准噶尔盆地玛湖凹陷风城组云质泥页岩储层成岩作用及其对储层发育的指示意义

准噶尔盆地玛湖凹陷风城组页岩油资源潜力巨大，成岩作用对储层的发育至关重要。然而在成岩过程中受构造运动和深部流体作用等众多因素的综合影响，导致其储层成岩演化过程复杂，成岩作用阶段及其对储层物性的影响尚未明确，限制了页岩油资源的勘探开发。本研究针对玛湖凹陷风城组典型云质泥页岩储层，通过薄片鉴定、碳氧同位素、阴极发光、扫描电镜、矿物成分等分析测试，结果表明，风城组云质泥页岩储层为封闭咸水湖泊环境，沉积后经历了机械压实/压溶—溶蚀—多期次胶结—多类型交代综合交替的成岩过程。对储层孔隙度影响较大的成岩作用主要为压实作用、胶结作用和溶蚀作用。其中压实作用和胶结作用是储层物性变差的主要原因，溶蚀作用是改善储层物性的主要因素。研究明确了成岩作用对风城组云质泥页岩储层物性的影响，为风城组泥页岩储层的发育机制研究提供了理论支持，有利于提高页岩油勘探精度。

Diagenesis of dolomitic shale reservoir and its indicative significance for reservoir development in the Fengcheng Formation, Mahu sag of Junggar basin

The Fengcheng Formation, located in the Mahu sag of the Junggar basin, has significant potential for shale oil resources. Diagenesis plays a critical role in reservoir development; however, its complex evolution, influenced by tectonic movements and deep hydrothermal fluids, has obscured the understanding of diagenetic stages and their impacton reservoir properties. This lack of clarity restricts the exploration and development of oil and gas resources in the area. This study employed a comprehensive suite of techniques, including thin section identification, carbon and oxygen isotope analysis, cathode luminescence, scanning electron microscopy, and mineral composition analysis, to investigate the diagenetic history of the Fengcheng Formation. The results reveal that the dolomitic shale reservoir originated in a closed saline lacustrine environment and underwent a complex diagenetic sequence characterized by mechanical compaction/pressure solution, dissolution, multistage cementation, and multitype metasomatic alternation. Compaction, cementation, and dissolution emerged as the main diagenesis processes influencing porosity development within the reservoir.Compaction and cementation significantly contributed to the deterioration of reservoir properties, while dissolution played a crucial role in enhancing porosity and improving reservoir quality. This study provides insights into the complex relationship between diagenesis and the physical properties of the dolomitic shale reservoir in the Fengcheng Formation. The findings offer a theoretical framework for comprehending the development mechanism of shale reservoirs in this formation and facilitate the enhancement of shale oil exploration accuracy.