You didn't know that?
Although Iraq had considerable oil reserves of her own, revenues were not sufficient to meet the demands of her creditors. This problem was exacerbated in 1990 when Kuwait and other oil states began to lower oil prices and increase production beyond agreed upon levels. Iraq was forced to follow suit or lose even more revenues. To make matters worse, Iraq suspected the Kuwaiti's were drilling diagonally from their side of the border to tap Iraqi oil reserves.
indepthinfo.com
I'm surprised you aren't aware of the root causes of the Gulf War. For more info, try this Google search: "Gulf War" kuwait "slant drilling"