Continental Resources Inc, the second-largest North Dakota oil producer, spent $2.3 million at a state land auction for the right to explore for crude on 160 acres, outbidding its nearest rival with just seconds left on the clock. The deal, secured this week with a check to state officials, shows that despite the more-than 60 percent drop in crude prices since last summer, demand for oil-rich acreage in the state remains high.