the effectiveness of the operation additionally there is typically a limit to how much tension can be applied by some rigs hoists and a limit to the tensile rating of the drill string or another type of conveyance member however by using the overpull generator 100 in the wellbore 10 the overpull generator 100 enables these limitations to be circumvented by ensuring the necessary load is applied directly to the bottom assembly 200 additionally not only is it possible to generate a higher load but a known load can be applied based upon the known piston characteristics of the overpull generator 100 further when the overpull generator 100 is used in combination with downhole instrumentation and optional data communication e g wires em mud pulse the operational characteristics can be determined and then tailored to suit the situation in the wellbore 10 the overpull generator 100 is configured to create a force which is used by the other components in the bottom hole assembly 200 to dislodge the object 20 the energy is generated by moving a piston rod 110 of the overpull generator 100 between an extended position and a retracted position as shown in fig1 3 although the bottom hole assembly 200 in fig1 3 shows the overpull generator 100 in a downward position the overpull generator 100 may be in an upward position thereby reversing the direction of the actuation force and the release force without departing from principles of the present invention generally the overpull generator 100 includes a plurality of pistons 125 that activate due to a pressure drop in the.