Modelling induced polarization effects due to pyrite in geochemical alteration zones above hydrocarbon accumulations
P.C.H. Veeken, E.O. Kudryavceva, O.F. Putikov, P.Y. Legeydo and S.A. Ivanov
Journal name: Petroleum Geoscience
Issue: Vol 18, No 1, February 2012 pp. 59 - 72
Organisations: Geological Society of London
Info: Article, PDF ( 7.26Mb )
Price: € 30
Geoelectrical methods measure resistivity and induced polarization (IP) effects in the subsurface. The differentially normalized electromagnetic method (DNME) detects geochemical alteration zones due to anomalous electrical responses which are often located above a hydrocarbon accumulation. Leakage above a non-perfect top seal is postulated to change the pH in the overlying sediments where a shallower mobility barrier is encountered. Epigenetic pyrite mineral growth is stimulated when iron and sulfur ions are available. Leakage and mineral growth are modelled by mathematical formulae assuming diffusion migration through the overburden.