Calculating Fault and Fracture Failure Plane Size From Microseismic Events and Rock Elastic Properties

The availability of microseismic data has expanded data sampling of fracture distributions from the 1D wellbore scale to 3D for 100s of meters away from the well, filling the scale gap between wellbore and seismic data. These data also provide information about the stress state in the reservoir when the full source mechanism solution for each event is available. Applying characteristic rock elastic properties to the reservoir zones in which the microseismic events are generated allows development of a more realistic DFN model. This paper describes different models for seismic slip and rigidity relationships as applied to a microseismic data set using event energy, rock rigidity typical for the rock type, and realistic assumptions of slip magnitude. The resulting DFN distributions and event locations produce well-defined fault damage zones around large events clustering around large planes as the main fault surface. The volumetric component of each event source mechanism was used to estimate locations of proppant placement from the stimulation treatment. These types of fracture realizations have applications not only for oil and gas reservoir production, but also for assessing permeability requirements for geothermal reservoirs and for fluid flow in fractured aquifers and aquifers bounded by faults.