Community Research and Development Information Service - CORDIS

Abstract

EQ3NR/EQ6 is a model which incorporates kinetic and equilibrium features of the chemical interaction of groundwater with granitic rock under hydrothermal conditions. This model is applied to the development of an HDR geothermal system in Cornwall (UK). The model is used to evaluate the results of a batch autoclave experiment, reaching Carnmenellis Granite with fluid at a 10:1 fluid/solid ratio. Natural historic reactions are deduced from the composition of deep groundwater and vein infillings within the granite. The main feature of both experimental and computer simulation studies is the rapid rate of reaction, such that most steady-state concentrations in the fluid phase are achieved well within 200 days. EQ6 identifies a series of precipitated minerals, giving an assemblage in the final stages that is similar to that observed in the lowest temperature (15 C) veins in the drillcore. The lack of precipitation kinetics has been identified as a major source of discrepancy between simulation and experiment. Best fit dissolution rate constants of individual phases of the granite are within an order of magnitude of those determined experimentally.

Additional information

Authors: FALCK W E, British Geological Survey, Keyworth, Nottingham (GB);SAVAGE D, British Geological Survey, Keyworth, Nottingham (GB)
Bibliographic Reference: EUR 12364 EN (1988) 40 pp.
Availability: Sales Desk, British Geological Survey, Keyworth, Nottingham NG12 5GG (GB)
Record Number: 199010149 / Last updated on: 1994-12-01
Category: PUBLICATION
Original language: en
Available languages: en