辫状河储层内部建筑结构及剩余油分布研究

储层内部建筑结构是影响开发效果的决定性因素，对剩余油分布具有控制作用。基于河流相建筑结构分析理论，在辫状河沉积模式指导下，采用层次分析法，从开发角度对砂体内部结构进行精细解剖，识别和确定出辫状河道、心滩坝、废弃河道和落淤层等结构要素，弄清各级次、各期次结构要素的接触关系，完成辫状河储层内部结构的精细表征；基于内部结构表征成果，结合不同时期水淹层测井解释结果和生产动态资料，恢复不同开发调整时期的水淹特征，动态表征辫状河储层内部结构控制下的水淹过程，并依据小井距密闭取芯井精细水洗结果验证，总结不同储层结构控制下的剩余油分布模式。结果表明，辫状河储层整体以高含水为主，水淹呈不均匀立体式、随机式特征，不具有分段水淹的特点，未水淹部位分布非常零散，局部物性变差部位、落淤层和低渗屏障遮挡部位直接控制了剩余油的分布。

Study on the Reservoir Architecture and Remaining Oil Distribution of Braided Channel

The reservoir architecture is the key factor influencing the outcome of oil and gas production, and controls the distribution of the remaining oil. Based on the theory of architectural-element of fluvial reservoir and the depositional model of braided rivers, this study performed hierarchical analysis and dissected the reservoir architecture elements of sandbodies in detail for the purpose of future production. Structural elements including braided channels, channel bars, abandoned channels, and mud drapes, were identified and confirmed. Contact modes among architectural elements of different levels and periods were recognized to complete the detailed characterization of the reservoir architecture of braided channel. Based on these results, and in conjunction with interpretation of water-flooded layers from logging data of different time periods and dynamic production performance, water-flooding characteristics at various production and adjustment stages were reconstructed. The water-flooding process controlled by reservoir architecture of braided channel was dynamically characterized. The distribution of the remaining oil controlled by the reservoir architecture is summarized and confirmed by the detailed water-flooding results of densely spaced sealed coring wells. The results show that the braided river reservoir has a generally high water content, with three-dimensional inhomogeneous and random water-flooding characteristics that do not occur in segmentations. The non-flooded regions are very scattered. Locations with local deterioration of reservoir physical properties, mud drapes, and low-permeability barrier occlusion directly control the distribution of the remaining oil.