浅水扇三角洲沉积特征及演化规律:以准噶尔盆地玛东斜坡区百口泉组为例  

Sedimentary characteristics and evolution of the shallow-water fan delta:A case study of the Baikouquan Formation in the Madong slope area,Junggar Basin

作　　者：代超 康逊 谭静强 鲁锋 连丽霞 胡瑞璞 DAI Chao;KANG Xun;TAN Jingqiang;LU Feng;LIAN Lixia;HU Ruipu(School of Geosciences and Info-Physics,Central South University,Changsha 410083,China;Research Institute of Experiment and Detection,PetroChina Xinjiang Oilfield Company,Karamay Xinjiang 834000,China;Xinjiang Key Laboratory of Conglomerate Petroleum Reservoir,Karamay Xinjiang 834000,China)

机构地区：[1]中南大学地球科学与信息物理学院,长沙410083 [2]中国石油新疆油田分公司实验检测研究院,新疆克拉玛依834000 [3]新疆砾岩油藏重点实验室,新疆克拉玛依834000

出　　处：《地质科技通报》2025年第2期285-304,共20页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(42272179)。

摘　　要：砾岩作为一类特殊的油气储集层,理解其沉积成因及发育规律对于准确预测优质储层的分布至关重要。基于岩心描述、岩矿鉴定、重矿物与粒度分析等研究,结合测井、录井等资料,明确了准噶尔盆地玛东斜坡区下三叠统百口泉组砾岩的沉积特征、空间展布规律与沉积物来源,厘清了该组砾岩的沉积机制并构建了其沉积模式。研究结果表明,玛东斜坡区百口泉组沉积于浅水扇三角洲,扇体发育了扇三角洲平原、扇三角洲前缘、前扇三角洲3个亚相,包括泥石流、水上辫状河道、洪泛沉积、水下泥石流、水下主干河道、水下分支河道、砂质碎屑流、远砂坝、前扇三角洲泥共9种沉积微相,其中包含了10类岩相。结合研究区早三叠世由干旱转为湿润的古气候背景,确定该组砾岩为洪水诱发重力流的沉积产物,具有岩相组合复杂、事件性沉积标志显著、沉积模式受古气候主导、后期湖浪改造明显等特点。在空间上,玛东斜坡区百口泉组砾岩自下而上粒度逐渐变细,体现出湖侵的退覆式沉积序列,同时呈现出泥石流、水下泥石流和水下河道沉积多期叠置的特点。研究结果可为下一步油气勘探开发提供理论支持。[Objective]Conglomerates are unique petroleum reservoirs,and understanding their sedimentary origin and evolution is crucial for accurately predicting the distribution of high-quality reservoirs.[Methods]Based on core logging,petrologic identification,heavy mineral and grain size analysis,and well logging data,the sedimentary characteristics,spatial distribution,and sedimentary provenance of the Lower Triassic Baikouquan Formation conglomerate in the Madong slope area are defined.Meanwhile,the sedimentary mechanism of the formation is clarified,and a sedimentary model is established.[Results]The Baikouquan Formation was deposited as a shallowwater fan delta,and the fan body consists of three subfacies:the fan delta plain,fan delta front,and pro-fan delta,and can be divided into nine microfacies:debris flow,braided channel,flood deposit,subaqueous debris flow,subaqueous main channel,subaqueous branch channel,sandy clastic flow,far sand bar,and pro-fan delta mudstone deposits.Summarily,it contains 10 lithofacies types.The conglomerate was a sedimentary product of flood-induced gravity flow,reflecting complex lithofacies associations,significant evidence of event deposition,a sedimentary model dominated by paleoclimate,and a clear transformation of lake waves.Spatially,the grain size of the Baikouquan Formation conglomerate in the Madong slope region becomes finer from bottom to top,indicating a sedimentary sequence of lake transgression and a multi-period superposition of debris flows,underwater debris flows,and subaqueous channel deposits.

关 键 词：砾岩成因 扇三角洲 洪水成因重力流 百口泉组 准噶尔盆地 玛东斜坡区 

分 类 号：P618.13[天文地球—矿床学]