The Iraq-Kuwait war was settled 20 years before the Iraq invasion. So to answer your question Iraq invaded Kuwait for the same reasons U.S invaded Iraq: oil. Thus the reason we have a U.S invasion of Iraq, not a U.S-Iraq war.

The pretext of invasions were different though. Busch said it was because Saddam was evil and had weapons of mass destruction. Saddam was more decent in its allegations and said Kuwait was stealing Iraqi petroleum through slant drilling.

Btw Saddam Hussein regime was "created" by the US and the UK...