RECOVERY AND COMPARATIVE RESEARCH OF THERMAL HISTORY ON JIUQUAN BASIN GROUP
2000; Wiley; Linguagem: Inglês
ISSN
2326-0440
Autores Tópico(s)Geological Studies and Exploration
ResumoJiuquan basin group is formed by the stacking of two stage basins with different property and different generation. It was rift basin in Late Jurassic Early Creaceous and squeezed sag basin since Cenozoic. The present geothermal gradient between 2.5℃/100m and 3.00℃/100m and heat flow between 50mW/m 2 and 57mW/m 2 is low in Jiuquan basin group. Jiuquan basin group is rift basin and its palaeothermal gradient is higher in late Mesozoic, which reached 3.75—4.50℃/100m. The thermal gradient has decreased since Cenozoic. Huahai basin and Shibei depression of Jiuxi basin have subsided at a small increase since Cenozoic, the palaeotemperature of lower Cretaceous source rock is higher than present, the maturity of lower Cretaceous sources rock is controlled by palaeotemperature. There is only one stage of main oil generation, Early Cretaceous. Qingxi depression of Jiuxi basin and Yinger depression of Jiudong basin have subsided at a big increase since Cenozoic, the maturity of lower Cretaceous source rock is mainly controlled by present temperature. There are two stages of main oil generation, late of Early Cretaceous and Late Tertiary, main stage of oil generation is Late Tertiary. The difference of tectonic thermal history in different basin and different units of a basin result in difference of stage of main oil generation and difference of oil gas exploration prospect. [
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