Patent Abstract:
A drill pipe connector assembly capable of connecting drill pipe segments without rotation. The assembly includes the pin end of a first drill pipe stabbed within the connector end of a second drill pipe. A connector nut is threadedly connected or snap locked to the connector end of the second drill pipe. The connector nut includes a retaining shoulder cooperating with a beveled shoulder on the pin end of the first drill pipe to retain the first drill pipe. The assembly includes seals to provide pressure integrity and prevent leaking. Cooperating rotational torque transfer profiles in the first and second drill pipes enable operational rotation of the drill string.

Full Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a drill pipe connector and method and more particularly to a drill pipe connector and method that connects without rotation of the drill pipe and without requiring high make-up torque. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the exploration and production of oil and gas, drill pipe or a column of drill pipe (e.g., a drill pipe string) may be employed for a variety of purposes. On a drilling rig, the drill string is made up on the rig&#39;s platform. The drill string is run downhole and into the well bore. The drill string transmits drilling fluid (via mud pumps) and rotational power (via a Kelly or top drive) to the drill bit, which is part of a bottom hole assembly positioned at the end of the drill string. The drilling fluid is pumped down through the internal bore in the drill string, exits at or near the drill bit, and circulates back up the well annulus (void between the drill string and the well bore). The drill pipe string may also run casing, a liner, or a landing string downhole. The drill pipe string may also be used to work-over a hydrocarbon well. Drill strings can reach a length of 30,000 feet for a vertically drilled well and 35,000 feet for a deviated or horizontal drilled well. 
         [0003]    The drill string includes a column of individual joints or segments of drill pipe threadedly connected together by threaded ends. A joint or segment of drill pipe may vary in length. Typically, the length of a drill pipe joint ranges from 30 feet to 33 feet. A joint or segment of drill pipe has a box member secured at one end and a pin member secured at the other end. The box member is internally threaded and adapted to receive the pin member of another drill pipe joint, which has external threads. Mating joints of drill pipe are interconnected via the threads to make up the drill string. The joints of drill pipe must be securely made up to prevent leakage, wobbling, or unscrewing. Typically, power tongs are used to transmit sufficient rotational torque to the pipe joints to ensure that the pin end is tightly threaded in the box end; this is called make-up torque. The amount of torque required depends in part on the specific frictional properties of the threaded connections. A higher friction coefficient means increased torque transmitting ability thereby lessening instances of tool joints unscrewing and having to be made up downhole. A lower friction coefficient with less torque transmitting ability may cause too much torque to be applied when making up the joints. Excessive torque could stretch or burst the box member or crack or break the pin member. This is undesired as drill pipe is expensive. 
         [0004]    Pipe “dope” may be applied to the threaded connections of the joints to maintain a high coefficient of friction. The dope permits easier breaking down of the tool joints and helps prevent excessive make up. Despite the application of pipe dope, excessive make up and joint damage remains a problem. Moreover, the use of power tongs to make up pipe increases operational costs as additional equipment and personnel are required. The need exists for equipment and methods to connect drill pipe joints without rotating the drill pipe into itself. 
       SUMMARY OF THE INVENTION 
       [0005]    It is an object of the present invention to provide a drill pipe connector and method that does not require rotation to make up the drill pipe. 
         [0006]    It is a further object of the present invention to provide a drill pipe connector and method that eliminates the need for power tongs. 
         [0007]    It is a further object of the present invention to provide a drill pipe connector and method that imparts tensile strengths. 
         [0008]    It is a further object of the present invention to provide a drill pipe connector and method that achieves pressure integrity. 
         [0009]    It is a further object of the invention to provide a drill pipe connector and method that is capable of transferring rotational torque. 
         [0010]    These and other objects and advantages are achieved by the novel drill pipe connector assembly described herein, which may include a first drill pipe segment. The first drill pipe segment may include an outer surface and an inner surface. The inner surface may form a first bore. The first drill pipe segment may have a pin end. The assembly may also include a second drill pipe segment having an outer surface and an inner surface. The inner surface may form a second bore. The second drill pipe segment may have a connector end, which is adapted to receive the pin end of the first drill pipe segment within the second bore. The assembly may also include a connector nut interconnecting the first drill pipe segment with the second drill pipe segment. Such interconnection achieves fluid communication between the first bore and the second bore. The connector nut may also include an outer surface, an inner surface, an upper section, and a lower section. The lower section of the connector nut may be detachably affixed to the connector end of the second drill pipe segment. The upper section of the connector nut may operatively retain the pin end of the first drill pipe segment. 
         [0011]    The inner surface of the lower section of the connector nut may include a first set of threads. The outer surface of the connector end of the second drill pipe segment may include a second set of threads. The lower section of the connector nut may be threadedly affixed to the connector end of the second drill pipe segment via mating engagement of the first set of threads with the second set of threads. In one embodiment, the first and second set of threads may each be wicker-type threads. In another embodiment, the first and second set of threads may each be breech lock-type threads. 
         [0012]    The inner surface of the upper section of the connector nut may include a retaining shoulder. The outer surface of the pin end of the first drill pipe segment may include a beveled shoulder. The retaining shoulder may cooperatively engage the beveled shoulder to operatively retain the pin end of the first drill pipe segment. 
         [0013]    In another embodiment, the drill pipe connector assembly may include seal means. For example, the outer surface of the pin end of the first drill pipe segment may include one or more seal means forming a pressure seal between the outer surface of the pin end of the first drill pipe segment and the inner surface of the connector end of the second drill pipe segment. 
         [0014]    In a further embodiment, the pin end of the first drill pipe segment may include a first rotational torque transfer profile. The inner surface of the connector end of the second drill pipe segment may include a second rotational torque transfer profile. The first and second rotational torque transfer profiles may operatively engage each other to transfer torque from the first drill pipe segment to the second drill pipe segment via the interconnection provided by the connector nut. In another embodiment, the pin end of the first drill pipe segment includes a distal end. The distal end may contain the first rotational torque transfer profile. In a further embodiment, the first rotational torque profile may include a first lateral surface and a tapered surface. The second rotational torque profile may include a second lateral surface and a second tapered surface. The first and second lateral surfaces and the first and second tapered surfaces may cooperatively engage each other to transfer the rotational torque through the drill string as a result of drilling or other operations. 
         [0015]    The present invention is also directed to a method of making up drill pipe. The method may comprise providing a drill pipe connector assembly as previously described herein. The method may further include the step of stabbing the pin end of the first drill pipe segment into the connector end of the second drill pipe segment so that the first bore and the second bore are placed in fluid communication. The method may further include the step of detachably affixing the lower section of the connector nut to the connector end of the second drill pipe segment. The method may further include the step of causing the upper section of the connector nut to operatively retain the pin end of the first drill pipe segment. The method may further include the step of causing the seal means or plurality of seals to operatively seal the assembly to prevent leaking of a pressurized fluid flowing through the first and second bores. 
         [0016]    In a further embodiment of the method of the present invention, the step of detachably affixing the lower section of the connector nut to the connector end of the second drill pipe segment may be accomplished by threadedly affixing the lower section of the connector nut to the connector nut end of the second drill pipe segment via mating engagement of the first set of threads with the second set of threads. Alternatively, the detachably affixing step may be accomplished by snap locking the lower section of the connector nut to the connector end of the second drill pipe segment via mating engagement of the first set of wicker-type threads with the second set of wicker-type threads. Alternatively, the detachably affixing step may be accomplished by rotating the lower section of the connector nut to the connector end of the second drill pipe segment via mating engagement of the first set of breech lock-type threads with the second set of breech lock-type threads via ½ turn of the connector nut. 
         [0017]    In a further embodiment, the step of causing the upper section of the connector nut to operatively retain the pin end of the first drill pipe segment may be accomplished by positioning the retaining shoulder of the connector nut in cooperative engagement with the beveled shoulder of the first drill pipe segment to operatively retain the pin end of the first drill pipe segment. 
         [0018]    In yet a further embodiment, the step of causing the seal means to operatively seal the assembly to prevent leaking of the pressurized fluid flowing through the first and second bores may be accomplished by causing the plurality of seals to form a pressure seal between the outer surface of the pin end of the first drill pipe segment and the inner surface of the connector end of the second drill pipe segment. 
         [0019]    In an alternative embodiment, the method may include the step of causing the first and second rotational torque transfer profiles to operatively engage in order to transfer rotational torque from the first drill pipe segment to the second drill pipe segment via the interconnection provided by the connector nut. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a perspective view of the connector assembly of the present invention. 
           [0021]      FIG. 2  is a cross-sectional view of the connector assembly of  FIG. 1 . 
           [0022]      FIG. 3  is a partial cross-sectional view of the holding means of the connector assembly of the present invention shown as a set screw. 
           [0023]      FIG. 4  is a partial cross-sectional view of the holding means of the connector assembly of the present invention shown as a snap latch. 
           [0024]      FIG. 5  is a cross-sectional view of an alternative embodiment of the connector assembly of the present invention. 
           [0025]      FIG. 6  is an exploded, partial cut-away, perspective view of a further alternative embodiment of the connector assembly of the present invention. 
           [0026]      FIG. 7  is a schematic of a platform with a drill string composed of a plurality of connector assemblies of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    With reference to the figures where like elements have been given like numerical designation to facilitate an understanding of the present invention, and in particular with reference to the embodiment of the present invention illustrated in  FIG. 1 , connector assembly  10  may include first drill pipe  12 , second drill pipe  14  and connector nut  16 . 
         [0028]      FIG. 2  shows that first drill pipe  12  may include pin end  18 . Pin end  18  may include outer surface  20  and inner surface  22 . Outer surface  20  of pin end  18  may include beveled shoulder  24 . Shoulder  24  may include retaining face  26 , holding face  28 , and stop face  30 . Shoulder  24  may also include one or more recesses  32  in holding face  28  for receiving a holding device  34  (not shown). Lower section  36  of pin end  18  may have one or more seals  38  positioned in outer surface  20 . Seals  38  may be pressure seals formed of rubber, urethane, steel, plastic or other material capable of forming a seal that is leak resistant. Lower section  36  may include distal end  40 . Distal end  40  may have torque transfer profile  42 . Profile  42  may include lateral surface  96  and tapered surface  98 . 
         [0029]    With reference to  FIG. 2 , second drill pipe  14  may have connector end  44 . Connector end  44  may have outer surface  46  and inner surface  48 . Outer surface  46  may contain shoulder  50 . Connector end  44  may also include upper section  52 . Outer surface  46  of upper section  52  may include connector nut means  54 . Connector nut means  54  may be any device capable of detachably affixing connector nut  16  to upper section  52  of connector end  44  of second drill pipe  14 . Connector nut means  54  may be threads  56 . Upper section  52  may include support surface  57 . Inner surface  48  of connector end  44  may have torque transfer profile  58 . Profile  58  may include lateral surface  100  and tapered surface  102 . 
         [0030]    Again with reference to  FIG. 2 , connector nut  16  may be a tubular device having outer surface  60  and inner surface  62 . Connector nut  16  may also include upper section  64  and lower section  66 . Lower section  66  may include distal surface  67 . Inner surface  62  of upper section  64  may have shoulder  68 . Inner surface  62  of lower section  66  may contain connector end means  70 . Connector end means  70  may be any device capable of cooperating with connector nut means  54  to detachably affix connector nut  16  to upper section  52  of connector end  44  of second drill pipe  14 . Connector end means  70  may be threads  72  that cooperatively engage and disengage from threads  56 . Threads  72  may also threadedly engage and disengage from threads  56 . Connector nut  16  may contain one or more thru holes  74 . Each hole  74  may house or contain holding device  34  (not shown). Each hole  74  may align with recess  32  in holding face  28  of pin end  18  of first drill pipe  12 . Holding device  34  (not shown) may be positioned within aligned hole  74  and recess  32 . 
         [0031]    To make up or connect first drill pipe  12  to second drill pipe  14 , pin end  18  of first drill pipe  12  is stung into connector end  44  of second drill pipe  14 . Stop face  30  of beveled shoulder  24  acts as a stop for pin end  18  by contacting support surface  57  of upper section  52  of second drill pipe  14 . Connector nut  16  is secured to upper section  52  of second drill pipe  14  by rotating connector nut  16  so that connector nut  16  is threadedly connected to upper section  52  via threaded engagement of threads  54  and threads  70 . Shoulder  50  of connector end  44  of second drill pipe  14  acts as a stop for connector nut  16  by contacting lower section  66  of connector nut  16  at distal surface  67 . The detachable affixation of connector nut  16  to second drill pipe  14  compresses first drill pipe  12  and second drill pipe  14  together into operative connection. First drill pipe  12  is operatively connected to second drill pipe  14  via connector nut  16 . Shoulder  68  of connector nut  16  cooperates with or engages beveled shoulder  24  of first drill pipe  12 , and in particular, retaining face  26  of beveled should  24 , to hold or maintain first drill pipe  12  in position and operatively connected to second drill pipe  14 . The operative connection of first and second drill pipes  12 ,  14  forms bore  75  through which pressurized fluid (e.g., drilling mud) may be pumped. Seals  38  form a seal between outer surface  20  of first drill pipe  12  and inner surface  48  of second drill pipe  14  to maintain pressure within first and second drill pipes  12 ,  14  and to prevent leaking of the drilling fluid. The operative connection of first and second drill pipes  12 ,  14  also causes operative engagement of torque transfer profile  42  of pin end  18  of first drill pipe  12  and torque transfer profile  58  of connector end  44  of second drill pipe  14 . For example, lateral surface  96  cooperatively engages lateral surface  100  and tapered surface  98  cooperatively engages tapered surface  102 . The operative engagement of torque transfer profiles  42 ,  58  permits rotational torque to be transferred from first drill pipe  12  to second drill pipe  14  through connector nut  16  (and in like fashion to any other drill pipe segments made up and comprising the drill pipe strand) during exploration or production operations such as drilling of a well. 
         [0032]    To ensure that connector nut  16  remains secured about first and second drill pipes  12 ,  14 , holding device  34  may be employed to retain connector nut  16  in a fixed or stationary position relative to first and second drill pipes  12 ,  14 . Holding device  34  ensures that connector nut  16 , namely connector end means  70  or threads  72 , do not detach or threadedly detach from connector nut means or threads  56  of second drill pipe  14  while connector assembly  10  rotates during operation of the drill string incorporating connector assembly  10 . Holding device  34  may be any type of device capable of maintaining connector nut  16  in fixed position about first drill pipe  12 . One or more holding devices  34  may be used, as for example, two, three, or four holding devices  34 . Preferably, holding device  34  fixedly connects connector nut  16  to beveled shoulder  24  of pin end  18  of first drill pipe  12 . For example, holding device  34  may be set screw  76  as show in  FIG. 3 . Screw  76  may be inserted into thru hole  74  of connector nut  16  and into recess  32  of beveled shoulder  24  to thereby fixedly attach connector nut  16  to beveled shoulder  24  of first drill pipe  12 . Removal of screw  76  from recess  32  disengages the direct fixed connection between connector nut  16  and beveled shoulder  24  of first drill pipe  12 . 
         [0033]    As seen in  FIG. 4 , holding device  34  may also be snap latch  78 . Latch  78  may be inserted into thru hole  74  and into recess  32  to affix connector nut  16  to beveled shoulder  24  of first drill pipe  12 . Latch  78  may also be made integral with connector nut  16  or fixed to inner surface  62  (e.g., via welding) and extend outward from inner surface  62 . Latch  78  would snap into recess  32  when connector nut  16  is connected to connector end  44  of second drill pipe  14  and disengage from recess  32  when connector nut  16  is detached from connector end  44  of second drill pipe  14 . 
         [0034]      FIG. 5  shows an alternative embodiment of connector assembly  10 . Connector nut means  54  of second drill pipe  14  are formed as wicker-type threads  80 . Connector end means  70  of connector nut  16  are formed as wicker-type threads  82 . Rather than threadedly connecting connector nut  16  to connector end  44  of second drill pipe  14 , in the alternative embodiment of assembly  10 , wicker-type threads  82  of connector nut  16  and wicker-type threads  80  of second drill pipe  14  operatively engage when pin end  18  of drill pipe  12  is stabbed into connector end  44  of second drill pipe  14  to thereby make up first and second drill pipes  12 ,  14 . Connector nut  16  may be disengaged from connector end  44  of second drill pipe  14  by rotating connector nut  16  of wicker-type threads  80  of second drill pipe  14 . Alternative assembly  10  may include or not include one or more holding devices  34 . If one or more holding devices  34  are included with alternative assembly  10 , one or more holding devices  34  may be set screw  76  or snap latch  78  to prevent connector nut  16  from rotating off and disengaging from second drill pipe  14  during rotation of alternative assembly  10  as would occur, for example, during drilling operations.  FIG. 5  shows assembly  10  with set screws  76 . 
         [0035]      FIG. 6  reveals a further alternative assembly  10 . In the further alternative assembly  10 , connector nut means  54  of second drill pipe  14  are formed as breech lock-type threads  104 . Breech lock-type threads  104  are interrupted helically threads that contain thread-sections  106  and gaps  108 . Connector end means  70  of connector nut  16  are formed as breech lock-type threads  110 . Breech lock-type threads  110  are interrupted helically threads that contain thread-sections  112  and gaps  114 . Connector nut  16  is connected to connector end  44  of second drill pipe  14  by positioning each of thread-sections  112  of connector nut  16  within respective gaps  108  of second drill pipe  14  and rotating connector nut  16  in a first direction by a ½ turn causing mating engagement of each thread-section  106  of second drill pipe  14  with a corresponding thread-section  112  of connector nut  16 . Thus, drill pipe  12  (operatively engaged within connector nut  16 ) and drill pipe  14  are made up. Drill pipes  12 ,  14  may be disengaged by rotating connector nut  16  in the opposite direction by a ½ turn and removing connector nut  16  (and associated drill pipe  12 ) from connector end  44  of second drill pipe  14 . If one or more holding devices  34  are included with further alternative assembly  10 , one or more holding devices  34  may be set screw  76  or snap latch  78  to prevent connector nut  16  from rotating off and disengaging from second drill pipe  14  during rotation of further alternative assembly  10  as would occur, for example, during drilling operations.  FIG. 6  shows assembly  10  with set screws  76 . 
         [0036]      FIG. 7  shows a schematic of floating platform  84  containing drilling rig  86 . Drilling rig  86  contains hoisting system  88  that is used to make up drill string  90  that is run down through marine riser  92  and into well  94 . Drill string  90  comprises a series of first and second drill pipes  12 ,  14  connected together via connector assemblies  10 . 
         [0037]    While preferred embodiments of the present invention have been described, it is to be understood that the embodiments described are illustrative only and that the scope of the invention is to be defined solely by the appended claims when accorded a full range of equivalents, many variations and modifications naturally occurring to those skilled in the art from a perusal hereof.

Technology Classification (CPC): 4