Needs and requirements for high temperature instrumentation in extreme geothermal environment

1. Needs and requirements for high temperature instrumentation in extreme geothermal environment -description based on EC HITI application and recent developments Dr. Ragnar K. Ásmundsson, ÍSOR Presentation for ENGINE Launching Conferance, Feb. 2006

2. Members of HITI HIgh Temperature Instruments for supercritical geothermal reservoir characterization and exploitation 1 ÍSOR Iceland 2 CNRS Montpellier France 3 BRGM France 4 Calidus Engineering Ltd. U.K 5 ALT Luxembourg 6 ANTARES Germany 7 Oxford Applied Technology U.K. 8 GFZ-Potsdam Germany 9 CRES Greece Submitted in Dec. 2004

3. IDDP – Iceland Deep Drilling Project The main objective of the HITI project is to develop sensors and methods to accurately determine the existing conditions of the reservoir and fluids in-situ at the base of a deep geothermal system in Reykjanes, Iceland.

4. Figure 1. Pressure-enthalpy diagram for pure H2O with selected isotherms. The conditions under which steam and water coexist is shown by the shaded area, bounded by the boiling point curve to the left and the dew point curve to the right. The arrows show various different possible cooling paths (Fournier, 1999).

5. Main objectives Developing downhole instruments capable of tolerating temperatures over 300 °C, and preferably up to 500 °C. • develop and field test downhole instruments and methods tolerating temperatures above current limits. These instruments include: temperature, pressure, fluid and rock electrical resistivity, natural gamma radiation, televiewer acoustic images, pH, casing collar locator, casing monitoring, fluid sampling, fluid flow, chemical temperature sensing and organic tracers, • adapt an existing HPHT (High Pressure, High Temperature) laboratory facility to the measurement of electrical resistivity at appropriate reservoir conditions and varying fluid nature, • validate the new instruments from the analysis of downhole data and samples (either core or fluid) from field tests in either hot existing wells, or the new IDDP hole.

6. Tool/method deliverables 1 MultiSensor, PLT400, 400°C 2 High temperature wireline T sensor 3 Fluid sampler, 400°C 4 Gamma ray (GR) detector, 300 °C 5 Dual Laterolog (DLL), 300 °C 6 Televiewer with casing thickness evaluation to 300°C 7 Distributed temperature sensing 8 HPHT rig 600°C laboratory 9 Na-Li temperature evaluation to 500°C 10 Organic tracers to 350°C

7. 400°C Memory tools, temperature, pressure, flow, casing collar and conductivity 350 °C Pressure / Temperature / flow Comparison: Kuster K10, 350°C (4h) HITI: To develop a memory based production-logging tool (Multi-sensor) with additional wireline surface readout transmission sub, capable of measuring pressure (P), temperature (T), flow rate (Q), casing collar location (CCL) and fluid conductivity (Cw) rated for use at temperatures of 400°C (CalEng)

8. 320 °C wireline temperature sensor 200 °C Pressure (qtz) / Temperature / Flow / Gamma - production tool – 200 °C rated digital electronics, 140MPa (20kpsi). Higher temperatures and functionality under development Comparison: Kuster, 177°C, 114 MPa HITI: To develop a wireline sensor measuring temperatures up to 320°C (BRGM)

9. Fluid sampler, 400 °C DEVELOPED 250 / 350 / 400 °C Fluid sampler - sold into Japan HITI: To develop a memory based borehole fluid sampler system to capture high quality fluid samples at well temperatures of 400 °C and transfer these to surface transportation vessels for onward shipment and analysis (CalEng).

10. Gamma ray (GR) detector, 300 °C 200 °C Temperature / Gamma / CCL - sold into Europe and USA  HITI: To develop a natural gamma radioactivity wireline logging sensor with 300 °C rating for basement alteration identification at reservoir level (ANTARES)

11. Dual Laterolog (DLL), 300 °C DEVELOPED 350 °C Resistivity tool - dual laterolog, 100MPa, microprocessor- digital electronics HITI: To develop a dual laterolog wireline logging sensor with 300 °C rating for rock electrical resistivity measurements and reservoir porosity evaluation

12. Televiewer with casing thickness evaluation to 300°C DEVELOPED HITI: Casing monitoring tool prototype improved from deployment at the test sites (ALT)

13. Distributed temperature sensing, 300°C Typical borosilicate glass can withstand temperatures up to 900°F (482°C) before deterioration begins. In the photo above, the glow of the furnace can be seen in the core bar as a glass combination begins the transformation process. Groß Schönebeck°: 143°C, 4.2 km HITI: DTS sensor cable will be tested in a high-enthalpy geothermal reservoir in Iceland and further developed (GFZ)

14. HPHT rig 600°C laboratory Complex resistivity measurements on mantle rocks were achieved with success up to 800°C (Gilbert & Mainprice) HITI: To modify the Montpellier University Paterson press in order to allow for electrical resistivity measurements at temperatures up to 600 °C, pressures up to 200 MPa, and variable fluid salinity (D8 deliverable as an "HPHT" rig).

15. Organic tracers to 350°C and Li analysis HITI: To estimate the reservoir temperature from chemical analyses performed on fluid samples collected either in-situ or at surface. Isotopic Li analyses, performed by ICP-MS/MC on high temperature fluid samples for the first time, are proposed to ameliorate the knowledge of this geothermometer and to confirm the nature of the reservoir rocks in contact with the geothermal fluid. To use organic compounds (sulfonate naphthalene family) to carry out tracer tests in high temperature geothermal wells (up to 350°C) in order to detect possible hydraulic connections between wells and to estimate the reservoir capacity (storativity) and the fluid flow rate.

16. Complete oxide isolation of all transistors TiW barrier layer on all metals and contacts Variable width oxide trench Twin well technology CrSi thin film resistors available N+poly to N+silicon linear capacitor 0.8 micron 5 volt digital capability Designed for 50,000 hours of 225°C operation Final test at 225°C ambient Burn-in at 250°C

17. 7