沁水盆地中东部热演化史模拟及油气成藏响应

为还原沁水盆地中东部热演化史,以某页岩气井山西组及太原组26件海陆过渡相泥页岩实测数据为基础,利用Petro Mod软件进行了热演化史模拟,依据模拟结果对油气生成及成藏进行了分析,结果表明:研究区内烃源岩干酪根类型以Ⅲ型为主,有机质演化成熟度高,具有良好的生烃潜力;热演化史与构造演化史存在耦合作用,受印支运动及燕山运动影响,地层温度经历了缓慢上升-缓慢冷却-异常高温-快速冷却四个阶段;太原组及山西组烃源岩有机质演化过程中镜质组反射率(Ro)值发生一次跃变,最终演化至2. 0%左右,于早白垩世烃源岩发生二次生烃作用进入产气阶段,加之上覆致密的盖层形成了良好的煤系气藏。

Modeling of Thermal Evolution History and Hydrocarbon Accumulation Response in the Central and Eastern Qinshui Basin

In order to restore the thermal evolution history of the central and Eastern Qinshui Basin, based on 26 measured data of shale gas wells in Shanxi and Taiyuan formations, the thermal evolution history was simulated by PetroMod software. Based on the simulation results, the hydrocarbon generation and accumulation were analyzed. The results show that the kerogen type of source rocks in the study area is mainly type III, and the maturity of organic matter evolution is mainly type III. The thermal evolution history is coupled with the tectonic evolution history. Influenced by Indosinian movement and Yanshanian movement, the formation temperature experienced four stages: slow rise-slow cooling-abnormal high temperature-rapid cooling. During the evolution of organic matter in source rocks of Taiyuan and Shanxi Formations, a jump in the value of Ro occurred, which eventually evolved to about 2.0%, and it occurred in the Early Cretaceous source rocks. Secondary hydrocarbon generation enters the gas production stage, and a good coal-bearing gas reservoir is formed by the dense caprock overlying it.