Abstract:
An adapter comprises a generally cylindrical adapter, engagement member bores, retention member bores, and an attachment structure configured for allowing the adapter to be fixedly attached to a mating portion of the drilling head equipment. The engagement member bores extend effectively parallel to the central bore. The retention member bores are each adjacent a respective one of the engagement member bores. The retention member bores are positioned such that the engagement pin bores and retention member bores intersect. The retention member bore is configured for having a retention member engaged therein in a manner allowing the retention member to be selectively displaced along a length of the retention member bore. The adapter includes a central bore to accommodate a down hole tubular. The attachment structure includes a surface adjacent the central bore comprising fastener bores substantially parallel to the central bore for facilitating connection of the adapter to the drilling head equipment.

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure relates to connectors and connector systems for making mechanical connections. More particularly, the disclosure provides apparatus, systems and methods for connecting or disconnecting a stripper rubber to or from equipment, such as a bearing assembly, of a drilling head to pressure-seal the interior of a well bore for the circulation, containment or diversion of drilling fluid through the well during drilling operations. 
     BACKGROUND 
     Oil, gas, water and geothermal wells are typically drilled with a drill bit connected to a hollow drill string which is inserted into a well casing cemented in the well bore. A drilling head is attached to the well casing, wellhead or to associated blowout preventer equipment, for the purposes of sealing the interior of the well bore from the surface and facilitating forced circulation of drilling fluid through the well while drilling or diverting drilling fluids away from the well. Drilling fluids include, but are not limited to, water, steam, drilling muds, air, and other gases. 
     In the forward circulation drilling technique, drilling fluid is pumped downwardly through the bore of the hollow drill string, out the bottom of the hollow drill string and then upwardly through the annulus defined by the drill string and the interior of the well casing, or well bore, and subsequently out through a side outlet above the well head. In reverse circulation, a pump impels drilling fluid through a port, down the annulus between the drill string and the well casing, or well bore, and then upwardly through the bore of the hollow drill string and out of the well. 
     Drilling heads typically include a stationary body, often referred to as a bowl, which carries a rotatable spindle such as a bearing assembly, rotated by a kelly apparatus or top drive unit. One or more seals or packing elements, often referred to as stripper packers or stripper rubbers, is carried by the spindle to seal the periphery of the kelly or the drive tube or sections of the drill pipe, whichever may be passing through the spindle and the stripper rubber, and thus confine or divert the core pressure in the well to prevent the drilling fluid from escaping between the rotating spindle and the drilling string. 
     As modern wells are drilled ever deeper, or into certain geological formations, very high temperatures and pressures may be encountered at the drilling head. These rigorous drilling conditions pose increased risks to rig personnel from accidental scalding, burns or contamination by steam, hot water and hot, caustic well fluids. There is a danger of serious injury to rig workers when heavy tools are used to make a stripper rubber connection at the drilling head. The connection should be made quickly and achieve a fluid tight seal. 
     Rotating blowout preventers and diverters are well known to those of ordinary skill in the art of well pressure control. Rotation of the diverter/preventer is facilitated by a sealing engaged bearing assembly through which the drill string rotates relative to the stationary bowl or housing in which the bearing assembly is seated. Typically, a rubber O-ring seal, or similar seal, is disposed between the stripper rubber and the bearing assembly to improve the fluid-tight connection between the stripper rubber and the bearing assembly. 
     Pressure control is achieved by means of one or more stripper rubbers connected to the bearing assembly and disposed around the drill string. At least one stripper rubber rotates with the drill string. Stripper rubbers typically taper downward and include rubber or other resilient substrate so that the downhole pressure pushes up on the rubber, pressing the rubber against the drill string to achieve a fluid-tight seal. Stripper rubbers often further include a metal insert that provide support for bolts or other attachment means and which also provide a support structure to minimize deformation of the rubber cause by down hole pressure forces acting on the rubber. 
     Stripper rubbers are connected or adapted to equipment of the drilling head to establish and maintain the pressure control seal around a down hole tubular (i.e., a drill string). It will be understood by those skilled in the art that a variety of means are used to attach a stripper rubber to associated drilling head equipment. Such attachment means include bolting from the top, bolting from the bottom, screwing the stripper rubber directly onto the equipment via cooperating threaded portions on the top of the stripper rubber and the bottom of the equipment, and clamps. 
     It will be understood that, depending on the particular equipment being used at a drilling head, a stripper rubber at one well may be connected to equipment specific to that well while at another well a stripper rubber is connected to different equipment. For example, at one well the stripper rubber may be connected to the bearing assembly while at another well the stripper rubber may be connected to an inner barrel or an accessory of the drilling head. While the present disclosure is made here in relation to connecting the stripper rubber to the bearing assembly, it will be evident that the disclosure contemplates connection of the stripper rubber to any selected equipment of the drilling head. 
     It is common practice to tighten the bolts or screws of the connection with heavy wrenches and sledge hammers. The practice of using heavy tools to tighten a bolt, for example, can result in over-tightening, to the point where the threads or the bolt head become stripped. The results of over-tightening include stripped heads, where the bolt or screw cannot be removed, or stripped threads, where the bolt or screw has no grip and the connection fails. Both results are undesirable. 
     Even worse, vibration and other drilling stresses can cause bolts or screws to work themselves loose and fall out. If one or more falls downhole, the result can be catastrophic. The drill bit can be ruined. The entire drillstring may have to tripped out, and substantial portions replaced, including the drill bit. If the well bore has been cased, the casing may be damaged and have to be repaired. 
     Drilling head assemblies periodically need to be disassembled to replace stripper rubbers or other parts, lubricate moving elements and perform other recommended maintenance. In some circumstances, stripped or over tightened bolts or screws make it very difficult if not impossible to disengage the stripper rubber from the drilling head assembly to perform recommended maintenance or parts replacement. 
     It is desirable, therefore, to obtain a connector for optionally connecting a stripper rubber assembly to a bearing assembly, or other equipment, of a drilling head that is effective, safe, simple, fast and elegant. 
     SUMMARY OF THE DISCLOSURE 
     In view of the foregoing, the present invention, through one or more of its various aspects, embodiments and/or specific features or sub-components, is thus intended to bring out one or more of the advantages that will be evident from the disclosures made herein. More specifically, the present invention facilitates connection of a stripper rubber to drilling head equipment. Embodiments of the present invention provide a fast, simple and reliable means for detachably attaching the stripper rubber to drilling head equipment and facilitating transmission of rotary torque loads applied on the stripper rubber from the rotating drill string and exerted from the stripper rubber onto a corresponding rotating component of the drilling head equipment (e.g., an inner barrel of the rotating control head). 
     In one embodiment of the present invention, a system is provided for disconnectably connecting a stripper rubber to drilling head equipment. The system comprises a stripper rubber, an adapter and a plurality of retention members. The stripper rubber includes an insert that has one or more engagement members extending vertically therefrom. The adapter is configured for being connected between the drilling head equipment and the stripper rubber. The adapter includes a central bore, engagement member bores substantially parallel to the central bore, retention member bores substantially perpendicular to the central bore, and attachment means configured for allowing the adapter to be fixedly attached to a mating portion of the drilling head equipment. Each one of the engagement member bores intersects a respective one of the retention member bores. Each one of the retention members is retractably engagable within a respective one of the retention member bores. Each one of the retention members lockingly engages a respective one of the engagement members upon sufficient displacement in a first direction within the respective one of the retention member bores thereby precluding withdrawal of the respective one of the engagement members from within the respective one of the engagement member bores. Each one of the retention members disengages from the respective one of the engagement members upon sufficient displacement in a second direction within the respective one of the retention member bores thereby allowing withdrawal of the respective one of the engagement members from within the respective one of the engagement member bores. 
     In another embodiment of the present invention, an adapter is provided for selectively connecting a stripper rubber to drilling head equipment of a well. The adapter comprises a central bore, an engagement member bore, a retention member bore, and a drill head equipment engaging structure. The central bore is configured to accommodate a down hole tubular. The engagement member bore extends effectively parallel to the central bore. The retention member bore is adjacent the engagement member bore. The drill head equipment engaging structure is adjacent the central bore. The retention member bore is positioned such that the engagement member bore and the retention member bore intersect. The retention member bore is configured for having a retention member engaged therein in a manner allowing the retention member to be selectively displaced along a length of the retention member bore. The drill head engaging structure is configured for being engaged with a mating portion of the drilling head equipment for attaching the adapter to the drilling head equipment. 
     In another embodiment of the present invention, an adapter is provided for selectively connecting a stripper rubber to drilling head equipment of a well. The adapter comprises a generally cylindrical adapter, engagement member bores, retention member bores, and attachment means configured for allowing the adapter to be fixedly attached to a mating portion of the drilling head equipment. The engagement member bores extend effectively parallel to the central bore. The retention member bores are each adjacent a respective one of the engagement member bores. The retention member bores are positioned such that the engagement member bores and retention member bores intersect. The retention member bore is configured for having a retention member engaged therein in a manner allowing the retention member to be selectively displaced along a length of the retention member bore. The adapter includes a central bore to accommodate a down hole tubular. The attachment means includes a surface adjacent the central bore comprising a plurality of fastener bores substantially parallel to the central bore for facilitating connection of the adapter to the drilling head equipment. 
     These and other objects, embodiments, advantages and/or distinctions of the present invention will become readily apparent upon further review of the following specification, associated drawings and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is further made in the detailed description that follows, by reference to the noted drawings, by way of non-limiting examples of embodiments in which like reference numerals represent similar parts throughout several views of the drawings, and in which: 
         FIG. 1  shows a first embodiment of a stripper rubber connection system in accordance with the present invention; 
         FIG. 2  is a cross-sectional view taken along the line  2 - 2  in  FIG. 1 ; 
         FIG. 3  is a cross-sectional view taken along the line  3 - 3  in  FIG. 1 ; 
         FIG. 4  is a top perspective view of an adapter of the stripper rubber connection system of  FIG. 1 ; 
         FIG. 5  is a bottom perspective view of an adapter of the stripper rubber connection system of  FIG. 1 ; and 
         FIG. 6  shows a second embodiment of a stripper rubber connection system in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an embodiment of a system  100  for disconnectably connecting a stripper rubber to drilling head equipment in accordance with the present invention is shown. The system  100  includes a stripper rubber  102 , an adapter  104  and a plurality of retention members  106 . As is discussed below in greater detail, the stripper rubber  102 , the adapter  104  and the retention members  106  are jointly configured for being interconnected in a manner that is advantageous, novel and non-obvious. Aspects of the present invention that contribute to such advantageous, novel and non-obvious interconnection include, but are not limited to, such interconnection providing a fast, simple and reliable means for detachably attaching the stripper rubber  102  to the adapter  104  in a manner that facilitates transmission of rotary torque loads applied on the stripper rubber  102  from a rotating drill string (not shown) that extends through a central bore  108  of the stripper rubber  102 . 
     The stripper rubber  102  includes an insert  110  and a stripper rubber body  112 . In a typical stripper rubber, the insert  110  is made from steel and the stripper rubber is made from an elastomeric material (e.g., synthetic rubber). The insert  110  includes a mechanical bonding portion  114  and an adapter engaging portion  116 . The stripper rubber body  112  is formed over the mechanical bonding portion  114  and can optionally be formed over the at least a portion of the adapter engaging portion  116 . Preferably, the mechanical bonding portion  114  includes one or more features that enhance the mechanical interface between the stripper rubber body material and the insert  110 . Examples of the mechanical interface enhancing features include undercuts, windows, passages and the like. In addition to mechanical interface enhancing features, it is also known to coat all or a portion of an insert with a bonding agent that enhances adhesion between the stripper rubber body material and the insert. 
     Engagement pins  118  are fixedly attached to the insert  110 . The engagement pins  118  extend vertically from an upper face  119  of the adapter engaging portion  116 . Preferably, but not necessarily, the engagement pins  118  are uniformly spaced apart. The term “pin” is disclosed herein to be broadly construed to include any suitable engagement member configuration for carrying out the intended functionality. Means for attaching the engagement pins  118  to the insert  110  are well known (e.g., threaded interface, welding, etc). 
     Referring now to  FIGS. 1-5 , the adapter  104  is configured for being connected between drilling head equipment (e.g., an inner barrel, spindle, etc) and the stripper rubber  102 . To this end, the adapter  104  is configured for being attached to the drilling head equipment and for having the stripper rubber  102  attached thereto. The adapter  104  is not limited to a particular means for facilitating attachment to the drilling head equipment. Various known means and yet to be conceived means for attachment will suitably facilitate such attachment. 
     The adapter  104  includes a central bore  120 , engagement pin bores  122 , and retention member bores  124 . The engagement pin bores  122  extend substantially parallel to the central bore  120  through a stripper rubber engaging face  126  of the adapter  104  (i.e., a bottom face). The stripper rubber engaging face  126  and the adapter engaging portion  116  of the stripper rubber  102  are jointly configured for being in abutted engagement. 
     The retention member bores  124  extend substantially perpendicular to the central bore  120 . Each one of the retention member bores  124  extends through an exterior side face  127  of the adapter  104  and intersects a respective one of the engagement pin bores  122  to form a respective aperture  128  therebetween. Each one of the retention members  106  engages the respective one of the engagement pins  118  through the respective aperture  128  when the engagement pins  118  are positioned within the engagement pin bores  122  and the retention members  106  are then secured in the retention member bores  124 . 
     As shown in  FIGS. 1-3 , each one of the retention members  106  includes an adapter engaging portion  130  (i.e., a head portion) and an engagement pin engaging portion  132  (i.e., a tip portion), and is retractably engagable within a respective one of the retention member bores  124 . The adapter engaging portion  130  is configured for allowing the respective retention member  106  to be selectively translated along a longitudinal axis of an engaged one of the retention member bores  124  in an engagement direction (i.e., a first direction that is toward the respective engagement pin) and a disengagement direction (i.e., a second direction that is away from the respective engagement pin). 
     Each one of the engagement pins  118  includes a retention member engaging portion  134  (i.e., receives a tip portion of a retention member). The retention member engaging portion  134  is configured and positioned such that it is exposed within the aperture  122  of the engagement pin bore  122  in which the respective engagement pin  118  is positioned. When the stripper rubber  102  and the adapter  104  are positioned such that the engagement pins  118  are disposed within the engagement pin bores  122 , the engagement pin engaging portion  132  of each retention member  106  lockingly engages the retention member engaging portion  134  of the respective one of the engagement pins upon sufficient displacement of each retention member  106  in the engagement direction from a disengaged position (i.e., a position thereby allowing insertion of an engagement pin into the respective engagement pin bore  122 ). In this manner, the retention members  106  and the engagement pins  118  are jointly configured for selectively precluding withdrawal of the respective engagement pin  118  from within the respective engagement pin bore  122 . To allow the stripper rubber  102  to be detached from the adapter  104  once attached, the engagement pin engaging portion  132  of each one of the retention members  106  disengages from the retention member engaging portion  134  of the respective one of the engagement pins  118  upon sufficient displacement in the disengagement direction. In this manner, the retention members  106  and the engagement pins  118  are jointly configured for selectively allowing withdrawal of the engagement pins  118  from within the respective one of the engagement pin bores  122 . 
     As shown, the retention member engaging portion  134  of each engagement pin  118  and the engagement pin engaging portion  132  of each retention member  106  is straight (i.e., non-tapered). Thus, engagement of the retention members  106  with the engagement pins  118  result in minimal, if not negligible, biasing of the stripper rubber  102  toward the adapter  104 . However, it is disclosed herein that the retention member engaging portion  134  of each engagement pin  118  and the engagement pin engaging portion  132  of each retention member  106  can be made in a manner (e.g., tapered) whereby engagement of the retention members  106  with the engagement pins  118  biases the stripper rubber  102  toward the adapter  204 . 
     As shown in  FIGS. 1-3 , selective translation of the retention members  106  is provided for via the adapter engaging portion  130  of each retention member  106  having threads that engage mating threads of the respective retention member bore  124 . Thus, rotation of each retention member  106  in a first rotational direction causes translation in the engagement direction and rotation of each retention member  106  in a second rotational direction causes translation in the disengagement direction. Such threaded engagement is one example of facilitating selective translation of the retention members  106  within the retention member bores  124 . 
     It is disclosed herein that the present invention is not limited to a particular arrangement for allowing selective translation of the retention members  106  within the retention member bores  124 . A skilled person will appreciate that other arrangements for allowing selective translation of retention members within retention member bores can be used in place of the threaded arrangement. One example of such other arrangements is a twist-lock arrangement where a retention member is slid to a depth in the respective retention member bore where it is engaged with respective engagement pins, and is then locked in place by being twisted a fraction of a complete rotation. In such an arrangement, it can be useful to implement some form of anti-rotation mechanism to prevent unintentional rotation of the retention member. Another example of such other arrangements is where a retention member is slidably and captive disposed within a respective retention member bore, being spring biased in the engagement direction such to it is manually displaced to in the disengaged position for along the an engagement pin to be fully inserted within a respective engagement pin bore. 
     With respect to attaching the adapter  104  to the drilling head equipment, a surface  136  adjacent a central bore  137  of the adapter  104  ( FIGS. 4 and 5 ) includes a plurality of fastener bores  138 . Each one of the fastener bores  138  extends substantially parallel to the central bore  137  for facilitating connection of the adapter  104  to the drilling head equipment. The fastener bores  138  are spaced around the central bore  137 . Preferably, but not necessarily, the adapter  104  is generally cylindrical shaped having an inner surface  140  that encompasses the central bore  137 . The fastener bores  138  extend through the inner surface  140 . 
     Various approaches for attaching the adapter  104  to the drilling head equipment are known. Numerous variations of the present invention will be apparent to those of ordinary skill in the art from the preceding exemplary description. For example, an adapter of the present invention may be connected to the drilling head by any suitable means other than bolting. Examples of such other means include, but are not limited to, welding and screwing (e.g., a threaded adapter may be screwed onto a threaded barrel). 
     The engagement pins  118 , the retention members  106 , the engagement pin bores  122  and the retention member bores  124  shown in  FIGS. 1-5  jointly represent a first embodiment of a stripper rubber connection arrangement in accordance with the present invention.  FIG. 6  shows an embodiment of a system  200  for disconnectably connecting a stripper rubber to drilling head equipment in accordance with the present invention. The system  200  is the same as the system  100  of  FIGS. 1-5  with the following exceptions. Thus, elements of the system  200  that are identical to those of the system  100  will be denoted using the same reference numeral for the same element of the system  100 . 
     The stripper rubber connection arrangement of the system  200  is an alternate embodiment with respect to the stripper rubber connection arrangement of the system  100 . The stripper rubber connection arrangement of the system  200  includes a plurality of engagement pins  218 , retention members  206 , engagement pin bores  222  and retention member bores  224  (one each shown). A longitudinal axis of each engagement pin bore  222  intersects a longitudinal axis of each retention member bore  224 . 
     Each retention member  206  includes a tapered engagement pin engaging portion  232  and an adapter engaging portion  230 , and is retractably engagable within a respective one of the retention member bores  224 . The adapter engaging portion  230  is configured for allowing the retention member  206  to be selectively translated along the longitudinal axis of an engaged one of the retention member bores  224  in the engagement direction and the disengagement direction. The tapered engagement pin engaging portion  232  engages a mating tapered aperture  225  within a respective one of the engagement pins  218  whereby such engagement biases the stripper rubber  102  toward the adapter  104 . Alternatively, the tapered engagement pin engaging portion  232  and the tapered aperture  225  can both be made non-tapered such that engagement of the retention members  206  with the engagement pins  118  result in minimal, if not negligible, biasing of the stripper rubber  102  toward the adapter  104 . 
     Alternatively, with respect to the system  200 , the tip portion of the retention members  206  and the tip receiving portion of the engagement pins  218  can be configured such that a tip receiving portion of each engagement pin  218  does not extend fully therethrough and the tip portion of the retention members  206  are correspondingly truncated with respect to those shown. It is disclosed herein that the present invention is not limited to a particular shape of such truncated tip portion and tip receiving portion. Examples of suitable shapes, include, but are not limited to, pointed, flat, rounded, cylindrical, and the like. 
     It is good practice to periodically replace or maintain stripper rubbers because stripper rubbers tend to wear out. To replace a stripper rubber, the stripper rubber must be disconnected from the drilling head equipment. To disconnect a stripper rubber pursuant to the present invention, it is a simple matter of rotating each retention member such that each retention member retracts a required distance to disengage from the respective engagement pin. A new stripper rubber can then be installed by inserting engagement pins thereof into the engagement pin bores, followed by engaging the retention members to a sufficient depth in the retention member bores such that each retention member engages a respective engagement pin. 
     Although the invention has been described with reference to several exemplary embodiments, it is understood that the words that have been used are words of description and illustration, rather than words of limitation. Changes may be made within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the invention in all its aspects. Although the invention has been described with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed; rather, the invention extends to all functionally equivalent technologies, structures, methods and uses such as are within the scope of the appended claims.