Can you explain in a precise way the difference between conventional and unconventional? A woman having a career was not long ago considered unconventional. Some people might say body art and piercings are unconventional today, but this has always depended on the culture.
When we use words like good and bad, tall and small we generally know what we mean. But do we know specifically enough to use them in policy or legal documents?
It turns out Canada’s top experts; the Canadian Society for Unconventional Resources (CSUR) can’t explain precisely the difference between conventional and unconventional either. CSUR uses a surrogate definition. They say if an oil and gas reservoir requires frac’ing then it unconventional. Though they freely admit this also creates anomalies.
For example, a low permeability rock that is naturally fractured is conventional but the exact same rock not fractured by nature is unconventional. More perplexing, due to variability in permeability the exact same reservoir can require frac’ing in some places and not others. Is it conventional or unconventional or can it be both? What about a reservoir that flows naturally but flows better with frac’ing?
Even the word shale is not that precise. Technically shale is clay metamorphosed in to rock. However, for just two examples: the Montney is primarily silt but referred to as a shale and the key interval in the Utica is primarily carbonate and mudstone but is still referred to as the Utica Shale. Today shale is commonly used to describe any small grain sized rock. There is that word small again. How small does the grain size need to be to be referred to as shale? Answer: ‘pretty darn small’.
Can we at least agree the Utica is unconventional? Not really. We were originally looking for naturally fractured rock and there is plenty of that in the Quebec Utica. So it can be both conventional and unconventional by the CSUR definition.
It turns out whether a type of rock is conventional or unconventional is not a concept recognized by Mother Nature, who loves all rock equally. And, the methane produced by nature that comes out of rocks is all the same. We have many different names: coal gas, deep gas, tight gas, bio-gas, shallow gas, liquids rich gas, solution gas, and shale gas to name a few. But it’s all natural gas no matter what rock it comes out of, frac’ed by nature or by man or not at all.
In truth, in industry, we no longer find the terms conventional and unconventional of much practical use. The unconventional reservoir of yesterday is simply not very unconventional today. Just the opposite: unconventional is the new conventional. Who knows; body art and piercings may not be far behind.