南襄盆地中、新生代构造演化与油气成藏

Tectonic involution and hydrocarbon accumulation in Mesozoic-Ce-nozoic Era,Nanxiang Basin

运用平衡剖面原理和沉降史分析方法,对南襄盆地中、新生代的构造演化进行了研究。结果表明,南襄盆地经历了白垩纪基底差异裂陷、晚白垩纪—早新生代基底差异反转拗陷、古近纪玉皇顶组—核桃园组沉积时期基底差异裂陷、古近纪廖庄组沉积时期基底差异反转拗陷及新近纪基底整体拗陷5个演化阶段。构造活动控制了盆地沉积层序及生储盖层的发育,为油气运聚提供了动力来源,而构造变形的分带性是盆地内各凹陷油气分布与富集差异性的决定性因素。对比分析认为,泌阳凹陷古近系玉皇顶组是今后勘探应当重视的新层系。

Mesozoic-Cenozoic tectonic evolution of Nanxiang Basin has been researched in this paper by applying the balanced cross -section principle and the sedimentation history analysis method. The results indicate that there were five evolutionary phases in the basin including the basement differential chasmic stage in Cretaceous Period, basement differential reversal depression stage in late-Cretaceous and early-Cenozoic Period, basement differential chasmic stage in the sedimentary period of Yuhuangding-Hetaoyuan Formation in Paleogene Period, basement differential reversal depression stage in the sedimentary period of Li-aozhuang Formation in Paleogene Period and the basement regional depressing in Neogene Period. Development of basin sedimentary sequence and source-reservoir-cap beds were under the control of tectonic activities, which provided dynamic resources for hydrocarbon migration and accumulation, however, the zonation from tectonic deformation was found to be the key factor in determining the hydrocarbon distribution and enrichment diversities of each depression in the basin. After contrastive analysis, Yuhuangding Formation of Paleogene System in Biyang Depression is considered to be the next layer system being worth of further exploration.