 40 can be dropped through the outlet device 22: At this point in time, the passage 46 in the position shown in Figure 2 is fully obstructed as it is aligned with the solid portion of the tubular component 32 between passages 34 and 40.
As shown in Figure 1, a curved component 49 in entrance 28, upon further counterclockwise rotation of the outlet device 22, will engage the flapper that is in the downward position shown in Figure 1 and force it up-wardly to the position also shown in Figure 1 in the course of rotation of the outlet device 22. While a curved component 49 is preferred, other shapes can be used without departing from the spirit of the invention.
The apparatus A shown in Figure 1 can be operated in stacks as long as the lowermost units are aligned for flow-through. The dropping of objects can begin from the uppermost unit and proceed down to the lowermost unit, or vice versa. When being used as a flow-through unit, a guide 70 is rotated with outlet device 22 to provide a smooth fluid transition from flowpath 20 to outlet device 22. This will allow alternate operation of the stacked plug-dropping heads. Plugs may be dropped in any sequence, regardless of the number of heads stacked. This will allow the sequence to be changed without reloading or stopping circulation. The bottom of guide 70 shown in Figure 4 also includes passage 71 shown in Figure 8, which functions like passage 46. A drive shaft 72 transmits torque from outlet device 22 to guide 70.
The base of guide 70 also covers the top of bores 36, 38, and 40 to prevent possible damage or movement from unexpected flow events.
The top plug-dropping head will have a spider 73 to block upward exit of any of the balls, plugs, or other devices in case ef reverse flow, planned or otherwise.
Any number of parallel passages can be provided in tubular component 32 depending on the space or weight limitations applicable.
It should be noted that there are no seals between the outlet device 22 and cavity 50 in the bottom sub 14 in which it is disposed. The only seals necessary are 52, which seal around the drive 26 shown schematically in Figure 1.

Accordingly, the apparatus A is easy to fabricate and operates reliably to drop in sequence a multiplicity of objects downhole. The drive is simple and the sealing requirements are minimal, thus ensuring low maintenance for the apparatus A.
Additional performance enhancements can be added, such as remote operation, as well as some sort of flag device which indicates the position of the outlet device 22 with respect to the passages in the tubular component 32.
The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and mate-vials, as well as in the details of the illustrated construction, may be made without departing from the spirit of the invention.
baker~patents1607 dropping articles downhole.wpd ss

Claims (17)

1. An apparatus for dropping at least one object downhole, comprising:
at least one housing defining a plurality of passages; and at least one rotatably mounted outlet member having a passage thereon selectively movable into alignment with said passages in said housing so as to allow an object in any one of said passages in said housing to drop.
2. The apparatus of claim 1, further comprising:
a relief passage in said outlet member positioned to allow fluid flow through one passage in said housing until an object is dropped through an adjacent passage in said housing by virtue of rotation of said outlet member.
3. The apparatus of claim 2, further comprising:
a retaining member in at least one of said passages in said housing to selectively hold an object to be dropped;
said retaining member movable to a drop position by rotation of said outlet member.
4. The apparatus of claim 3, wherein:
said retaining member is movable to a closed position by rotation of said outlet member.
5. The apparatus of claim 3, wherein:
said retaining member comprises a pivotally mounted valve member which can move into said passage in said outlet member when said passage in said outlet member is placed in substantial alignment with said passage in said housing where said valve member is mounted.
6. The apparatus of claim 1, wherein:
said outlet member has a longitudinal axis and said housing has a common longitudinal axis, said passage in said outlet member having an entrance offset from said axis whereupon rotation of said outlet member, said entrance aligns with different passages in said housing.
7. The apparatus of claim 6, wherein:
said housing comprises at least one unobstructed passage;
remaining passages in said housing each further comprising a retaining member to selectively hold an object to be dropped.
8. The apparatus of claim 7, wherein:
rotation of said outlet member actuates said retaining member between an open and closed position.
9. The apparatus of claim 8, wherein:
said retaining member is actuated towards the closed position by contact with said outlet member.
10. The apparatus of claim 8, further comprising:
a relief passage in said outlet member positioned to allow fluid flow through one passage in said housing until an object is dropped through an adjacent passage in said housing by virtue of rotation of said outlet member.
11. The apparatus of claim 10, wherein:
each said retaining member further comprises a pivotally mounted plate that opens when said entrance in said outlet member is in alignment with said passage in said housing where said plate is mounted.
12. The apparatus of claim 11, wherein:
said outlet member is mounted within said housing;
said outlet member is rotated by a drive external to said housing;
said drive is sealed at said housing; and said outlet member has no seals internal to said housing.
13. The apparatus of claim 12, further comprising:
a plurality of housings with outlet members, vertically stacked.
14. The apparatus of claim 1, wherein:
said outlet member is mounted within said housing;
said outlet member is rotated by a drive external to said housing;
said drive is sealed at said housing; and said outlet member has no seals internal to said housing.
15. The apparatus of claim 1, further comprising:
a plurality of housings with outlet members, vertically stacked.
16. The apparatus of claim 15, further comprising:
said vertical stack comprises an uppermost unit which further comprises a catch device to prevent an object from escaping said housing when a backflow condition from downhole occurs.
17. The apparatus of claim 1, further comprising:
an inlet member mounted in a spaced relation to said outlet member and movable in tandem therewith, said inlet member having a passage thereon to selectively move into alignment with said passage in said housing in tandem with said passage on said outlet member.
CA002311464A 1999-06-14 2000-06-12 Apparatus for dropping articles downhole Expired - Fee Related CA2311464C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US09/332233 1999-06-14
US09/332,233 US6206095B1 (en) 1999-06-14 1999-06-14 Apparatus for dropping articles downhole

Publications (2)

Publication Number Publication Date
CA2311464A1 CA2311464A1 (en) 2000-12-14
CA2311464C true CA2311464C (en) 2005-04-26

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CA002311464A Expired - Fee Related CA2311464C (en) 1999-06-14 2000-06-12 Apparatus for dropping articles downhole

Country Status (5)

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US (1) US6206095B1 (en)
AU (1) AU765593C (en)
CA (1) CA2311464C (en)
GB (1) GB2351102B (en)
NO (1) NO318456B1 (en)

Families Citing this family (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK1392953T3 (en) 2001-05-18 2007-07-23 Dril Quip Inc Pipe carrier, built-in tool and method
EP1712730B1 (en) 2001-05-18 2010-12-15 Dril-Quip, Inc. Ball and plug dropping head
US6672384B2 (en) 2002-01-31 2004-01-06 Weatherford/Lamb, Inc. Plug-dropping container for releasing a plug into a wellbore
US7055611B2 (en) * 2002-01-31 2006-06-06 Weatherford / Lamb, Inc. Plug-dropping container for releasing a plug into a wellbore
US6715541B2 (en) 2002-02-21 2004-04-06 Weatherford/Lamb, Inc. Ball dropping assembly
US6776228B2 (en) 2002-02-21 2004-08-17 Weatherford/Lamb, Inc. Ball dropping assembly
US8726994B2 (en) 2002-09-09 2014-05-20 Mako Rentals, Inc. Double swivel apparatus and method
US7281582B2 (en) 2002-09-09 2007-10-16 Mako Rentals, Inc. Double swivel apparatus and method
US8057551B2 (en) * 2004-04-23 2011-11-15 Prosthetic Design, Inc. Lanyard suspension system for a prosthetic limb
US7387165B2 (en) * 2004-12-14 2008-06-17 Schlumberger Technology Corporation System for completing multiple well intervals
US7281589B2 (en) * 2005-07-29 2007-10-16 Mako Rentals, Inc. Ball dropping tool method and apparatus
US7699100B2 (en) * 2006-05-02 2010-04-20 Mako Rentals, Inc. Dropping sub method and apparatus
US7533720B2 (en) 2006-05-24 2009-05-19 Mako Rentals, Inc. Seal configuration for top drive swivel apparatus and method
CO5930087A1 (en) * 2006-12-06 2008-06-27 Ecopetrol Sa DOSING EQUIPMENT AND PROCEDURE FOR THE CAPTION OF DERIVATIONS IN FLUID TRANSPORTATION DUCTS BASED ON SUCH EQUIPMENT
US8069922B2 (en) 2008-10-07 2011-12-06 Schlumberger Technology Corporation Multiple activation-device launcher for a cementing head
US9163470B2 (en) 2008-10-07 2015-10-20 Schlumberger Technology Corporation Multiple activation-device launcher for a cementing head
US8196650B1 (en) 2008-12-15 2012-06-12 Mako Rentals, Inc. Combination swivel and ball dropper
WO2011146866A2 (en) 2010-05-21 2011-11-24 Schlumberger Canada Limited Method and apparatus for deploying and using self-locating downhole devices
US9382790B2 (en) 2010-12-29 2016-07-05 Schlumberger Technology Corporation Method and apparatus for completing a multi-stage well
US8944171B2 (en) 2011-06-29 2015-02-03 Schlumberger Technology Corporation Method and apparatus for completing a multi-stage well
US9752407B2 (en) 2011-09-13 2017-09-05 Schlumberger Technology Corporation Expandable downhole seat assembly
US9033041B2 (en) 2011-09-13 2015-05-19 Schlumberger Technology Corporation Completing a multi-stage well
US10364629B2 (en) 2011-09-13 2019-07-30 Schlumberger Technology Corporation Downhole component having dissolvable components
US9534471B2 (en) 2011-09-30 2017-01-03 Schlumberger Technology Corporation Multizone treatment system
US9238953B2 (en) 2011-11-08 2016-01-19 Schlumberger Technology Corporation Completion method for stimulation of multiple intervals
US9394752B2 (en) 2011-11-08 2016-07-19 Schlumberger Technology Corporation Completion method for stimulation of multiple intervals
US9279306B2 (en) 2012-01-11 2016-03-08 Schlumberger Technology Corporation Performing multi-stage well operations
US8844637B2 (en) 2012-01-11 2014-09-30 Schlumberger Technology Corporation Treatment system for multiple zones
US9650851B2 (en) 2012-06-18 2017-05-16 Schlumberger Technology Corporation Autonomous untethered well object
US9988867B2 (en) 2013-02-01 2018-06-05 Schlumberger Technology Corporation Deploying an expandable downhole seat assembly
US9631468B2 (en) 2013-09-03 2017-04-25 Schlumberger Technology Corporation Well treatment
US9587477B2 (en) 2013-09-03 2017-03-07 Schlumberger Technology Corporation Well treatment with untethered and/or autonomous device
US10487625B2 (en) 2013-09-18 2019-11-26 Schlumberger Technology Corporation Segmented ring assembly
US9534469B2 (en) 2013-09-27 2017-01-03 Baker Hughes Incorporated Stacked tray ball dropper for subterranean fracking operations
US9644452B2 (en) 2013-10-10 2017-05-09 Schlumberger Technology Corporation Segmented seat assembly
US10538988B2 (en) 2016-05-31 2020-01-21 Schlumberger Technology Corporation Expandable downhole seat assembly
GB201814299D0 (en) * 2018-09-03 2018-10-17 Oil States Ind Uk Ltd Apparatus for use with a drill string assembly and method of use thereof

Family Cites Families (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2713909A (en) 1952-12-13 1955-07-26 Baker Oil Tools Inc Multiple plug feeding and ejecting conduit head
US3396789A (en) 1966-09-15 1968-08-13 Mobil Oil Corp Storage method and system for tel tools
US3403729A (en) * 1967-03-27 1968-10-01 Dow Chemical Co Apparatus useful for treating wells
US3785525A (en) * 1972-01-31 1974-01-15 Safe Well Mfg Co Chemical tablet dispensing device for wells
US4317486A (en) 1980-03-10 1982-03-02 The Dow Chemical Company Cementing head apparatus and method of operation
DE3035905C2 (en) 1980-09-24 1982-12-30 Christensen, Inc., 84115 Salt Lake City, Utah Device for the remote transmission of information from a borehole to the surface of the earth during the operation of a drilling rig
US4354278A (en) 1980-12-10 1982-10-12 Northrop Corporation Laser telemetry
JPS584090A (en) 1981-06-22 1983-01-11 ビ−・ジエイ・ヒユ−ズ・インコ−ポレイテツド Derrick hoist
US4427065A (en) 1981-06-23 1984-01-24 Razorback Oil Tools, Inc. Cementing plug container and method of use thereof
JPS5944135A (en) 1982-09-07 1984-03-12 Tokyo Tatsuno Co Ltd Transmitting device of optical information in oil station
US4671353A (en) 1986-01-06 1987-06-09 Halliburton Company Apparatus for releasing a cementing plug
DE3617227A1 (en) 1986-05-22 1987-11-26 Wirth Co Kg Masch Bohr DEVICE WITH AN END OF A TUBE CLAMPABLE SPIDER OR THE LIKE.
US4721158A (en) 1986-08-15 1988-01-26 Amoco Corporation Fluid injection control system
US4782894A (en) 1987-01-12 1988-11-08 Lafleur K K Cementing plug container with remote control system
JPS63180294A (en) 1987-01-22 1988-07-25 Man Design Kk Measurement data source
US4785880A (en) * 1987-06-12 1988-11-22 Robert Ashton Apparatus for dispensing chemicals into oil and gas wells
US4767280A (en) 1987-08-26 1988-08-30 Markuson Neil D Computerized controller with service display panel for an oil well pumping motor
US4854383A (en) 1988-09-27 1989-08-08 Texas Iron Works, Inc. Manifold arrangement for use with a top drive power unit
US5033113A (en) 1989-05-31 1991-07-16 Susan Wang Infrared receiver system for a remote control ceiling fan
US5095988A (en) 1989-11-15 1992-03-17 Bode Robert E Plug injection method and apparatus
US5040603A (en) 1990-04-30 1991-08-20 Halliburton Company Sequential remote control plug release system
US5142534A (en) 1990-10-17 1992-08-25 O'neill Communications, Inc. Wireless integrated voice-data communication system
US5191937A (en) 1991-02-22 1993-03-09 Texaco Inc. Offshore well remote control system
US5188178A (en) * 1991-08-01 1993-02-23 Texaco Inc. Method and apparatus for automatic well stimulation
US5293933A (en) 1992-02-13 1994-03-15 Halliburton Company Swivel cementing head with manifold assembly having remote control valves and plug release plungers
US5279305A (en) 1992-08-06 1994-01-18 Pedifutures, Inc. Electroencephalograph incorporating at least one wireless link
US5383044B1 (en) 1992-09-18 1998-09-01 Recoton Corp Systems methods and apparatus for transmitting radio frequency remote control signals
US5435390A (en) 1993-05-27 1995-07-25 Baker Hughes Incorporated Remote control for a plug-dropping head
DE19632344A1 (en) 1996-08-10 1998-02-12 Mann & Hummel Filter Pigging system
US6044905A (en) * 1997-05-20 2000-04-04 The Harrison Investment Trust Chemical stick storage and delivery system
US6182752B1 (en) * 1998-07-14 2001-02-06 Baker Hughes Incorporated Multi-port cementing head
US6056058A (en) * 1998-10-26 2000-05-02 Gonzalez; Leonel Methods and apparatus for automatically launching sticks of various materials into oil and gas wells

Also Published As

Publication number Publication date
AU765593C (en) 2004-07-01
GB2351102A (en) 2000-12-20
AU3793800A (en) 2000-12-21
GB0014033D0 (en) 2000-08-02
GB2351102B (en) 2001-08-22
NO20003011D0 (en) 2000-06-13
AU765593B2 (en) 2003-09-25
NO318456B1 (en) 2005-03-21
NO20003011L (en) 2000-12-15
CA2311464A1 (en) 2000-12-14
US6206095B1 (en) 2001-03-27

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