US20080230274A1

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Publication number: US20080230274A1
Application number: US12/012,616
Authority: US
Inventors: Svein Stubstad
Original assignee: National Oilwell Varco LP
Current assignee: National Oilwell Varco LP
Priority date: 2007-02-22
Filing date: 2008-02-04
Publication date: 2008-09-25
Also published as: EP2126269A1; CA2678686A1; WO2008102175A1

Abstract

A top drive system for wellbore operations, the top drive system, in at least certain aspects, including a motor, a main shaft driven by the motor, the main shaft having a top end and a bottom end, a speed reduction system interconnected with the main shaft, a washpipe shaft interconnected with the speed reduction system for driving the washpipe shaft at a speed of rotation less than a speed of rotation of the main shaft. This abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, 37 C.P.R. 1.72(b).

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present invention and the application for this patent claim priority under the U.S. Patent law §120 of U.S. Application Ser. No. 60/902,798 filed Feb. 22, 2007.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is directed to wellbore drilling top drive systems; to washpipe apparatuses for such systems; and to sealing systems for rotating members.

2. Description of Related Art

Drilling fluids are transmitted to drilling swivels and top drive drilling systems through a high-pressure swivel apparatus known as a “washpipe” with a seal known as a “washpipe packing” assembly. This packing assembly consists of a tubular component which is held stationary, and through which the drilling fluid flows under high pressure. A rotating seal assembly of contact lip seals is mechanically fixed to and rotates with the main shaft of the top drive or swivel, and forms a dynamic seal against the outer surface of the tubular washpipe as the main shaft rotates while drilling. Due to the high pressures and surface speeds involved in this arrangement, service life of the washpipe packing is limited. Drilling fluid leaks are therefore common on many drilling rigs, causing contamination and damage to associated components and environmental disruption.

The prior art discloses a variety of top drive systems; for example, and not by way of limitation, the following U.S. patents present exemplary top drive systems and sealing assemblies: U.S. Pat. Nos. 4,458,768; 4,807,890; 4,984,641; 5,433,279; 6,276,450; 4,813,493; 6,705,405; 4,800,968; 4,878,546; 4,872,577; 4,753,300; 6,007,105; 6,536,520; 6,679,333; 6,923,254.

In top drives and rotary drilling the washpipe typically sealingly engages a set of circumferential seals contained within a seal housing. Often, the washpipe remains stationary while the seals and the seal housing rotate. Such seal assemblies have conventionally included a series of reinforced, elastomeric, chevron-type seals interspersed with a series of reinforcing back-up rings. In certain prior art systems, one seal is exposed to full hydraulic pressure on one side, and atmospheric pressure on the opposite side. Full differential pressure of the drilling mud acts on one seal until that seal fails and the next seal in the assembly then acts as the primary seal. Some prior art swivel designs have sought to compensate for potential run-out and offset problems by allowing the washpipe and the seal housing to articulate.

BRIEF SUMMARY OF THE INVENTION

The present invention, in certain aspects, provides a shaft sealing assembly in which an auxiliary shaft rotated by a rotating main shaft is connected to and rotates with the shaft via a speed reducer, e.g., a gear drive apparatus, between the main shaft and the auxiliary shaft so that the auxiliary shaft rotates at a reduced speed compared to the speed of the main shaft, e.g. about one-half the main shaft speed, thus exposing seals dynamically sealing against the auxiliary shaft to a surface which is moving at the reduced speed, thus enhancing seal life.

In one particular aspect the main shaft is the main drive shaft of a top drive used in wellbore operations, e.g. drilling operations, and the auxiliary shaft is in fluid communication with a washpipe through which drilling fluid or mud flows to and through the top drive system.

The present invention discloses, in certain embodiments, a top drive system with a drive motor; a drive quill or main shaft; a gear system coupled to the drive motor; a top drive support system for supporting various items; and a washpipe shaft according to the present invention connected with the top drive main shaft via a speed reducer for rotation at a speed less than that of the main shaft to enhance the life of seal assemblies, e.g. with packings used to seal against the washpipe shaft.

Accordingly, the present invention includes features and advantages which are believed to enable it to advance top drive shaft sealing technology. Characteristics and advantages of the present invention described above and additional features and benefits will be readily apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments and referring to the accompanying drawings.

Certain embodiments of this invention are not limited to any particular individual feature disclosed here, but include combinations of them distinguished from the prior art in their structures, functions, and/or results achieved. Features of the invention have been broadly described so that the detailed descriptions that follow may be better understood, and in order that the contributions of this invention to the arts may be better appreciated. There are, of course, additional aspects of the invention described below and which may be included in the subject matter of the claims to this invention. Those skilled in the art who have the benefit of this invention, its teachings, and suggestions will appreciate that the conceptions of this disclosure may be used as a creative basis for designing other structures, methods and systems for carrying out and practicing the present invention. The claims of this invention are to be read to include any legally equivalent devices or methods which do not depart from the spirit and scope of the present invention.

What follows are some of, but not all, the objects of this invention. In addition to the specific objects stated below for at least certain preferred embodiments of the invention, there are other objects and purposes which will be readily apparent to one of skill in this art who has the benefit of this invention's teachings and disclosures. It is, therefore, an object of at least certain preferred embodiments of the present invention to provide:

New, useful, unique, efficient, non-obvious sealing for drive shafts, for top drive shafts, sealing arrangements for such shafts, and methods of their use.

The present invention recognizes and addresses the problems and needs in this area and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one of skill in this art who has the benefits of this invention's realizations, teachings, disclosures, and suggestions, various purposes and advantages will be appreciated from the following description of preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent's object to claim this invention no matter how others may later attempt to disguise it by variations in form or additions of further improvements.

The Abstract that is part hereof is to enable the U.S. Patent and Trademark Office and the public generally, and scientists, engineers, researchers, and practitioners in the art who are not familiar with patent terms or legal terms of phraseology to determine quickly from a cursory inspection or review the nature and general area of the disclosure of this invention. The Abstract is neither intended to define the invention, which is done by the claims, nor is it intended to be limiting of the scope of the invention or of the claims in any way.

It will be understood that the various embodiments of the present invention may include one, some, or all of the disclosed, described, and/or enumerated improvements and/or technical advantages and/or elements in claims to this invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

A more particular description of embodiments of the invention briefly summarized above may be had by references to the embodiments which are shown in the drawings which form a part of this specification. These drawings illustrate certain preferred embodiments and are not to be used to improperly limit the scope of the invention which may have other equally effective or equivalent embodiments.

FIG. 1 is a schematic view of a prior art top drive drilling system.

FIG. 2 is a front view of a top drive system according to the present invention with washpipe apparatus according to the present invention.

FIG. 3 is a cross-section view of one embodiment of part of the system ofFIG. 2.

FIG. 4 is a cross-section of one embodiment of part of the system ofFIG. 2.

FIG. 4A is a schematic side cross-section view of the system according to the present invention.

FIG. 5 is a cross-section view of part of the embodiment ofFIG. 4.

Presently preferred embodiments of the invention are shown in the above-identified figures and described in detail below. Various aspects and features of embodiments of the invention are described below and some are set out in the dependent claims. Any combination of aspects and/or features described below or shown in the dependent claims can be used except where such aspects and/or features are mutually exclusive. It should be understood that the appended drawings and description herein are of preferred embodiments and are not intended to limit the invention or the appended claims. On the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims. In showing and describing the preferred embodiments, like or identical reference numerals are used to identify common or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.

As used herein and throughout all the various portions (and headings) of this patent, the terms “invention”, “present invention” and variations thereof mean one or more embodiment, and are not intended to mean the claimed invention of any particular appended claim(s) or all of the appended claims. Accordingly, the subject or topic of each such reference is not automatically or necessarily part of, or required by, any particular claim(s) merely because of such reference. So long as they are not mutually exclusive or contradictory any aspect or feature or combination of aspects or features of any embodiment disclosed herein may be used in any other embodiment disclosed herein.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a typical prior art drilling system with a derrick DK supporting a top drive TD which rotates drill pipe DP. The top drive is supported from a travelling block TB beneath a crown block CB. A drawworks, DS, on a rig floor RF raises and lowers the top drive. The top drive moves on a guide track GT.

FIG. 2 shows a system S according to the present invention with atop drive1 with adrive motor2; agear system3 coupled to thetop drive1 with abearing support4 andsupport links4a; awashpipe apparatus10 with a washpipe shaft according to the present invention; anelevator load ring5; a mud saver system9; a lowerinternal blowout preventer6; asaver sub7; agooseneck24; and apipe gripper8 with supports8A connected to theelevator load ring5.

The present inventors have recognized the problems associated with the rotation of a shaft with respect to packing or seals and have realized that effective reduction of the speed of shaft rotation can enhance seal life and reduce seal wear.

By reducing the surface speed at which the seals effectively operate, the present invention extends the service life of washpipe packing. Instead of the packing rotating at main shaft speed against a stationary washpipe, the present invention provides a speed reducing mechanism (e.g. a gear drive apparatus) which rotates a washpipe shaft at, e.g., one-half the speed of the main shaft, thus the washpipe packing is not subjected to the full speed of the main shaft. In one embodiment of the present invention, a similar dynamic sealing assembly is, optionally, added at the upper, formerly stationary, end of the washpipe. By rotating the washpipe shaft with the main shaft, but at a lower speed than the main shaft, e.g. at one-half main shaft speed, the or each of the sealing assemblies are only subjected to one-half the original surface speed (thus one half the original contact with a rotating surface), increasing the overall service life of the packing and washpipe assembly. Rotation of the washpipe shaft is driven by the main shaft through a speed reducing mechanism.

As shown inFIG. 3 anapparatus10 according to the present invention has amain washpipe body12 disposed above and in fluid communication with a main shaft M of the top drive system S.A washpipe shaft70 projects into anupper packing assembly16 and rotates with the main shaft M (but is connected to the main shaft only via a gear system described below). Upper and

lower packing assemblies

16 and18 respectively, have seals which seal against thewashpipe shaft70.

Drilling mud flows through a channel22 of thegooseneck24 into an interior70aof thewashpipe shaft70 and from there down a channel C through the main shaft M into the drill pipe.

Packing

15 of theupper packing assembly16 does not rotate with thewashpipe shaft70. The outer surface of thewashpipe shaft70 rotates against the packing15. Thegooseneck24 is connected togooseneck support25 withbolts26. For assembly purposes asupport28 is connected to theupper packing assembly16 with a bolt (or bolts)32 connected to ahousing34. A bolt (or bolts)36 connect thelower packing assembly18 adjacent the main shaft M. Following assembly, thesupport28 and the

bolts

32,36 are deleted.

Aprimary gear40 is secured to and rotates with the main shaft within thehousing34.Teeth40aon theprimary gear40 mesh withteeth42aonplanetary gears42 which are mounted onshafts44 of agear carrier46.Ball bearings48 in alower part52 of thehousing34 andball bearings49 under anupper part54 of thehousing34 isolate thehousing34 from the rotation of the main shaft M, rotation of theprimary gear40, and rotation of the planetary gears42. Ashield62 shields items below it from falling drilling mud and inhibits the leakage or flow of mud from going into apparatuses below theshield62, e.g. a top drive gear box.

FIGS. 4 and 5 show another embodiment of a system100 according to the present invention useful as a washpipe apparatus in the system S ofFIG. 2. An s-pipe extension101 is connected to a gooseneck102 (sometimes referred to as a washpipe apparatus). Drilling mud flows through achannel101ain the s-pipe extension101 into achannel102athrough thegooseneck102 down into achannel121 of awashpipe shaft120 and then to achannel141 through atop drive shaft140 driven by a top drive motor105 (e.g. a rotating shaft projecting from a top drive gear box104 (shown in dotted line). Aconnector103 with

seals

103a,103b, connects the s-pipe extension101 to thegooseneck102.

Anupper seal carrier106 connected too thegooseneck102 houses seal assemblies107 (which include seal carriers and seals) which seal against an outer surface of thewashpipe shaft120. Theupper seal holder106 maintains the top of thewashpipe shaft120 in place. Alower seal holder108 connected to theshaft140 houses seal assemblies109 (which include seal carriers and a seal) which seal against an outer surface of thewashpipe shaft120. Thelower seal carrier108 maintains the bottom of thewashpipe shaft120 in place.

Aspeed reducer160 interconnected between theshaft140 and thewashpipe shaft120 reduces the speed of thewashpipe shaft120 as compared to the speed of theshaft140. Thus the

seals

107 and109 seal against a shaft (the washpipe shaft120) rather than against the lower shaft (the top drive shaft140) and the seals are, therefore, subjected to a shaft surface rotating at a speed less than (e.g., in certain aspects, at least 25% less than, and, in other aspects about 50% less than) the speed of the lower shaft.

Ports

106pand108p

house bolts

106b,108b, respectively, which maintain theseal assemblies107, respectively, in place.Bolts102bbolt the gooseneck to other structure. Atorque arrester112 is connected to the washpipe, e.g. to theupper seal holder106 and to thespeed reducer160. Thistorque arrester112 prevents thering housing164 of thespeed reducer160 from rotating with other parts of thespeed reducer160. Thering housing164 provides a housing for bearings and gears of thespeed reducer160. Asplash shield114 is connected to theshaft140.

Asun gear162 is connected to thelower seal holder108 and rotates with theshaft140. Planetary gears166 (e.g., but not limited to, four planetary gears) mounted onshafts167 to aplanetary gear carrier168 mesh with and are driven by thesun gear162.Splines169 on theplanetary gear carrier168 mesh withcorresponding splines128 on thewashpipe shaft120 to rotatively drive thewashpipe shaft120.

Thering housing164 houses a bearingassembly170 withbearings172 between thering housing164 and thesun gear162. Thering housing164 houses a bearingassembly174 withbearings176 between the ring gear and theplanetary gear carrier168. The sun gear and the planetary gears are sized, designed and configured to achieve a desired gear reduction to reduce the speed of theshaft120 as compared to the speed of theshaft140. For example, in one particular aspect, the gears are designed so that theshaft140 rotates twice as fast as theshaft120. In certain prior systems seals (like the seals109) were subjected to a shaft (like the shaft140) rotating at its operational speed and seals (like the seals107) were held stationary. The seals (like twoseals107; and the seals109) in systems according to the present invention are now subjected to a shaft rotating at a much lower speed.

FIG. 4A shows schematically asystem200 according to the present invention in which awashpipe shaft202 connected to awashpipe204 is interconnected via aspeed reduction device206 to a rotatabletop drive shaft208.

Seals

211,212 seal against thewashpipe shaft202. Both seals are subjected to a surface of thewashpipe shaft202 against which they seal that is rotating at a speed less than the rotational speed of thetop drive shaft208. Theseals211 are in aseal holder218 connected to thewashpipe204. Although theseals212 are connected to alower seal holder214 that is connected to thetop drive shaft208, theseals212 only “see” a surface speed of thewashpipe shaft202 which is less than that of thetop drive shaft208 since thewashpipe shaft202 and thetop drive shaft208 are rotating in the same direction. Thespeed reduction device206 may be any suitable speed reducer, including, but not limited to, a gear system.

The present invention, therefore, provides in at least certain embodiments, a top drive system for wellbore operations, the top drive system having: a main shaft with a main shaft channel therethrough; drive apparatus for rotating the main shaft at a main shaft speed; a speed reducer apparatus connected to the main shaft; a washpipe shaft connected to the speed reducer apparatus so that the washpipe shaft is rotatable by the speed reducer apparatus at a washpipe shaft speed less than the main shaft speed; the washpipe shaft having a top end and a bottom end, and a washpipe shaft channel therethrough; a washpipe having a washpipe channel therethrough, the washpipe shaft channel in fluid communication with the washpipe channel; the washpipe shaft channel in fluid communication with the main shaft channel; a first seal holder connected to the washpipe and holding first seal assemblies for sealing against the top end of the washpipe shaft; and a second seal holder connected to the main shaft and holding second seal assemblies for sealing against the second end of the washpipe. Such a system may have one or some, in any possible combination, of the following: the speed reducer apparatus reducing the washpipe shaft speed to at least 25% less than the main shaft speed; the speed reducer apparatus reducing the washpipe shaft speed to about 50% of the main shaft speed; the speed reducer apparatus is a gear system including first gear apparatus connected to the main shaft and second gear apparatus connected to the washpipe shaft, the first gear apparatus for driving the second gear apparatus; the first gear apparatus includes a first gear, the second gear apparatus includes a plurality of second gears, and the first gear drives the plurality of second gears to rotate the washpipe shaft; the speed reducer apparatus having a ring housing, and a torque arrester connected to the ring housing and to the washpipe; wherein the torque arrester is connected to the first seal holder which is connected to the washpipe; and/or wherein the drive apparatus includes a top drive motor and a top drive gear system driven by the top drive motor.

The present invention, therefore, provides in at least certain embodiments, a top drive system for wellbore operations, the top drive system having: a main shaft with a main shaft channel therethrough; drive apparatus for rotating the main shaft at a main shaft speed; a speed reducer apparatus connected to the main shaft; a washpipe shaft connected to the speed reducer apparatus so that the washpipe shaft is rotatable by the speed reducer apparatus at a washpipe shaft speed less than the main shaft speed; the washpipe shaft having a top end and a bottom end, and a washpipe shaft channel therethrough; a washpipe having a washpipe channel therethrough, the washpipe shaft channel in fluid communication with the washpipe channel; the washpipe shaft channel in fluid communication with the main shaft channel; a first seal holder connected to the washpipe and holding first seal assemblies for sealing against the top end of the washpipe shaft; a second seal holder connected to the main shaft and holding second seal assemblies for sealing against the second end of the washpipe; the speed reducer apparatus reduces the washpipe shaft speed to about 50% of the main shaft speed; the speed reducer apparatus is a gear system including first gear apparatus connected to the main shaft and second gear apparatus connected to the washpipe shaft; the first gear apparatus for driving the second gear apparatus; and the drive apparatus includes a top drive motor and a top drive gear system driven by the top drive motor.

The present invention, therefore, provides in at least certain embodiments, a method for dynamically sealing a drive shaft of a top drive system, the top drive system suitable for wellbore operations, the method including: rotating a washpipe shaft of a top drive system; sealing against a top end and a bottom end of the washpipe shaft, the washpipe shaft being part of the top drive system, the top drive system having a main shaft with a main shaft channel therethrough, drive apparatus for rotating the main shaft at a main shaft speed, a speed reducer apparatus connected to the main shaft, a washpipe shaft connected to the speed reducer apparatus so that the washpipe shaft is rotatable by the speed reducer apparatus at a washpipe shaft speed less than the main shaft speed, the washpipe shaft having a top end and a bottom end, and a washpipe shaft channel therethrough, a washpipe having a washpipe channel therethrough, the washpipe shaft channel in fluid communication with the washpipe channel, the washpipe shaft channel in fluid communication with the main shaft channel, a first seal holder connected to the washpipe and holding first seal assemblies for dynamically sealing against the top end of the washpipe shaft, a second seal holder connected to the main shaft and holding second seal assemblies for dynamically sealing against the second end of the washpipe, and rotating the washpipe shaft at a speed less than the speed of the main shaft; wherein the washpipe shaft speed is at least 25% less than the main shaft speed; wherein the washpipe shaft speed is about 50% of the main shaft speed; wherein the speed reducer apparatus is a gear system including first gear apparatus connected to the main shaft and second gear apparatus connected to the washpipe shaft, and the first gear apparatus for driving the second gear apparatus, the method further including: driving the second gear apparatus with the first gear apparatus; wherein the first gear apparatus includes a first gear, the second gear apparatus includes a plurality of second gears, and the first gear is for driving the plurality of second gears to rotate the washpipe shaft, the method further including: driving the plurality of second gears with the first gear to rotate the washpipe apparatus; wherein the speed reducer apparatus has a ring housing, and a torque arrester connected to the ring housing and to the washpipe; wherein the drive apparatus includes a top drive motor and a top drive gear system driven by the top drive motor, the method further including driving the top drive gear system with the top drive motor, and driving the main shaft with the top drive gear system.

The present invention, therefore, provides in at least certain embodiments, a top drive shaft system including: a main shaft with a main shaft channel therethrough; drive apparatus for rotating the main shaft at a main shaft speed; a speed reducer apparatus connected to the main shaft; a washpipe shaft connected to the speed reducer so that the washpipe shaft is rotatable by the speed reducer apparatus at a washpipe shaft speed less than the main shaft speed; the washpipe shaft having a top end and a bottom end, and a washpipe shaft channel therethrough; a washpipe having a washpipe channel therethrough, the washpipe shaft channel in fluid communication with the washpipe channel; and the washpipe shaft channel in fluid communication with the main shaft channel. Such a system may have one or some, in any possible combination, of the following: a first seal holder connected to the washpipe and holding first seal assemblies for sealing against the top end of the washpipe shaft, and a second seal holder connected to the main shaft and holding second seal assemblies for sealing against the second end of the washpipe; wherein the speed reducer apparatus reduces the washpipe shaft speed to at least 25% less than the main shaft speed; and/or wherein the speed reducer apparatus reduces the washpipe shaft speed to about 50% of the main shaft speed; and/or the speed reducer apparatus having a ring housing, and a torque arrester connected to the ring housing and to the washpipe.

The present invention, therefore, provides in at least certain embodiments, a drive shaft system including: a main shaft with a main shaft channel therethrough; drive apparatus for rotating the main shaft at a main shaft speed; a speed reducer apparatus connected to the main shaft; a secondary shaft connected to the speed reducer apparatus so that the secondary shaft is rotatable by the speed reducer apparatus at a secondary shaft speed less than the main shaft speed; the secondary shaft having a top end and a bottom end, and a secondary shaft channel therethrough; a pipe having a pipe channel therethrough, the secondary shaft channel in fluid communication with the pipe channel; the secondary shaft channel in fluid communication with the main shaft channel; first sealing apparatus for sealingly contacting the secondary shaft for sealing a main-shaft secondary-shaft interface; and second sealing apparatus for sealingly contacting a secondary-shaft-pipe interface.

In conclusion, therefore, it is seen that the present invention and the embodiments disclosed herein and those covered by the appended claims are well adapted to carry out the objectives and obtain the ends set forth. Certain changes can be made in the subject matter without departing from the spirit and the scope of this invention. It is realized that changes are possible within the scope of this invention and it is further intended that each element or step recited in any of the following claims is to be understood as referring to the step literally and/or to all equivalent elements or steps. The following claims are intended to cover the invention as broadly as legally possible in whatever form it may be utilized. The invention claimed herein is new and novel in accordance with 35 U.S.C. §102 and satisfies the conditions for patentability in §102. The invention claimed herein is not obvious in accordance with 35 U.S.C. §103 and satisfies the conditions for patentability in §103. This specification and the claims that follow are in accordance with all of the requirements of 35 U.S.C. §112. The inventors may rely on the Doctrine of Equivalents to determine and assess the scope of their invention and of the claims that follow as they may pertain to apparatus not materially departing from, but outside of, the literal scope of the invention as set forth in the following claims. All patents and applications identified herein are incorporated fully herein for all purposes. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. §112,paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function. In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are including, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

Claims

1. A top drive system for wellbore operations, the top drive system comprising

a main shaft with a main shaft channel therethrough,

drive apparatus for rotating the main shaft at a main shaft speed,

a speed reducer apparatus connected to the main shaft,

a washpipe shaft connected to the speed reducer apparatus so that the washpipe shaft is rotatable by the speed reducer apparatus at a washpipe shaft speed less than the main shaft speed,

the washpipe shaft having a top end and a bottom end, and a washpipe shaft channel therethrough,

a washpipe having a washpipe channel therethrough, the washpipe shaft channel in fluid communication with the washpipe channel,

the washpipe shaft channel in fluid communication with the main shaft channel,

a first seal holder connected to the washpipe and holding first seal assemblies for sealing against the top end of the washpipe shaft, and

a second seal holder connected to the main shaft and holding second seal assemblies for sealing against the second end of the washpipe.

2. The top drive system ofclaim 1 wherein the speed reducer apparatus reduces the washpipe shaft speed to at least 25% less than the main shaft speed.

3. The top drive system ofclaim 1 wherein the speed reducer apparatus reduces the washpipe shaft speed to about 50% of the main shaft speed.

4. The top drive system ofclaim 1 wherein

the speed reducer apparatus is a gear system including first gear apparatus connected to the main shaft and second gear apparatus connected to the washpipe shaft,

the first gear apparatus for driving the second gear apparatus.

5. The top drive system ofclaim 4 wherein

the first gear apparatus includes a first gear,

the second gear apparatus includes a plurality of second gears, and

the first gear drives the plurality of second gears to rotate the washpipe shaft.

6. The top drive system ofclaim 1 further comprising

the speed reducer apparatus having a ring housing, and

a torque arrester connected to the ring housing and to the washpipe.

7. The top drive system ofclaim 6 wherein the torque arrester is connected to the first seal holder which is connected to the washpipe.

8. The top drive system ofclaim 1 wherein the drive apparatus includes a top drive motor and a top drive gear system driven by the top drive motor.

9. A top drive system for wellbore operations, the top drive system comprising

a main shaft with a main shaft channel therethrough,

drive apparatus for rotating the main shaft at a main shaft speed,

a speed reducer apparatus connected to the main shaft,

the washpipe shaft channel in fluid communication with the main shaft channel,

a first seal holder connected to the washpipe and holding first seal assemblies for sealing against the top end of the washpipe shaft,

a second seal holder connected to the main shaft and holding second seal assemblies for sealing against the second end of the washpipe,

the speed reducer apparatus reduces the washpipe shaft speed to about 50% of the main shaft speed,

the first gear apparatus for driving the second gear apparatus, and

the drive apparatus includes a top drive motor and a top drive gear system driven by the top drive motor.

10. A method for dynamically sealing a drive shaft of a top drive system, the top drive system suitable for wellbore operations, the method comprising

rotating a washpipe shaft of a top drive system,

sealing against a top end and a bottom end of the washpipe shaft, the washpipe shaft comprising part of the top drive system, the top drive system comprising a main shaft a with a main shaft channel therethrough, drive apparatus for rotating the main shaft at a main shaft speed, a speed reducer apparatus connected to the main shaft, a washpipe shaft connected to the speed reducer apparatus so that the washpipe shaft is rotatable by the speed reducer apparatus at a washpipe shaft speed less than the main shaft speed, the washpipe shaft having a top end and a bottom end, and a washpipe shaft channel therethrough, a washpipe having a washpipe channel therethrough, the washpipe shaft channel in fluid communication with the washpipe channel, the washpipe shaft channel in fluid communication with the main shaft channel, a first seal holder connected to the washpipe and holding first seal assemblies for dynamically sealing against the top end of the washpipe shaft, a second seal holder connected to the main shaft and holding second seal assemblies for dynamically sealing against the second end of the washpipe, and

rotating the washpipe shaft at a speed less than the speed of the main shaft.

11. The method ofclaim 10 wherein the washpipe shaft speed is at least 25% less than the main shaft speed.

12. The method ofclaim 10 wherein the washpipe shaft speed is about 50% of the main shaft speed.

13. The method ofclaim 10 wherein the speed reducer apparatus is a gear system including first gear apparatus connected to the main shaft and second gear apparatus connected to the washpipe shaft, and the first gear apparatus for driving the second gear apparatus, the method further comprising

driving the second gear apparatus with the first gear apparatus.

14. The method ofclaim 5 wherein the first gear apparatus includes a first gear, the second gear apparatus includes a plurality of second gears, and the first gear is for driving the plurality of second gears to rotate the washpipe shaft, the method further comprising

driving the plurality of second gears with the first gear to rotate the washpipe apparatus.

15. The method ofclaim 10 wherein the speed reducer apparatus has a ring housing, and a torque arrester connected to the ring housing and to the washpipe.

16. The method ofclaim 10 wherein the drive apparatus includes a top drive motor and a top drive gear system driven by the top drive motor, the method further comprising

driving the top drive gear system with the top drive motor, and

driving the main shaft with the top drive gear system.

17. A top drive shaft system comprising

a main shaft with a main shaft channel therethrough,

drive apparatus for rotating the main shaft at a main shaft speed,

a speed reducer apparatus connected to the main shaft,

a washpipe shaft connected to the speed reducer so that the washpipe shaft is rotatable by the speed reducer apparatus at a washpipe shaft speed less than the main shaft speed,

a washpipe having a washpipe channel therethrough, the washpipe shaft channel in fluid communication with the washpipe channel, and

the washpipe shaft channel in fluid communication with the main shaft channel.

18. The top drive system ofclaim 17 further comprising

19. The top drive system ofclaim 17 wherein the speed reducer apparatus reduces the washpipe shaft speed to at least 25% less than the main shaft speed.

20. The top drive system ofclaim 17 wherein the speed reducer apparatus reduces the washpipe shaft speed to about 50% of the main shaft speed.

21. The top drive system ofclaim 17 further comprising

the speed reducer apparatus having a ring housing, and

a torque arrester connected to the ring housing and to the washpipe.

22. A drive shaft system comprising

a main shaft with a main shaft channel therethrough,

drive apparatus for rotating the main shaft at a main shaft speed,

a speed reducer apparatus connected to the main shaft,

a secondary shaft connected to the speed reducer apparatus so that the secondary shaft is rotatable by the speed reducer apparatus at a secondary shaft speed less than the main shaft speed,

the secondary shaft having a top end and a bottom end, and a secondary shaft channel therethrough,

a pipe having a pipe channel therethrough, the secondary shaft channel in fluid communication with the pipe channel,

the secondary shaft channel in fluid communication with the main shaft channel,

first sealing apparatus for sealingly contacting the secondary shaft for sealing a main-shaft secondary-shaft interface, and

second sealing apparatus for sealingly contacting a secondary-shaft-pipe interface.