Undisturbed core sampler

Abstract

A core sampler that complies with European Standard BS EN ISO 22457-1 and takes Class 1 samples, while being able to withstand forces associated with sonic drilling. The core sampler includes a smaller diameter, thin-walled sampler shoe portion that transitions to a larger diameter, thick-walled tube at a specific distance along the longitudinal axis of the core sampler. The smaller diameter shoe portion allows for an undisturbed sample, while the larger diameter tube imparts sufficient strength to the core sampler such that the core sampler can handle forces associated with sonic drilling techniques. Optionally, the larger diameter tube can provide the thickness needed for a liner.

1 . A core sampler for advancement within a geologic formation to obtain a core sample, the core sampler having a longitudinal axis, the core sampler comprising:
 a shoe portion having an inner surface, an outer surface, a proximal end, and an opposed distal end, the inner surface of the shoe portion defining a central bore surrounding the longitudinal axis of the core sampler and extending between the proximal end and the distal end of the shoe portion, the distal end of the shoe portion defining an opening in communication with the central bore and configured to receive the core sample, the shoe portion having a thickness corresponding to the radial distance between the inner surface and the outer surface of the shoe portion, the distal end of the shoe portion comprising a tapered portion in which the outer surface of the shoe portion is inwardly tapered relative to the longitudinal axis of the core sampler moving along the longitudinal axis of the core sampler toward the opening of the distal end of the shoe portion; and   a tube portion having an inner surface, an outer surface, a proximal end, and an opposed distal end, the distal end of the tube portion being secured to the proximal end of the shoe portion, the inner surface of the tube portion defining a central bore surrounding the longitudinal axis of the core sampler and extending between the proximal end and the distal end of the tube portion, the tube portion having a thickness corresponding to the radial distance between the inner surface and the outer surface of the tube portion,   wherein the thickness of the tube portion is greater than the thickness of the shoe portion.   
     
     
         2 . The core sampler as recited in  claim 1 , further comprising a liner removably received within the central bore of the tube portion. 
     
     
         3 . The core sampler as recited in  claim 1 , wherein the shoe portion and the tube portion of the core sampler each have a substantially annular cross-sectional shape along the longitudinal axis of the core sampler, wherein the shoe portion has a maximum outer diameter defined by the outer surface of the shoe portion, wherein the tube portion has a maximum outer diameter defined by the outer surface of the tube portion, and wherein the maximum outer diameter of the tube portion is greater than the maximum outer diameter of the shoe portion. 
     
     
         4 . The core sampler as recited in  claim 1 , wherein the shoe portion and the tube portion of the core sampler each have a substantially annular cross-sectional shape along the longitudinal axis of the core sampler, wherein the shoe portion has an inner diameter defined by the inner surface of the shoe portion, wherein the tube portion has an inner diameter defined by the inner surface of the shoe portion, and wherein the inner diameter of the tube portion is substantially equal to the inner diameter of the shoe portion. 
     
     
         5 . The core sampler as recited in  claim 1 , wherein the distal end of the tube portion comprises a tapered portion in which the outer surface of the tube portion is inwardly tapered relative to the longitudinal axis of the core sampler moving along the longitudinal axis of the core sampler toward the shoe portion of the core sampler. 
     
     
         6 . The core sampler as recited in  claim 1 , wherein the tapered portion of the distal end of the shoe portion is inwardly tapered relative to the longitudinal axis of the core sampler at an angle of about fifteen degrees or less. 
     
     
         7 . The core sampler as recited in  claim 2 , wherein the liner has a radial thickness, and wherein the combined thickness of the liner and the tube portion is at least about twice the thickness of the shoe portion. 
     
     
         8 . The core sampler as recited in  claim 5 , wherein the shoe portion and the tube portion of the core sampler each have a substantially annular cross-sectional shape along the longitudinal axis of the core sampler, wherein the shoe portion has an inner diameter defined by the inner surface of the shoe portion, wherein the tapered portion of the distal end of the tube portion is spaced a selected distance from the distal end of the shoe portion, and wherein the selected distance by which the tapered portion of the distal end of the tube portion is spaced from the distal end of the shoe portion is between about 1.0 and about 2.0 times larger than the inner diameter of the shoe portion. 
     
     
         9 . The core sampler as recited in  claim 1 , further comprising an adapter coupled to the proximal end of the tube portion, wherein the adapter is configured for operative coupling to a drill string component. 
     
     
         10 . A core sampler for advancement within a geologic formation to obtain a core sample, the core sampler having a longitudinal axis, the core sampler comprising:
 a shoe portion having an inner surface, an outer surface, a proximal end, and an opposed distal end, the inner surface of the shoe portion defining a central bore surrounding the longitudinal axis of the core sampler and extending between the proximal end and the distal end of the shoe portion, the distal end of the shoe portion defining an opening in communication with the central bore and configured to receive the core sample, the shoe portion having a thickness corresponding to the radial distance between the inner surface and the outer surface of the shoe portion;   a tube portion having an inner surface, an outer surface, a proximal end, and an opposed distal end, the distal end of the tube portion being secured to the proximal end of the shoe portion, the inner surface of the tube portion defining a central bore surrounding the longitudinal axis of the core sampler and extending between the proximal end and the distal end of the tube portion, the tube portion having a thickness corresponding to the radial distance between the inner surface and the outer surface of the tube portion,   wherein the thickness of the tube portion is greater than the thickness of the shoe portion.   
     
     
         11 . The core sampler as recited in  claim 10 , further comprising a liner removably received within the central bore of the tube portion. 
     
     
         12 . The core sampler as recited in  claim 10 , wherein the shoe portion and the tube portion of the core sampler each have a substantially annular cross-sectional shape along the longitudinal axis of the core sampler, wherein the shoe portion has a maximum outer diameter defined by the outer surface of the shoe portion, wherein the tube portion has a maximum outer diameter defined by the outer surface of the tube portion, and wherein the maximum outer diameter of the tube portion is greater than the maximum outer diameter of the shoe portion. 
     
     
         13 . The core sampler as recited in  claim 10 , wherein the shoe portion and the tube portion of the core sampler each have a substantially annular cross-sectional shape along the longitudinal axis of the core sampler, wherein the shoe portion has an inner diameter defined by the inner surface of the shoe portion, wherein the tube portion has an inner diameter defined by the inner surface of the shoe portion, and wherein the inner diameter of the tube portion is substantially equal to the inner diameter of the shoe portion. 
     
     
         14 . The core sampler as recited in  claim 10 , wherein the distal end of the tube portion comprises a tapered portion in which the outer surface of the tube portion is inwardly tapered relative to the longitudinal axis of the core sampler moving along the longitudinal axis of the core sampler toward the shoe portion of the core sampler. 
     
     
         15 . The core sampler as recited in  claim 10 , wherein the distal end of the shoe portion comprises a tapered portion in which the outer surface of the shoe portion is inwardly tapered relative to the longitudinal axis of the core sampler moving along the longitudinal axis of the core sampler toward the opening of the distal end of the shoe portion. 
     
     
         16 . The core sampler as recited in  claim 15 , wherein the tapered portion of the distal end of the shoe portion is inwardly tapered relative to the longitudinal axis of the core sampler at an angle of about fifteen degrees or less. 
     
     
         17 . The core sampler as recited in  claim 11 , wherein the liner has a radial thickness, and wherein the combined thickness of the liner and the tube portion is at least about twice the thickness of the shoe portion. 
     
     
         18 . The core sampler as recited in  claim 14 , wherein the shoe portion and the tube portion of the core sampler each have a substantially annular cross-sectional shape along the longitudinal axis of the core sampler, wherein the shoe portion has an inner diameter defined by the inner surface of the shoe portion, wherein the tapered portion of the distal end of the tube portion is spaced a selected distance from the distal end of the shoe portion, and wherein the selected distance by which the tapered portion of the distal end of the tube portion is spaced from the distal end of the shoe portion is between about 1.0 and about 2.0 times larger than the inner diameter of the shoe portion. 
     
     
         19 . The core sampler as recited in  claim 10 , further comprising an adapter operatively coupled to the proximal end of the tube portion, wherein the adapter is configured for operative coupling to a drill string component. 
     
     
         20 . A core sampler for advancement within a geologic formation to obtain a core sample, the core sampler having a longitudinal axis, the core sampler comprising:
 a shoe portion having an inner surface, an outer surface, a proximal end, and an opposed distal end, the inner surface of the shoe portion defining a central bore surrounding the longitudinal axis of the core sampler and extending between the proximal end and the distal end of the shoe portion, the distal end of the shoe portion defining an opening in communication with the central bore and configured to receive the core sample, the shoe portion having a thickness corresponding to the radial distance between the inner surface and the outer surface of the shoe portion, the distal end of the shoe portion comprising a tapered portion in which the outer surface of the shoe portion is inwardly tapered relative to the longitudinal axis of the core sampler moving along the longitudinal axis of the core sampler toward the opening of the distal end of the shoe portion;   a tube portion having an inner surface, an outer surface, a proximal end, and an opposed distal end, the distal end of the tube portion being secured to the proximal end of the shoe portion, the inner surface of the tube portion defining a central bore surrounding the longitudinal axis of the core sampler and extending between the proximal end and the distal end of the tube portion, the tube portion having a thickness corresponding to the radial distance between the inner surface and the outer surface of the tube portion;   an adapter operatively coupled to the proximal end of the tube portion, wherein the adapter is configured for operative coupling to a drill string component; and   a check valve positioned within the adapter and in operative communication with the central bore of the tube portion of the core sampler,   wherein the thickness of the tube portion is greater than the thickness of the shoe portion.