KL油田沙三下亚段混合沉积特征及演化

针对目前莱州湾凹陷南斜坡带KL油田沙河街组三段下亚段陆源碎屑与碳酸盐岩混合沉积形成条件、沉积特征及模式认识程度较低的问题，利用该区壁芯、薄片及扫描电镜等资料，结合构造演化、古气候和古地貌背景，在层序格架约束下研究沉积环境，分析其沉积特征。结果表明，研究区发育混合沉积，形成于宽缓斜坡、亚热带湿润气候，兼具湖平面、物源、水动力条件周期性变化等条件；该混合沉积包括相缘渐变混合与原地混合两种沉积类型，互层式和组分式两种混合模式，以及4种混合样式。两种混合沉积类型沉积机理不同，混合模式及组合样式表现较大差异，因而具有不同的储层微观特征。

Mixed Sedimentation Characteristics and Evolution of Lower Member 3 of the Shahejie Formation in the KL Oilfield

There is still limited understanding of the formation conditions, sedimentation characteristics, and modes of the terrestrial debris-carbonate rock mixed sedimentation in the lower sub-member of Member 3 of the Shahejie Formation in the KL Oilfield in the southern slope of the Laizhou Bay Depression. In this study, data from side-wall cores from the area, thin sections, and scanning electron microscopy were obtained and integrated with contextual information, including tectonic evolution, paleoclimate, and paleogeomorphology. The sedimentary and sedimentary characteristics were analyzed within a sequence stratigraphic framework. The results reveal that mixed sedimentation developed in the study area due to wide and gentle slopes, humid subtropical climate, and periodically varying lake surfaces, water sources, and hydraulic conditions. This mixed sedimentation includes two sedimentation modes, gradual mixing along the facies edges and in situ mixing; two mixing modes, rhythmic bedding and compositional mixing; and four mixing patterns. The two mixed sedimentation modes differ in their mechanisms, while the mixing modes and mixing patterns show relatively significant variations, which has resulted in different microscopic characteristics in the reservoir.