鄂尔多斯盆地东北部山西组河道砂体构型特征——基于陕西府谷剖面
- 收稿日期:
2025-10-23
- 网络出版日期:
2026-05-25
摘要: 摘要：【目的】鄂尔多斯盆地北部山西组致密砂岩气是盆地的重要产层之一，但山西组不同层段砂体的垂向叠置关系和横向分布差异大，给开发井的部署和建产区的优选带来挑战。【方法】本次通过剖面实测和无人机倾斜摄影建模，建立山西组数字剖面。在岩相划分和层次界面识别的基础上，进行砂体构型识别。研究不同构型砂体的叠置关系和分布规律。【结果】研究结果表明：①山西组为三角洲平原沉积，砂体主要为辫状河道沉积微相。温暖潮湿气候条件下植物发育，决口不明显，取而代之的是漫溢。②砂体构型主要有四种类型，分别是纵坝、横坝、下切河道和层状砂。③自下而上山西组砂体构型为下部纵坝与层状砂复合，中部横坝，上部下切河道。【结论】研究区河道砂体构型的有序变化是北部索伦洋逐渐关闭、盆地北部构造隆升的响应。构造隆升导致分流河道从早期的宽浅型过渡为中期的宽深型，最终变为窄深型下切河道。研究揭示了构造—气候协同控制下河道演化—构型分异—储层非均质性的响应机制，为盆地东北部山西组储层研究提供了新视角。
Channel Sandstone Architecture of the Shanxi Formation in the Northeastern Ordos Basin: Evidence from Fugu Outcrop in Shaanxi
- Received Date:
2025-10-23
- Available Online:
2026-05-25
Abstract: Abstract: [Objective] Tight gas sandstone within the Shanxi Formation is a significant gas-producing zone in the northern Ordos Basin. However, the variations in the vertical stacking patterns and lateral distribution of sandbodies across different intervals of the Shanxi Formation pose challenges for development well placement and gas production area selection. [Methods] This study establishes a three-dimensional digital outcrop model of the Shanxi Formation through measured stratigraphic sections and drone oblique photography modeling. Based on lithofacies classification and hierarchical bounding surface identification, sandbody architecture analysis was conducted. [Results]The results demonstrate that:①The Shanxi Formation represents a delta plain depositional environment, where sandbodies primarily correspond to the braided distributary channel microfacies. Under warm and humid climatic conditions, well-developed vegetation restricted crevasse formation, with overbank flooding (splay deposition) being the dominant process instead.②Four main types of sandbody architecture are identified: longitudinal bar, transverse bar, incised channel, and laminated sandstone.③The vertical succession of sandbody architectures within the Shanxi Formation, from base to top, is characterized by: composite longitudinal bars and laminated sandstones in the lower part, transverse bars in the middle part, and incised channels in the upper part. [Conclusions]The systematic variation in fluvial channel sandbody architecture within the study area records the gradual closure of the northern Solon Ocean and coeval tectonic uplift in the Ordos Basin's north. This uplift drove the evolution of distributary channels from an initial wide and shallow form, through a wide and deep intermediate stage, to a final narrow and deep, incised morphology. Our study elucidates the response mechanism linking channel evolution, architectural differentiation, and reservoir heterogeneity under coupled tectonic-climatic controls, offering a novel perspective for research on the Shanxi Formation reservoirs in the northeastern Ordos Basin.
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