Geothermal Well Engineering: Risk Analysis and Design Perspectives

ABSTRACT Amidst growing concerns over greenhouse gas emissions and the imperative to transition to renewable energy sources, geothermal drilling emerges as a promising avenue. This paper delves into the intricacies of adapting well engineering and operational practices to meet the specific requirements of geothermal energy extraction. By ensuring longevity and efficiency over a 25+ year operational span, we aim to contribute to the sustainable energy landscape. Key considerations include the customization of casing designs to effectively withstand the unique load cases associated with geothermal production. Our research focuses on two critical aspects: Process Safety and Well Barriers, which necessitate tailored approaches for Geothermal (GT) Wells. Through a meticulous methodology, we propose a comprehensive framework for constructing well barrier diagrams specifically tailored to GT Wells. Unlike conventional drilling in oil and gas, geothermal projects face singular financial constraints, underscoring the importance of rigorous risk assessment. To address this, we introduce a novel risk assessment matrix and GT Wells Risk Index, offering both qualitative and quantitative insights into the risks inherent in geothermal projects. The analyses reveal promising insights into the feasibility and risk profile of geothermal drilling projects. Through Geothermal Well Risk Assessment and detailed engineering design, we have calculated the risk profile of the proposed Geothermal Well Prospect, shedding light on its viability and potential challenges. Moreover, our casing design analysis, employing the Von Misses Triaxial equation, validates the suitability of L80 casing for anticipated load cases, providing a robust foundation for further project development. The calculated GT Well Index serves as a key indicator of project readiness, paving the way for advancements through the well delivery process. Effective risk management strategies, including barrier generation and implementation, ensure risks are mitigated to As Low As Reasonably Practical (ALARP) levels, thereby ensuring project success and sustainability.