An Attempt to Study Natural H2 Resources across an Oceanic Ridge Penetrating a Continent: The Asal–Ghoubbet Rift (Republic of Djibouti)

Dihydrogen (H2) is generated by fluid–rock interactions along mid-ocean ridges (MORs) and was not, until recently, considered as a resource. However, in the context of worldwide efforts to decarbonize the energy mix, clean hydrogen is now highly sought after, and the production of natural H2 is considered to be a powerful alternative to electrolysis. The Afar Rift System has many geological features in common with MORs and offers potential in terms of natural H2 resources. Here, we present data acquired during initial exploration in this region. H2 contents in soil and within fumaroles were measured along a 200 km section across the Asal–Ghoubbet rift and the various intervening grabens, extending from Obock to Lake Abhe. These newly acquired data have been synthesized with existing data, including those from the geothermal prospect area of the Asal–Ghoubbet rift zone. Our results demonstrate that basalt alteration with oxidation of iron-rich facies and simultaneous reduction in water is the likely the source of the hydrogen, although H2S reduction cannot be ruled out. However, H2 volumes at the surface within fumaroles were found to be low, reaching only a few percent. These values are considerably lower than those found in MORs. This discrepancy may be attributed to bias introduced by surface sampling; for example, microorganisms may be preferentially consuming H2 near the surface in this environment. However, the low H2 generation rates found in the study area could also be due to a lack of reactants, such as fayalite (i.e., owing to the presence of low-olivine basalts with predominantly magnesian olivines), or to the limited volume and slow circulation of water. In future, access to additional subsurface data acquired through the ongoing geothermal drilling campaign will bring new insight to help answer these questions.

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

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.

Investigation of Old Exploration Boreholes in the Lublin Basin with Regard to Potential Rotary-Percussion Drilling of Shale Gas Wells

The rotary-percussion drilling method is a prospective way to decrease drilling costs. It is obvious, based on literature analyses and finished geothermal drilling, that the Lublin Basin can be perceived as the one where rotary-percussion drilling can be used to drill an overburden of shale rocks. The paper explained the geology of the Lublin Basin, its’ geological structures, and the possibility of the use of drilling with a down-the-hole hammer, which could significantly decrease the cost of the whole shale gas drilling investment. Data collected from the wells drilled in the Lublin Basin were compared and analyzed to determine the viability of rotary-percussion drilling. Provided analyses showed that using the rotary-percussion drilling method in the Lublin Basin had a greater possibility of application than in other Polish shale basins (Baltic and Podlasie).

Comparison of Rotary and Linear Cutting Methodology in Determining Specific Cutting Energy of Granite

Single polycrystalline diamond compact (PDC) cutting is a practical technique to understand the rock-tool interactions in drag-bit type geothermal drilling operations. This paper introduces a rotary cutting method to determine specific cutting energy (SCE) and compares it with the conventional linear cutting method. In this work, granite is selected to represent hard rock formations in geothermal drilling. Cutting tests are conducted on a CNC machine with a realistic cutting speed of 12.7 m/min and several chip loads ranging from 0.08 to 0.25 mm. The cutting force is measured using a dynamometer, and then converted to SCE. The results show that the rotary method produces an inverse relationship between SCE and chip load, whereas the linear method shows the opposite. As a result, the produced SCE by the rotary method tends to be lower than that of the linear method at a higher chip load at and over 0.16 mm. The difference may be attributed to the cutting configuration and associated force components.

Corrosion Analysis On Internal Plastic Coating Drill Pipe 5 Inch 19.50 PPF Grade G-105

In the oil, gas and geothermal drilling industry, the use of a drill pipe is vital for its use as an addition to the length of the drilling depth. Another function of the drill pipe is to channel high pressure drilling mud (drilling fluid / fluid) to the drill bit. During the drill pipe operation, several problems were encountered, such as broken, bent, and leaking or wash-out drill pipes. This is very detrimental to the company because the time to replace a new drill pipe will take a long time, and will disrupt the drilling program which will result in high drilling operational costs. This study analyzes the corrosion of the drill pipe which can cause damage to the drill pipe. The analysis on the drill pipe includes analysis of thickness, corrosion rate, remaining life, internal plastic coating damage, and SEM. The results show that the storage and use of drill pipes greatly affect the conductivity of the drill pipe.

Geothermal resource potential assessment of Erdaobaihe, Changbaishan volcanic field: Constraints from geophysics

Geothermal resources occurring in the Changbaishan volcanic field are directly or indirectly controlled by volcanic activity and exhibit a close correlation with deep-seated faults. Energy and thermal transfer are generally controlled by groundwater circulation and hot gas emission. This article considers the detectability of hot water and gas by geophysical methods. The controlled source acoustic magnetotelluric (CSAMT) and radon (222Rn) gas methods give straightforward information on electrical resistivity and natural radon emissions, respectively, to assess the geothermal condition. The CSAMT method detected five-banded low-apparent resistivity bodies (decreasing from 3,000 to 300 Ωm), indicating that there exists a high degree of water-bearing capacities in the subsurface. The radon (222Rn) gas concentrations were monitored in two rapid growth zones: one zone showing values ranging from 3,000 to 23,000 Bq/m3, and the other with values from 4,000 to 24,000 Bq/m3. These changes demonstrate that the heat energies available in these areas were very high and that there is potential for geothermal resources in those zones. Combining with previously published data from geothermometry and geothermal drilling, we argue that there is great potential in Erdaobaihe for geothermal exploitation and that the geothermal resource type should be classified into uplift mountain geothermal system no magma type.