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Stimulation of reservoir and induced microseismicity - Zurich, Switzerland, Workshop3
Stimulation of reservoir and induced microseismicity - Zurich, Switzerland, Workshop3
from 29 June 2006 to 01 July 2006 Kartause Ittingen, Switzerland
Modelling the geochemical effects of acid treatments and comparison with field observations at soultz-sous-forets geothermal site.
Acid treatments have been successfully applied in many cases to increase or to 
recover geothermal wells production rates to commercial levels. These stimulation 
techniques were originally developed to address similar problems in oil and gas 
production wells. The applicability of these stimulation techniques to a high 
temperature, naturally-fractured reservoir is less well known. High temperatures 
increase the acid-rock reaction rate. The development of Enhanced Geothermal 
Systems (EGS) depends on the creation of permeable and connected fractures. Acid 
stimulation jobs intend to clean(pre-existing) fractures by dissolving filling 
materials (secondary minerals or drilling muds) and mobilizing them for an 
efficient removal by flow transport. Recent acid treatments were performed on the 
EGS wells at Soultz-sous-Forêts (France). This 200°C and 5-km deep granitic 
reservoir contains fractures partially filled with secondary carbonates (calcite 
and dolomite). In order to dissolve these carbonates and to enhance the 
productivity around the wells, each of the three boreholes (GPK2, 3 and 4) were 
successively treated with various amounts of hydrochloric acid. The FRACHEM code, a 
Thermo-Hydraulic-Chemical coupled code, has been developed especially to forecast 
the evolution of the Soultz reservoir. Reactive transport modelling with FRACHEM 
code has been used to simulate acid injection and its impact on brine-rock 
interactions. Comparisons between FRACHEM simulations and field observations will 
be tested to forecast the impact of acid treatments on reservoir properties. Our 
goal is to simulate the effect of acid injection on permeability evolution in 
fractures at pressure and temperature conditions of the Soultz geothermal site.
Id: 18
Place: Kartause Ittingen, Switzerland
CH-8532 Warth TG
Starting date:
29-Jun-2006   16:25
Duration: 15'
Primary Authors: PORTIER, Sandrine (CREGE (c/o CHYN, Neuchâtel, Switzerland))
Co-Authors: VUATAZ, François-David (CREGE (c/o CHYN, Neuchâtel, Switzerland))
ANDRE, Laurent (BRGM)
Presenters: PORTIER, Sandrine
Material: paper Paper
slides Slides

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