Integrating UAV Imagery with Traditional Fieldwork for Multi-Scale Analysis of Natural Fracture Networks: A Case Study of the Parmelan Plateau

Abstract

This thesis attempts to evaluate the extent to which UAV imagery can complement traditional geological fieldwork and to assess the behaviour of natural fracture networks across multiple scales. By conducting detailed field surveys and capturing high-resolution UAV images, the study provides a comprehensive comparison of the data, particularly in terms of fracture orientations, lengths, density, intensity and topology. The Parmelan plateau in France has been studied as a potential geothermal reservoir analogue. This study utilises an integrated approach combining fieldwork, high-resolution Unmanned Aerial Vehicle (UAV) imagery, and satellite imagery.

Field data collected using field scanlines were compared with data obtained from UAV imagery to evaluate the efficacy of each approach. The results indicate that UAV imagery, while advantageous for covering large and inaccessible areas, faces significant limitations in accurately identifying fracture types and orientations without supplementary field data. This discrepancy is primarily attributed to factors such as image resolution - limited visibility of small-scale fracture-type indicators.

The multi-scale analysis performed in this study shows that natural fracture networks exhibit similar behaviour across different scales, though some scale-dependent variations are evident. The findings highlight the importance of integrating UAV data with traditional field methods to achieve a better understanding of fracture networks. This integration is particularly important for optimizing outcrop analogue data used in modelling subsurface geothermal reservoirs, which can significantly enhance the efficiency of geothermal energy extraction.