盐间页岩油形成有利条件与地质甜点评价关键参数——以潜江凹陷潜江组潜34-10韵律为例

江汉盆地潜江凹陷潜江组潜34-10韵律盐间细粒沉积岩是页岩油勘探开发有利层系。基于页岩油专探井/兼探井取心段分析结果与前人资料，阐述潜34-10韵律盐间细粒沉积岩总体是一套好—优质烃源岩，有机质以腐泥组无定形体组分为主，类型主要为Ⅱ₁、Ⅰ型，现今处于生排油高峰期；其储集条件优越，与国内外主要页岩油产层储集条件相当，尤以白云岩、泥质白云岩相最佳；盐间细粒沉积岩上部和下部连续分布的厚层盐岩构成了盐间页岩油优质的顶板和底板封盖层。潜34-10韵律盐间细粒沉积岩层系发育层内侧向运移富集型和原位—近源聚集富集型2类页岩油，前者发育于王场背斜构造带，后者发育于蚌湖洼陷的深洼与南斜坡带。提出了2类页岩油富集类型的地质甜点评价关键参数与指标，为潜江凹陷其他盐间细粒沉积层系页岩油勘探开发评价提供依据与借鉴。 

Favorable conditions of inter-salt shale oil formation and key parameters for geological sweet spots evaluation: a case study of Eq34-10 rhythm of Qianjiang Formation in Qianjiang Sag,Jianghan Basin

The inter-salt fine-grained sedimentary rocks of the Eq₃4-10 rhythm of the Qianjiang Formation in the Qianjiang Sag, Jianghan Basin, are favorable for shale oil exploration and development. They are excellent source rocks according to the analysis of cored intervals from specialized/concurrent shale oil exploration wells and the archival data. The organic matter is composed of the amorphous components of the sapropelic group, mainly of types Ⅱ₁ and I, and is currently in the peak period of oil generation and expulsion. The reservoir properties are good especially for dolomites and argillaceous dolomites, and are equivalent to the reservoir properties of main shale oil production layers at home and abroad. Thick layers of salt distributed continuously above and below the inter-salt fine-grained sedimentary rocks constitute high-quality top and bottom seals of the inter-salt shale oil. The inter-salt fine-grained sedimentary rocks of the Eq₃4-10 rhythm developed two types of shale oil, including the lateral migration and enrichment type in the sedimentary rocks in the Wangchang anticline area, and the in situ and near-source enrichment type in the Benghu Deep Sag and the southern slope area. Some key parameters and limits for geological sweet spot evaluation for the two enrichment types were put forward. The results provided the evidence and reference for shale oil exploration and development evaluation of other inter-salt fine-grained sedimentary rocks in the Qianjiang Sag, Jianghan Basin.