Clay mineral occurrences in volcanic and granitic geothermal - PowerPoint PPT Presentation

Clay mineral occurrences in volcanic and granitic geothermal contexts: signatures of high temperature fluid circulations in natural permeable fractures Genter Albert 1 , Patrier-Mas P.², Beaufort D.², Dezayes Ch. 1 , Guisseau D. 2 , Ledesert B. 3 , Mas A. 2 , Traineau H. 4 1 BRGM Orléans,²Hydrasa Poitiers, 3 Univ. Cergy-Pontoise, 4 CFG Services Department of Geothermal Energy (GTH) ENGINE Workshop, Volterra (Italy), April 2-4, 2007

Objective • Relationships between clays, natural fractures and permeability • Volcanic area of Bouillante (Guadeloupe)) • Granite basement of the EGS Soultz wells (France) Department of Geothermal Energy (GTH) > 2 ENGINE Workshop, Volterra (Italy), April 2-4, 2007

Hydrothermal alteration at Bouillante Smectite Illite Chlorite Geothermal Field data Well BO-6 Department of Geothermal Energy (GTH) > 3 ENGINE Workshop, Volterra (Italy), April 2-4, 2007

Clays-fractures-permeability at Soultz 300 Cross Section Area cm2 Bulk density g/cm3 Production log 8l/s Damaged fracture zone Gamma Ray GAPI DT Shear µs/feet Injection log 18 l/s DT Comp µs/feet Permeable fracture Potassium % Caliper inch UBI Transit Time Thorium ppm Uranium ppm Depth (m) Depth (m) Facies Dip UBI Amplitude Clays: illite + tosudite 12.25 1.70 2.20 2.70 0.04 0.08 6.25 9.25 100 200 100 125 200 -0.5 0.5 10 25 40 45 60 75 75 45 90 1 3 0 0 2 3482 3482 3483 3483 Secondary quartz deposition 3484 3484 3485 3485 3486 3486 High porosity 3487 3487 3488 3488 3489 3489 Brines 100g/L F-ma F-ma 3490 3490 3491 3491 3492 3492 3493 3493 3494 3494 F-ma F-ma 3495 3495 3496 3496 3497 3497 3498 3498 Thin section - Fracture Well GPK1, 3500 m Illite, calcite, hematite Department of Geothermal Energy (GTH) > 4 ENGINE Workshop, Volterra (Italy), April 2-4, 2007