Behavior of Horizontal Wells Intersecting Multiple Hydraulic and Natural Fractures in Unconventional Unfractured and Naturally Fractured Reservoirs

In this paper, we investigated pressure transient behavior of nanodarcy unconventional shale formations via derivatives for two cases: 1) a horizontal well with 40 vertical hydraulic fractures in a homogenous reservoir and 2) a horizontal well intersects several natural fractures in a discretely fractured reservoir. The effect of fracture conductivities on flow regimes and their duration. We have shown the fundamental difference between the behavior of hydraulically fractured horizontal wells and intersecting naturally fractures in nanodarcy unconventional reservoirs. We have shown that the fracture spacing of more than a few hundred feet is not effective for draining nanodarcy shale formations for a reasonable time frame. It takes hundreds of years to observe any effect of outer no-flow boundaries if it is more than a few thousand feet away from the well. Fracture conductivities and the number of fractures are the key parameters that affect the pressure derivative curve, i.e., well productivity.

As the space increases between hydraulic (SRV) and natural fractures that intersect a horizontal well, the fracture pseudosteady-state flow regime tends to disappear.