Though he had to deploy forces along the border with KSA as a defensive action at the very least. He was certainly tricked into thinking Kuwait would be invaded from the sea, but he cannot put all his forces on or inland from the coast and pay no heed to the long border with KSA. The battle of Khafji was, IMO, an incursion designed to throw co-alition forces off balance and to show that he was in fact willing to engage in real fighting, not just blowing hot air. But with no effective airforce, EW capability and crap equipment in general, he never had a chance of holding Kuwait, let alone marching into KSA with serious intent of invasion once the boots were on the line in the sand.
At the very start he probably thought that a quick and successful invasion of Kuwait would present a fait accompli, and while there would be a lot of screaming and shouting, sanctions and stuff like that, he would at the end of the day retain Kuwait. Compared to taking KSA, Kuwait is nothing, as it proved, so best to do the main job first and mop up Kuwait later, but as that did not happen, I don't think he ever intended to take on KSA, except if the response to Kuwait was weak, but was that ever going to be a thing, letting him take that much oil, no.