In the context of global efforts to transition toward renewable energy and reduce greenhouse gas emissions, geothermal energy is increasingly recognized as a viable and sustainable option. This paper presents a comprehensive assessment derived from a subset of a larger sample collection within the Dunántúli Group of the Pannonian Basin, Hungary, focusing on optimizing micro-computed tomography (µ-CT) resolution for analyzing pore structures in sandstone formations. By categorizing samples based on geological properties and selecting representatives from each group, the study integrates helium porosity and gas permeability measurements with µ-CT imaging at various resolutions (5 µm, 2 µm, and 1 µm). The findings reveal that µ-CT resolution significantly affects the discernibility and characterization of pore structures. Finer resolutions (2 µm and 1 µm) effectively uncovered interconnected pore networks in medium- to coarse-grained sandstones, suggesting favorable properties for geothermal applications. In contrast, fine-grained samples showed limitations in geothermal applicability at higher resolutions due to their compact nature and minimal pore connectivity, which could not be confidently imaged at 1 µm. Additionally, this study acknowledges the challenges in delineating the boundaries within the Dunántúli Group formations, which adds a layer of complexity to the characterization process. The research highlights the importance of aligning µ-CT findings with geological backgrounds and laboratory measurements for accurate pore structure interpretation in heterogeneous formations. By contributing vital petrophysical data for the Dunántúli Group and the Pannonian Basin, this study provides key insights for selecting appropriate µ-CT imaging resolutions to advance sustainable geothermal energy strategies in the region. The outcomes of this research form the basis for future studies aimed at developing experimental setups to investigate physical clogging and enhance geothermal exploitation methods, crucial for the sustainable development of geothermal resources in the Pannonian Basin.

A geothermal well can experience a decrease in the production of fluid (steam) due to the presence of scaling. The scaling usually is formed in the slotted liner hole. The purposes of this study were to determine the fluid flow pattern, the zone of scaling accumulation, and the scaling type in the well “X”. In determining the fluid flow pattern, the manual calculation using the Hewitt-Robert method and the simulation calculation using WellSim software were conducted. In determining the zone of scaling accumulation, the pressure, temperature, and spinner (PTS) survey data were utilized. In determining the scaling type, the geochemical analysis data were utilized. The results showed that the fluid flow pattern was annular flow based on the Hewitt-Robert method and mist flow based on WellSim software. There is no flow pattern type of mist in the grouping of flow patterns based on Hewitt-Robert. Because the characteristics of mist flow and annular flow are almost the same, the annular flow pattern can be considered similar to mist flow. Furthermore, the results were validated with PTS survey data so that the flashing zone was known at a depth of 1458.27 m from a total depth of 1700 m. Based on the geochemical analysis, it was known that the scaling type in the well “X” is of the calcite type.

Scaling in geothermal production wells poses a critical challenge to sustainable energy production, particularly in vapor-dominated systems where scaling mechanisms are less understood. This study investigates scale treatment planning using the broaching method in Well X at Indonesia’s Kamojang geothermal field. Through well integrity testing, geochemical analysis, and XRD characterization, silica (quartz) scale formations were identified in the production casing. Performance monitoring revealed gradual decreases in steam production and wellhead pressure over a three-year period. The selection of the broaching method was validated through analysis of scale characteristics, well geometry, and economic feasibility, offering a significantly more cost-effective solution compared to conventional methods with a substantially shorter payback period. Broaching has effectively operated on multiple geothermal wells, restoring significant production capacity at approximately half the expense of conventional well workover methods. Our results challenge accepted assumptions on scaling in vapor-dominated systems and provide a methodical framework for scale treatment planning. This study demonstrates how strategic scale management can efficiently preserve well productivity while lowering operating costs, thus enabling sustainable geothermal resource development for operators worldwide.