THE SUBDIVISION AND CORRELATION OF THE JURASSIC SYSTEM OF THE MINHE BASIN
ZHANG Hu-quan~ 1)2) , WANG Ting-dong~ 2) , YAN Cun-feng~ 2) , and YUAN Jian-ying~ 1) 1) Northwest Branch of the Research Institute of Petroleum Exploration and Development, CNPC, Lanzhou, 730020; 2) Southwest Petroleum Institute, Chengdu, 610500
The Minhe Basin contains abundant oil, coal and natural gas resources. The Jurassic System in the Minhe Basin includes the Lower Jurassic Tandonggou (Daxigou) Formation, the Middle Jurassic Yaojie and Honggou formations, and the Upper Jurassic Xiangtang Formation. The early-middle Middle Jurassic is characterized by warm and wet paleoclimate and swamp facies, where major source rocks such as coals, organic-rich lacustrine mudstone, and oil-shale were formed. The Late Jurassic to Cretaceous is characterized by drier paleoclimate and consists of fluvial sandstones that are major reservoir rocks. The stratigraphy system of the Minhe Basin is revised on the basis of new biostratigraphic and lithostratigraphic data, as well as electric log, coal seams, tectonic, and paleoclimatic data. Type sections for the Mesozoic and Cenozoic stratigraphic system in the Minhe Basin have been established, forming a solid foundation for petroleum exploration in the Minhe Basin.