| Title | Recent Slimhole Drilling Experience for Geothermal Exploration in Indonesia: Problem Summary and Potential Improvement |
|---|---|
| Authors | Daniel W ADITYATAMA, Rizqi Al ASYARI, Nadya ERICHATAMA, Vincentius Adven BRILIAN, Dorman PURBA, Ferdino R. FADHILLAH |
| Year | 2024 |
| Conference | Stanford Geothermal Workshop |
| Keywords | Indonesia, geothermal, exploration, geothermal drilling, slimhole, derisking, drilling problems, coring, rotary drilling |
| Abstract | Slimhole drilling has emerged as a preferred method to mitigate risks during geothermal exploration, especially in fields marked by high resource uncertainty. Although this method has seen both global and regional adoption—with significant use in Indonesia during the early 90s—recent exploration efforts using slimhole techniques have faced numerous challenges. Extended drilling times and difficulties in reaching the target depths stand out as common problems. Several drilling campaigns, including those in Tangkuban Perahu, Ijen, Cisolok-Cisukarame, Nage, and Hu’ Daha, have reported difficulties in reaching Target Depth (TD) and occurrences of stuck pipes. Interestingly, mineral coring drilling, even when operating in hard rock terrains, has managed to achieve depths of 1500 m, and even 2000m. Such inconsistencies highlight pressing concerns about the specific challenges of geothermal slimhole drilling. This paper aims to consolidate and analyze the encountered issues to extract valuable lessons for future endeavors. The research underscores several key factors: insufficient rig capacities, the hiring of inexperienced contractors, less-than-ideal drilling strategies, and well designs predominantly based on traditional rotary drilling techniques. In conclusion, several improvements are suggested. These encompass adapting well designs to the unique limits of the drilling rig, aligning exploration goals with achievable outcomes, and assessing the options of using mineral coring drilling contractors to achieve better results. |