钟市油田潜江组含盐层系高分辨率层序地层格架及砂体分布规律

以钟市油田潜三段储层为例, 进行了盐湖盆地高分辨率层序地层研究。在冲刷面、湖泛面以及盐岩界面基础上, 根据相组合特征, 在潜三段识别出向上“变深”不对称旋回、向上“变浅”不对称旋回以及向上“变浅”复“变深”对称旋回等3 类基本短期旋回。根据短期旋回叠加样式, 将潜三段划分为5 个中期旋回和1 个长期旋回。中期旋回内砂体分布规律受可容纳空间与沉积物供给比(A/S) 的控制。指出在A/S<<1 时, 砂体最为发育, 且连通性最好。但基准面最低时, 气候干燥, 湖盆水体浓缩, 碎屑供给不充分, 发育盐岩沉积; 在A/S<<1 向A/S<1 过渡时砂体较发育, 但隔夹层逐渐丰富; 在A/S>>1 时, 砂体不发育, 多为孤立砂体。

High resolution sequence stratigraphy framework and the distribution of sand bodies in salt lake of Qianjiang Formation in Zhongshi Oilfield

The high resolution sequence stratigraphy of salt lake in the third member of Qianjiang Formation in Zhongshi Oilfield is studied. Based on the characteristics of scoured surface, flooding surface and the rock salt boundary surface, and the facies association, three short-term base level cycles are identified, including deepeningupward asymmetry base level cycle, shallowing-upward asymmetry base level cycle, and symmetry base level cycle. According to the stacked pattern, the third member of Qianjiang Formation is divided into five middle-term base level cycles and one long-term base level cycle. The distribution of sand bodies is controlled by the ratio of accommodation to supply （A/S）. When A/S is very smaller than 1, the sand bodies are best developed, with best formation communication, and under the condition that the weather is hot and the lake evaporation is greater than the supply, the salt is deposited. When A/S is close to 1, the sand bodies are relatively developed. When A/S is very greater than 1, the sand bodies are undeveloped.