MINOT, N.D. ( TheStreet) -- The biggest concern for potential investors in the Bakken Shale oil-producing region of western North Dakota is: "How long will it last?"Judging from the huge amount of explorative drilling and infrastructure building going on and witnessed in a tour of the region, most of the world's leading oil industry firms are here to stay, given estimates there's at least a 30-year window of prosperity. A big lure is that it is a "can't miss" oil field, as the odds are that an explorative well will be productive are 98%. Local experts say this oil play is more like "mining" rather than "wildcatting" where historically the odds were one-in-three that a well would come in. A completed Bakken well, which has an average life of 29 years, generates $22 million in net profit over its lifetime, according to the North Dakota Industrial Commission's Oil and Gas Division. The wells here, which use the hydraulic fracturing or "hydro-fracking" technology, cost about $8.5 million on average to drill and complete, with break-even pricing linked to market prices at $55 to $70 per barrel. Bakken oil is a light, sweet crude that should be able to replace some of the expensive North Sea and West African crudes that make up some of the U.S. supply. It recently traded at about $10 to $15 below the benchmark West Texas Intermediate (WTI) market price, which was at $95 for October delivery and has averaged about a $17 per barrel discount to the North Sea Brent benchmark crude recently. There are 209 wells active now, and given the current pace of wells coming on line, it is estimated there will be about 2,250 within a few years, which means there will be $19 billion spent by exploration and production companies to reach that level, according to state estimates. The lure is the ready source of oil and natural gas available in the Bakken Shale reserve. A conservative estimate by the federal government is that it holds 4.3 billion barrels of oil, but other assessments peg it much higher. North Dakota officials say the state has already jumped into second place, behind only Texas, in terms of oil production among contiguous U.S. states, with an average daily production of 650,000 barrels.