Calibration of fracture information from seismic for flow properties
In order to transform the geometric natural fracture information derived from seismic data into volumes that show variations in flow properties, we must assess the stress state and its effect on effective permeability for the given fracture configuration. Here we provide two calculators that can help you get a sense of how we approach the calibration of a 3D volume with fracture intensities and orientations that are used as input to create effective fracture permeability volumes for flow simulation.
Estimation of the stress state
The stress polygon allows the estimation of the stress state for a given set of observations from image logs, pore pressure, vertical stress, minimum horizontal stress Shmin, and mechanical properties. Once we get an idea of the possible ranges of stress anisotropy, we can use this information to calibrate a given fracture geometry with effective permeability measurements at the well. Click here to go to the stress polygon calculator and estimate the stress state using your own geomechanical data.
Estimation of effective fracture permeability for a given stress state and natural fracture geometry
The effective fracture permeability anisotropy in a cell is controlled not only by the particular fracture geometry and intensity but also by the individual fracture apertures and stress state that affects them by making critically stressed fractures more conductive than non-critically stressed ones. Click here to use an effective fracture permeability anisotropy calculator that takes into account all these aspects with your own data to get a sense of how we would calibrate a complete 3D volume derived from seismic data. You can also use this calculator to calibrate with your own measured perms at the well.