A very short USIP commentary 'Regional Security Lessons from the Attack on Algeria's In Amenas Gas Plant', which draws attention to:
average annual attacks on energy infrastructure have risen from slightly more than 200 worldwide during 1980-99 to 380 over the last decade, 2000-11.

Not only do attacks tend to cluster in certain regions, they also occur in waves. The crests of these waves tend to correspond with flashpoints of instability that are characterized by localized ‘bursts’ of violence aimed at energy infrastructure. Algeria and the Maghreb are not peculiar in this regard. Other recent waves and clusters could be identified in Colombia, Iraq, Pakistan, Afghanistan, Nigeria, and Russia.
Four lessons:
Four important lessons can be gleaned from USIP's project on the vulnerability of energy infrastructure. First, attacks on energy facilities historically occur in 'waves,' and we might be at the start of one such wave in the Maghreb and the Sahel. Second, attacks are likely to cluster around natural gas and oil installations because they are often far removed from major administrative centers and because they provide a wide variety of high-value targets.

Third, the interconnected nature of causes demands an examination of the people, equipment and virtual networks that support energy operations. This will help tailor solutions to fit the local context. Fourth, violent non-state actors are less likely to be homogenous groups with a singular focus.
Link:http://www.usip.org/publications/reg...enas-gas-plant

USIP are IMHO a long way behind the "oil majors" in thinking about the issues, the "majors" have long had facilities in vulnerable areas, which has included Algeria for at least twenty years. Somehow I doubt the "majors" or insurers will comment preferring discretion and commercial confidentiality.