地层剥蚀厚度恢复研究——以南黄海北部盆地东北凹陷为例

Study on Strata Eroded Thickness Restoration——A Case Study of Northeast Depression in Northern South Yellow Sea Basin

地层抬升剥蚀是沉积盆地中普遍存在的现象。地层剥蚀厚度的准确恢复对正确重建沉积盆地原始沉积—构造演化史、热史及油气生、排、运、聚史和定量评价油气资源潜力至关重要。在充分结合南黄海北部盆地东北凹陷区域构造和演化特征研究的基础之上,依据东北凹陷实际地质情况和资料条件,选取参考层厚度变化率法和沉积速率法,对东北凹陷始新统戴南组和三垛组地层的剥蚀厚度进行了定量恢复。研究结果表明,渐新世末的三垛运动使东北凹陷内始新统戴南组和三垛组地层遭受强烈的剥蚀改造,戴南组和三垛组地层在凹陷内各个构造带表现出不同的剥蚀响应特征。

The uplift and erosion of strata is ubiquitous in sedimentary basins. Restoration of the exact thickness of eroded strata is very important to rebuild the primary sedimentary and structural evolution history, the geothermal history, the history of hydrocarbon generation, expulsion, migration, and accumulation, and also to evaluate the potential of oil and gas resources accurately. Based on structural evolution research in the Northeast Depression of northern South Yellow Sea Basin, according to the practical geological conditions and data, the methods of variance ratio on thickness of reference layers and sedimentary rate are applied to eroded thickness restoration of Eocene Dainan Formation and Sanduo Formation in Northeast Depression. The final result shows that the Sanduo structural movement that happened at the last stage of Eocene leads to the intense erosion of the strata of Eocene Dainan Formation and Sanduo Formation, as well as the two formations above mentioned indicate distinct characteristics in different structural zones of Northeast Depression.