The south-eastern Karoo Basin is considered to be one of the most prospective areas for shale gas exploration in South Africa. The basin has several dolerite intrusions that possibly introduced heat into the basin and resulted in the large scale conversion of oil to gas. To date, the geometry of these dolerites and variations in electrical resistivity of the purported shale gas hosting Ecca Group is poorly documented. Herein, we investigate the variations in resistivity of the Ecca Group and produce gravity models that reveal the configuration of the basin and interconnectivity of dolerites. The magnetic map shows some ring-like structures and lineaments which coincides with the mapped dolerite intrusions. The average depth to the top of the shallow and deep magnetic sources is estimated to be about 700 m and 15100 m, respectively. Depth slicing revealed that the intrusions are pervasive in the area, extending up to 5400 m. The subsurface apparent resistivity of the Ecca Group varies between 2 ?m and 557000 ?m. The gravity models revealed the basin architecture and that the dolerite intrusions form a network of interconnected sills and dykes. The dolerites could have impacted the shale resources and still poses threat to fracking operation.
Presentation Date: Monday, October 15, 2018
Start Time: 1:50:00 PM
Location: Poster Station 9
Presentation Type: Poster
