Of course they did care about minerals. They cared about salt, gold, tin, copper, iron. Also about navigable seaports, sea passages, fertile land, forests, and also workforce. For these resources wars were waged all the time in the Middle ages.
Oil was not as valuable as nowadays, but it was a priced export used as lighting fuel, weapon component for Greek fire, and also as a drug for some health conditions since ~400 BC, and more so later. It was not the central fuel for the economy, but it was considered a valuable resource, though not one for which a war would be started probably.