塔北隆起异常压力与油气成藏分析

Abnormal formation pressure and hydrocarbon reservoir forming in residual uplift in north of Tarim basin.

克拉通盆地富集油气且分布的非均一性明显 ,中国典型的克拉通复合盆地在地质特征和油气分布上具有多期演化、多期叠合、多期成藏和油气相对富集的特点。根据地层压力的分布特征、烃类性质和成藏组合配置关系把塔北隆起划分为四个压力旋回系统 ,其分割性源于地层欠压实、热解生烃和粘土矿物脱水等机制 ,异常压力对次生孔隙储集体的形成、构造微裂隙的产生和盖层的封闭性能都有一定影响 。

Hydrocarbon is enriched with obviously uneven distribution in craton basin. Typical composite craton basins of China are characterized as polyphase evolution, multistage coincidence and reservoir forming, and relative oilgas enrichment. According to the distribution feature of formation pressure, hydrocarbon property and combination relationship of reservoir forming assemblage, four pressure cycle systems can be identified in north of Tarim craton basin. Its division is based on the mechanisms of undercompaction, pyrolysed hydrocarbon generating, dehydration of clay mineral and so on. The abnormal pressure is in favor of hydrocarbon reservoir forming by its effect on forming secondary pore reservoirs, generating microtectonics fracture and enclosed capability of cap rocks.