准噶尔盆地西北缘侏罗系三工河组沉积特征

Sedimentary Characteristics of Sangonghe Formation of Jurassic in Northwest Margin of Junggar Basin

在岩心、地球物理和分析测试资料分析基础上,对准噶尔盆地西北缘三工河组辫状河三角洲平原开展详细分析,研究表明:三工河组沉积相类型包括辫状河流相和辫状河三角洲相,后者是三工河组主要的沉积相类型,可进一步划分为内平原和外平原亚相。内平原亚相分流河道砂体粒度粗,厚度大,成熟度低,煤层不发育。外平原亚相砂岩粒度细,厚度薄,成熟度较高,煤层发育。内平原储层物性明显好于外平原,三工河组优质砂岩储层均分布在内平原亚相,应是油气勘探的重点。

Based on the analysis of core,geophysical and analytical data,the braided river delta plain of Sangonghe formation is analyzed in detail.The study shows that the sedimentary facies types of Sangonghe formation include braided river facies and braided river delta facies,in which braided river delta facies is the main sedimentary facies type of Sangonghe formation,which can be further divided into inner plain and outer plain subfacies.The distributary channel sand body of the inner plain subfacies is coarse-grained,thick,low maturity,and the coal seam is not very developed.The outer plain subfacies have fine grain size,thin thickness,high maturity of sandstone and developed coal seams.The physical properties of the inner plain reservoir are obviously better than that of the outer plain.The high-quality sandstone reservoirs of Sangonghe formation are all distributed in the inner plain subfacies,which is the focus of oil and gas exploration.