With regards to natural gas production, I would recommend that you take a look at this article form the oildrum.com

http://www.theoildrum.com/node/5323

Most of the NG production growth has come from unconventional shale wells where energy intensive fracturing has to be implemented. The decline rates on these wells can be extremely high (like greater than 20% per year). Given the recent collapse in rig utilization, I would expect a quicker recovery of natural gas than the "years" you mentioned. However, if I have learned anything from this recession, even when i think i know what I’m talking about, I usually don’t.