准噶尔盆地玛湖凹陷风城组页岩油地质特征与分级评价

准噶尔盆地玛湖凹陷风城组页岩油资源丰富，但勘探程度较低，对页岩油资源的潜力评价和资源禀赋差异缺少系统研究，制约着勘探部署和有利区优选。以玛页1井为例，综合钻井、测井、岩心和岩石矿物组成、有机地球化学特征、储集物性、含油性等地质资料，系统分析了风城组页岩油地质特征，探讨了页岩油甜点评价标准。结果表明，风城组页岩主要由长英质和碳酸盐矿物组成，黄铁矿发育，黏土矿物较少。风城组页岩主要发育Ⅱ₂型干酪根，总有机碳（TOC）含量分布在0.08%~2.33%，多处于成熟阶段。页岩储集空间类型主要为狭缝状孔隙，孔隙分选性较好；总体上，宏孔较发育，孔隙体积分布在0.001~0.008 cm³/g，平均为0.003 cm³/g。风城组页岩内部烃类聚集，游离烃含量为0.52~13.31 mg/g，吸附烃含量为0.16~5.17 mg/g。明确了页岩岩相、微观孔隙特征、页岩油赋存形式是风城组页岩含油性的主控因素，在此基础上建立了风城组页岩油甜点的划分标准，在玛页1井风城组优选出8个最有利的页岩油勘探层段，有利储集岩相以长英质页岩为主。

Geological characteristics and classification evaluation of shale oil in Fengcheng Formation in Mahu sag,Junggar Basin

There are abundant shale oil resources in Fengcheng Formation in Mahu sag, Junggar Basin. However, due to the low degree of exploration, the potential evaluation and resource endowment differences of shale oil resources have not been systematically studied, thus restricting the exploration deployment and favorable zone optimization. This paper is a case study of Well Maye1. Based on the geological data of drilling, logging, core and rock mineral composition, organic geochemical characteristics, reservoir properties, and oil-bearing properties, the paper systematically analyzes the geological characteristics of shale oil in Fengcheng Formation, and discusses the sweet spots evaluation standard of shale oil. The results show that the Fengcheng Formation shale is mainly composed of quartz, feldspar and carbonate minerals, in which pyrites are well developed and few clay minerals can be found. The shale in Fengcheng Formation is dominated by typeⅡ₂ kerogen, with the TOC content ranging from 0.08% to 2.33%, mostly in the mature stage. The reservoir space is dominated by slit-like pores, characterized by good pore sorting. On the whole, macropores are well developed, and the pore volume is distributed in the range of 0.001 to 0.008 cm³/g, with an average of 0.003 cm³/g. The content of free hydrocarbon and absorbed hydrocarbon is in the range of 0.52 to 13.31 mg/g and 0.16 to 5.17 mg/g, respectively, indicating that Fengcheng Formation shale is rich in hydrocarbons. It is clear that shale lithofacies, microscopic pore characteristics, and shale oil occurrence state are the main controlling factors for the oil-bearing properties of shale in Fengcheng Formation. On the basis, the paper establishes the classification criteria for shale oil sweet spots, and selects 8 most favorable exploration zones of shale oil in Fengcheng Formation of Well Maye1. The reservoir rock facies are mainly shown as felsic shale.