徐家围子地区天然气成藏期次及其模式

利用实测流体包裹体均一温度的分布特征，结合埋藏史和热史，确定出徐家围子地区烃类气体的注入时期。根据该区沙河子-营城组生烃排气期、登二段泥岩盖层封闭形成时期和断裂活动时期，得到徐家围子地区天气藏主要形成于泉头组沉积时期。有断裂沟通的气藏可以形成于泉头组沉积时期。有断裂沟通的气藏可以形成于嫩江组沉积末期，但规模有限。徐家围子地区具有4种天然气成藏模式：沿不整合面运移至其岩风化壳圈闭成藏、沿裂缝运移至源岩内火山岩圈闭成藏、沿断裂运移至古隆起之上各种类型圈闭成藏、沿砂体侧向运移至地层超覆圈闭成藏。

Gas Accumulation Periods and Models in Xujiaweizi Region

Using the distribution characteristics of homogenization temperature measured in the fluid inclusion enclave,this paper determines the gas injected periods of K 1sh+yc-K 1D 2 accumulation system combining with buried history and thermal history.According to the gas expulsion period of K 1sh+yc,the sealing formation period of K 1D 2 mudstone caprock and the active period of faults,this paper considers the gas reservoirs of K 1sh+yc-K 1D 2 accumulation system were mainly formed during K 1q period,the gas reservoirs communicated by the faults can be formed in the end of K 1n period,but the scales are limited.There are four accumulation models in Xujiaweizi region:the accumulation model of gas migrating through surface of unconformity into weathering crust of basement,gas migrating through fracture into volcanic rock in gas source rock,gas migrating through faults into all kinds of traps over the ancient uplift,as well as the accumulation model of gas migrating laterally through sandbody into stratigraphic overlap traps.