He invaded Kuwait because he wanted to expand his oil reserves and make Iraq the dominant power in the region. However. the invasion of Kuwait was the consequences of the Iraq -Iran war. Iraq was greatly in debt after the conflict and so countries like Kuwait refused to write off Iraq loans. As a result Saddam invaded Kuwait for money and to expand the oil reserves. Saddam did that by claiming that Kuwait was producing way too much oil,flooding the market, therefore lowering the oil prices their for harming the Irag economy eve more.
:)