Geothermal Asset Integrity Model

C53-21a-271193Assuring trouble-free performance of downhole and surface components is critical for generation of low- cost electricity from geothermal energy systems. Because geothermal environments can be extremely corrosive, managing the corrosion of alloys used in geothermal system through a combination of proper alloy selection and operational practices is essential. Unfortunately, materials selection and operational guidance for geothermal systems at present are qualitative, and operators work only with lagging indicators of performance. Mineral scaling from geothermal fluids is another major obstacle, fouling devices, wells, and aquifers close to filters, which lowers operating efficiency by decreasing the flow rate from the well and heat transfer efficiency. Scaling also may exacerbate corrosion by acting as a crevice, thereby reducing concentrations of inhibitors that can reach the metal surface. While current models can address aspects of scaling or corrosion, no modeling tool accurately predicts both these problems. OLI Systems proposes an integrated tool to mitigate scaling and corrosion risk in geothermal energy production to lower the cost of geothermal systems. The tool will also be combined with probabilistic assessment and offered as a cloud-based software solution. In Phase 1, the OLI Mixed-Solvent Electrolyte model was refined to model electrochemical kinetics and localized corrosion of alloys and chemistries encountered in geothermal systems. Limited experimental data were used to demonstrate the feasibility of the approach, and the model was validated using existing geothermal corrosion data. Mineral scale prediction for some systems is already available in OLI software. In Phase 2, the corrosion model will be further extended using new experimental data to ascertain the performance of alloys at high temperatures. The model will include alloys representing the broadest range of Corrosion Resistant Alloys likely to be used in geothermal applications. The existing OLI Mixed Solvent Electrolyte thermodynamic model will be enhanced to predict the formation of mineral scales from various crystalline and amorphous forms of carbonates, sulfates, silicates, and sulfides over low to extreme ranges of salinity, temperature, and pressure. An advisory module will be created to convert the detailed model predictions into implementation action items/recommendations, including probabilistic assessment. The model will be incorporated into a cloud platform to enable real-time monitoring and process automation. These new capabilities will enable accurate estimation of technical and financial risk for geothermal energy production to make it more cost-competitive, scalable, and reliable than other alternatives. Broader benefits of the project will include the ability to model electrochemical kinetics in non-aqueous environments involved in energy storage and metal separation, as well as material performance in oil and gas production systems.