I would suggest actually reading the book before criticising its premise. Basically, it's a calculated gamble on the part of the USSR. They need oil, ergo, they need to take the mideast's oil by invasion. It's assumed that the NATO nations won't sit still for ian invasion of the mideast, ergo they need to knock NATO out before they can turn to the mideast. Destroy your worst enemy first, then turn at your leisure to the mideast without western interference.
Umm, where have we seen this historically...? How about Japan's strategic calculations leading to war with the US in WW2. Spend oil temporarily in order to gain access to much greater loads of it, when the US cuts off oil supplies to the Japanese pre-war.
As for the single refinery, it's actually an pipeline hub as well as the refinery, and supposedly the largest in the USSR.
Suspension of disbelief, yes, but not nearly so much as you make out.