This picture shows a block valve on the right of the wellhead.  The field is injecting CO2, and as a result of the increased pressure, some wells are flowing on their own even when pumpjacks are stopped.  In order to allow the control center to shutdown a flowing well remotely, the block valve is wired into the pump controller.  Initially, the producer followed the advice of a third party engineering firm, and installed third party RTUs that were not capable of pump control.  Those are now being replaced with DrSCADA pump controllers that produce much greater value in pump management.  The DrSCADA P700 pump controller can not only stop the pumpjack and close the block valve to ensure that the well is not producing, but also monitor and control rod loading and measure pump efficiency when the pump is running.