Jar device

Abstract

A jar for use in a downhole environment comprises a mandrel, a spline body, and a tool body, where the spline body provides a slideable engagement with the mandrel and anvil surfaces for absorbing the impact of the mandrel when the jar is fired, thereby providing a jar with no threaded connections in the impact path on a strong, one-piece mandrel.

1 . A jar comprising 
 an annular tool body, comprising an interior,    an annular spline body, comprising an exterior, wherein said spline body is in mechanical engagement with said annular tool body and wherein said interior of said annular tool body is in fluid communication with said exterior of said annular spline body, and    a mandrel, in slideable and essentially non-rotatable engagement with said spline body.    
     
     
         2 . The jar of  claim 1 , wherein said spline body additionally comprises a fluid channel.  
     
     
         3 . The jar of  claim 2 , wherein fluid communication between said interior of said annular tool body and said exterior of said annular spline body occurs via said fluid channel.  
     
     
         4 . The jar of  claim 1 , wherein said annular spline body comprises an inner surface, and wherein said inner surface comprises a plurality of spline slots.  
     
     
         5 . The jar of  claim 4 , wherein said mandrel is held in engagement with said spline body by splines in said spline slots.  
     
     
         6 . The jar of  claim 1 , wherein said mandrel comprises a plurality of spline troughs.  
     
     
         7 . The jar of  claim 1 , wherein said mandrel is held in engagement with said spline body by splines in mechanical engagement with said spline body.  
     
     
         8 . The jar of  claim 6 , wherein said mandrel is held in engagement with said spline body by splines in slideable engagement with said spline troughs.  
     
     
         9 . The jar of  claim 1 , wherein said annular spline body comprises an inner surface, and wherein said inner surface comprises a plurality of splines.  
     
     
         10 . The jar of  claim 9 , wherein said mandrel is held in engagement with said spline body by said splines.  
     
     
         11 . The jar of  claim 1 , wherein said spline body comprises a plurality of separable sections.  
     
     
         12 . The jar of  claim 11 , wherein said spline body additionally comprises a fluid channel.  
     
     
         13 . The jar of  claim 12 , wherein fluid communication between said interior of said annular tool body and said exterior of said annular spline body occurs via said fluid channel.  
     
     
         14 . The jar of  claim 13 , wherein said annular spline body comprises an inner surface, and wherein said inner surface comprises a plurality of spline slots.  
     
     
         15 . The jar of  claim 13 , wherein said annular spline body comprises an inner surface, and wherein said inner surface comprises a plurality of splines.  
     
     
         16 . The jar of  claim 1 , wherein slideable motion of said mandrel relative to said annular spline body is arrested in a first longitudinal direction by contact between said mandrel and said annular spline body.  
     
     
         17 . The jar of  claim 1 , wherein slideable motion of said mandrel relative to said annular spline body is arrested in a second longitudinal direction by contact between said mandrel and said annular spline body.  
     
     
         18 . The jar of  claim 14 , wherein slideable motion of said mandrel relative to said annular spline body is arrested in a first longitudinal direction by contact between said mandrel and said annular spline body.  
     
     
         19 . The jar of  claim 14 , wherein slideable motion of said mandrel relative to said annular spline body is arrested in a second longitudinal direction by contact between said mandrel and said annular spline body.  
     
     
         20 . The jar of  claim 14 , wherein slideable motion of said mandrel relative to said annular spline body is arrested in both a first longitudinal direction and a second longitudinal direction by contact between said mandrel and said annular spline body.