Earthstone Energy (formerly Basic Earth Science Systems) taps into some of Planet Earth's basic energy sources --  oil and gas. It is involved in exploration, production, operation, and development activities, exploiting crude oil and natural gas assets in Colorado's Denver-Julesburg Basin, the Williston Basin of Montana, North Dakota, and along the Gulf Coast. The company drills about 48 net wells a year and has proved reserves of 638,000 barrels of oil and 936 million cu. ft. of gas. Most of Earthstone Energy's productive wells are in Montana, North Dakota, and Texas. The company acquired Lynden Energy in 2016.