A/S对断陷湖盆三角洲时空演化的控制及数值模拟——以珠江口盆地陆丰22洼古近系文昌组为例  

A/S control on spatiotemporal evolution of deltas in rifted lacustrine basin and its numerical simulation:A case study of Paleogene Wenchang Formation in Lufeng 22 subsag,Pearl River Mouth Basin

作　　者：张威 李磊 邱欣卫 龚广传 程琳燕 高毅凡 杨志鹏 杨蕾 ZHANGWei;LI Lei;QIU Xinwei;GONG Guangchuan;CHENG Linyan;GAO Yifan;YANG Zhipeng;YANG Lei(School of Earth Sciences and Engineering,Xi’an Shiyou University,Xi’an 710065,China;Shaanxi Key Laboratory of Petro-leum Accumulation Geology,Xi’an 710065,China;Shenzhen Branch of CNOOC China Limited,Shenzhen 518000,China;Research Institute of Exploration and Development,PetroChina Huabei Oilfield Company,Renqiu 062550,Hebei,China)

机构地区：[1]西安石油大学地球科学与工程学院,西安710065 [2]陕西省油气成藏地质学重点实验室,西安710065 [3]中海石油(中国)有限公司深圳分公司,深圳518000 [4]中国石油华北油田分公司勘探开发研究院,河北任丘062550

出　　处：《岩性油气藏》2022年第3期131-141,共11页Lithologic Reservoirs

基　　金：国家自然科学基金项目“深水重力流流态转化研究”(编号:41302147)与“研究生创新与实践能力培养计划”(编号:YCS21112049)联合资助。

摘　　要：湖盆可容空间与沉积物供给的比值(A/S)与三角洲沉积地层的层序结构及其在剖面上的叠置样式存在重要关联。通过高分辨率三维地震资料、钻测井资料,基于层序地层学、沉积学理论与沉积数值模拟技术,建立了珠江口盆地陆丰22洼古近系文昌组的等时地层格架,并结合沉积数值模拟技术探索了A/S对断陷湖盆三角洲时空演化的控制作用。研究结果表明:(1)陆丰22洼文昌组可划分为6个三级层序,自下而上分别为SQ1,SQ2,SQ3,SQ4和SQ5+6,发育了杂乱前积型、下超前积型、斜交前积型、叠瓦前积型等4类三角洲沉积体系;(2)文昌组SQ3和SQ4层序沉积体系具有明显差异。SQ3层序沉积期,A/S大于1,湖盆三角洲多为近源沉积,洼陷内部发育大面积半深湖—深湖沉积;SQ4层序沉积期,A/S小于等于1,三角洲发育规模扩大,向湖盆中心推进,洼陷内部广泛发育滨浅湖沉积;(3)选择研究区文昌组SQ3和SQ4层序开展三角洲沉积体系数值模拟,在软件中设置可容空间、沉积物供应和搬运方式等3个主要参数,模拟结果与实际地质认识较一致,进一步明确了研究区砂体的空间分布。The ratio of accommodation to sediment supply(A/S)of lacustrine basin shows a strong correlation with sequence structure and the stacking pattern of deltas on profile. By using high-resolution 3D seismic data and logging data,based on sequence stratigraphy,sedimentology theory and sedimentary numerical simulation technology,the isochronous stratigraphic framework of Paleogene Wenchang Formation in Lufeng 22 subsag of Pearl River Mouth Basin was established. Combined with sedimentary numerical simulation technology,the control effects of A/S on the spatiotemporal evolution of deltas in rifted lacustrine basin were explored. The results show that:(1)Wenchang Formation in Lufeng 22 subsag can be divided into six third-order sequences,including SQ1,SQ2,SQ3,SQ4 and SQ5+6 from bottom to top. Four types of delta systems are identified in Wenchang Formation in the study area,including chaotic foreset,downlap foreset,oblique foreset and imbricated foreset.(2)There are obvious differences between SQ3 and SQ4 sequence sedimentary systems of Wenchang Formation.During the SQ3 period,the A/S was greater than 1,sediments deposited in the lacustrine basin deltas mostly came from near-source,and large area of semi-deep to deep lacustrine deposits were developed in the subsag. During the SQ4 period,the A/S was less than or equal to 1,the delta advanced into the center of the lacustrine basin,and shore shallow lacustrine deposits were widely developed in the subsag.(3)The SQ3 and SQ4 sequences of Wenchang Formation in the study area were selected to carry out numerical simulation of delta sedimentary system.During the simulation,three main parameters such as accommodation,sediment supply and transportation patterns were set in the software. The simulation results are consistent with the actual geological understanding,and the spatial distribution of sand bodies in the study area was determined.

关 键 词：可容空间 沉积物供给 断陷湖盆三角洲 数值模拟 文昌组 古近系 陆丰22洼 珠江口盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探] P618.13[天文地球—矿床学]