FLOW STOP VALVE

摘要

A flow stop valve (120) positioned in a downhole tubular (6), wherein: the flow stop valve (120) is in a closed position when a pressure difference between fluid outside the downhole tubular (6) and inside the downhole tubular (6) at the flow stop valve (120) is below a threshold value, thereby preventing flow through the downhole tubular; and the flow stop valve (120) is in an open position when the pressure difference between fluid outside the downhole tubular (6) and inside the downhole tubular (6) at the flow stop valve (120) is above a threshold value, thereby permitting flow through the downhole tubular (6).