Abstract

Take the lacustrine delta in the second member of Paleogene Shahejie Formation in block Wang43, Dongying depression, Bohai Bay Basin as an example, the deposition architectural characteristics of lacustrine deltaic sand bodies controlled by syn-depositional faults in complex fault blocks of rift basin are examined from the aspect of the tectonic-deposition response, using cores, well logs and three-dimensional seismic data. The small-scale syn-depositional faults in complex fault blocks are dense and different in dip, the activity along the strike of syn-depositional fault varies in different positions, and all these control the sedimentary process of deltaic sand bodies. Influenced by syn-depositional faults, the deltaic distributary channel is more likely to pass through the position with weak fault activity, and be deflected or limited at the position with strong fault activity. In downthrown side of a single syn-depositional fault or micro-graben areas, sand bodies increase in thickness and planar scale, and sand bodies of multiple stages are likely to stack over each other vertically. In micro-horst areas controlled by syn-depositional faults, the sand bodies decrease in abundance, and appear in intermittent superimposed pattern vertically. This study can provide new research ideas and theoretical basis for exploration and development research in complex fault blocks.

中文翻译：

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裂谷湖盆地同沉积断层控制的三角洲砂体分布规律

摘要

以渤海湾盆地东营凹陷王43段古近纪沙河街组第二段湖相三角洲为例，研究了裂谷盆地复杂断块中同沉积相控制的湖相三角洲砂体的沉积构造特征。从构造沉积响应的角度出发，使用岩心，测井曲线和三维地震数据。复杂断块中的小规模同沉积断层致密，倾角不同，沿同沉积断层走向的活动性在不同位置变化，这些都控制了三角洲砂体的沉积过程。受同沉积断层的影响，三角洲分布通道更可能通过断层活动性较弱的位置，并在故障活动强烈的位置偏转或限制。在单个同沉积断层或微颗粒区的下倾侧，砂体的厚度和平面尺度增加，并且多级砂体可能会相互垂直堆叠。在同沉积断层控制的微岩溶区，砂体丰度下降，垂直呈间歇性叠加模式。该研究可以为复杂断层块的勘探开发研究提供新的研究思路和理论依据。在同沉积断层控制的微岩溶区，砂体丰度下降，垂直呈间歇性叠加模式。该研究可以为复杂断层块的勘探开发研究提供新的研究思路和理论依据。在同沉积断层控制的微岩溶区，砂体丰度下降，垂直呈间歇性叠加模式。该研究可以为复杂断层块的勘探开发研究提供新的研究思路和理论依据。