辽河断陷盆地地层划分对比标志研究

辽河断陷地质构造十分复杂, 造成了古近系分割性强、厚度和岩性纵横向变化大等特点. 寻找识别标志层, 进行精细地层划分对比一直是本区地层研究的难点, 制约了油气勘探开发部署. 从盆地构造沉积演化分析入手, 通过多重地层划分对比方法, 对西部凹陷近千口探井进行系统研究, 识别了古近系7个区域标志层, 描述了古近系沙河街组共14种不同类型底界的接触关系和岩电特征, 并以各种类型底界的代表井为基准, 划分出同一地层单元内不同类型底界的分布区, 使陆相断陷盆地地层划分对比更加简单、具体、易操作, 为油气精细勘探提供基础支撑.

MARKER BEDS FOR STRATIGRAPHIC DIVISION AND CORRELATION IN LIAOHE FAULT BASIN

The Paleogene system is characterized by violent segmentation, greatly various thickness and lithology vertically and horizontally as a result of the complex geological structure of Liaohe fault basin. Finding and identifying marker beds for fine stratigraphic division and correlation have always been the difficulty in stratigraphic research in the area, thus restricting the deployment of oil-gas exploration and development. Based on the analysis of tectonic sedimentary evolution of the basin, the paper systematically studies nearly 1 000 exploratory wells in the Western Sag through multiple stratigraphic division and correlation, identifying 7 regional marker beds of Paleogene, describing the contact relations and lithologic-electric characteristics for 14 types of bottom boundaries of Paleogene Shahejie Formation, and dividing different distribution areas by bottom boundary types within one stratigraphic unit on the basis of representative wells, which makes the stratigraphic division and correlation of continental fault basins more simple, detailed and easy to operate, and provides basic support for fine oil and gas exploration.