what's driving the oil majors?

What's driving the oil majors?

I assume that the answer to the question as to what is driving the oil majors when considering take over bids of smaller players is straight forward. Their future viability depends on their ability to access resources. I found the statistics on this website interesting.

http://www.petrostrategies.org/Links/Worlds_Largest_Oil_and_Gas_Companies_Sites.htm

Have a look a the reserves by company. If you compare the likes of Shell, Chevron, Mobil etc with the national companies in Saudi Arabia, Iraq, Iran etc then the Shells of this world possess rather modest reserves.

Putting some perspective on the numbers.
1.Shell's reserves oil and gas reserves at around 10.8 billion barrels of oil equivalent are similar to that of Oman (Petroleum Development Oman). Oman is regarded as a small player in the middle East.
2.The world yearly consumption of natural gas and oil is approx 50 billion barrels of oil equivalent (2008 estimate). (ref http://www.bp.com/liveassets/bp_internet/austria/corporate_austria/STAGING/local_assets/downloads_pdfs/0_999/20090709_statistical_review_of_world_energy_full_report_slidepack_2009.pdf

If my calculations are correct Shell's reserves are only about 22% of the annual world consumption.

Again if my calculations are roughly correct, I would have thought that the oil majors like Shell, Chevron, Mobil etc would be pulling out all stops to increase their reserves. Shell for example talks about a 20 to 30 year planning horizon.

If they are serious about such a long planning horizon then the acquisition of companies like Arrow makes sense to provide resources for the medium term.

A question struck me. I wonder why Shell doesn't go for a handful of promising CSG exploration companies like BUL and ROG (I know about these as I have shares in these companies). They could be bought out for a song relative to what they have to pay for companies with proven reserves, and only a few would have to prove themselves to make these acquisitions worthwhile (in my opinion).

Any thoughts?

I have attempted to be careful with my calculations, but could have made errors.