Numerical study of the stimulation related thermo-hydro-mechanical processes in tight gas and deep geothermal reservoirs : Promotion an der Technischen Universität Clausthal, Arbeitsgruppe Rock Mechanics in Petroleum Engineering, Prof. Dr.-Ing. habil. Mic

Hydraulic fracturing in combination with horizontal well is playing a key role in the efficient development of unconventional gas/oil reservoirs and deep geothermal resources. However, the integral operation, especially from the perspective of THM (Thermal-Hydraulic-Mechanic) interactions have not been studied systematically. In this thesis, targeted improvements were achieved through developing a series of mathematical/physical models, and their implementation into the existing numerical tools (FLAC3Dplus and TOUGH2MP-FLAC3D), including: (a) a new thermal module for FLAC3Dplus based entirely on the finite volume method (FVM), which is especially developed for the fracturing process and can also achieve the modeling of gel breaking; (b) a rock damage module of TOUGH2MP-FLAC3D, which also considers the impacts of rock damaging process on evolution of permeability; (c) an in-depth improved FLAC3Dplus simulator that obtains the ability to simulate a 3D fracture propagation with arbitrary orientation. After the corresponding verifications, the improved tools were applied in different case studies to reveal: a) influences of the fluid's viscosity on the fracturing results in tight sandstone reservoirs; b) the induced seismicity during the fracturing operation and the reactivation of the natural faults; and c) the fracture propagation with arbitrary orientation. 1. Introduction 2. Fundamentals for describing the reservoir stimulation in a geosystem 3. Numerical study of the fluid viscosity’s influences on shaping of a stimulated fracture in tight sandstone in consideration of thermal effects and THM coupled processes 4. Numerical investigation on the geothermal operation induced microseismic by case study and influencing factors 5. Advanced FLAC3Dplus – a further developed 3D-Simulatorfor modeling of hydraulic fracturing in consideration offracture propagation with arbitrary orientation and hydro-mechanical coupling effects 6. Conclusion and outlook 7. References