地质科技通报2026，Vol.45Issue(1)：81-94,14.DOI:10.19509/j.cnki.dzkq.tb20240130
鄂尔多斯盆地北部新召地区山西组砂岩储层压力演化与低压成因
Pressure evolution and underpressure generation in the Shanxi Formation sandstone reservoirs of the Xinzhao area,northern Ordos Basin
摘要
Abstract
[Objective]The Upper Paleozoic sandstone reservoirs in the Xinzhao area,northern Ordos Basin,are rich in natural gas and characterized by underpressure.The mechanisms of paleo-pressure evolution and underpressure generation are unclear,constraining the understanding of tight sandstone gas accumulation and the enhancement of natural gas production.[Methods]This study comprehensively analyzed the petroleum charging history in the second member of the Shanxi Formation using fluid inclusion petrographic,micrometry,and laser Raman analysis.Subsequently,we obtained the paleo-pressure during the key reservoir formation period.The paleo-pressure evolution history was established by the basin simulation methods,and the coupling between paleo-fluid pressure evolution and petroleum charging was established.The relationship between the causes of underpressure and tight gas accumulation is further discussed.[Results]The results indicate that:①CO2 was trapped in the second member of the Shanxi Formation in the Xinzhao area from 180 to 170 Ma,when the source rock was at a middle-low maturity stage,and the methane inclusion was captured at the peak of hydrocarbon generation from 138 to 121 Ma.②Overpressure in the second member of the Shanxi Formation began developing in the Early Jurassic and reached a maximum paleo-pressure of 50 MPa and a paleo-pressure coefficient of 1.31 by the end of the Early Cretaceous.③The formation pressure decrease in the second member of the Shanxi Formation,driven by temperature drop,pore rebound,and gas diffusion,accounted for 49%,14.5%,and 36.5%of the total formation pressure decrease,respectively.[Conclusion]The tight gas reservoir in the second member of the Shanxi Formation experienced a pressure evolution from normal pressure to medium overpressure,back to normal pressure,and finally to underpressure.Hydrocarbon-generation-induced overpressure and pressure-conduction are the main factors contributing to ancient overpressure,while temperature decrease and natural-gas diffusion are the primary factors driving underpressure formation in the second member of the Shanxi Formation.关键词
致密砂岩储层/古压力演化/低压成因/山二段/鄂尔多斯盆地Key words
tight sandstone reservoir/paleo-pressure evolution/underpressure generation/second member of the Shanxi Formation/Ordos Basin分类
天文与地球科学引用本文复制引用
景海杰,王琳霖,任克雄,叶云飞,刘宇坤,陈芳,马立元,侯宇光..鄂尔多斯盆地北部新召地区山西组砂岩储层压力演化与低压成因[J].地质科技通报,2026,45(1):81-94,14.基金项目
中国石化科技部项目(P21088-2) （P21088-2）
国家自然科学基金(41772143) （41772143）
