Thermal, mechanical and chemical influences on the performance of optical fibres for distributed temperature sensing in a hot geothermal well

Structural well-bore integrity is an important issue for sustainable provision of geothermal energy. Raman scattering based fibre optic distributed temperature sensing (DTS) can help to monitor the status of a well and therefore help to optimize expensive work-over activities. This study reports on the installation of a fibre-optic cable in the cemented annulus behind the anchor casing in the high temperature geothermal well HE-53, Hellisheiði geothermal field, SW Iceland. Although the cable has been damaged during the installation, temperature data could be acquired during the entire length of installation down to 261.3 m. Temperature measurements were performed during the installation in spring 2009, during the onset of a flow test in summer 2009 and after a 8.5 month shut-in period in summer 2010. During the flow test, maximum temperatures of 230 °C were measured after 2 weeks fluid production. Using optical time domain reflectometry (OTDR), attenuation measurements at 850 and 1,300 nm enabled to identify mechanical, thermal, and chemical degradation along the optical fibre. The observed degradation led to erroneous temperature readings and limits, due to the optical budget of the DTS system, the accessible length of the fibre. The characteristics and the influence of the different degradation mechanisms on the accuracy of the DTS measurements are discussed and recommendations for an optimized installation are given.

[1]  Jiten D. Kaura,et al.  High-temperature fibers provide continuous DTS data in a harsh SAGD environment , 2008 .

[2]  H. Wilhelm,et al.  Estimation of the in-situ thermal resistance of a borehole using the Distributed Temperature Sensing (DTS) technique and the Temperature Recovery Method (TRM) , 2000 .

[3]  H. Fabian,et al.  Analysis of OH absorption bands in synthetic silica , 1996 .

[4]  S P Potter,et al.  Energy supply. , 1973, Science.

[5]  S. Arnórsson.  Geothermal systems in Iceland: Structure and conceptual models—I. High-temperature areas , 1995 .

[6]  Zhi Zhou,et al.  Casing Pipe Damage Detection with Optical Fiber Sensors: A Case Study in Oil Well Constructions , 2010 .

[7]  D. Simoff,et al.  Thermal Stability of Specialty Optical Fibers , 2008, Journal of Lightwave Technology.

[8]  David John Hill,et al.  Distributed fibre optic sensors for pipeline protection , 2009 .

[9]  D. Blackwell,et al.  Application of optical‐fiber temperature logging—An example in a sedimentary environment , 1997 .

[10]  M. Kraume,et al.  Thermal–hydraulic measurements and modelling of the brine circuit in a geothermal well , 2013, Environmental Earth Sciences.

[11]  Bernhard Prevedel,et al.  The CO 2 SINK Boreholes for Geological Storage Testing , 2008 .

[12]  Kazuo Kyuma,et al.  Development of fibre optic sensing systems—A review , 1982 .

[13]  Chung E. Lee.  Self-calibrating technique enables long-distance temperature sensing , 2007 .

[14]  J. Stone,et al.  Overtone vibrations of OH groups in fused silica optical fibers. Technical report , 1981 .

[15]  J. Cella.  Degradation and stability of polyimides , 1992 .

[16]  S. Saito,et al.  The Iceland deep drilling project: Its global significance , 2003 .

[17]  S. Frick,et al.  Energetic Use of EGS Reservoirs , 2010 .

[18]  Ernst Huenges,et al.  In situ thermal conductivity of gas‐hydrate‐bearing sediments of the Mallik 5L‐38 well , 2005 .

[19]  Barry Freifeld,et al.  Ground surface temperature reconstructions: Using in situ estimates for thermal conductivity acquired with a fiber‐optic distributed thermal perturbation sensor , 2008 .

[20]  T. J. Nowak.  The Estimation of Water Injection Profiles From Temperature Surveys , 1953 .

[21]  B. T. Meggitt,et al.  Optical Fiber Sensor Technology , 1999 .

[23]  Susan C. Steele-Dunne,et al.  Double-Ended Calibration of Fiber-Optic Raman Spectra Distributed Temperature Sensing Data , 2012, Sensors.

[24]  T. Driesner,et al.  The system H2O–NaCl. Part I: Correlation formulae for phase relations in temperature–pressure–composition space from 0 to 1000 °C, 0 to 5000 bar, and 0 to 1 XNaCl , 2007 .

[25]  A. Hartog.  A distributed temperature sensor based on liquid-core optical fibers , 1983, Journal of Lightwave Technology.

[26]  Eckart Hurtig,et al.  Fibre-optic temperature measurements in shallow boreholes: experimental application for fluid logging , 1994 .

[27]  W. M. Cobb,et al.  Static Formation Temperature From Well Logs - An Empirical Method , 1975 .

[28]  Wilfred A. Elders,et al.  The Iceland Deep Drilling Project: a search for deep unconventional geothermal resources , 2005 .

[29]  Kwang Suh,et al.  Auto-correction method for differential attenuation in a fiber-optic distributed-temperature sensor. , 2008, Optics letters.

[30]  M. McLinden,et al.  NIST Standard Reference Database 23: Reference Fluid Thermodynamic and Transport Properties-REFPROP, Version 8.0 , 2007 .

[31]  Saiied M. Aminossadati,et al.  Distributed temperature measurements using optical fibre technology in an underground mine environment , 2010 .

[32]  J Weiss,et al.  Development of Fibers Optic Cables for Permanent Geothermal Wellbore Deployment , 2001 .

[33]  B. Kristjansson,et al.  The Hengill-Hellisheiði Geothermal Field. Development of a Conceptual Geothermal Model , 2004 .

[34]  Kazuya Saito,et al.  Silica glass: A material for photonics , 2000 .

[35]  J. Henninges.  Thermal Properties of Gas-Hydrate-Bearing Sediments and Effects of Phase Transitions on the Transport of Heat Deduced from Temperature Logging at Mallik, NWT, Canada , 2005 .

[36]  Emir Karamehmedovic,et al.  Fibre optic distributed temperature sensing using IOFDR , 2004, European Workshop on Optical Fibre Sensors.

[37]  C. Smithpeter,et al.  Evaluation of a Distributed Fiber-Optic Temperature Sensor for Logging Wellbore Temperature at the Beowawe and Dixie Valley Geothermal Fields , 1999 .

[38]  J. A. Buck,et al.  Fundamentals of optical fibers , 1995 .

[39]  George Albert Brown,et al.  Distributed temperature sensing (DTS) to characterize the performance of producing oil wells , 2000, SPIE Optics East.

[40]  Thomas Reinsch,et al.  Temperature-dependent characterization of optical fibres for distributed temperature sensing in hot geothermal wells , 2010, 1206.1853.

[41]  G. Zimmermann,et al.  Wireline Distributed Temperature Measurements and Permanent Installations Behind Casing , 2004 .

[42]  K. L. Mittal,et al.  Polyimides: Fundamentals and Applications , 1996 .

[43]  D. Peckham,et al.  Light-Guiding Fundamentals and Fiber Design , 2007 .

[44]  Sverrir Þórhallsson.  Geothermal well operation and maintenance , 2003 .

[45]  G. Chilingarian,et al.  Determination of True Static Formation Temperature from Well Logs , 1986 .

[46]  H. Franzson,et al.  Geology and Hydrothermal Alteration of the Hverahlid HT-System , SW-Iceland , 2009 .