江汉盆地潜江凹陷王场地区古近系潜江组沉积微相及其演变

Sedimentary microfacies and evolution of the Qianjiang Formation of Paleogene at Wangchang area in Qianjiang Sag,Jianghan Basin

潜江凹陷是一个中新生代断陷型盐湖盆地。其中蕴藏着丰富的石油、天然气和盐。在始新世晚期—渐新世早期潜江组沉积期 ,湖盆的构造活动和沉积充填作用极为活跃 ,形成了厚达 4 5 0 0m的含盐岩系。通过对凹陷西北部王场地区王平 1井、王云 1 0 - 6井和王 80 - 2井取心段共约 1 5 1m岩心的精细研究 ,在潜江组古盐湖韵律性含盐岩系中识别出 1 7个典型的微相类型 ,并按成因与形成环境和岩类归纳为 7个微相系列 ,对每个微相的特征与形成环境进行了分析。在潜江组淡化段中 ,沉积微相的纵向演变过程或组合类型复杂多变 ,总体上由潜四段至潜二段组成 ,湖盆的蒸发强度越来越大 ,水深越来越浅。最后 。

The Qianjiang Sag is a Meso Cenozoic faulted saline basin, and bears abundant oil,gas and salt During the depositional period of the Qianjiang Formation (from Late Eocene to Early Oligocene),the tectonic activity and sedimentation infilling of the lacustrine basin were very active,thus forming the salt bearing rock series with a thickness of 4 500 m Through the detailed study on a total of about 151m thick cores in the interval of the Qianjiang Formation of wells Wangping 1,Wangyun 10-6 and Wang 80-2,of the Wangchang area,northwestern Qianjiang Sag,17 typical sedimentary microfacies are recognized,and 7 microfacies series are generalized according to origin,formation environment and rock types The characteristics of each microfacies are described,and the formation environment conditions are also analyzed The evolution process or association types of the microfacies in the intervals between the salt beds of the Qianjiang Formation is complex and various The evaporation degree of the lacustrine basin was gradually increasing,and the water depth was gradually shallower from Member 4 to Member 2 of Qianjiang Formation At last,the formation conditions of the Qianjiang saline basin and the evolution of the sedimentary environment are also analyzed briefly