Source Rock Detection by Magnetotellurics
Magnetotellurics, a geophysical method applied for revealing the distribution of the electrical conductivity in the subsurface, is particularly appropriate for encountering and delineating deep good conductors, which may be due to TOC and pyrite-rich black shales, considered as potential hydrocarbon source rocks.
From an integrated geological and geophysical interpretation of 88 magnetotelluric soundings in the North German Basin, new models of the temporal and spatial development of the deep sub-surface and, in particular, of the regional distribution of potential source rock in the pre-Westphalian have been derived. Good electrical conductors in depths of 7 - 11 km have been found in the northern and southern areas of the North German Basin. In the central part of the North German Basin any indications of good conductors within the pre-Westphalian sediments are missing.
Distribution of potential hydrocarbon source rock in the pre-Westphalian sediments derived from a magnetotelluric survey
Source: BGR
| Good conductors in the Cambrian and Ordovician («Scandinavian alum shale») |
| Area of potential hydrocarbon source rock in the Cambrian and Ordovician |
| Good conductors in the Lower Carboniferous and Early Namurian («Rhenohercynian alum shale») |
| Area of potential hydrocarbon source rock in the Lower Carboniferous and Early Namurian |
| Good conductors in the contact aureolae of potential intrusion bodies (mantle diapirs) |
| Area without regionally distributed hydrocarbon source rock |
| No conductive sediments in the pre-Westphalian |
| Magnetic anomalies of Pritzwalk (PA), Dambeck (DA) and Klütz (KA) |
| Offshore well G14 with «Scandinavian alum shale» |
| Pröttlin 1 well with «Rhenohercynian alum shale» |
