关键词: 鄂尔多斯盆地, 热演化, 古地温, 梯度, 裂变径迹

Abstract: Based on analyses of the basin tectonic evolution history and many methods of geothermat study such as vitrinite reflectance,fluid inclusions and apatite fission track,this paper has recovered thermal history of Ordos basin,the temperature gradient was low (2.2-3.0℃/100m) from Paleozoic to Early Mesozoic and increased to 3.3-4.5℃/100m in Late Mesozoic.It has gradually decreased to 2.8℃/100m since Cenozoic era.Research on relations between the thermal history of the Ordos basin and oil-gas accumutation suggests that low temperature gradient and low thermal maturation of gas resource rocks was favourable for preservation of organic materials from Paleozoic to Early Mesozoic.The Late Mesozoic characterized by higher temperature gradient is main period of gas generation and migration of Paleozoic coal series and carbonates.Bacause the temperature gradient gradually decrease in Cenozoic era,the intensity of gas generation gradually decrease or stop.The lack of faults and late gas generation stage in Ordos basin were favourable for preservation of giant gas fields.The central paleouplift in the basin which has good carbonate reserviors and is close to main gas generation regions,it should be the first exploration target to be chosen.

Key words: Ordos basin, thermal evolution, paleotemperature, gradient, fission track