利用包裹体PVTx和PetroMod盆地模拟系统反演鄂尔多斯盆地上古生界古流体压力

Retrieving Paleo-Pressure of the Upper Paleozoic Fluid of the Ordos Basin Using Inclusion PVTx Modeling and Petro Mod Basin Simulation System

包裹体捕获压力反映了油气藏形成时的流体压力,对于成藏过程具有重要的指示意义。本文尝试结合包裹体PVTx相态模拟及Petro Mod盆地模拟两种方法反演鄂尔多斯盆地上古生界古流体压力。以鄂尔多斯盆地天环凹陷地区布1井为例,利用包裹体PVTx相态模拟得到布1井2个包裹体样品均一温度及捕获压力分别为98.2℃,34.38MPa和121℃,30.01MPa。由Petro Mod盆地模拟生成布1井的热演化史及古流体压力史,将二者结果结合推导出包裹体形成时间。结果表明,鄂尔多斯盆地天环凹陷地区主要成藏时间为122-100Ma（晚白垩世）。结合烃源岩生烃史,推测包裹体流体形成于上古生界烃源岩快速生烃阶段,对应成熟度范围约为Ro≈0.68%-0.76%。

Inclusion trapped pressure reflects the fluid pressure when oil-gas reservoir was forming. It also has important implications for accumulation process of hydrocarbons. In this paper,we combined inclusion PVTx modeling and Petro Mod basin simulation system to retrieve the Paleo fluid pressure of the Upper Paleozoic in the Ordos Basin. Taking the well Bu-1 located in the Tianhuan depression of the Ordos Basin as an example,we calculated the homogeneous temperature and pressure of two inclusions of the well Bu-1 respectively are 98. 2℃,34. 38 MPa and 121℃,30. 01 MPa by using the inclusions PVTx phase modeling,and obtained the thermal histories and the fluid pressure＇s evolution history by using the Petro Mod simulation system. Finally,the trapping time of inclusions were estimated by combining the results from two methods. The results showed that oil and gas accumulation time of the Tianhuan depression of the Ordos Basin is mainly between 122-100 Ma（ Late Cretaceous）. Combining with the history of hydrocarbon generation,we deduced that the fluid inclusions were formed in the rapid hydrocarbon generation stage in Upper Paleozoic strata,and maturity range are around Ro≈0. 68% ~0. 76%.