Staff | David Prambudi Sahara, ST., MT.
David grew up in a mountainous area of Trenggalek, East Java. He use to explore geological-related sites, e.g. active and dormant volcanoes, karst cave, rivers along the faulted block. His great passion in nature motivated him to move to bandung at 2005 and pursued degree at geophysical engineering department, Institut Teknologi Bandung (ITB). He finished his Master degree at 2011 and has worked as an academic staff from then on. Currently he is finishing his PhD at Institute of Applied Geoscience, Karlsruhe Institute of Technology (KIT).
During his bachelor at ITB he had a chance to collaborate with Dr. Hiroshi Asanuma from Tohoku University in developing an in-house software for hypocenter relocation using double-difference method. This work was also supervised by Prof. Sri Widiyantoro and Dr. Moh. Rachmat Sule. His work had been presented at the 2010 European Geothermal PhD day at Potsdam (Germany) and was awarded the best poster and presentation. Currently this method is becoming hot topic for student thesis and is widely used in geothermal as well as oil gas industry.
His current main research is in rock mechanics field. Hydraulic stimulation has been booming lately for enhancing the hydraulic connectivity of the unconventional reservoir. This motivated him to perform an improved characterization of the mechanical properties of fractured reservoirs and their impact on hydraulic stimulation. He is working with vast geo-datase from arguably the best enhanced geothermal system (EGS) site Soultz-sous-Forets, France. His work includes:
1. Stress inversion from borehole data and focal mechanism
2. Numerical modeling of failure mechanism in complex material
3. Analysis of wellbore stability
4. Mechanics-related interpretation of hydraulic stimulation
Doctoral Degree Program, Doctor, 2012 - now, Karlsruhe Institute of Technology (KIT),Karlsruhe, Germany.
Master Degree Program, Master , 2010-2011, Department of Geophysical Engineering, Institut Teknologi Bandung (ITB), Bandung, Indonesia.
Undergraduate Degree Program, Sarjana, 2005-2009, Department of Geophysical Engineering, Institut Teknologi Bandung (ITB), Bandung, Indonesia.
PhD project funded by Energie Baden-Wuerttemberg (EnBW) and the Helmholtz Association of German Research Centres: Deep reservoir stress characterization, 2015 - now
Research assistant in the LOGRO project funded by BMBF Germany: Developing the microseismic semi-realtime monitoring in Bruchsal geothermal field, 2012 - 2015
Junior Geophysicist in the Microseismic project funded by Pertamina Geothermal Energy project: Study of the possibility of the microseismic method in characterizing the reservoir structure from pre-production microseismic recorded data, 2011
Junior Geophysicist in the 3 years join research ITB - Pertamina Geothermal Energy : Developing Petrel Plugin for Double-Difference (DD) hypocenter relocation, tomography DD and fochal mechanism analysis at the PGE geothermal field, 2011
Sahara, D. P.; Schoenball, M.; Gerolymatou, E.; Kohl, T.; (submitted): Analysis of borehole breakout development using continuum damage mechanics. In International Journal of Rock Mechanics and Mining Sciences
Sahara, D. P.; Schoenball, M.; Kohl, T.; Müller, B.I.R. (2014): Impact of fracture networks on borehole breakout heterogeneities in crystalline rock. In International Journal of Rock Mechanics and Mining Sciences 71, pp. 301–309. DOI: 10.1016/j.ijrmms.2014.07.001
Schoenball, M.; Sahara, D. P.; Kohl, T. (2014): Time-dependent brittle creep as a mechanism for time-delayed wellbore failure. In International Journal of Rock Mechanics and Mining Sciences 70 (0), pp. 400–406. DOI: 10.1016/j.ijrmms.2014.05.012
Sahara, D. P.; Kusumo, A. W.; Widiyantoro, S.; Sule, M. R. (2011): Aplikasi Metode Double Differential Untuk Penentuan Relokasi Hiposenter Gempa Vulkanik Gunung Kelud Secara Akurat, in Jurnal Teknologi Mineral (JTM) ITB
CONFERENCES (selected in the last 5 years)
Sahara, D. P.; Schoenball, M.; Kohl, T; Gerolymatou, E. (2015): Modeling of inelastic failure leading to borehole breakout, in 4th European Geothermal Workshop, Strasbourg, France
Sahara, D. P.; Schoenball, M.; Kohl, T; Mueller, B. (2015): Analysis of Stress Heterogeneities in Fractured Crystalline Reservoir, in World Geothermal Congress 2015, Australia-New Zealand
Sahara, D. P.; Schoenball, M.; Kohl, T; Mueller, B. (2014): Breakout Orientation Perturbation Modeling in Fractured Crystalline Rock, in 3rd European Geothermal Workshop, Karlsruhe, Germany
Sahara, D. P.; Schoenball, M.; Kohl, T. (2013): The role of active fractures on borehole breakout development, in American Geosciences Union Fall Meeting 2013, San Francisco, USA
Sahara, D. P.; Kohl, T. (2013): Stress heterogeneity in the fractured crystalline reservoir, in 2nd European Geothermal Workshop, Strasbourg, France
Schoenball, M.; Sahara, D. P.; Kohl, T. (2013): Time-dependent brittle creep as mechanism for time-delayed wellbore failure, in 6th International Symposium on In-Situ Rock Stress Sendai, Japan
Sahara, D. P.; Kohl, T. (2013): Importance of active fractures in the borehole breakouts heterogeneity, in 9th International Geothermal Conference 2013, Freiburg, Germany (invited paper)
Sahara, D. P.; Kohl, T.; Schoenball, M. (2012): Numerical calculation of a stress field near a borehole under complex conditions, in Celle International Drilling Workshop, Celle, Germany
Sahara, D. P.; Widiyantoro, S.; Nugraha, A.D.; Sule, M. R.; Lühr, B.G. (2011): Understanding the mechanism of subduction process and its implication to surface seismicity and volcanic activity in Central Java - Indonesia from high resolution tomography, in SEGJ International Symposium, Kyoto, Japan
Sule, M. R.; Sahara, D. P.; Kusnadi, Y.; Imaduddin, I; Nugraha, A; Nugraha, A.D.; Setiawan, T.; Widiyantoro, S.; Matsuoka, T. (2011): Development of Hard- and Software of Microseismic for Geothermal Exploration and Monitoring, in World Renewable Energy Congress, Denpasar, Indonesia
Sahara, D. P.; Widiyantoro, S,; Nugraha, A. D.; Sule, M. R.; Lühr, B. G. (2011): Resolution Improvement of The Tomographic Inversion by Incorporating Difference Data: Case Study of Meramex Data From Central Java – Indonesia, Joint Conference Meeting HAGI-IAGI, Makasar, Indonesia
Sahara, D.P.; Widiyantoro, S.; Nugraha, A.D.; Sule, M. R.; Luehr, B. G. (2011): Determination of Subsurface Velocity Structure and Precise Hypocenter Relocation by using Double-Difference Technique: Case Study of MERAMEX Data from Central Java – Indonesia, European Geothermal Union, Viena, Austria
Lühr, B.G.; Koulakov, I.; Rabbel, W.; Zschau, J.; Ratdomopurbo, A.; Brotopuspito, K.S.; Fauzi, Sahara, D. P. (2011): Fluid Ascent and Magma Storage Beneath Gunung Merapi, European Geothermal Union, Viena, Austria
E-mail Address david.sahara[at]outlook.de