Permanent Distributed Temperature Sensing at the Ketzin CO 2 Storage Test Site. ieaghg 6th Wellbore Network Meeting, April 28-29, 2010

Transcription

1 Permanent Distributed Temperature Sensing at the Ketzin CO 2 Storage Test Site Jan Henninges ieaghg 6th Wellbore Network Meeting, April 28-29, 2010

2 Introduction Objectives of temperature measurements at Ketzin: Monitoring of CO 2 migration during injection into a saline aquifer, and the thermal state of borehole and reservoir. Methods: Passive: fiber-optic distributed temperature sensing (DTS) Active: heat-pulse measurement (collaboration LBNL) Outline: Method of distributed temperature sensing Installation of sensor cables at Ketzin Results from temperature monitoring, with focus on borehole integrity and detection of near-wellbore flow (cementing, CO 2 injection)

3 Distributed Temperature Sensing (DTS) m < 12 km

4 DTS accuracy and precision DTS unit: Sensa DTS 800 M10 Fiber length: 2908 m Spatial resolution: 1 m

5 DTS downhole cable design 150 C, psi Tube: 316SS / Incoloy 825 OD 6.35 mm (1/4 ) AFL Telecommunications

6 Ketzin: Permanent downhole sensors

7 Permanent installation of sensor cables

8 DTS-Monitoring: Well cementing stage tool packer Temp. increase: setting of cement (heat of hydration) filter Failure!

9 DTS-Monitoring during injection Injection temperatures t (upper filter): +/- 5 C from formation temperature

10 Temperature changes injection well Injection intervals filters cement

11 DTS-Monitoring during injection Minor variations (~0.5 C) Distinct anomalies (~1.5 C) Injection temperatures t (upper filter): +/- 5 C from formation temperature

12 Temperature profiles obs. well (Ktzi200) Anomaly at lower filter between start of injection and b.t. of CO2 Reference points timeseries plots: Upper filter Lower filter down/cross-flow

13 Temperature and fluid density Ktzi200 Fluid density: 1.14 (brine) 0.17 (CO 2, gas) 0.81 (CO 2, liq.) liq. / s.c. CO 2 density = f(p,t) 0.34 (CO 2, s.c.) Heat-pipe effect Temperature: Baseline (before injection) Anomaly (12/08) Successive increase at top, decrease at bottom Equilibrium (after 3/09)

14 Camera inspection Ktzi202: 300m depth

15 Pressure temperature diagram Ktzi 200 ressure (kpa) Vapor pressure curve Crit. point PWPRE (kpa) hydrostatic WPRE (kpa) CTP (kpa) WPRE (kpa) Temperature ( C) June 2009 measurement: < 400m: equal/close to vapor pressure curve for CO 2 (2-phase conditions) > 400m: liquid and supercritical CO 2 Implications: difficult to predict downhole pressure, P/T conditions fixed to vapor pressure curve (2-phase region)

16 Active heating of borehole with electical heater cable, temperature monitoring with DTS Heat-pulse measurement Numerical inversion: in-situ thermal conductivity (collaboration with B. Freifeld, LBNL) Heated zone

17 Change in thermal conductivity after start of CO 2 injection Blue: baseline Red: repeat after injection of t CO 2 Purple: decrease due to replacement of brine by CO 2 Distinct zone with decrease in thermal conductivity: main zone of CO 2 injection. (collaboration with B. Freifeld, LBNL)

18 Summary Borehole temperature monitoring using DTS: Advantages: continuous monitoring of downhole conditions and processes along entire well, no downhole electronics Drawbacks: lower accuracy, higher drift of data over time Temperature: good indicator for flow processes inside well DTS monitoring during cementing: operations, setting of cement DTS monitoring during CO 2 injection: Detection of behind-casing flow using temperature 2-phase conditions: Temp. fixed to vapor pressure curve Heat-pulse measurements: changes of thermal conductivity

19 Outlook DTS and heater cables: Hybrid wireline cables for temporary / retrievable deployment Borehole integrity: Methods for on-line analysis of DTS data to derive information about cement quality, flow (leakage) rates Enhanced detection of flow / advective transport of heat using heat pulse method

20 Acknowledgements: DTS monitoring i team GFZ (J. Schrötter, M. Poser, C. Cunow, T. Reinsch), B.M. Freifeld (LBNL), Schlumberger Carbon Services, VNG Verbundnetz Gas AG, B. Prevedel, C. Schmidt-Hattenberger (GFZ), H. Schütt (GFZ/StatoilHydro). CO 2 SINK was funded by the European Commission (Sixth Framework Program, FP6), the German Federal Ministry of Economics and Technology (COORETEC Program) and the Federal Ministry of Education and Research (GEOTECHNOLOGIEN Program). Thank you for your attention!