This paper attempts to outline the principal criteria relevant to the selection of a surface controlled subsurface valve for a known application. Since the sub-surface safety valve is arguably the most important element of any completion, careful consideration should be given to its selection: this is especially true of an offshore installation since the safety the effective performance of this valve. The considerations and parameters discussed in this paper cover valve type and design options whilst keeping paper cover valve type and design options whilst keeping in mind constraints imposed by well conditions, production requirements and safety philosophies.
The primary function of the downhole safety valve in a well is to contain that well in a safe condition in the event of a catastrophe, any other attributes must be considered as secondary. This philosophy must be rigorously applied not only to the selection of the valve itself, but also to ancillary items such as locking mandrels, landing nipples, service tools, control lines etc. Virtually all of the offshore operators and regulatory bodies around the world today specify the use of hydraulically actuated, surface-controlled sub-surface safety valves (SSSV) which in most cases interface with the platforms emergency shutdown system-the scope of this paper will therefore be confined to such surface controlled valves and furthermore is limited to discussion of valves which are currently in common use.
