A flow control system includes a pump positioned in a well to remove liquid from the well. An isolation device having a valve body and a valve spool is positioned downhole of the pump. The valve spool is rotatably received by the valve body and is capable of rotating between an open position and a closed position. During removal of the liquid from the well, the valve spool is in the closed position to substantially reduce fluid flow past the valve spool and thus gas interference at the pump.