Abstract: The exploitation of geothermal resources will change the temperature and pressure of the thermal reservoir, affect its consolidation deformation characteristics and cause environmental geological problems. In this study, porous geothermal reservoir in the sandstone thermal reservoir exploitation area in northwest Shandong Province was studied as a research object. Consolidation deformation experiments under different stress and temperature conditions were carried out to analyze the characteristics of consolidation deformation, and the preconsolidation pressures calculated by Casagrande method and energy method were compared. The results showed that the consolidation deformation of geothermal reservoir was negatively related to water content and temperature. The self-weight compressibility of geothermal reservoir is about 10% of the standard compressibility. When calculating the preconsolidation pressure, the energy method can be used for low compressibility soil, and the Harris model, Gaussian model and energy method can be used for medium and high compressibility soil. There is a negative correlation between preconsolidation pressure and temperature. In the range of 25–80 ℃, the higher the initial temperature is, the faster the preconsolidation pressure decreases due to temperature rise.

Key words: porous geothermal reservoir, thermal consolidation, preconsolidation pressure, casagrande method, energy method