A 20 Years Systemic Study of Drilling Practices in a Geothermal Venture Reveals Insightful Findings

Abstract

Abstract Geothermal drilling has increased in the recent years with the renewable energy initiatives. Geothermal plants provide more than 6% of California's electricity. A large sum from the development budget is consumed by the drilling. This paper systematically analyzes and reviews the drilling activities and operations in a geothermal venture in Hawaii for more than 20 years to enhance the drilling operations and save costs. The paper starts by studying the geology of the area, which is located in an active volcanic region. Then, an extensive data collection was performed that went back to more than 20 years. The data was preprocessed and cleaned to be used in the analysis. The well designs were analyzed and the distribution of the drilling time was determined. After that, the performance of the geothermal drilling was benchmarked with the oil and gas drilling and the geothermal drilling in different parts around the world. The geology of the area is challenging with basaltic formation and tectonic movements. Volcanic eruptions that leads to closing wells were encountered in the recent years. As for the drilling, six challenges were identified and deeply analyzed. These challenges include: lost circulation, stuck pipe, cementing, low rate of penetration (ROP), logistics issues, and safety concerns. Each of these challenges was intensely investigated and solutions were proposed. The benchmarking with the oil and gas industry and other geothermal drilling operations shows that the geothermal drilling operations can be enhanced significantly. This improvement in the drilling in the geothermal venture will result in huge cost savings. A set of recommendations to improve the performance is presented as new organizational and workflow changes, analysis and elimination of nonproductive time (NPT), and novel engineering redesigns.