陆相箕状断陷湖盆沉积差异性研究-以冀中富油凹陷为例

以冀中富油凹陷古近系沙河街组为研究对象,通过对工区内地震资料、岩心资料、测录井资料的研究,将陆相箕状断陷湖盆按盆缘类型划分为高盆缘型和低盆缘型两种;并且对廊固、霸县及饶阳三个凹陷各个时期的盆缘类型进行了判定。在整个Es3-Es4发育时期,廊固凹陷大部分时期属于高盆缘类型,霸县凹陷既有高盆缘型也有低盆缘型的特征,饶阳凹陷均为低盆缘型。在此基础上,对不同凹陷相同构造带的沉积特征进行了对比。对比发现,高盆缘型陆相箕状断陷湖盆陡坡带主要发育粗粒的近岸水下扇,中央洼槽带半深湖-深湖沉积范围广阔并发育湖底扇;低盆缘型陆相箕状断陷湖盆陡坡带主要发育较细粒的扇三角洲,中央洼槽带发育规模较小的滨浅湖;二者之间缓坡带沉积特征没有太大差异,都主要发育辫状河三角洲。最后分析得出箕状断陷湖盆沉积特征差异性主要受构造活动等因素控制。

Study on sedimentary difference of the continental fault lacustrine basin-taking Jizhong oil-rich Depression as an example

This thesis take Shahejie Formation of Jizhong oil-rich Depression as an example, based on seismic data, core discretion, and well logging data, this thesis divides the basin margin of the continental fault lacustrine basin into two types: high basin margin and low basin margin, and assesses the type of the third and fourth Member of Shahejie Formation (Es3-Es4) in Langgu, Baxian, and Raoyang Depression. During the period of Es3-Es4, Langgu Depression developed high basin margin, Baxian Depression Had the characteristics of both high basin margin and low basin margin, and Raoyang Depression developed low-basin margin only. On the basis of the different types of basin margin, combined with the previous study of the sequence stratigraphy and sedimentary systems in each depression , this thesis establishes a uniform sequence stratigraphy framework throughout three depression, and studies the sedimentary characteristics of the same tectonic belt in different depressions. By comparing the sedimentary characteristics, it can be found that the continental fault lacustrine basin with high basin margin mainly develops nearshore subaqueous fan deposition, which develops a large scale of mid-deep to deep lake deposition and sublacustrine fan deposition in subsags central belt; the continental fault lacustrine basin with low basin margin mainly develops finer grained fan delta deposition in the steep slope belt, and it mainly develops minor shore-shallow lacustrine subfacies deposition in the subsags belt. There is not much different in the gentle slope belt of these two types, the braided river delta deposition is the main facies in both type of basin. Last,This thesis point out sedimentarySdifference of the continental fault lacustrine basin is mainly controlled by tectonicSfactors.