Unconventional Reservoirs
Nanodarcy Rock
Shale and tight rock have nanodarcy matrix permeability, far too low to flow on its own. Production comes instead from a horizontal well with many transverse hydraulic fractures: the fractures carry the flow and the matrix slowly feeds them by linear transient flow.
Stimulated Rock and Steep Decline
The contacted rock is only the stimulated volume around the fractures, so closer spacing and longer fractures lift the early rate, but the small matrix blocks deplete quickly and the decline is steep.
Modeling the Fractures
Capturing this needs fine near-fracture grids or dual-porosity models that treat matrix and fracture as overlapping continua. A conventional grid that ignores the fractures simply cannot produce these wells.