Greaseless core barrel head assembly

Abstract

A core sampling tool having a core barrel and a core barrel head assembly coupled to a proximal end of the core barrel. The core barrel head assembly does not include a grease port or a grease fitting. The core barrel head assembly has a spindle and at least one bearing that rotationally engages the spindle. Each of the bearings is a self-lubricating bearing, such as, for example, a solid oil bearing.

1 . A core sampling tool comprising:
 a core barrel having a proximal end; and   a core barrel head assembly coupled to the proximal end of the core barrel,   wherein the core barrel head assembly does not comprise a grease port or a grease fitting.   
     
     
         2 . The core sampling tool of  claim 1 , wherein the core barrel head assembly comprises a spindle and at least one bearing that rotationally engages the spindle, wherein the at least one bearing is a self-lubricating bearing. 
     
     
         3 . The core sampling tool of  claim 2 , wherein the spindle is a hollow spindle that defines a bore that extends axially through the spindle. 
     
     
         4 . The core sampling tool of  claim 3 , wherein the core barrel head assembly further comprises a check valve assembly positioned distal of the hollow spindle. 
     
     
         5 . The core sampling tool of  claim 3 , wherein the core barrel head assembly further comprises a check valve assembly positioned proximal of the hollow spindle. 
     
     
         6 . The core sampling tool of  claim 2 , wherein the spindle comprises a solid spindle that does not define an axial bore extending through the spindle. 
     
     
         7 . The core sampling tool of  claim 6 , wherein the core barrel head assembly further comprises a check valve assembly positioned distal of the hollow spindle. 
     
     
         8 . The core sampling tool of  claim 6 , wherein the core barrel head assembly further comprises a check valve assembly positioned proximal of the hollow spindle. 
     
     
         9 . A core barrel head assembly configured for coupling to a core barrel, the core barrel head assembly comprising:
 an elongate body having a proximal end and a distal end;   a bearing subassembly configured to engage the proximal end of the elongate body   a spindle subassembly that is rotationally engaged by the bearing subassembly,   wherein the spindle subassembly comprises a hollow spindle having an inner diameter of at least ⅝ inch, and wherein the bearing subassembly comprises one or more self-lubricating bearings.   
     
     
         10 . The core barrel head assembly of  claim 9 , wherein the one or more self-lubricating bearings are solid oil bearings. 
     
     
         11 . The core barrel head assembly of  claim 9 , wherein the core barrel head assembly does not comprise a grease port or a grease fitting. 
     
     
         12 . The core barrel head assembly of  claim 9 , further comprising a check valve subassembly, wherein the check valve subassembly engages the distal end of the elongate body. 
     
     
         13 . A method comprising:
 advancing a core sampling tool within a formation, the core sampling tool comprising a core barrel head assembly coupled to a core barrel; and   receiving core within the core barrel,   wherein the method does not comprise delivering grease to or within the core barrel head assembly.   
     
     
         14 . The method of  claim 13 , wherein the core barrel head assembly comprises a bearing subassembly and a spindle, wherein the bearing subassembly comprises one or more self-lubricating bearings that rotationally engage the spindle. 
     
     
         15 . The core sampling tool of  claim 1 , wherein the core barrel head assembly comprises:
 an elongate tube body having an outer surface, an interior cavity, a proximal end, and a distal end, wherein the elongate tube body defines a helical groove that extends from the interior cavity to the outer surface of the elongate tube body, wherein the helical groove is configured to allow the elongate tube body to elastically extend from a neutral length to an elongated length.   
     
     
         16 . The core sampling tool of  claim 15 , wherein the elongate tube body defines at least one aperture that extends between the interior cavity and the outer surface, wherein the helical groove is configured to allow the elongate tube body to elastically compress from the neutral length, wherein the core barrel head assembly further comprises a valve body that is attached to the elongate tube body and is movable with respect to the proximal end of the elongate tube body along the longitudinal axis, as the elongate tube body compresses, from a first position to a second position, wherein, when in the second position, the valve body causes a greater restriction to flow through the at least one aperture than when the valve body is in the first position. 
     
     
         17 . The core sampling tool of  claim 16 , wherein the core barrel head assembly further comprises an electronics compartment having an outer surface, wherein the valve body defines an interior cavity, wherein the electronics compartment is disposed within the interior cavity of the valve body, wherein the electronics compartment is attached to the valve body so that the interior surface of the interior cavity of the valve body and the outer surface of the electronics department define a fluid passage, wherein the valve body, the electronics compartment, or a combination of at least one interior surface of the valve body and at least one exterior surface of the electronics compartment defines at least one opening for providing fluid communication between the fluid passage and the distal end of the valve body. 
     
     
         18 . A drilling system comprising:
 a drill string having:
 a drill bit at a distal end of the drill string; 
 the core sampling tool of  claim 15 , wherein the core barrel head assembly has a distal end, and wherein the core barrel has a distal end; and
 a core lifter case at the distal end of the core barrel; 
 
 wherein, when the drill bit is in a drilling configuration, the drill bit is spaced distally of the core lifter case, and wherein, when the drill bit is in a core break configuration, the drill bit is in contact with the core lifter case, and the elongate tube body is elongated from the neutral length. 
   
     
     
         19 . A method comprising:
 positioning the drill string of the system of claim  18  within a borehole;   receiving a core sample within the core barrel; and   retracting the drill string until the drill bit is in the core break configuration.   
     
     
         20 .- 37 . (canceled)