Until now, most shale gas and shale oil coverage in the media has been focused on the top end of town, especially in the way BHP Billiton splashed out with $US20 billion ($A19.5 billion) to make strategic investments in US shale plays.

And if the $US20 billion isn't enough for a decent headline, there is the $US60-80 billion said to have been earmarked by BHP Billiton for ongoing capital investment, as the big resource house carves out an entirely new division which has the potential to dominate its conventional oil operations.

Interesting as the BHP Billiton adventure in shale gas is, there is another aspect to the company's actions so far - it applied the lion's share of its interest in the US shale industry.

There are reasons for that, though one of them is certainly not the price of gas, which has plunged across the US as shale gas production has risen to both satisfy domestic demand and trigger plans for a start in exporting gas via terminals originally designed as gas import facilities.

Particularly appealing to BHP Billiton is the sheer scale of the US energy market and the vast infrastructure systems which include a myriad of pipelines linking the entire country.

Australia is different but there is also a US connection most people in the oil and gas game have forgotten - mainly because it led to multiple failures and played a role in the dramatic decline in the small end of the Australian oil exploration industry.

About 20 years ago, what had been a trickle of interest by Australian explorers in the US oil industry became a stampede.

Just as curious fashions can take off in the clothing and alcoholic drinks market (can anyone remember ultra-low alcohol beer?), it became important for every small explorer to have a US project.

What a disaster the US rush turned out to be.

Of the approximately 44 small Australian stock exchange-listed explorers to dash across the Pacific, only a handful survived in what now looks like a wipe-out of biblical proportions, with most "falling on stony ground" and disappearing - for a full-blown description of what it means to fall on stony ground, try Matthew 13:8 for the parable of the sower.

Not only did few of the small Aussies in the US ever discover anything but they also found the US dollar was falling rapidly, which meant they had to send increasing amounts of Australian dollars over to pay for exploration, just as the gas price started to tumble.

Today, if The Slug is reading the signs correctly, the small end of the Australian oil and gas industry has a chance to undergo a born-again experience thanks to the shale gas discovery and extraction technologies developed in the US.

First signs something big is developing in the small end of the business can be seen in a shortlist of which companies are leading the hunt for Australian shale gas, such as Beach, AWE, Buru, Norwest and New Standard, none of which fit the description of global player in the oil and gas industry.

But what the small companies can do is something that doesn't interest the bigger players.

They can focus on onshore exploration, often in remote locations and often with an interest in a discovery which will change their future, if not the future of the Australian oil industry.

In a classic example of growing an oak tree from an acorn, companies such as Buru and AWE are revisiting onshore gas discovery locations abandoned by the major explorers, those big companies that were able to switch exploration spending to the offshore search - to the parts of the world containing major gas accumulations but also prohibitively expensive for small explorers.

Discoveries are what are needed next for Australian shale to ignite a burst of interest in the onshore opportunities presented by formations of shale long regarded as too difficult and too remote.

Smaller companies, thanks to the move offshore by big oil, have a wonderful opportunity to blossom in a way they have not for decades.

It's too early to say the companies that lost their way in the great US oil and gas exploration adventures of the 1980s and ‘90s will re-emerge in the Australian shale gas hunt but it is possible to say the seeds have been sown.