Abstract

This paper builds upon our industry's history of experimenting to learn/innovate (Fast 1952, Northrop et al. 1984, Fast et al. 1993, Warpinski et al. 1993, Cipolla et al. 2008, Raterman et al. 2017). We introduce the innovative concept of Augmented Drainage Development (ADD) and document the journey from first discovery to field trials. ADD is a process where un-cemented, open hole laterals are drilled contemporaneously between offset "standard" wells, using the ADD wells to "harvest" productivity from offset well hydraulic fractures. A "standard" well or "frac well" refers to typical development wells that use hydraulic fracturing to achieve economic productivity. Microseismic and fiber optic measurements and offset well fracture interactions confirm fracture half-lengths in the Bakken extend 1000 ft to 1500 ft. However, there is uncertainty in the efficiency of drainage between the far-field fractures and the laterals.

One important observation in the Bakken is that most Fracture Driven Interactions or FDIs result in increased parent well productivity. The positive impact of FDIs may be due to the un-cemented completions that are typical for most parent wells in the Bakken. This was a key observation that contributed to the discovery of ADD. Over the past 10 years, extensive field measurements were used to calibrate fracture geometry and reservoir simulation models. These models were the other piece to the ADD puzzle, enabling the evaluation of the ADD concept. The modeling suggested that there is a potential to "augment" drainage by placing open-hole laterals in between the standard wells prior to fracturing. This paper documents the "discovery process" from field observations to detailed modeling.

The first ADD well was drilled in 2021, about 300 ft from the nearest offset "standard" well. There were four "standard" wells on this pad and extensive data acquisition, with permanent fiber optics and lateral pressure gauges in two wells and deployable fiber in the other two wells. These measurements characterize the hydraulic fractures that intersected the ADD well. Upon flowback, the ADD well produced frac sand and higher than expected total fluid rates. With 2.5 years of production, the productivity of the ADD well is about 40% of the "standard" offset wells, validating the ADD concept. Two more ADD wells were drilled in 2022 to evaluate the limits of ADD productivity, confirming that ADD productivity decreases as distance increases from the offset standard wells. ADD could lead to a step-change in productivity and recovery in unconventional developments.

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