Reservoir Engineering at two Geothermal field in El Salvador Manuel - - PowerPoint PPT Presentation

Reservoir Engineering at two Geothermal field in El Salvador

Manuel Monterrosa July 2007 Reykjavik, ENGINE WP 4

Contents

• 1. Field and well locations
• 2. Production and thermodynamic monitoring
• 3. Well testing
• 4. Pressure trend under exploitation
• 5. Numerical modeling
• 6. Forecasting
• 7. Production enhacement
• 8. Conclusion

Ahuachapán Geothermal Field

Berlin Geothermal Field

Monitoring

• Pressure and temperature profile in static or flowing

conditions into the wells are used to know the permeable zones, flashing point, down flow, flow pattern into reservorio, pressure and temperature decline, etc

• Steam yield and injection flow rate are used to correlate

with the electricity production (efficiency Sustainability)

• Production characteristic (Q vrs WHP) indicate the
• perational condition to the power plant
• Chemistry of fluids (liquid, steam and gas) and

steam/liquid flowrate are requiered to know which are the processes happening into the reservoir (dilution, boiling, injection return, thermal breakthrough, scaling

• r corrosion, mineral scaling inhibition,etc)

PRESION Y TEMPERATURA POZO AH-35C 200 400 600 800 1000 1200 1400 1600 25 50 75 100 125 150 175 200 225 250 TEMPERATURA (°C) PROFUNDIDAD (m) 200 400 600 800 1000 1200 1400 1600 10 20 30 40 50 60 70 80 90 100 110 120 PRESION (Bar) T.Est.5Jun T.Dinamico T.Est.13Jun P.Estatico P.Dinamico

PRUEBA DE PRODUCCION POZO AH-35 C

20 40 60 80 100 120 140 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0

WHP ( Bar g ) Masas ( kg/s )

4 Jun 20 Jun

WHP: 7.4 bar Steam: 19.4 kg/s Liquid: 96.8 kg/s Enthalpy 1,070 kJ/kg.

Discharge test well AH-35C Junio 20th, 2007

10 15 20 25 30 35 40 1975 1978 1982 1986 1989 1993 1997 2000 2004 2008 2011 Pressure [bar] 500 1000 1500 2000 2500 3000 Mass [T/h]

AH25 Pressure at +200 m asl Extracted Mass

Mass and pressure historical trend, Ahuachapán Field

I II

50 MW

III

50 MW

IV

65 MW

V

80 MW Operation w/injection Not injection

Power production and Pressure, Ahuachapan field

5 10 15 20 25 30 35 40 45 06-Dic-99 05-Dic-00 05-Dic-01 05-Dic-02 05-Dic-03 04-Dic-04 04-Dic-05 04-Dic-06 04-Dic-07 bar 100 200 300 400 500 600 700 800 900 Masa total (kg/s)

Mass and pressure trend at the Berlin Field

U1 and U2 U3

Numerical modeling for the Ahuachapán field

Numerical modeling for the Berlín field

500 1000 1500 2000 2500 3000 1992 1997 2002 2007 2012 2017 2022 2027 Years Flow Rate [t/h] 25 50 75 100 125 150 Pressure [bar] Liquid Phase Measured produced liquid Steam Phase Measured produced steam Pressione TR5 @ -1150 Reservoir Pressure at -1150 mbsl

Simulation from the beginning to year 2026

Production enhancement

• Due to mud damage or

naturally self sealling formation, permeability in the feed zone could be lower than the expected

• ne
• To enhance the steam

production acid injection could be used.

• In 2006 well TR-5B was

stimulated using 38 m3 HCl as preflusing and 57 m3 of HCL and ammonium bifluorine

10 20 30 40 50 60 70 80 90 100 5 10 15 20 25 30 bara kg/s Vapor Pre Total Pre Vapor Post Total Post

Conclusions

• The monitoring is the best way to gatter

information from the wells and the whole geothermal system.

• Reservoir engineering technics contribute to

welldone field management and the sustainable resource utilization.

• There are several way to increase the energy

yield from the reservoir: pressure declining, steam enhance by acid or hidrofracturing estimulation, drilling make up wells, etc.