Pre-Cenozoic geological characteristics and oil-gas significance in Weihe basin, Shaanxi Province

The Weihe basin is a Cenozoic fault basin located at the junction of Ordos basin and Qinling orogrenic belt. In this paper, the pre-Cenozoic geological characteristics are discussed based on an integrated analysis of the sedimentary and tectonic evolution of Weihe basin, the evolution and uplift characteristics of the Weibei uplift and the Qinling orogenic belt during Mesozoic-Cenozoic period, the drilling data and the hydrocarbon gas of geothermal water isotope in the Weihe basin. It is considered that the Weihe area was a paleo-slope zone between Qinling orogenic belt and Ordos Basin with relatively older pre-Cenozoic groups at the edge and newer ones in the middle. Most of the northern slope zone of Weihe basin is occupied by the early Paleozoic carbonate, while in the south-central deep sags of Weihe basin, the late Paleozoic Carboniferous-Permian coal measures might be widely existent, with the local existence of Mesozoic strata, which are important potential source rocks in the Weihe basin. The results achieved by the authors are of great significance for the formation-evolution study of Weihe basin and its gas exploration.