A new numerical well testing approach: Application to characterization of complex fault structures

Fluid flow in hydrocarbon reservoirs and consequently optimum scenario for hydrocarbon production, is heavily influenced by reservoir heterogeneities. Faults are one of the most common types of heterogeneity found in reservoirs. Leaky faults, baffles (limited extent faults) and complex multiple fault geometries are among the most complicated and important types of faults that are difficult to characterize. Leaky faults, unlike the sealing faults, are in partial communication with other portions of the reservoir. Because of faults' effect on reservoir connectivity and possible infill drilling plan for accessing all parts of the reservoirs, possible communication across the fault must be precisely modeled. In order to detect the effect of a fault on communication within the reservoir, we need to analyze dynamic data. There are a few analytical methods for modelling partially communicating faults, however, these methods may not be accurate enough and may be limited in application, especially in complex situations. Numerical methods (i.e. finite difference or finite element) are also not computationally economical when a large number of grid blocks are simulated. In the current work, the Fast Marching Method (FMM) is applied to effectively mimic fluid flow in the heterogeneous areas, such as complex faults. It is shown that FMM can capture the effect of different fault configurations on the bottom hole pressure and is also able to capture different linear, radial and spherical flows. •A novel numerical well testing approach has been introduced.•This approach has been used for characterization of leaky faults, baffles and can be used for any type of complex fault arrangements.•Flow diagnostic approach has been introduced to calibrate reservoir flow models.•The proposed method can be considered as a very fast proxy in compare with numerical simulation.