Abstract:
A bail support and a top drive system with such bail supports, the top drive system including a top drive apparatus, the bails having a body with an upper head portion and two spaced-apart legs, each leg with an upper leg portion and a lower leg portion, the upper leg portions non-parallel to each other and extending from the head portion at an angle to a centerline of the bail, and each lower leg portion extending down from a corresponding upper leg portion in a reverse bend. 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 CFR 1.72(b).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field Of The Invention 
         [0002]    This invention is directed to wellbore drilling top drive systems; bails to support parts thereof; and methods of their use. 
         [0003]    2. Description of Related Art 
         [0004]    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 components thereof: 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—all these patents incorporated fully herein for all purposes. 
         [0005]    Certain typical prior art top drive drilling systems have a derrick supporting a top drive which rotates tubulars, e.g., drill pipe. The top drive is supported by bails, often on a becket suspended beneath a travelling block beneath a crown block. A drawworks on a rig floor raises and lowers the top drive. 
         [0006]    Certain prior art bails for supporting top drives have straight legs in which a three-cornered bail shape imparts stress-inducing bending moments throughout a bail when it is under load often with concentrated high stress locations at lower pin lugs and at a topmost upper bend. As larger and larger top systems have evolved, bails have simply been enlarged and made more massive to accommodate heavier system. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    The present invention, in certain aspects, provides a top drive system for wellbore operations, which is suspended by bails having integral dual section legs with adjacent sections at angles to each other (a “reverse bend”) to create opposite bending moments which counteract the effects of each other, thereby reducing stress in the bail. 
         [0008]    In certain aspects, the present invention discloses a bail with opposed upper leg portions each of which is at an angle (a reverse bend) to a corresponding lower leg portion. 
         [0009]    In certain top drives support bails connect to main body lugs of a main body of the top drive using bails according to the present invention with reverse bends results in less stress on the main body lugs. 
         [0010]    Accordingly, the present invention includes features and advantages which are believed to enable it to advance top drive bail 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. 
         [0011]    In certain aspects, bails according to the present invention with bends in the legs take up less vertical space than similar bails with straight legs. In certain aspects bails according to the present invention which can handle a particular load and/or level of stress have a smaller cross-section than straight-legged bails. 
         [0012]    In certain aspects, different parts of a bail according to the present invention are, optionally, larger or more massive in cross-section than other parts; e.g., a top curved portion may be larger in cross-section than leg portions below the top portion. 
         [0013]    In certain aspects, using bail legs with bends between leg portions reduces over all stresses in the bail legs and stresses on a main body to which leg lugs are connected are reduced. 
         [0014]    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. 
         [0015]    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&#39;s teachings and disclosures. It is, therefore, an object of at least certain preferred embodiments of the present invention to provide the embodiments and aspects listed above and: 
         [0016]    New, useful, unique, efficient, non-obvious top drive systems, bails to support them, and methods of their use; and 
         [0017]    Such systems with bails with legs with a reverse bead or dual leg sections at angles to each other and, optionally, with bottom lugs on each leg at an angle to the leg. 
         [0018]    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&#39;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&#39;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. 
         [0019]    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. 
         [0020]    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 DRAWINGS 
         [0021]    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. 
           [0022]      FIG. 1A  is a side view of a top drive system according to the present invention. 
           [0023]      FIG. 1B  is a front view of the top drive system of  FIG. 1A . 
           [0024]      FIG. 2A  is a front view of the top drive system support bail according to the present invention. 
           [0025]      FIG. 2B  is a side view of the bail of  FIG. 2A . 
           [0026]      FIG. 2C  shows cross-sectional shapes for bails according to the present invention. 
           [0027]      FIG. 3A  is a side view of a top drive system bail according to the present invention. 
           [0028]      FIG. 3B  is a front view of the bail of  FIG. 3A . 
           [0029]      FIG. 3C  is a side view (opposite the side of  FIG. 3A ) of the bail of  FIG. 3A . 
           [0030]      FIG. 3D  is a rear view of the bail of  FIG. 3A . 
           [0031]      FIG. 3E  is a top view of the bail of  FIG. 3A . 
           [0032]      FIG. 3F  is a bottom view of the bail of  FIG. 3A . 
           [0033]      FIG. 3G  is a cross-section view along line  3 G- 3 G of  FIG. 3D . 
           [0034]      FIG. 4A  is a perspective view of a system according to the present invention with bails according to the present invention. 
           [0035]      FIG. 4B  is a front view of the system of  FIG. 4A . 
           [0036]      FIG. 4C  is a side view of the system of  FIG. 4A . 
       
    
    
       [0037]    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. 
         [0038]    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 
       [0039]      FIGS. 1A and 1B  illustrate a top drive system  100  according to the present invention which has supporting bails  104  according to the present invention suspended from a becket  102 . Motors  120  which rotate a main shaft  160  are supported on a main body  130 . A bonnet  110  supports a gooseneck  106  and a washpipe  108  through which fluid is pumped to and through the system  100 . 
         [0040]    A gear system housing  140  is below the motors  120 . 
         [0041]    A ring gear housing  150  encloses a ring gear  152  and associated components. 
         [0042]    An optional drag chain system  170  below the gear system encloses a drag chain and associated components including hoses and cables. Instead of the drag chain system, a rotating head system may be used to provide sufficient rotation for reorientation of a link adapter  180  and items connected thereto. 
         [0043]    Upper parts of the bails  104  extend over and are supported by arms  103  of the becket  102 . Each bail  104  has two spaced-apart lower ends  105  pivotably connected by pins  107  to the body  130 . Such a use of two bails distributes the support load on the main body and provides a four-point support for this load. 
         [0044]      FIGS. 2A and 2B  show a bail  10  according to the present invention (like the bails  104 ,  FIG. 2B ) with a body  12  having an upper head  14 , upper leg portions  16 , lower leg portions  18 , and bottom lugs  20  with pin holes  21  therethrough. The upper head portion is curved to accommodate a becket or other support. The upper leg portions  16  are at an angle A with respect to a centerline C of the bail and the lower leg portions  18  are at an angle B to the centerline C. As shown the angle A is 3.5 degrees and the angle B is 13.6 degrees. In certain aspects, and as is true for any bail according to the present invention, the angle A can range between 2 degrees and 7 degrees. In certain aspects, and as is true for any bail according to the present invention, the angle B can range between 12 degrees and 16 degrees. A reverse bend N is formed between the upper leg portions 16 and the lower leg portions  18 . As is true of any bail according to the present invention, the reverse bend N may be anywhere along the length of the bail legs (i.e., near the top, near the bottom, or anywhere in between). As is true for any bail according to the present invention, the radius of the reverse bend N can vary between a sharp bend radius (radius=0) to a large radius that eliminates straight segments of the legs. The curvature (length/radius) of the legs without straight sections can be as small as zero (straight leg, infinite radius). The overall height of any bail according to the present invention may be any desired height and the bail width may be any desired width suitable for application to particular equipment, e.g. particular hoisting equipment. 
         [0045]    The bottom lugs  20  are parallel to the centerline C. The bottom lugs are at an angle D to the lower leg portions  18 . D may range, in certain aspects, between one and forty-five degrees. The bail  10  as shown has a cross-section CS which is generally oval. It is within the scope of the present invention for this cross-section to be any desirable shape (e.g., the shapes shown in  FIG. 2C ). This cross-sectional shape may be any shape which satisfies known stiffness and strength criteria based on standard beam design practice. The top curved part is, in certain aspects, curved to match a saddle of a supporting becket. Upper leg portions may have a cross-sectional shape different from that of the lower leg portions. 
         [0046]      FIGS. 3A-3F  show a bail  50  according to the present invention which is like the bails of  FIGS. 1A and 2A . The bail  50  has a top curved part  52 , upper leg portions  54 , lower leg portions  56  and lugs  58  with pin holes  59 . As shown in  FIG. 3G , the bail has a generally oval cross-sectional shape. In certain aspects for the bail  50  the angle A is 5.9 degrees and the angle B is 14.5 degrees; or the angle A is 5.9 degrees and the angle B is 13.8 degrees. 
         [0047]    The reverse bends S in the legs create opposite bending moments throughout the bail, partially counteracting the effect of the bending moments which would be present if the legs were straight. The bends create local stresses where they are located, but these are relatively low stresses. By increasing the stresses at the bend locations, the overall maximum stresses (at the lower-leg-/upper-leg-portion interfaces portion and at the lower lugs) are reduced significantly (e.g. in some aspects, by 33%). This allows the use of smaller cross-sections, an overall lighter part using less steel, and one that is, therefore, more economical to manufacture. 
         [0048]    As shown in  FIG. 3G  the bails have an oval cross-section. Any suitable cross-section shape may be used including circular (e.g. see  FIG. 2C ). 
         [0049]      FIGS. 4A-4C  show a system  140  according to the present invention with bails  150  according to the present invention. The bails  150  pinned with pins  142  to a main body  104  of a top drive apparatus  146 . The top drive apparatus  146  includes motors  148 , a gooseneck  141 , a washpipe  143 , a bonnet  145 , and a gear system  147 . A top drive shaft  136  is turned by the motors  148 . 
         [0050]    Each bail  150  has a body  152  with a top curved part  154 , upper leg portions  156 , lower leg portions  158 , and lugs  159 . There is a reverse bend between the leg portions  156  and  158 . The pins  142  extend through holes  157  in the lugs  159 ; through holes  139  in projections  137  of the main body  144 ; and into holes  149  of the main body  104 . 
         [0051]    It is within the scope of the present invention for the cross-sections of parts of the bails to be similar throughout (top curved part, upper leg portions, lower leg portions); or, as shown in  FIGS. 4A and 4B , the top curved part, e.g. part  154 , may be larger or more massive in cross-section than the leg portions. In certain aspects, the geometry of the bend is designed to balance the bending moments in the bail (“geometry” refers to the vertical location of the bend and the offset of the bend and “offset” is the distance from the apex of the bend to the theoretical centerline of the leg that would exist if the leg were straight). In such a case when the geometry of the bend balances the bending moments in the bail, the cross-section is constant. In other cases of bend location, e.g. with the bend in a non-ideal location that makes the moments higher at the top of the bail than at the bottom or vice versa, the cross-section at the high moment area (e.g. at or near the top of the bail) is increased to keep the stresses down. 
         [0052]    The present invention, therefore, provides in some, but not in necessarily all, embodiments a top drive system for wellbore operations, the top drive system including a top drive apparatus, bails for supporting the top drive apparatus and from which the top drive apparatus is suspended, the bails comprising a first bail and a second bail, each of the first bail and second bail has a body with an upper head portion, the body having two spaced-apart legs, each leg with an upper leg portion and a lower leg portion, the two upper leg portions connected to the upper head portion and projecting down therefrom, the upper leg portions non-parallel to each other and each upper leg portion extending from the upper head portion at an upper angle to a centerline of the bail, and each lower leg portion extending down from a corresponding upper leg portion, each lower leg portion at an angle to its corresponding upper leg portion, and projecting out from the centerline of the bail in a reverse bend with respect to its corresponding upper leg portion, each lower leg portion having a bottom end. 
         [0053]    The present invention, therefore, provides in some, but not in necessarily all, embodiments a bail for supporting an item, the bail including a body with an upper head portion; the body having two spaced-apart legs, each leg comprising an upper leg portion and a lower leg portion; the two upper leg portions connected to the upper head portion and projecting down therefrom, the upper leg portions non-parallel to each other and each upper leg portion extending from the upper head portion at an upper angle to a centerline of the bail; and each lower leg portion extending down from a corresponding upper leg portion, each lower leg portion at an angle to its corresponding upper leg portion, and projecting out from the centerline of the bail in a reverse bend with respect to its corresponding upper leg portion, each lower leg portion having a bottom end. Such bail may have one or some, in any possible combination, of the following: each leg body having an oval shape in cross-section; wherein the upper angle ranges between 2 degrees and 7 degrees; wherein each lower leg portion extends down at a lower angle to the centerline of the bail and the lower angle ranges between 12 and 16 degrees; wherein a bend is formed at an interface of each upper leg portion and lower leg portion, the bend located to balance bending moments in each bail; wherein each bail has a constant size cross-section throughout the bail body; wherein a first portion of each bail body has a first cross-section size and a second portion of the bail body has a second cross-section size, the first cross-section size different from the second cross-section size; and/or wherein the first portion is located in an area of the bail at a top of the bail that is an area of relatively high bending moment and the first cross-section size is larger than the second cross-section size. 
         [0054]    The present invention, therefore, provides in some, but not in necessarily all, embodiments a bail for supporting a top drive for well operations, the bail including a body with an upper head portion; the body having two spaced-apart legs, each leg comprising an upper leg portion and a lower leg portion; the two upper leg portions connected to the upper head portion and projecting down therefrom, the upper leg portions non-parallel to each other and each upper leg portion extending from the upper head portion at an upper angle to a centerline of the bail; each lower leg portion extending down from a corresponding upper leg portion, each lower leg portion at an angle to its corresponding upper leg portion, and projecting out from the centerline of the bail at a lower angle in a reverse bend with respect to its corresponding upper leg portion; wherein the upper angle ranges between 2 degrees and 7 degrees; wherein the lower angle ranges between 12 and 16 degrees; and the reverse bend located to balance bending moments in each bail. 
         [0055]    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. What follows are some of the claims for some of the embodiments and aspects of the present invention, but these claims are not necessarily meant to be a complete listing of nor exhaustive of every possible aspect and embodiment of the invention. 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.