A new kind of horizontal well has emerged from an experiment in North Dakota’s Bakken and Three Forks shales. It uses an uncemented slotted liner to produce hydrocarbons by intercepting fractures that originate from offset wells. Hess Corp. revealed the concept over 2 years ago, confirming at an SPE conference that crude was flowing from the pilot well. The New York City-headquartered oil company also announced that additional trials were in progress, though it withheld specific production figures. The wait for those key details is now over. At the recent Unconventional Resources Technology Conference (URTeC) in Houston, Hess presented its first technical paper on the augmented drainage development (ADD) pilots which it claims have proven the approach to be, at the very least, a technical success. In URTeC 4044110, the company’s authors underlined their optimism in noting that ADD wells “could lead to a step change in productivity and recovery in unconventional developments.” Hess acknowledges that economic and technical hurdles currently stand in the way of that vision. But the upbeat assessment is backed by impressive production data from its inaugural pilot launched in 2021. Placed about 240 ft between two actively stimulated Middle Bakken wells, the first drainage well exceeded expectations, averaging nearly 1,700 B/D of crude in the first 8 days of flowback. Output fell to about 1,500 B/D over the next few days as the nearest actively stimulated well—called a “standard well” by Hess—began its flowback. This was one of several confirmations that the wells were in direct communication. “A lot of bets were lost on this well—maybe not by me, but by a lot of people,” remarked Craig Cipolla, a principle completions engineering advisor for Hess. Cipolla presented the company’s findings at the conference this past summer. He said the ADD well also pumped out about as much frac sand as is seen in a typical shale well, which in addition to tracer data, verified that it was well propped. During the initial production period, the first ADD well achieved about 85% of the output of the offsetting standard wells on the pad. Although this figure eventually dropped to just over 40% over the next 2 years, it was enough for Hess to consider the concept validated. Based on the results from all three pilots, Hess estimates ADD wells in the Bakken can be expected to achieve 10 to 45% of the output of typical hydraulically fractured horizontal wells. On the low end, the oil recovered from distant and low-conductivity fractures likely won’t justify drilling even a wellbore as barebones as the ADD concept calls for. Conversely, if a drainage well produces too much oil it is a sign that well spacing is too tight and that it is overly competing for resources with more-expensive offsets. This is likely the story of why the first ADD well came on so strong.