Skip to main content
SpringerLink
Log in

Characterization of 4.2-km-Deep Fractured Granodiorite Cores from Pohang Geothermal Reservoir, Korea

  • Original Paper
  • Published:
Rock Mechanics and Rock Engineering Aims and scope Submit manuscript

A Correction to this article was published on 31 July 2019

This article has been updated

Abstract

The rock core test is the most direct and reliable way to measure fundamental physical, hydraulic, and mechanical properties for underground reservoir characterization. A 10-cm diameter and 3.6-m-long granodiorite core was retrieved from a 4.2-km-deep geothermal well at the Pohang Enhanced Geothermal System (EGS) site in Korea. Numerous natural fractures were detected in the core and induced core disks were observed. We optimized the sample preparation with this limited core for various tests based on the scanned X-ray CT images that visualized all the fractures in the core. We measured the basic mechanical—the deformation and strength properties of intact rock—and thermal properties of intact samples. In particular, fracture deformation and strength properties were directly measured by conducting direct shear tests on pre-existing natural fractures. The seismic velocity and normal fracture stiffness were compared with the wireline logging and injection test measurements, respectively. The discrepancies between the in situ data and laboratory experiment are due to the stress dependency of properties. The measurements presented in this paper provide essential inputs for the EGS reservoir modelling and a dataset of properties for the fractured granite reservoir at a great depth from which few samples have been retrieved thus far.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2

(modified from Lee et al. 2015). The PX-2 well is located 600 m from the PX-1

Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9

Similar content being viewed by others

Change history

  • 31 July 2019

    We note that in the published article the number given in the Acknowledgements is incorrect. It should have been written: “The research was supported by a Grant (No. 20123010110010).

References

  • ASTM D4535-13e2 (2013a) Standard test methods for measurement of thermal expansion coefficient of rock using dilatometer. ASTM International, West Conshohocken

  • ASTM E1461-13 (2013b) Standard test method for thermal diffusivity by the flash method, ASTM International, West Conshohocken

  • ASTM E1269-11 (2018) Standard test method for determining specific heat capacity by differential scanning calorimetry. ASTM International, West Conshohocken

  • Aydin A, Basu A (2005) The Schmidt hammer in rock material characterization. Eng Geol 81(1):1–14

    Article  Google Scholar 

  • Barton N, Choubey V (1977) The shear strength of rock joints in theory and practice. Rock Mech 10(1–2):1–54

    Article  Google Scholar 

  • Beardsmore G, Cull J (2001) Crustal heat flow: a guide to measurement and modelling. Cambridge University Press, Cambridge

    Book  Google Scholar 

  • Berckhemer H, Rauen A, Winter H, Kern H, Kontny A, Lienert M, Nover G, Pohl J, Popp T, Schult A, Zinke J, Sofferl HC (1997) Petrophysical properties of the 9-km-deep crustal section at KTB. J Geophys Res Solid Earth 102(B8):18337–18361

    Article  Google Scholar 

  • Birch F, Clark H (1940) The thermal conductivity of rocks and its dependence upon temperature and composition. Am J Sci 238(8):529–538

    Article  Google Scholar 

  • Blöcher MG, Zimmermann G, Moeck I, Brandt W, Hassanzadegan A, Magri F (2010) 3D numerical modeling of hydrothermal processes during the lifetime of a deep geothermal reservoir. Geofluids 10(3):406–421

    Article  Google Scholar 

  • Byerlee JD (1978) Friction of rocks. Pure Appl Geophys 116(4–5):615–626

    Article  Google Scholar 

  • Chang C, Haimson B (2000) True triaxial strength and deformability of the German Continental Deep Drilling Program (KTB) deep hole amphibolite. J Geophys Res Solid Earth 105(B8):18999–19013

    Article  Google Scholar 

  • Chang C, Zoback MD, Khaksar A (2006) Emprical relations between rock strength and physical properties in sedimentary rocks. J Pet Sci Eng 51:223–237

    Article  Google Scholar 

  • Clauser C, Huenges E (1995) Thermal conductivity of rocks and minerals. In: Ahrens TJ (ed) Rock physics and phase relations: a handbook of physical constants. Am Geophys Union, Washington DC, pp 105–126

    Google Scholar 

  • Diaz M, Kim KY, Yeom S, Zhuang L, Park S, Min KB (2017) Surface roughness characterization of open and closed rock joints in deep cores using X-ray computed tomography. Int J Rock Mech Min Sci 98:10–19

    Article  Google Scholar 

  • Ellis DV (1987) Well logging for earth scientists. Elsevier, Amsterdam

    Google Scholar 

  • Emmermann R, Lauterjung J (1997) The German continental deep drilling program KTB: overview and major results. J Geophys Res Solid Earth 102(B8):18179–18201

    Article  Google Scholar 

  • Fjaer E, Holt RM, Horsrud P, Risnes R (2008) Petroleum related rock mechanics, 2nd edn. Elsevier, Amsterdam

    Google Scholar 

  • Genter A, Traineau H (1992) Borehole EPS-1, Alsace, France: preliminary geological results from granite core analyses for Hot Dry Rock research. Sci Drill 3:205–214

    Google Scholar 

  • Géraud Y, Rosener M, Surma F, Place J, Le Garzic É, Diraison M (2010) Physical properties of fault zones within a granite body: example of the Soultz-sous-Forêts geothermal site. C R Geosci 342(7–8):566–574

    Article  Google Scholar 

  • Grigoli F, Cesca S, Rinaldi AP, Manconi A, López-Comino JA, Clinton JF, Westaway R, Cauzzi C, Dahm T (2018) The November 2017 Mw 5.5 Pohang earthquake: a possible case of induced seismicity in South Korea. Science 360(6392):1003–1006

    Article  Google Scholar 

  • Häring MO, Schanz U, Ladner F, Dyer BC (2008) Characterisation of the Basel 1 enhanced geothermal system. Geothermics 37(5):469–495

    Article  Google Scholar 

  • Hofmann H, Zimmermann G, Farkas M, Huenges E, Zang A, Leonhardt M, Kwiatek G, Martinez-Garzon P, Bohnhoff M, Min KB, Fokker P, Westaway R, Bethmann F, Meier P, Yoon K, Choi J, Lee TJ, Kim KY (2018) First field application of cyclic soft stimulation at the Pohang Enhanced Geothermal System site in Korea. Geophys J Int (under review)

  • Jung R (2013) EGS—goodbye or back to the future. In: International conference for effective and sustainable hydraulic fracturing, Brisbane, pp 95–121

    Google Scholar 

  • Kern H (1978) The effect of high temperature and high confining pressure on compressional wave velocities in quartz-bearing and quartz-free igneous and metamorphic rocks. Tectonophys 44(1):185–203

    Article  Google Scholar 

  • Kim H (2017) Integrated estimation of in-situ rock stress at Pohang geothermal reservoir in Korea. PhD Dissertation, Seoul National University

  • Kim HC, Lee Y (2007) Heat flow in the Republic of Korea. J Geophys Res 112:B05413

    Google Scholar 

  • Kim H, Xie L, Min KB, Bae S, Stephansson O (2017) Integrated in-situ stress estimation by hydraulic fracturing, borehole observation and numerical analysis at the EXP-1 borehole in Pohang, Korea. Rock Mech Rock Eng. https://doi.org/10.1007/s00503-017-1284-1

    Google Scholar 

  • Korea Meteorological Administration (2018) Earthquake information. http://www.kma.go.kr/eng/weather/current_state/information.jsp. Accessed 26 Mar 2018

  • Lavrov A (2003) The Kaiser effect in rocks: principles and stress estimation techniques. Int J Rock Mech Min Sci 40(2):151–171

    Article  Google Scholar 

  • Lee SW, Song JJ (2006) A study on the change of uniaxial compressive strength and Young’s modulus according to the specimen size of intact material. Tunn Tech 8(3):205–207 (Korean)

    Google Scholar 

  • Lee Y, Park S, Kim J, Kim HC, Koo MH (2010) Geothermal resource assessment in Korea. Renew Sustain Energy Rev 14(8):2392–2400

    Article  Google Scholar 

  • Lee TJ, Song Y, Park DW, Jeon J, Yoon WS (2015) Three dimensional geological model of Pohang EGS Pilot Site, Korea. In: World Geothermal Congress 2015, Melbourne (paper 31025)

    Google Scholar 

  • Li Y, Schmitt DR (1998) Drilling-induced core fractures and in situ stress. J Geophys Res Solid Earth 103(B3):5225–5239

    Article  Google Scholar 

  • Li Y, Zhang Y (2015) Quantitative estimation of joint roughness coefficient using statistical parameters. Int J Rock Mech Min Sci 77:25–35

    Google Scholar 

  • Muralha J, Grasselli G, Tatone B, Blumel M, Chryssanthakis P, Yujing J (2014) ISRM suggested method for laboratory determination of the shear strength of rock joints: revised version. Rock Mech Rock Eng 47:291–302

    Article  Google Scholar 

  • Paillet FL, Cheng CH (1991) Acoustic waves in boreholes. CRC Press, Boca Raton

    Google Scholar 

  • Park S, Kim KI, Xie L, Kwon S, Yoo H, Min KB, Choi J, Yoon WS, Yoon K, Song Y, Lee TJ, Kim KY, Zimmermann G, Guinot F, Meier P (2018) The first hydraulic stimulations in a fractured geothermal reservoir in Pohang, South Korea—part I. Observations and analysis (manuscript)

  • Rider M (2002) The geological interpretation of well logs. Rider-French Consult Ltd., Scotland

    Google Scholar 

  • Rutqvist J, Rinaldi AP, Cappa F, Moridis GJ (2013) Modeling of fault reactivation and induced seismicity during hydraulic fracturing of shale-gas reservoirs. J Pet Sci Eng 107:31–44

    Article  Google Scholar 

  • Santarelli FJ, Marsala AF, Brignoli M, Rossi E, Bona N (1998) Formation evaluation from logging on cuttings. SPE Reserv Eval Eng 1(3):238–244

    Article  Google Scholar 

  • Shen B (2008) Borehole breakouts and in situ stresses. In: Proceedings of the First Southern Hemisphere International Rock Mechanics Symposium, Australian Centre for Geomechanics, Perth, pp 407–418

    Google Scholar 

  • Spencer JW, Nur AM (1976) The effects of pressure, temperature, and pore water on velocities in Westerly granite. J Geophys Res 81(5):899–904

    Article  Google Scholar 

  • Trčková J, Živor R, Přikryl R (2002) Physical and mechanical properties of selected amphibolite core samples from the Kola Superdeep Borehole KSDB-3. Terra Nova 14(5):379–387

    Article  Google Scholar 

  • Ulusay R (2015) The ISRM suggested methods for rock characterization, testing and monitoring: 2007–2014. Springer, Cham

    Google Scholar 

  • Ulusay R, Hudson JA (2007) The complete ISRM suggested methods for rock characterization, testing and monitoring: 1974–2006. ISRM Turkish National Group, Ankara

    Google Scholar 

  • Valley B, Evans KF (2007) Stress state at Soultz-sous-Forêts to 5 km depth from wellbore failure and hydraulic observations. In: Proceedings, 32nd workshop on geothermal reservoir engineering, Stanford, pp 17481–17469

  • Valley B, Evans KF (2015) Estimation of the stress magnitude in Basel enhanced geothermal system. In: World Geothermal Congress 2015, Melbourne, pp 19–25

    Google Scholar 

  • Yoo H, Park S, Xie L, Min KB, Rutqvist J, Rinaldi AP (2018) The first hydraulic stimulations in a fractured geothermal reservoir in Pohang, South Korea—Part II. Numerical Modeling (manuscript)

  • Zajas J, Heiselberg P (2013) Measurements of thermal diffusivity, specific heat capacity and thermal conductivity with LFA 447 apparatus. DCE technical report 144. Aalborg University, Denmark

    Google Scholar 

Download references

Acknowledgements

This research was supported by a Grant (No. 20133030000240) from the New and Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning, and funded by the Ministry of Trade, Industry and Energy of the Korean Government. Institute of Engineering Research at Seoul National University is acknowledged for the support on manuscript preparation. NexGeo Inc. provided support on the acquisition of the deep rock cores.

Author information

Authors and Affiliations

  1. Seoul National University, (08826) 1, Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea

    Saeha Kwon, Linmao Xie, Sehyeok Park, Kwang-Il Kim & Ki-Bok Min

  2. Korea Institute of Civil Engineering and Building Technology, (10223) 283, Goyang-daero, Ilsanseo-gu, Goyang, Gyeonggi, Republic of Korea

    Kwang Yeom Kim & Li Zhuang

  3. NEXGEO Inc, (05703) 16-15, Garakbon-Dong, Songpa-Gu, Seoul, Republic of Korea

    Jaiwon Choi

  4. Korea Institute of Geoscience and Mineral Resources, (34132) 124, Gwahak-ro, Yuseong, Daejeon, Republic of Korea

    Hanna Kim & Tae Jong Lee

Authors
  1. Saeha Kwon
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Linmao Xie
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Sehyeok Park
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Kwang-Il Kim
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Ki-Bok Min
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Kwang Yeom Kim
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Li Zhuang
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Jaiwon Choi
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Hanna Kim
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Tae Jong Lee
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Ki-Bok Min.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Kwon, S., Xie, L., Park, S. et al. Characterization of 4.2-km-Deep Fractured Granodiorite Cores from Pohang Geothermal Reservoir, Korea. Rock Mech Rock Eng 52, 771–782 (2019). https://doi.org/10.1007/s00603-018-1639-2

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00603-018-1639-2

Keywords

Search

Navigation