Shock inducement in core barrel assembly

Abstract

A core barrel assembly for a drill string comprising a core barrel, an inner tube assembly removably positionable within the core barrel, and a mechanical shock inducement mechanism for inducing at least one shock, and preferably a plurality of shocks, in the inner tube assembly. This induced shocks help reduce occurrences of blockage of core samples entering the inner tube assembly in fractured or brittle rock formations.

1 . A core barrel assembly for a drill string comprising:
 a core barrel;   an inner tube assembly removably positionable within the core barrel; and   a mechanical shock inducement mechanism for inducing at least one shock in the inner tube assembly.   
     
     
         2 . The core barrel assembly according to  claim 1 , wherein the mechanical shock inducement mechanism induces a plurality of shocks to the inner tube assembly. 
     
     
         3 . The core barrel assembly according to  claim 1 , wherein the mechanical shock inducement mechanism is actuated and coupled to a rotation of a drill string. 
     
     
         4 . The core barrel assembly according to  claim 1 , wherein the mechanical shock inducement mechanism is actuated by an electrical power source. 
     
     
         5 . The core barrel assembly according to  claim 1 , wherein the mechanical shock inducement mechanism is actuated by a pneumatic source. 
     
     
         6 . The core barrel assembly according to  claim 1 , wherein the mechanical shock inducement mechanism is actuated by drilling fluid circulating under pressure within the drill string. 
     
     
         7 . The core barrel assembly according to  claim 1 , wherein the mechanical shock inducement mechanism is integrated with the inner tube assembly. 
     
     
         8 . The core barrel assembly according to  claim 1 , wherein the mechanical shock inducement mechanism is integrated with the core barrel assembly. 
     
     
         9 . The core barrel assembly according to  claim 6 , wherein the mechanical shock inducement mechanism comprises a hammer element being actuated and impacting the inner tube assembly upon attainment of a built-up drilling fluid pressure within the drill string and wherein the built-up drilling fluid pressure is attenuated upon impact of the hammer element onto the inner tube assembly. 
     
     
         10 . The core barrel assembly according to  claim 3 , wherein the mechanical shock inducement mechanism comprises a sliding sawtooth clutch mechanism, and further comprises a spring that is compressible by backward movement of the inner tube assembly upon an occurrence of blockage in the inner tube, the backward movement of the inner tube assembly causing the sliding sawtooth clutch mechanism to engage and to repetitively impact the inner tube assembly, the impacts combined with the compression of the spring pushing the inner tube assembly back into an original position. 
     
     
         11 . The core barrel assembly according to  claim 6 , wherein the mechanical shock inducement mechanism comprises a turbine assembly, wherein drilling fluid circulating under pressure within the drill string actuates the turbine assembly thereby causing the turbine assembly to repetitively impact the inner tube assembly. 
     
     
         12 . The core barrel assembly according to  claim 11 , wherein the turbine assembly comprises an eccentric feature. 
     
     
         13 . The core barrel assembly according to  claim 11 , the turbine assembly repetitively impacts the inner tube assembly upon an occurrence of a blockage within the inner tube assembly. 
     
     
         14 . The core barrel assembly according to  claim 1 , wherein the mechanical shock inducement mechanism comprises a hammer element being actuated and impacting the inner tube assembly upon an occurrence of a blockage within the inner tube assembly.