Geomechanical Investigations for a North American Shale Gas Play

For a multi-well multi-stage hydraulic fracturing campaign of a North American shale gas play we investigate geomechanical effects on drawdown management to improve our understanding of declining production rates. We calibrate a geomechanical model by determining and constraining rock properties, pore pressures and stresses along the well trajectory as well as demonstrate its role in estimating the rock strength (UCS) for significant underbalanced drilling conditions. In this way, we find the area under investigation to be quite heterogeneous, as data from offset wells show different UCS magnitudes. To better understand the mechanism of production decline rates, we analyse the productivity of corresponding wells in line with their choke size and drawdown control. This identifies a positive production-related choke and drawdown management effect for a distinct and simultaneous decrease in both choke size and drawdown pressures. Finally, we utilize the geomechanical model to investigate injection and depletion effects on critically stressed fractures. Our results suggest that with depletion the number of critically stressed fractures significantly decreases. Hence, a successful proppant settlement is critical for minimising loss of production.