in the ball catcher of the targeted valve 14 the ball significantly restricts if not seals off the central passageway of the string 12 below the ball so that fluid pressure may be applied above the ball to generate a force to cause the valve to open as further described below as a more specific example a ball may be dropped from the well 39 s surface into the central passageway of the string 12 for purposes of opening a previously unopened valve 14 n that has previously been placed in a ball catching state in response to the fluid pressure that is applied to the resultant restricted central passageway the valve 14 n opens to allow a fracturing operation to be performed on the associated layer 15 n the opening of the valve 14 n in turn places the next valve 14 n u2212 1 in the sequence in the ball catching state once the fracturing operation on the layer 15 n is complete another ball is dropped into the central passageway of the string 12 for purposes of opening the valve 14 n u2212 1 so that the layer 15 n u2212 1 can be fractured thus this sequence continues until the last valve 14 1 is opened and the associated layer 15 1 is fractured as a more specific example in accordance with some embodiments of the invention fig2 and 3 depict upper 14 a and lower 14 b sections of an exemplary valve 14 that is closed and has not been placed in ball catching state i e the valve 14 is in its initial states when run into the well thus as depicted in fig2 and.