Evidence of the Near‐Source Accumulation of the Tight Sandstone Gas in Northern Ordos Basin, North‐Central China
Evidence of the Near‐Source Accumulation of the Tight Sandstone Gas in Northern Ordos Basin, North‐Central China
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DOI：
10.1111/1755-6724.13413
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发表时间：
2017-10
期刊：
影响因子：
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通讯作者：
Zhi Yang;Qiyan Li;Songtao Wu;Senhu Lin;Xinshe Liu
中科院分区：
文献类型：
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作者：
Zhi Yang;Qiyan Li;Songtao Wu;Senhu Lin;Xinshe Liu
鄂尔多斯盆地北部上古生界致密砂岩气是典型的巨型非常规致密气省。地球化学、储层地质和浅构造背景的证据都证实了鄂尔多斯盆地致密砂岩气的成藏是近源成藏的结果。结果表明：致密砂岩气主要分布在生气强度高的地区；气体成分不受分馏影响；随着离烃源岩距离的增加，含气饱和度显著降低；气体同位素表明其成因相同，成熟度与原地烃源岩一致；储层经历了强压实作用、硅质胶结作用和钙质胶结作用3种致密成岩作用，这些致密成岩作用发生在大量致密砂岩气形成之前，形成了低孔低渗、孔喉细、毛管阻力大的致密储层；从主要生烃期至今，古构造梯度比较小。研究表明，鄂尔多斯盆地北部致密砂岩气的分布是近源短距离运聚的结果。
The tight sandstone gas in Upper Paleozoic Formation of the northern Ordos Basin is a typical giant unconventional tight gas province. Evidences from geochemistry, reservoir geology and pale‐otectonic setting all verify that the present‐day tight sandstone gas accumulation in the Ordos Basin is the result of near‐source accumulation. The evidences are listed as following: tight sandstone gas is mainly distributed in the area with high gas‐generating strength; gas composition was not subjected to fractionation; gas saturation significantly decreases with the distance away from the source rocks; gas isotopes suggest their origin is the same and maturity is consistent with in‐place source rocks; reservoirs have experienced three types of densification digenesis, including intense compaction, siliceous cementation and calcareous cementation, which took place before the formation of a large amount of tight sandstone gas, forming tight reservoirs with low porosity and permeability, fine pore throat and great capillary resistance; the paleo‐structural gradient ratio is small from the main hydrocarbon generation period to present. It is indicated the present distribution of tight sandstone gas in the northern Ordos Basin is the result of near‐source and short‐distance migration and accumulation.