Estimating the Curie Point Depth Using Magnetic Field Data to Assess the Geothermal Potential
J. Drolet, B. Giroux and C. Bouligand
Event name: 79th EAGE Conference and Exhibition 2017
Session: Potential Fields - Gravity, Magnetics and Integration
Publication date: 12 June 2017
Info: Extended abstract, PDF ( 1.34Mb )
Price: € 20
New technologies that allow geothermal energy production in colder conditions result in interest for geothermal exploration in low heat flux regions. The Province of Québec, eastern Canada, is such a case. Mapping the Curie point depth (CPD) is appealing as an exploration tool due to the scarcity of the direct data. We have revisited a methodology to estimate the CPD using a fractal source distribution model and aeromagnetic data. Our methodology relies on a statistical model of crustal magnetization having a constant magnetization direction and random magnetization amplitude. The shape of the radial average of the logarithm of the power spectrum of magnetic anomalies is predicted using this model. The model parameters (thickness and depth to the top of the magnetic layer, the fractal exponent β and the constant C') are obtained by calculating the best fit between the theoretical and observed radial power spectra using a non-linear least-square algorithm. Rather than using a constant value for the fractal exponent β, we propose a new calibration workflow based on heat flux measurements and lithology. This workflow includes the use of normal kriging of heat flux data. Mapping the CPD will help identifying potential areas for further detailed exploration programs.