Your kids are being sort of taught right, but not the complete story. The essence is right, the origin is off.
Petroleum is decayed organic matter that was, over time, converted by bacteria into its current (semi, in some cases) liquid form. Most of it is NOT decayed dinosaurs, but sea plankton. In Alberta's case (and also true of the Middle East, by the way), many many millions of years ago, the land was under water. When the tectonic plates shifted, the land mass was pushed up above sea level (the Rocky mountains were formed at the same time). The water eventually either drained off or evaporated, and the plankton that was in the ocean prior to the landmass rising, died off and started to decay. Eventually, the plankton got buried, and the bacteria in the soil began to convert the dead plankton into petroleum. In Alberta's case, the type of bacteria and the lower oxygen content caused the petroleum to have a lot of sulfur in the petroleum, so we have "sour" petroleum. In Texas (commonly called "West Texas Intermediate"/WTI) the sulfur content is lower, so it is "intermediate", and Saudi Arabian and North Sea (common name is Brent) petroleum have very low sulfur content, so it is called "sweet".
Fracking, as a technology has been around for 50 years or so. It is being used more often now as conventional oil wells begin to dry up. As well, when the world price of oil spiked up, that prompted companies to go after every little bit of oil that there was. A lot of the oil shale production is based on fracking, as the individual pockets of oil that are trapped in the shale are not worth drilling for. Before the world price of oil got high enough, there wasn't any money in trying to get the oil shale out, because conventional oil was priced so low. It is a higher cost of operation than the conventional oil, as not only do you have to do the fracking in the first place, you also need to separate out the oil from the bits of rock, and early on, the fracking mud as well.
Not arguing, just a discussion.