Safty valve ,DST tools

Safety Valve Features & Benefits: Subsurface safety valves Subsurface safety valves are an integral part of the well completions that protect production installations against uncontrolled flow from producing wells in case of catastrophic damage to wellhead equipment. A subsurface safety valve must be pressure-equalized above and below the flapper before opening. The self-equalizing mechanism allows shut-in pressure below the valve to be vented to the tubing above the flapper.