流体动力系统对流体包裹体均一温度的影响及其意义——以准噶尔盆地陆东地区为例

在准噶尔盆地陆东地区 ,纵向上存在两个流体动力系统 ,即下部高压流体动力系统和中上部正常 -低压流体动力系统 ,对下部高压流体动力系统 ,流体包裹体均一温度可用来确定油气成藏期 ,而对中上部正常 -低压流体动力系统 ,流体包裹体均一温度不适于用来确定油气成藏期 ,这主要由包裹体捕获时的流体动力学环境和相态不同所致。高压流体动力学环境中形成的包裹体在捕获时更易呈均一相 ,包裹体的均一温度可有效用于成藏期的判定 ,而在正常 -低压系统中形成的包裹体在捕获时有呈非均一相的可能 ,在此情况下 ,流体包裹体均一温度就无法用于成藏期的确定 ,在用包裹体均一温度判定成藏期时 ,结合具体的地质条件做具体分析是十分必要的。

Influence of Fluid Dynamic Systems on Homogenization Temperatures of Fluid Inclusions and Its Significance--An Application Example from the Ludong Area of the Junggar Basin,Northwestern China

The Ludong area in the Junggar Basin can be divided vertically into two petroleum migration-accumulation fluid dynamic systems: the abnormal deep high-pressure system and the normal middle-shallow low-pressure system. In the former case, homogenization temperatures of fluid inclusions can be effectively used to determine the time of hydrocarbon accumulation and the filling history. However, it is not applicable to the latter case. This is mainly because of the different fluid dynamic environments of the two systems, which influence fluid phases when the inclusions are captured. In the abnormal high-pressure fluid dynamic environment, the inclusions are easily formed in a homogenization phase, while in the normal low-pressure system it is possible that the inclusions are captured in multiple phases. Therefore, the homogenization temperatures of fluid inclusions cannot be applied to determining the time of hydrocarbon accumulation and the filling history. It is emphasized that the corresponding fluid dynamic conditions should be considered when the homogenization temperatures of fluid inclusions are used to determin the time of petroleum accumulation.