Details of the Researcher

PHOTO

Eko Pramudyo
Section
Graduate School of Environmental Studies
Job title
Specially Appointed Assistant Professor(Research)
e-Rad No.
20994891

Research History 1

  • 2023/10 - Present
    Tohoku University Graduate School of Environmental Studies　Department of Environmental Studies for Advanced Society　Specially appointed assistant professor

Education 3

  • Tohoku University　Graduate School of Environmental Studies　Doctoral

    2020/10 - 2023/09

  • Tohoku University　Graduate School of Environmental Studies　Master's

    2018/10 - 2020/09

  • Bandung Institute of Technology　Geology　Bachelor

    2010/08 - 2014/10

Professional Memberships 2

  • Japanese Society for Rock Mechanics

    2022/11 - Present

  • Society of Petrophysicists and Well Log Analysts

    2020/11 - Present

Research Interests 2

  • Geothermal

  • Geomechanics

Research Areas 1

  • Energy / Earth resource engineering, energy science /

Awards 5

  1. Doctoral Thesis Award

    2024　Japanese Society for Rock Mechanics　Creating granitic geothermal reservoirs by carbon dioxide injection

  2. Professional Director for Sustainable Environment

    2023/09　Graduate School of Environmental Studies, Tohoku University

  3. Paper Award

    2022　Japanese Society for Rock Mechanics　Creating Cloud-Fracture Network by Flow-Induced Microfracturing in Superhot Geothermal Environments

  4. SPWLA International Student Paper Contest, 1st place oral MSc category

    2020/06　Society of Petrophysicists and Well Log Analysts (SPWLA)　Creating complex fracture patterns at lower pressures by CO2-based fracturing in granite from conventional to superhot geothermal conditions.

  5. Best presentation and extended abstract

    2019/09　Japan Formation Evaluation Society (JFES)　Supercritical carbon dioxide fracturing of granite from conventional to superhot geothermal conditions

Papers 17

  1. Static friction-coefficient increase in chelating-agent-treated granite saw-cut fractures associated with selective mineral dissolution and void formation

    Lena Muhl, Eko Pramudyo, Luis Salalá, Jiajie Wang, Guido Blöcher, Ingo Sass, Noriaki Watanabe

    Geothermics　2026/12

    DOI： 10.1016/j.geothermics.2026.103826 　

  2. Reactive viscous fluid fracturing of volcanic rocks: Chemical weakening offsets viscosity-induced pressure increase

    Eko Pramudyo, Nagi Obata, Luis Salalá, Jiajie Wang, Noriaki Watanabe

    Geothermics　2026/11

    DOI： 10.1016/j.geothermics.2026.103752 　

  3. Shear Slip Induced by CO2 and Water Injection into Volcanic Rocks Under Geothermal Environment

    Kazumasa Sueyoshi, Eko Pramudyo, Koki Miyazaki, Kiyotoshi Sakaguchi, Sho Ogata, Kazumi Osato, Takuya Teraoka, Noriaki Watanabe

    Rock Mechanics and Rock Engineering　2026/07/10

    DOI： 10.1007/s00603-026-05657-y 　

  4. Green chelating agent‒hydrofluoric acid synergy enables sustained mineral dissolution for near-wellbore stimulation in geological CO2 storage formations

    Jiajie Wang, Ryota Tamura, Hitomi Hirano, Masahiko Yagi, Tetsuya Tamagawa, Luis Salalá, Eko Pramudyo, Noriaki Watanabe

    Communications Earth & Environment　2026/06/05

    DOI： 10.1038/s43247-026-03658-x 　

  5. Enhancing permeability in deep, medium-temperature granitic geothermal systems via chelating agent stimulation

    Lena Muhl, Luis Salalá, Eko Pramudyo, Jiajie Wang, Ingo Sass, Noriaki Watanabe

    Geoenergy Science and Engineering　2026/02

    DOI： 10.1016/j.geoen.2025.214252 　

  6. Unlocking geothermal potential: Activating calcite-filled veins using chelating agents to improve granitic rock permeability

    Lena Muhl, Luis Salalá, Eko Pramudyo, Jiajie Wang, Ingo Sass, Noriaki Watanabe

    Geothermics　2025/09

    DOI： 10.1016/j.geothermics.2025.103356 　

  7. Characteristics and effectiveness of water-assisted CO2 fracturing for creating geothermal reservoirs in volcanic rocks

    Eko Pramudyo, Kohei Takuma, Yuto Watanabe, Kiyotoshi Sakaguchi, Yutaro Maeda, Sho Ogata, Kazumasa Sueyoshi, Jiajie Wang, Kazumi Osato, Amane Terai, Noriaki Watanabe

    Geoenergy Science and Engineering　213280-213280　2024/09

    Publisher: Elsevier BV

    DOI： 10.1016/j.geoen.2024.213280 　

    ISSN： 2949-8910

  8. CO2 fracturing of volcanic rocks under geothermal conditions: Characteristics and process

    Takuma, K., Maeda, Y., Watanabe, Y., Ogata, S., Sakaguchi, K., Pramudyo, E., Fukuda, D., Wang, J., Osato, K., Terai, A., Watanabe, N.

    Geothermics　120　2024/06

    DOI： 10.1016/j.geothermics.2024.103007 　

    ISSN： 0375-6505

  9. Permeability enhancement by CO2 injection and chelating agent stimulation for creating geothermal reservoirs in granite

    Pramudyo, E., Salal{\'a}, L., Goto, R., Wang, J., Sueyoshi, K., Muhl, L., Sakaguchi, K., Watanabe, N.

    Geoenergy Science and Engineering　234　2024/03

    DOI： 10.1016/j.geoen.2023.212586 　

    ISSN： 2949-8910

  10. Cooling-induced permeability enhancement for networks of microfractures in superhot geothermal environments

    Goto, R., Nakayama, D., Takahashi, R., Pramudyo, E., Takuma, K., Watanabe, N.

    Geothermal Energy　11　(1)　2023/04/17

    DOI： 10.1186/s40517-023-00251-9 　

    ISSN： 2195-9706

  11. CO2 Injection-Induced Shearing and Fracturing in Naturally Fractured Conventional and Superhot Geothermal Environments

    Eko Pramudyo, Ryota Goto, Kiyotoshi Sakaguchi, Kengo Nakamura, Noriaki Watanabe

    Rock Mechanics and Rock Engineering　2023/03

    Publisher: Springer Science and Business Media {LLC}

    DOI： 10.1007/s00603-022-03153-7 　

    ISSN： 0723-2632 1434-453X

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    <jats:title>Abstract</jats:title><jats:p>This study elucidates the possibility of CO<jats:sub>2</jats:sub> injection-induced formation of a complex cloud-fracture network (CFN) in granite, along with shearing (shear slip) of natural pre-existing fractures under conventional (~ 150–300 °C) and superhot (&gt; ~ 400 °C) geothermal conditions, potentially providing additional connecting flow paths between the stimulated natural fractures. Here, we conduct a set of experiments under triaxial stress states at 150 °C and 450 °C on cylindrical granite samples containing a sawcut (representing a natural fracture) inclined 45° from the sample’s axis. CO<jats:sub>2</jats:sub> injection induced dynamic shear slip on the sawcut, with higher slip velocities at 150 °C owing to the higher elasticity of the rock than that at 450 °C. The lower viscosity of CO<jats:sub>2</jats:sub> also allowed it to more uniformly pressurize the sawcut, resulting in higher slip velocities and slip displacements compared with those based on water injection in the 150 °C experiments. This implies that under conventional geothermal conditions, CO<jats:sub>2</jats:sub> injection can stimulate the same volume of rock as that of water injection at lower injection-well pressures. The CFNs then formed via CO<jats:sub>2</jats:sub> injection at pressures similar to those predicted by the Griffith failure criterion as the sawcut shear slip progressed at both experimental temperatures. The experiments also revealed potential challenges associated with CO<jats:sub>2</jats:sub> injection in naturally fractured geothermal environments, such as narrow aperture CFNs, owing to decreasing differential stress during their formation; all these factors should be addressed in future research.</jats:p>

  12. Erratum to “CO2 injection-induced complex cloud-fracture networks in granite at conventional and superhot geothermal conditions” [Geothermics 97 (2021) 102265] Peer-reviewed

    Eko Pramudyo, Ryota Goto, Noriaki Watanabe, Kiyotoshi Sakaguchi, Kengo Nakamura, Takeshi Komai

    Geothermics　101　102340-102340　2022/05

    Publisher: Elsevier BV

    DOI： 10.1016/j.geothermics.2021.102340 　

    ISSN： 0375-6505

  13. Wellbore stability in high-temperature granite under true triaxial stress

    Ryota Goto, Kiyotoshi Sakaguchi, Francesco Parisio, Keita Yoshioka, Eko Pramudyo, Noriaki Watanabe

    Geothermics　100　102334-102334　2022/03

    Publisher: Elsevier BV

    DOI： 10.1016/j.geothermics.2021.102334 　

    ISSN： 0375-6505

  14. CO2 injection-induced complex cloud-fracture networks in granite at conventional and superhot geothermal conditions

    Eko Pramudyo, Ryota Goto, Noriaki Watanabe, Kiyotoshi Sakaguchi, Kengo Nakamura, Takeshi Komai

    Geothermics　97　102265-102265　2021/12

    Publisher: Elsevier {BV}

    DOI： 10.1016/j.geothermics.2021.102265 　

    ISSN： 0375-6505

  15. A laboratory study of hydraulic fracturing at the brittle-ductile transition

    Francesco Parisio, Keita Yoshioka, Kiyotoshi Sakaguchi, Ryota Goto, Takahiro Miura, Eko Pramudyo, Takuya Ishibashi, Noriaki Watanabe

    Scientific Reports　11　(1)　2021/11/16

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41598-021-01388-y 　

    eISSN： 2045-2322

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    Abstract Developing high-enthalpy geothermal systems requires a sufficiently permeable formation to extract energy through fluid circulation. Injection experiments above water’s critical point have shown that fluid flow can generate a network of highly conductive tensile cracks. However, what remains unclear is the role played by fluid and solid rheology on the formation of a dense crack network. The decrease of fluid viscosity with temperature and the thermally activated visco-plasticity in rock are expected to change the deformation mechanisms and could prevent the formation of fractures. To isolate the solid rheological effects from the fluid ones and the associated poromechanics, we devise a hydro-fracture experimental program in a non-porous material, polymethyl methacrylate (PMMA). In the brittle regime, we observe rotating cracks and complex fracture patterns if a non-uniform stress distribution is introduced in the samples. We observe an increase of ductility with temperature, hampering the propagation of hydraulic fractures close to the glass transition temperature of PMMA, which acts as a limit for brittle fracture propagation. Above the glass transition temperature, acoustic emission energy drops of several orders of magnitude. Our findings provide a helpful guidance for future studies of hydro-fracturing of supercritical geothermal systems.

  16. Creating Cloud-Fracture Network by Flow-induced Microfracturing in Superhot Geothermal Environments

    Ryota Goto, Noriaki Watanabe, Kiyotoshi Sakaguchi, Takahiro Miura, Youqing Chen, Takuya Ishibashi, Eko Pramudyo, Francesco Parisio, Keita Yoshioka, Kengo Nakamura, Takeshi Komai, Noriyoshi Tsuchiya

    Rock Mechanics and Rock Engineering　54　(6)　2959-2974　2021/03/24

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s00603-021-02416-z 　

    ISSN： 0723-2632

    eISSN： 1434-453X

  17. Supercritical carbon dioxide fracturing of granite from conventional to superhot geothermal conditions Peer-reviewed

    Eko Pramudyo, Noriaki Watanabe, Sho Takeyama, Ryota Goto, Takahiro Miura, Kohki Hattori, Kiyotoshi Sakaguchi, Takeshi Komai

    SPWLA 25th Formation Evaluation Symposium of Japan, JFES 2019　2020

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Presentations 8

  1. Water-assisted CO2 fracturing of volcanic geothermal reservoirs

    Eko Pramudyo

    The 30th Japan Formation Evaluation Society (JFES) Symposium

  2. Water-assisted CO2 Fracturing of Volcanic Rocks under Geothermal Conditions: Characteristics and Effectiveness

    Eko Pramudyo

    EUROCK 2025　2025/06/16

  3. Characteristics and Effectiveness of Water-Assisted CO2 Fracturing in Various Volcanic Rocks under Geothermal Conditions

    Eko Pramudyo

    The 4th International Conference on Coupled Processes in Fractured Geological Media: Observation, Modeling, and Application (CouFrac2024)　2024/11/13

  4. Shear-slip and Complex Fracturing by CO2 Injection in Naturally Fractured Granite at Geothermal Conditions

    Eko Pramudyo

    European Geoscience Union (EGU) General Assembly 2023

  5. CO2 Injection-Induced Shearing and Complex Fracturing in Naturally Fractured Geothermal Environment

    Eko Pramudyo

    19th Conference on Flow Dynamics

  6. Characteristics and mechanism of CO2-based fracturing of granite in conventional and superhot geothermal environments

    Eko Pramudyo

    European Geoscience Union (EGU) General Assembly 2021

  7. Supercritical Carbon Dioxide Fracturing of Granite at Geothermal Conditions

    Eko Pramudyo

    Mining and Materials Processing Institute of Japan (MMIJ) annual conference

  8. Gas-based Fracturing in Granite from Subcritical/Brittle to Supercritical/Ductile Conditions

    Eko Pramudyo

    16th International Workshop on Water Dynamics

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