Flow Assurance Management in Geothermal Production Wells

Abstract

Flow assurance ensures that geothermal fluids (hot water and steam) flow properly in a pipe or well and are transferred to a power plant safely and cost-effectively. Inorganic deposition (scales) is regarded as the primary issue in geothermal fluid flow, and a reliable controlling strategy to predict and prevent scaling is essential. We introduced a practical scale integrity management strategy to predict and prevent scaling in the flowline to achieve this goal. Thermochemical modeling is the primary predictive model to predict why, where, and when scaling will occur. Then two treatment approaches (chemical and non-chemical) are investigated to prevent and treat scaling. What-if analysis is extensively applied to propose an economic plan. Due to the inability of laboratory research to replicate the extreme pressures and temperatures of geothermal wells, experts do not know precisely when and how minerals dissolve down in the well and are unable to offer regulating recommendations. Therefore, an efficient scale integrity management plan must be implemented. Simulation tools play a significant part in the development of flow assurance, as they provide a consistent framework for testing various what-if scenarios and aid in making the best operational solution. Injecting chemicals is not always economical to control scaling in geothermal operation due to the cost and inefficiency in high-pressure and high-temperature situations in these wells, and the non-chemical approach should be prioritized. Potential non-chemical approaches include sulfate reduction, operating wells outside critical scaling envelopes, reinjecting produced water, and lifting gas injection with more CO2. This research intends to broaden the flow assurance concept in geothermal wells by analyzing the impediments and treatments from wells to the surface facilities.