Retailing, of the sort seen at service stations, which make a bigger profit from flogging confectionary than gasoline, has always seemed an odd branch of the petroleum business. However, it was one forced on oil companies by tight government regulation and price controls.

Far better, goes current oil-sector thinking, to get back to the basics of exploration and production, leaving the tricky bits such as dealing with mum and pop consumers to people who actually like that sort of thing - though goodness knows why they do.

Layer on top of this re-think about retailing and refining a fundamental shift in the outlook for the price of oil and the scene is set for a dramatic decade or two in the petroleum business and a few meaningful conversations at Australia's premier oil conference which kicks off in Perth today.

Most of the formal talks at the annual gabfest of the Australian Petroleum Production and Exploration Association will be about domestic matters such as the perennial complaint about falling oil output and rising taxes with a few new topics to mull over such as the entry of billionaire media baron and tractor salesman, Kerry Stokes, into the industry.

Meanwhile, in the wider world of oil and gas there are much more interesting things happening that will shape the industry for decades to come, such as:

• the overdue arrival of the great oil-price slide which has been hovering in the background since the U.S. re-discovered the joys of energy self-sufficiency
• the development of rival energy sources, and the rise of gas as a global transportable and tradeable liquid fuel, could be pointing to 50 years of cheaper energy, with dramatic consequences for the world, not just the oil industry
• the schism opening between E&P and other parts of the industry which will prove to be as significant as the divide between Catholics and Protestants in the Christian world, or Sunni and Shia in the Muslim world
• the impact on Australian oil and gas of a rising (not falling) exchange rate caused, somewhat amusingly, by the oil and gas industry itself - a sort of oily own goal
• the great asset sell-off that some observers reckon could lead to $US300 billion in surplus oilfields, refineries and service stations offloaded by oil majors over the next few years.

Taken collectively, the falling oil price, a return by big oil to its E&P roots, the rising value of the Australian dollar and the wholesale dumping of assets deemed not fit for future use and the dramatic nature of change underway can be seen.

Consider first the oil price, which, according to the now ignored theory of Peak Oil, is heading for $US75 a barrel, and perhaps lower.

The knock-on consequences of oil at $US75/bbl are profound, especially on countries such as Russia, Venezuela and Saudi Arabia, which had assumed $US100/bbl to balance their budgets.

Edward Morse, head of global commodity research at the US investment bank Citigroup sees $US75/bbl as a plausible average future oil price with the: "$US90/bbl floor on the world oil price over the next few years becoming a $US90/bbl ceiling".

It is the price outlook as much as anything else that is forcing oil companies to reconsider what it is that they do best - flog Mars Bars, or discover the production crude oil and natural gas.

No prize for guessing that oil companies are going back to their roots in a concerted effort to discover more, preferably low-cost oil and gas, while hunkering down for the chill winds which come with a major fall in the oil price.

Locally, the rising (not falling) Australian dollar is a result of the country's strong improvement in its trade balance, which flipped from deficit to surplus late last year and will get much stronger as a wave of LNG projects start shipping out gas rather than shipping in high-price capital equipment needed in their construction phase.

Then there is the world-wide oil sector sell-off that New York-based private equity specialist Carlyle Group reckons totals about $US300 billion, mainly of refining and infrastructure assets so the oil majors can re-allocate capital to E&P.

It is a remarkable set of events - falling (not rising) oil, a rising (not falling) exchange rate, a massive asset sell-off and the return of big oil to E&P investment - which is changing the way the oil industry looks and behaves.