Abstract: Currently, sweet spot evaluation plays an important role in unconventional oil and gas exploration and development, which is of great significance to the large-scale efficient development of unconventional oil and gas. The concept connotation of sweet spot has been increasingly expanded and more diversified and regional the corresponding evaluation parameters and standard values are more diversified and regionally distinctive. At present, the commonly-used sweet spot evaluation and prediction methods include the contour map semi-quantitative plane superimposition evaluation method, the sweet spot quantitative and semi-quantitative evaluation method based on multi-parameter co-constraint, the radar graphic method, and the sweet spots quantitative evaluation method established based on the geological anomaly theory. In the practical application, the applicability evaluation and prediction method should be developed according to the basic data such as tectonic depositional settings, lithological association and resource type of the basin, and the principle of superposed progressive discrimination. Continental shales in China are highly heterogeneous, and there is a significant difference in the enrichment laws and main controlling factors of different types of shale oil. Both interlayer and hybrid shale oil have experienced migration and accumulation in the source. The main lithology of the reservoir is sandstone (siltstone) and carbonate rock (hybrid sedimentary rock). The reservoir property, hydrocarbon potential and brittleness of reservoirs are the key indicators. The pure shale oil intervals in the thick and ultra-thick layers is generally oil-bearing, and the oil is mainly retained in the source. The source rocks are the reservoirs. It is suggested to use the trichotomy method to divide hydrocarbon enrichment layers into Type I, Type II and Type III using 5~8 key parameters based on the data of sedimentary cycle, laminated texture type, lithological association, hydrocarbon potential, reservoir property, compressibility, mobility and recoverability. During the optimization of enrichment layers, zoning should be planned according to the thermal evolution maturity of different basins and zones. In the medium-low maturity zone, the medium-high TOC content shale interval (felsic laminae develop) adjacent to the high TOC content shale interval should be optimized; in the medium-high maturity zone, the high TOC content shale interval should be optimized. As the "gold target layer", Type I oil reservoir should be developed and produced initially, and progressively exploited according to technological maturity, so as to realize the maximum development and utilization of China's continental shale oil resources, and effectively serve to guarantee the national energy security.

Key words: shale oil, sweet spot, evaluation parameter, oil reservoir classification, gold target layer

摘要： “甜点”评价是目前非常规油气勘探开发中的一项重要内容，对非常规油气规模效益开发具有重要意义。"甜点"概念内涵不断扩展，评价参数的选择和取值标准更加多样化和地区性。目前常用的"甜点"评价预测方法包括等值线图半定量平面叠合评价方法、多参数共同约束开展"甜点"定量—半定量评价方法、雷达图示法和基于地质异常理论建立"甜点"定量评价方法，在实际应用过程中，要根据盆地构造沉积背景、岩性组合、资源类型等基础资料，遵循叠加递进判别原则，研发适用性评价预测方法。中国陆相页岩非均质性强，不同类型页岩油的富集规律和主控因素差异明显。夹层型、混积型页岩油均发生过源内运聚，源岩非储集层，储集层主体岩性为砂岩（粉砂岩）、碳酸盐岩（混积岩），储层的储集物性、含油气性和脆性是关键指标。厚层—巨厚层纯页岩油层段整体含油，以源内滞留为主，源岩即储集层，建议综合沉积旋回、纹层结构类型、岩性组合、含油气性、储集性、可压性、可动性、可采性等资料，应用5~8个关键参数，采用三分法划分出Ⅰ类、Ⅱ类、Ⅲ类富集层。在优选富集层时，要根据不同盆地、不同区带的热演化成熟度具体进行分区考虑，在中—低成熟度区应优选与高TOC含量页岩层段紧邻的中—高TOC含量页岩层段（长英质纹层发育），在中—高成熟度区应优选高TOC含量的页岩层段。Ⅰ类油层作为"黄金靶层"应优先开发动用，根据技术成熟度实行递进开发，以实现中国陆相页岩油资源最大限度开发利用，切实服务于保障国家能源安全。

关键词: 页岩油, 甜点, 评价参数, 油层分类, 黄金靶层