What do we mean by "unconventional gases"?
Non-conventional gases

Physically and chemically, unconventional gas is of the same nature as conventional gas: most of it is methane, commonly referred to as "natural gas" .

The classification of a gas in one category or another depends on the conditions under which it is formed and accumulated, and whether the reservoir is exploited conventionally or unconventionally.

The oil industry calls conventional gas deposits those contained in permeable rock, which are relatively easy to exploit. It calls all others unconventional, and the boundary...