玛湖西斜坡百口泉组扇三角洲地震沉积学研究

Seismic Sedimentary Study on the Fan-delta of the Baikouquan Formation on the Western Slope of the Mahu Sag

李全 李培俊 倪振 刘军 刘荷冲

LIQuan LIPeijun NIZhen LIUJun LIUHechong

中国海洋石油国际有限公司, 北京 朝阳 100028 河南理工大学资源与环境学院, 河南 焦作 454003 中国石油新疆油田公司风城油田作业区, 新疆 克拉玛依 834000

CNOOC International Limited, Chaoyang, Beijing 100028, China Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan 454003, China Fengcheng Oilfield Operating Area, Xinjiang Oilfield Company, CNPC, Karamay, Xinjiang 834000, China

针对扇三角洲前缘砂砾岩体层间物性变化大，优质储层难以预测的关键问题，在地震沉积学理论指导下，利用地震岩性学、地震地貌学及地层切片技术，结合测井和地震等资料对准噶尔盆地玛湖凹陷西斜坡风南地区百口泉组扇三角洲沉积相展布特征和充填过程进行了识别与描述。建立了玛湖凹陷西斜坡三叠系百口泉组高精度层序地层格架，划分出6个四级层序。识别出研究区内百口泉组扇三角洲平原分流河道、河道间，扇三角洲前缘水下分流水道、河口坝、席状砂等沉积微相及相应的测井相特征，通过岩性标定指出储层砂体与地震振幅之间的对应关系。利用四级层序格架内的地层切片技术，明确了百口泉组扇三角洲沉积体系的演化充填过程，指出了研究区内扇三角洲前缘优质储层的分布范围以及下步勘探方向。

Fan-delta front glutenite exhibits wide variation in physical properties, making it difficult to predict high-quality reservoirs. Aiming to address this key issue, we identified and described the sedimentary facies distribution characteristics and filling process of the fan-delta in Baikouquan Formation in the Fengnan region on the western slope of the Mahu Sag (Junggar Basin). The study was guided by seismic sedimentology theory, and was done by means of seismic lithology, seismic geomorphology, and stratigraphic slicing techniques with logging and seismic data. In this study, we first established a high-precision sequence stratigraphic framework of the Triassic Baikouquan Formation on the western slope of the Mahu Sag, and delineated six fourth-order sequences. Then, we identified the sedimentary microfacies of the diversion channels, river channels, fan-delta front subaqueous diversion channels, estuary dams, and sheeted sands, as well as the corresponding logging characteristics of the Baikouquan Formation in the study area. We also indicated the correspondence between reservoir sand bodies and seismic amplitude by lithology calibration. Finally, with the help of slicing techniques in a fourth-order sequence grid, we clarified the filling-evolution process of the fan-delta sedimentary system in the Baikouquan Formation and pointed out the distribution range of high-quality reservoirs in the fan-delta front and the consequent prospecting direction.

10.11885/j.issn.1674-5086.2019.01.29.01