DETAILED APPRAISAL OF THE WARM SPRING FRACTURE MODEL FOR THE REGION OF MALLOW

Información del proyecto

Identificador del acuerdo de subvención: EN3G0066

Proyecto cerrado

Fecha de inicio 1 Julio 1986

Fecha de finalización 31 Agosto 1989

Financiado con arreglo a

• Research and development programme (EEC) in the field of Non-Nuclear Energy, 1985-1988

Coste total

Sin datos

Aportación de la UE

Sin datos

Coordinado por

UNIVERSITY COLLEGE CORK, NATIONAL UNIVERSITY OF IRELAND, CORK
Ireland

Objetivo

THIS RESEARCH WILL LEAD TO A BETTER UNDERSTANDING OF THE HYDROGEOLOGY AND THEREFORE OF THE GEOTHERMAL POTENTIAL OF IRELAND.
A reappraisal of known warm springs in Ireland and the discovery of a number of additional ones enabled the selection of several sites with geothermal potential for further investigation. Field mapping and detailed geophysical surveys in the areas adjacent to these springs permitted the formulation of hydrogeological models accounting for their origin. The warm springs were confined to carbonate terrains and were invariably associated with fault zones. Exploratory boreholes have confirmed the importance of faulting. The primary permeabilities of these Carboniferous limestones were generally very low. They often had a porosity of less than 0.5%. However, during Variscan deformation, the limestones particularly the Waulsortian, behaved in a highly brittle fashion, producing faults with broad zones of breccia and intense jointing within the wall rocks. These acted as zones of high secondary permeability. The circulation of magnesium rich fluid along some faults resulted in the dolomitization of the wall rocks which increased the permeability. Solution channelling and opening of fissures along joints also made a significant contribution to the permeability. Thus with time, an interconnected network of fissures and cavities develoed in close associating with fault zones, allowing water to circulate to depths at which it became heated due to the geothermal gradient. The upward migrzation of the warm water was again localized by fault related zones of high secondary permeability. Rapid migration to the surface takes place along pipe like conduits produced by hydraulic cleaning and limestone solution along fault zones.

Large volumes of warm water are considered to occur in the hinge regions of limestone cored synclinal structures such as those of the Charleville-Kilmallock area and the Celbridge Syncline. However, the siting of production wells in such areas is highly speculative since a large volume of warm water will be extracted only if a zone of high secondary permea bility is intersected.
THE WORK COVERED IN THIS CONTRACT FORMS PART OF AN INTEGRATED IRISH GEOTHERMAL PROJECT CARRIED OUT IN COLLABORATION WITH THE GEOLOGICAL SURVEY OF IRELAND AND THE UNIVERSITY COLLEGE OF GALWAY. THREE TO FOUR DEEP HOLES WILL BE DRILLED IN THE CLARE-SHANNON AND DUBLIN BASINS. THE UNIVERSITY OF CORK WILL STUDY THE GEOLOGY AND HYDROGEOLOGY AT EACH SITE.

Ámbito científico (EuroSciVoc)

• ciencias naturales › ciencias de la tierra y ciencias ambientales conexas › hidrología › hidrogeología
• ciencias naturales › ciencias químicas › química inorgánica › metales alcalinotérreos
• ciencias naturales › ciencias de la tierra y ciencias ambientales conexas › geología

Programa(s)

• FP1-ENNONUC 3C - Research and development programme (EEC) in the field of Non-Nuclear Energy, 1985-1988

Tema(s)

Datos no disponibles

Convocatoria de propuestas

Datos no disponibles

Régimen de financiación

CSC - Cost-sharing contracts

Coordinador

UNIVERSITY COLLEGE CORK, NATIONAL UNIVERSITY OF IRELAND, CORK

• Aportación de la UE: Sin datos
• Dirección: WESTERN ROAD, PRESENTATION BUILDINGS ; 30 CORK ; Irlanda
• Coste total: Sin datos