Fault-related fracture modeling in a pre-salt lacustrine carbonate reservoir from Santos Basin, offshore Brazil: Predicting preferential fluid flow paths using 3D geological and flow simulation models

Abstract

The authors propose an integrated workflow from seismic to flow simulation to predict sub seismic and inter-well fracture distribution. This methodology provides insights in order to fulfill a knowledge gap in reservoir 3D modeling of naturally fractured carbonates applied in the industry. The workflow includes interpretation of borehole image logs, 3D seismic, geophysical and geomechanical attributes, and calibration with dynamic data. The main natural fracture parameters analyzed for the case study are direction, dip, and fracture intensity. The studied area is a naturally fractured Aptian lacustrine carbonate reservoir within the Santos Basin, offshore Brazil. The isolated platform developed over a series of elongated NE-SW horsts structures. The main seismic scale structures in the reservoir are NE-SW trending faults that show normal displacement, defining en échelon relay ramps that contain NW-SE sub seismic faults and diffuse fracture swarms. The damage zones that surround these main faults define continuous fracture corridors intercepted by oblique sub-seismic faults in relay-ramp zones. Structural analysis showed that fracture intensities are higher at the north domain in the Barra Velha Formation. The fractures were simulated stochastically using a discrete fracture network (DFN), generating a dual porosity and dual permeability model (DPDK) for the flow simulation resulting in a suitable model configuration for the history match.