In the event wellhead integrity is lost, the uncontrolled flow of hydrocarbons could risk life, property and the environment. To prevent this risk subsurface safety valves can be used to control the well below the wellhead. Conventional surface controlled subsurface safety valves (SCSSV) are used to control the production tubing. However, often the annular space between the tubing and casing contains large quantities of gas directly below the wellhead1 . An annular control (AC) safety valve is a surface controlled subsurface safety valve which allows annular flow when open but provides a barrier below the wellhead when closed. When the AC safety valve is used with a conventional SCSSV it can provide overall well safety.
The scope of this paper is to identify, review the design and summarize testing of the components that comprise an annular control safety system.