If we look at the international petroleum industry, most of the technical people have moved beyond the barrel. We used cubic meters or tonnes in our calculations.

However, we Canadians often convert the price to "$$ per barrel" to make historical comparisons of price changes. That price, between $10 to $200, is an easier figure for average people to relate to, plus the cultural significance.

I believe it is only in the USA where barrels are used in engineering and geological calculations.