Abstract
The Yanchang Formation in the Ordos Basin is an important tight oil reservoir in China. Its characteristics of tight reservoirs, low permeability, and complex accumulation mechanisms make it a key focus and challenge for oil and gas exploration and development. This paper systematically analyzes the accumulation mechanisms, reservoir characteristics, distribution patterns, and dynamic conditions of tight oil in the Yanchang Formation, uncovering the critical factors influencing its formation and distribution. Additionally, it explores theoretical and practical approaches for efficient development. The results indicate that the formation of tight oil in the Yanchang Formation is primarily controlled by the characteristics of source rocks, reservoir structures, the spatial relationship between oil shales and tight sandstones, and accumulation dynamic conditions. Under the combined influence of these factors, the distribution of tight oil exhibits significant regional differences, resulting in multiple accumulation models. This research elucidates the dynamic characteristics of tight oil accumulation, including hydrocarbon generation overpressure effects and oil and gas migration mechanisms, providing theoretical support for the efficient development of low-permeability reservoirs. Moreover, by integrating core samples, thin sections, seismic data, well logging, and geochemical data, this paper systematically reveals the accumulation patterns of tight oil in the Yanchang Formation, offering innovative insights and methods for reservoir development. The findings enrich the theoretical understanding of tight oil accumulation and provide valuable references for the exploration and development of other low-permeability reservoirs, advancing the sustainable development of low-permeability resources in China. This paper aims to clarify the formation and distribution patterns of tight oil in the Yanchang Formation, explore effective accumulation models, and provide theoretical guidance and practical references for the economic and efficient development of low-permeability oil resources.
