多期次油气成藏流体包裹体间接定年——以鄂尔多斯盆地东北部二叠系油气藏为例

多期次油气成藏年代学是多旋回叠合盆地油气成藏动力学研究的热点问题。运用流体包裹体测温与其宿主岩层磷灰石裂变径迹(AFT)热史模拟相结合的研究方法，探讨了鄂尔多斯盆地东北部二叠系多期次油气成藏的温度和时间序列。结果表明，研究区二叠系不同含油气层段中生代-新生代总体经历了2～3期油气成藏事件：①二叠系各层段在中生代早中期多旋回沉降埋藏增温阶段经历了2期原生油气成藏事件，成藏温度主要分布在78.9～89.3℃和120.7～124.5℃，成藏时间分别为距今162～153Ma和140～128Ma;②上二叠统在晚白垩世以来抬升改造阶段经历了1期油气次生成藏事件，成藏温度主要集中在98.6℃，成藏时间接近30Ma。对于多旋回叠合含油气盆地复杂成岩-成藏系统而言，多井段样品、多类型定年数据与其宿主岩石构造热演化史相结合的系统分析，有可能是更为客观地全面认识多旋回叠合盆地油气成藏期次和时间及其多期次油气动态成藏过程的重要途径。

Indirect dating of multi-stage hydrocarbon accumulations by fluid inclusion data:a case study of the Permian hydrocarbon accumulation in the northeast Ordos Basin

Geochronology of multi-stage hydrocarbon accumulations is a key frontier for petroleum reservoir-forming dynamics in a multi-cycle superimposed basin. An indirect dating method is introduced in the present paper that combines fluid inclusion (FI) analysis with FI homogenization temperature peaks of oil-gas-bearing sandstone samples and the apatite fission track (AFT) thermal modeling of the FI host rock. A case study of times of Permian multi-stage hydrocarbon accumulations in the northeast Ordos Basin was conducted, and it reveled generally that there have been 2～3 stages of hydrocarbons accumulations in different Permian strata since Meso-Cenozoic. The various Permian hydrocarbon-bearing intervals experienced 2 stages of primary hydrocarbon accumulations during 162～153Ma and 140～128Ma, respectively, corresponding to two domains of temperature peaks at 78.9～89.3℃ and 120.7～124.5℃, respectively, in coincidence with the Early-Middle Mesozoic multi-cycle subsidence-burial heating processes. The Upper Permian reservoirs further experienced at least 1 stage of secondary hydrocarbon accumulation in 30Ma, corresponding to a temperature peak at 98.6℃ in coincidence with the Late Cretaceous to Neogene uplifting process of the basin. The integrated analysis of muliti-well interval samples and multi-type dating data with techono-thermal history of the host rock is therefore considered as an important approach to systemically realize the time sequence and dynamic process of multi-stage oil-gas accumulations in the superimposed basin.