Lost-in-hole preventive initiative to successfully drill deep geothermal project in Continental Europe

In 2023, a major energy provider and operator of an extensive district heating network announced the development of a deep geothermal power plant. By the end of 2024, drilling operations commenced, and by May 2025, the third and final well successfully reached its planned total depth, targeting a naturally occurring hot water reservoir approximately 3,000 meters below the surface.As of now, production testing—intended to assess formation water temperature, chemical composition, and flow rates—has not been conducted. Therefore, this paper focuses on the planning and execution phases of the drilling campaign.We will present an application of the Weatherford’s Lost-in-Hole (LIH) Preventive Initiative as a continuous improvement strategy, highlighting lessons learned from the first to the third well. Emphasis is placed on the joint efforts of Weatherford’s Drilling Engineering and Interpretation and Evaluation teams in accurately interpreting downhole and surface data to assess risks and inform our client on mitigation strategies and drilling practices. It incorporates a two-phased assessment approach: an initial risk screening for early identification of high-risk well sections, followed by an in-depth assessment to develop targeted mitigation strategies. A Well Management System was developed and used to store and share Drilling Engineering studies, data and lessons learned from offset wells and LIH risk based on the Well Complexity Index (WCI).The Initiative serves as a replicable example, crucial for minimizing wellbore stability issues, preventing lost-in-hole incidents and tool damage, reducing Non-Productive Time (NPT), and ultimately enhancing drilling performance across the project.