256 / 2022-03-30 21:32:25

玛湖凹陷南斜坡区侏罗系三工河组二段沉积微相特征及砂体展布

玛湖凹陷；三工河组二段；沉积微相；砂体展布特征

摘要：准噶尔盆地玛湖凹陷南斜坡区作为中浅层油气勘探的主要有利区带，目前已钻遇工业气流，但对于主要含油层三工河组二段的沉积微相特征研究还尚属空白。本文基于三维地震资料、岩心资料、测井、录井资料，并结合地震模型反演技术，对玛湖凹陷南斜坡区侏罗系三工河组二段岩石类型、沉积构造和沉积模式进行了详细研究，进一步分析了研究区沉积微相和砂体展布的关系。结果表明：研究区发育冲刷面、交错层理、生物扰动构造等沉积构造；三工河组二段发育辫状河三角洲前缘亚相，进一步可细分出水下分流河道、辫状砂坝2个微相类型，水下分流河道微相发育于同生断层位置，不发育砂体，辫状砂坝分布于河道两侧，呈现出单砂体和复合砂体两级结构，是漫积和前积的结果。

关键词：玛湖凹陷； 三工河组二段 ； 沉积微相 ；砂体展布特征

Abstract  The south slope area of Mahu sag in Junggar basin is the major favorable area for medium and shallow oil and gas exploration. At present, industrial gas flow has been drilled, but the research on the sedimentary microfacies characteristics of the second member of Sangonghe formation is still blank.Based on three-dimensional seismic data, core data, logging and logging data, and combined with seismic model inversion technology, this paper makes a detailed study on the rock type, sedimentary structure and sedimentary model of the second member of Jurassic Sangonghe Formation in the south slope area of Mahu sag, and further analyzes the relationship between sedimentary microfacies and sand body distribution in the study area. The results show that sedimentary structures such as scouring surface, cross bedding and bioturbation structure are developed in the study area; Braided river delta front subfacies are developed in the second member of Sangonghe formation, which can be further subdivided into two microfacies types: underwater distributary channel and braided sand bar. Underwater distributary channel microfacies are developed in the position of syngenetic fault, and sand bodies are not developed. Braided sand bars are distributed on both sides of the river channel, showing two-stage structure of single sand body and composite sand body, which is the result of  flooding deposition and  progradation.

Key words Mahu Sag; Second member of Sangonghe formation; Sedimentary microfacies;Distribution characteristics of sand body