ABSTRACT
Unlike the offshore production industry, there are presently no regulations that dictate the use of subsurface safety valves in land completions. However, due to the increase in the number of fields moving toward CO2 injection as a means of tertiary recovery and the potential for injury or environmental damage, many producers have decided to install subsurface safety valves in their CO2 injection wells.
This paper will address why these wells need to be protected, discuss the parameters that must be considered in the selection of a tubing retrievable safety system and cover the unique features of the following types of safety valves.
Surface controlled
Flapper check
Fixed choke-velocity
Variable orifice-velocity
Pressure differential operated
An injection well safety system is necessary to shut-in the well in the event of a catastrophic failure such as accidental well head damage, injection line leaks or tubing separation. A catastrophic failure would result in the release of CO2, wellbore fluids and reservoir fluids possibly containing H2S.
