Abstract
Only a small fraction of fracturing fluid is recovered as flowback after hydraulic stimulation of low permeability formations. From the point of view of relative permeabilities, the minimization of fracturing fluid losses is desirable to maximize the flow of hydrocarbon. On the other hand, field observations indicate that wells where less fracturing fluid is recovered as flowback performed better in production, leading to an apparent contradiction. We present a physics-based model that can account for both of these observations. Our model is the result of an experimental investigation using a coreflooding sequence that simulates fracturing fluid invasion, fluid flowback and hydrocarbon recovery in a hydrocarbon-rich, hydraulically-fractured reservoir. We elucidate the interplay between capillary suction and viscous displacement of the fracturing fluid and the impact of water blocks on hydrocarbon permeability. This model reveals the inherent relationship between flowback and hydrocarbon production for different initial petrophysical properties and has implications on both well shut-in management and the use of chemical EOR techniques in tight reservoirs.
