Work

Impact of Injected Water Chemistry on Mineral Precipitation and Dissolution in Medium–Deep Geothermal Systems: A Case Study of the Wumishan Formation Dolomite Reservoir

Year: 2025

Type: article

Abstract: The geochemical characteristics of reinjection fluids play a crucial role in controlling water–rock interactions and the long-term stability of geothermal reservoirs. This study aims to evaluate how different fluid chemistries affect mineral dissolution–precipitation behavior and ion migration during geothermal reinjection. Five types of reinjection water—including geothermal source water (i.e., formation water from the reservoir), primary and secondary treated waters, and their mixtures—were reacted with carbonate rocks from the Wumishan Formation of the Xiong’an New Area, North China Basin, under reservoir-like conditions (70 °C, 17 MPa). A combination of batch experiments, inverse modeling using PHREEQC, and one-dimensional reactive transport simulations was employed. Results show that fluid pH, ionic strength, and saturation state significantly influence reaction pathways. Alkaline-treated waters enhanced silicate dissolution, increasing Na+, K+, and Si concentrations, while source water and its mixtures promoted carbonate precipitation, increasing the risk of clogging. Simulations revealed that the early injection stage is the most reactive, with rapid ion front advancement and strong mineral transformations. Reaction-controlled ions such as Ca2+ and SO42− formed enrichment zones, while conservative ions like Na+ and Cl− propagated more uniformly. Moderate alkaline regulation was found to mitigate carbonate scaling and improve silicate reactivity, thereby reducing permeability loss. This integrated approach provides mechanistic understanding and practical guidance for reinjection fluid design in medium-to-deep geothermal systems.

Source: Water

DOI: 10.3390/w17213099

Authors: Zheng Liu, Bo Feng, Kiryukhin Alexey, Jian Shen, Siqing He, Yilong Yuan

Institutions: Jilin University, Russian Academy of Sciences, Institute of Volcanology and Seismology, Ministry of Natural Resources

Language: English

Topic: Geothermal Energy Systems and Applications

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,137

Funder: National Science and Technology Major Project