The time of low-cost oil and gas is at an end and the world is entering a stage where finding resources will be more "complex" and require more money and investment, according to the head of Europe's biggest oil company.

Peter Voser, chief executive of Royal Dutch Shell, said the longer-term trend was for higher costs. "In the longer-term, you will clearly need higher oil and gas prices, or energy prices."

Mr Voser was speaking as Shell unveiled second-quarter profits of $8bn, an increase of more than 77 per cent from the same period the year before, buoyed by higher crude prices of more than $110 a barrel.

Excluding one-off items, the current cost of supply income, a measure that strips out the value of inventory, was $6.6bn - the highest earnings for the second quarter since Shell's record year in 2008 when it earned $8.6bn in the same period. First contributions from its new flagship projects in Canada and Qatar also buoyed earnings.

David Fuller's view The global supply / demand picture for oil and gas remains tight as the Asian-led growth economies require ever more energy; Japan and Germany use less nuclear power, and there are no petroleum exports from Libya for an indefinite period.

Against this background another global recession would be required to significantly lower oil and gas prices. The most likely trigger of another recession, in my opinion, is something which very few people are talking about today - another spike in oil prices (Brent & WTI). We saw the economic damage this helped to cause in 2008 and again this year following crude oil's smaller spike. There are also earlier examples from the 1970s and 1980s.

Interestingly, oil & gas are cheaper in the USA today than in most other major economies. This is due to the USA's pioneering of shale gas and shale oil production. When this technology is used extensively on a global basis - this may take 12 to 15 years - Fullermoney maintains that gas and oil prices will be less than they are today, in real (inflation-adjusted) terms.

Royal Dutch Shell (monthly, weekly & daily) remains the second largest holding in my personal long-term investment portfolio. I will certainly hold on to this position which currently has a PER of 8.3 and yields 4.62%.