鲁卜哈里盆地古生界油气藏成藏期分析

综合运用烃源岩生排烃史模拟、流体包裹体均一温度测定以及储层自生伊利石测年等方法确定了鲁卜哈里盆地古生界油气藏的主要成藏期次。中央凹陷区S2井生排烃史模拟结果表明中心凹陷区志留系源岩在三叠纪和白垩纪进入生排烃高峰。斜坡区A2井生排烃史模拟结果表明斜坡区志留系源岩在早白垩世进入生排烃高峰。流体包裹体均一温度结果表明中央凹陷区S2井古生界储层样品包裹体均一温度分布多为两期，个别样品有3期;结合热史分析认为这3期分别对应三叠纪、早白垩世和晚白垩世。斜坡区A2井古生界储层包裹体均一温度分布主要为两期，表明该井区奥陶系储层至少发生过2次重要的油气充注活动。结合热史分析认为这2期分别为早白垩世和晚白垩世。储层自生伊利石测年方法测试结果表明中央凹陷区S2井古生界成藏期为晚三叠世和晚侏罗世—早白垩世。综合分析认为，鲁卜哈里盆地古生界存在3期油气成藏：第一期为三叠纪，第二期为早白垩世，第三期为晚白垩世。其中第一期主要分布于中央坳陷区，第三期主要分布于斜坡区，第二期在中央坳陷区和斜坡区都有分布。

Timing of hydrocarbon accumulation of the Paleozoic reservoir in Rub Al Khali Basin

In order to determine the main stages of the hydrocarbon accumulation of the Paleozoic reservoir in Rub Al Khali Basin, four key methods are applied in this paper including hydrocarbon generation and expulsion history simulation, measurements of fluid inclusions homogenization temperature and Illite K-Ar dating.The simulation of hydrocarbon generation and expulsion history of Well S2 shows that hydrocarbon generation and expulsion of the Silurian source rocks in the central depression peaked in the Triassic and Cretaceous.The simulation of hydrocarbon generation and expulsion history of Well A2 shows that the hydrocarbon generation and expulsion of the Silurian source rocks in the slope zone peaked in the Early Cretaceous.The analysis of homogenization temperature of fluid inclusions of Well S2 shows that most of the samples can be divided into two main stages and only some samples can be divided into three stages.In combination with the geothermal history, these three stages are the Triassic, Early Cretaceous and Late Cretaceous respectively.In contrast, the homogenization temperature of fluid inclusions of Well S2 in the slope zone can be separated into two stages, indicating that at least two periods of oil and gas charging occurred in the Ordovician.In combination with the geothermal history, the two periods are in the Early Cretaceous and Late Cretaceous respectively.The result of Illite K-Ar dating shows that the hydrocarbon accumulation in the Paleozoic of Well S2 in the central depression occurred mainly in the Triassic and Late Jurassic-Early Cretaceous.A comprehensive analysis indicates that the hydrocarbon accumulation of the Paleozoic reservoir in Rub Al Khali Basin mainly occurred in three periods.The first one is the Triassic, the second one is the Early Cretaceous and the last one is the Late Cretaceous.The hydrocarbon accumulations formed in the first stage are mainly distributed in the central depression, and that in the third stage are mainly distributed in the slope zone, and that in the second stage occurred in both the central depression and slope zone.