Integrating Fracture Network Characterization in Geothermal Exploration Projects: A Case Study in the West Netherlands Basin

Abstract

Summary In the petroleum industry, production from low permeable reservoirs is believed to be highly influenced by the presence of open natural fractures. However, in geothermal exploration projects, natural fractures are generally not incorporated in estimating the economic viability of tight reservoir bodies. Therefore, in this study we expand on the key lessons learned from the Energy & Production industry and perform a naturally fractured reservoir characterisation study of 1) automated fault extraction, 2) image log and core data interpretation and 3) Discrete Fracture Network (DFN) modelling using Multiple Point Statistics (MPS). The workflow is exemplified on tight Triassic sandstones in the West-Netherlands Basin. Firstly, the seismic data analysis shows that the reservoir target is heavily faulted, with faults showing multiple orientations. Further, well data analysis indicate faults and fractures are most likely structurally related. Therefore, in the DFN modelling workflow, we assume fault related fracturing, so that fracture density estimations away from the well, are guided by the extracted fault model. Finally, using MPS, a reservoir scale DFN is generated and we suggest that this model can be used as input for fluid-flow models, to address the impact that natural fractures could have on geothermal production in low permeable reservoirs.