Carboniferous source rocks in the Ludong-Wucaiwan area, Junggar Basin, NW China

摘要

Natural gas in the Ludong-Wucaiwan area is characterized by typical source-controlled reservoirs. Combining outcrop data, well data and seismic data, this article makes a systematic research and evaluation on the abundance, type, and maturity characteristics of the Carboniferous source rocks in the Ludong-Wucaiwan area. The Carboniferous source rocks are dominantly dark grey and grey mudstones, secondarily tuffs, carbonaceous mudstones, silty mudstones and coals. The source rock abundance of the Upper Carboniferous Batamayineishan Formation (C2b) is higher than that of the Lower Carboniferous Dishuiquan Formation (C1d), while the kerogen type of the Lower Carboniferous source rock is better than that of the Upper Carboniferous. The maturity center of the Carboniferous source rocks is located in the west part of Dinan uplift to the Wucaiwan depression area, with maturity decreased towards south and north. The distributions of the Carboniferous source rocks and volcanic rocks are complementary. The source rocks are distributed in zonal shape in east-west direction, and are most developed in the west part of the Dinan uplift and its southern area.