CREDO Petroleum Corporation was founded in 1978 and is headquartered in Denver, Colorado.CREDO Petroleum Corporation, together with its subsidiaries, engages in the acquisition, exploration, development, and marketing of oil and gas properties in the Mid-Continent and Rocky Mountain regions of the United States. CREDO Petroleum Corporation operates projects in Texas, central Kansas, Wyoming, Colorado, Louisiana, and North Dakota. CREDO Petroleum Corporation also involves in developing, testing, refining, and patenting its patented Calliope Gas Recovery System from wellbores using pressure differentials enabling gas previously trapped by fluid build-up in the wellbore to flow to the surface. As of October 31, 2009, CREDO Petroleum operated approximately 135 wells, as well as owned working interests in 350 producing wells and overriding royalty interests in approximately 1,200 wells.