Jarring Tool

Abstract

A jarring tool that includes a first portion and a second portion. An impact point is located between the first portion and the second portion. The jarring tool has an internal energy source that generates an internal force to move one of the portions or an inner mass to cause a jarring force.

What is claimed is: 
     
         1 . A method for operating a jarring tool in a wellbore, wherein the method comprises:
 conveying a tool string and the jarring tool in the wellbore on a conveyance;   activating the jarring tool to generate an internal force; and   augmenting the internal force by applying tension to the conveyance.   
     
     
         2 . The method of  claim 1 , wherein an operational mode of the jarring tool is set prior to conveying the tool string and the jarring tool. 
     
     
         3 . The method of  claim 2 , wherein the jarring tool has three operation modes. 
     
     
         4 . The method of  claim 3 , further comprising sending a signal from surface to the jarring tool to change the operation mode of the jarring tool. 
     
     
         5 . A jarring tool comprising:
 a first portion;   a second portion; and   an impact point located between the first portion and the second portion.   
     
     
         6 . The jarring tool of  claim 5 , wherein one of the portions is configured to move relative to the other and engage the impact point to cause a jarring force. 
     
     
         7 . The jarring tool of  claim 5 , further comprising a mass located within one of the portions, wherein the mass is configured to move and strike the impact point to generate the jarring force. 
     
     
         8 . The jarring tool of  claim 6 , wherein an energy source is activated to cause the movement of one of the portions. 
     
     
         9 . The jarring tool of  claim 7 , wherein an energy source is activated to cause the mass to move. 
     
     
         10 . The jarring tool of  claim 5 , further comprising a selector in one of the portions for allowing selection of an operation mode of the jarring tool. 
     
     
         11 . A selectable force jarring tool comprising:
 a first portion;   a second portion;   an impact point located between the first portion and the second portion;   an energy source located within one of the portions;   a selector in one of the portions; and   communication equipment in communication with the selector, wherein the communication equipment is configured to allow remote selection of an operation mode of the jarring tool.