Discriminating Fracture Patterns in Fractured Reservoirs by Pressure Transient Tests

A new approach is described to characterise fractured reservoirs using a software code which can simulate transient well tests in a realistic 3D fracture/matrix model. By a process of iteration the geological and flow data can be reconciled to produce plausible models which could help to constrain reservoir simulation. The numerical results indicate that the simulated pressure derivatives generally show different characteristics with different fracture pattern configurations. The results also indicate that theoretical dual porosity behaviour is absent when a more realistic transient matrix to fracture flow solution is used. This approach has important implications in the use of well tests to determine parameters for input to a multiphase flow simulator, where the well positioning in relation to highly conductive fractures is critical. The advantage of the described approach, compared to conventional analytical analysis, is that the geological data are calibrated and preserved. Parameters can then be more accurately represented in a dynamic reservoir model.