Injection related cooling in the Unit 13 area of theSoutheast Geysers, California, usa

Eight years of water injection into southeast Geysers well CA 845A!0 has been bene_cial and without any water breakthrough to nearby producers[ Production wells with maximum injection bene_t did not show any wellhead temperature or enthalpy degradation for approxi! mately _ve years[ Production wells which showed no obvious injection e}ect did not exhibit any thermodynamic degradation for up to six years[ Producers located to the northwest of CA 845A!0 have not displayed any thermal degradation so far[ The thermal front appears to grow towards the southwest and east of the injection well[ Upon arrival of the thermal front\ a drop of 0[2 4[6>F "9[6 2[1>C# per year in wellhead temperature and 9[2 1[2 Btu:lbm "9[6 4[2 kJ:kg# per year in wellhead enthalpy has been observed[ The arrival of the thermal front signi_es a slowing down in boiling rate and\ therefore\ the recovery rate of the injected water[ 0888 Published by Elsevier Science Ltd on behalf of CNR[ All rights reserved[