a containment valve assembly using the upcoming pressures to control the flow of oil / gas through a riser pipe with a stop flow plug positioned within the valve housing that has an outer surface shaped to fit within and against the riser pipe , and an inner socket cavity having a conical nose receiver portion with a relief vent allowing the oil / gas to escape through the valve assembly , when desired . the stop flow plug is shaped to fit within the inner socket cavity and moves between an open position and a closed position , wherein the stop flow plug fits securely against the conical nose receiver portion , sealing the relief vent . at the top of the valve , a nut will lock the stop flow plug to the close out plate for additional stoppage . a second embodiment adds a heavy duty insert to supplement the sealing pressure , when needed . electronic monitors convey data remotely .