Injection tests at the EGS reservoir of Soultz-sous-Forêt. Seismic response of the GPK4 stimulations

The EuropeanEnhancedGeothermalSystem(EGS)programofSoultz-sous-Forêtsisorganizedaroundthree wells(GPK2,GPK3,andGPK4)drilledtoadepthofabout5000m.Hydraulicstimulationswereperformed inordertoincreasetheinjectivityofthereservoirandtheconnectivityamongthewells.Thestimulation ofGPK4wascarriedoutintwostages...

Full description

Saved in:
Bibliographic Details
Published in:Geothermics 2014, Vol.52, p.50-58
Main Authors: Calo, M., Dorbath, C., Frogneux, M.
Format: Article
Language:English
Subjects:
Earth Sciences
Geophysics
Sciences of the Universe
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The EuropeanEnhancedGeothermalSystem(EGS)programofSoultz-sous-Forêtsisorganizedaroundthree wells(GPK2,GPK3,andGPK4)drilledtoadepthofabout5000m.Hydraulicstimulationswereperformed inordertoincreasetheinjectivityofthereservoirandtheconnectivityamongthewells.Thestimulation ofGPK4wascarriedoutintwostages,inSeptember2004andinFebruary2005,followedby anacidificationtestperformedinMarch2005.Thestimulationsproducedfewerinducedeventsthanthose oftheotherwells,withinterpretationremainingdifficult.Inthisworkwepresentsomenewobservations ontheseismicityoftheGPK4stimulationsafteracompletereviewoftheseismicbulletinscollected in2004and2005.Furthermore,theeventswererelocatedusingthedoubledifferencemethod.The newimagesoftheseismicityarepresentedintemporalsequencesaccordingtothemainvariationsof theinjectionparameters.Theseismiceventsthatoccurredduringthe2004stimulationaregroupedin adensecloudandcenteredonthewellopen-holesection,whilein2005seismicitydepictsaspecificpattern suggestingthatthe“natural”stressfieldinthereservoirwasnotcompletelyrestored.Finally,theevents recordedduringtheacidifiedtestshowthatthereservoirbehaveddifferentlyfromthepreviousinjections, whichsuggeststhatadifferentmechanismhascontrolledtheinducedseismicity.
ISSN:0375-6505
DOI:10.1016/j.geothermics.2013.10.007