Subsurface safety valve

The figure on the right shows the well with a simple well completion including a production tubing with packer, a series of surface safety valves called a Christmas tree, a subsurface safety valve (SSSV), a circulating sleeve, and a series of perforations through the casing. 

Failure and Inventory Reporting System Offshore Oil and Natural Gas 8,000 failure events and causes Inventory data on ASME coded devices Safety and pollution prevention devices on offshore structures, eg. subsurface safety valves 72. 

American Petroleum Institute (API), Spec 14A. Specification for Subsurface Safety Valve Equipment. Eighth Edition, API, Washington, D.C., 1994. 

A minimum of equipment at each wellhead is used lo reduce the exposure to leaks. No separation or metering is done in the field. All flowlincs arc designed to withstand 5,200 psi, which is in excess of wellhead shut-in pressure. Double master valves are installed on each wellhead, one serving as the surface safety valve activated by low flowline pressure or activated remotely from either of two manual emergency shut-in stations. Each well also has a subsurface safety valve. 

Safety considerations (increased risks resulting from concentrating storage capacity in a small number of large facilities), as well as performance reasons (the flow is limited by pressure loss in the wells) made it appear that the maximum possible volumes (400,000 - 600,000 m3) had been reached in Europe where well diameter is limited by the installation of a buried blow-out preventer (SSV for Subsurface Safety Valve). 

Damage of downhole safety /well control components. Solids can erode and destroy subsurface safety valves. Failure of these well safety devices can result in uncontrolled production situations with tremendous consequences, such as loss of life or large economic losses. 

American Petroleum Institute (API). RP 14A, Specification for subsurface safety valve equipment. 11th ed. Washington, DC API 2012 [Reaffirmed]. 

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