Jar device for use in coil tubing drilling

Abstract

The invention relates to a jar operated by fluid pressure, specially designed for use in drilling or maintenance operations carried out in oil or gas wells. The jar comprises a first ( 1 ) and a second ( 2 ) end piece, where the second end piece ( 2 ) comprises a jar shoulder ( 15 ), an inner, cylindrical string part ( 8 ) connected to a valve head ( 9 ) with a first valve surface ( 14 ), and to a weight ( 12 ), an outer, cylindrical string part ( 17 ), arranged axially movably to the inner cylindrical string part ( 8 ), and comprising a second valve surface ( 30 ), which is arranged to go into abutment against the first valve surface ( 14 ) on the valve head ( 9 ). The jarring function is achieved by the inner string part ( 8 ) and thereby the weight ( 12 ) being set in axial motion and striking the shoulder ( 15 ).

1 . A jar operated by liquid pressure, specially designed for use in drilling or maintenance operations carried out in oil or gas wells, characterised in that it comprises
 a first ( 1 ) and a second ( 2 ) end piece, where the second end piece ( 2 ) comprises a jar shoulder ( 15 ),   an inner, cylindrical string part ( 8 ) connected to a valve head ( 9 ) with a first valve surface ( 14 ), and to a weight ( 12 ),   an outer, cylindrical string part ( 17 ), arranged axially movably to the inner cylindrical string part ( 8 ), comprising a second valve surface ( 30 ), which is arranged to go into abutment against the first valve surface ( 14 ) on the valve head ( 9 ),   where jarring function is achieved by the inner string part ( 8 ) and thereby the weight ( 12 ) being set in axial motion and striking the shoulder ( 15 ).   
   
   
       2 . A jar according to  claim 1 ,
 where the outer cylindrical string part ( 17 ) is concentrically enclosing the inner cylindrical string part ( 8 ).   
   
   
       3 . A jar according to one of the  claims 1 - 2 ,
 where the outer cylindrical string part ( 17 ) is further provided with openings ( 23 ).   
   
   
       4 . A jar according to one of the  claims 1 - 3 ,
 where on the valve head ( 9 ) there is mounted a sealing element ( 20 ) for abutment and flexible sealing against the shoulder ( 19 ).   
   
   
       5 . A jar according to one of the  claims 1 - 4 ,
 where between the inner ( 8 ) and the outer cylindrical string parts ( 17 ) there are provided openings ( 16 ,  29 ) for opening and closing ofthrough-flow.   
   
   
       6 . A jar according to one of the  claims 1 - 5 ,
 further comprising an outer, cylindrical casing ( 3 ,  4 ,  5 ) connected between the first ( 1 ) and the second ( 2 ) end piece.   
   
   
       7 . A jar according to  claim 6 ,
 where the outer cylindrical casing ( 3 ,  4 ,  5 ) comprises a first casing element ( 5 ) connected to a spacer ( 4 ), further connected to a second casing element ( 3 ).   
   
   
       8 . A jar according to  claim 4 ,
 designed to cause opening of the first valve surface ( 14 ) to approximately coincide with closing by the sealing element ( 20 ).