It could be a starting point for you. It has data from all over the world but in the oil industry only.
http://www.spe.org/spe-site/spe/spe/career/salary_survey/08SalarySurveyH...

Better to wait the interview and see their offer. Anyhow, most likely you'll receive the offer few days/weeks after that and you'll have time to decide.

There are many posts on the QL about accommodation, schools and day bay day costs.