3D model of fracture zones at Soultz-sous-Forêts based on geological data, image logs, induced microseismicity and vertical seismic profiles

Abstract : This study presents a new deterministic 3D model of the fracture zones observed in the granitic reservoir of the Soultz European geothermal project. The major fracture zones encountered around 6 wells (4550, EPS1, GPK1, GPK2, GPK3 and GPK4) consist in 53 main structures that are located and characterized in terms of size and orientation: 39 fracture zones, 8microseismic structures and 6 structures derived from vertical seismic profiles are represented in the 3Dmodel using Discrete Fracture Network tools of the gOcad modeling platform (ParadigmTM, Earth DecisionTM). This work illustrates the complexity of 3D fracture zone correlation and interpretation in crystalline rock masses characterized at meter scale (borehole) and at the reservoir scale (kilometer) thanks to geophysical imaging techniques.