川东五百梯地区石炭系岩溶古地貌识别及储集意义  

Identification and reservoir significance of Carboniferous karst paleogeomorphology in Wubaiti area,eastern Sichuan Basin

作　　者：王同川 陈浩如 温龙彬 钱玉贵[4] 李玉琢 文华国[1,2] WANG Tongchuan;CHEN Haoru;WEN Longbin;QIAN Yugui;LI Yuzhuo;WEN Huaguo(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;College of Environmental Science and Engineering,China West Normal University,Nanchong 637009,Sichuan,China;Research Institute of Exploration and Development,Southwest Oil and Gas Company,Sinopec,Chengdu 610041,China)

机构地区：[1]油气藏地质及开发工程全国重点实验室,成都理工大学,成都610059 [2]成都理工大学沉积地质研究院,成都610059 [3]西华师范大学环境科学与工程学院,四川南充637009 [4]中石化西南油气分公司勘探开发研究院,成都610041

出　　处：《岩性油气藏》2024年第4期109-121,共13页Lithologic Reservoirs

基　　金：四川省天然气成藏物质基础青年科技创新团队基金“四川盆地关键层系构造-沉积分异与成烃-成储效应”(编号:2022JDTD0004)资助。

摘　　要：综合利用钻井、测井、岩心及地震资料,通过建立地震正演模型模拟、RGB分频融合技术及波形分类分析等手段,对川东五百梯地区石炭系岩溶古地貌进行了识别与刻画。研究结果表明:(1)川东五百梯地区石炭系遭受的岩溶作用强度自西向东逐渐变小,东南部石炭系原始沉积厚度更大,但残余厚度分布不均匀,主要为10~30 m;西北部地层厚度较小,为0~15 m。(2)研究区石炭系自西向东可识别出岩溶高地和岩溶斜坡2个二级地貌单元,岩溶斜坡可划分为残丘和浅洼2个三级地貌单元,再依据其差异溶蚀特征,可进一步划分为陡斜坡浅洼和缓斜坡浅洼,浅洼内发育残丘、暗河及落水洞。反射同相轴的上提和下拉特征、岩溶角砾岩的发育、地震层拉平剖面、RGB分频融合及波形变化特征等均可识别出岩溶古地貌的发育。(3)研究区石炭系各地貌单元的分布受构造控制,浅洼和残丘多以椭圆状或不规则长条状呈北西—南东向展布,暗河的展布与浅洼长轴方向一致;岩溶古地貌控制着地层厚度以及溶蚀孔洞的发育,残丘残余厚度较大,岩溶作用强,充填作用较弱,溶蚀孔洞较发育,储层平均孔隙度为4.34%;缓斜坡浅洼残余厚度较小,充填作用较强,溶蚀孔洞不发育,储层平均孔隙度为2.68%,而陡斜坡浅洼虽然残余厚度小,但因潜水位低、泄水能力强,溶蚀作用强而充填作用弱,储集空间发育,储层平均孔隙度为5.05%;缓斜坡和陡斜坡储层平均孔隙度分别为3.67%和3.31%,岩溶高地孔隙度最小,平均为2.51%。By comprehensively utilizing drilling,logging,core and seismic data,the identification and charac‐terization of Carboniferous karst paleogeomorphology in Wubaiti area of eastern Sichuan Basin were carried out through the establishment of seismic forward modeling simulation,RGB frequency division fusion technology,and waveform classification analysis.The results show that:(1)The intensity of karstification of Carboniferous in Wubaiti area gradually decreases from west to east.The original sedimentary thickness of Carboniferous in the southeast is larger,but the distribution of residual thickness is uneven,mainly ranging from 10 to 30 meters.The thickness in the northwest is smaller,ranging from 0 to 15 meters.(2)The Carboniferous in the study area can be identified as two secondary karst morphological units,karst highlands and karst slopes,from west to east.The karst slopes can be divided into two tertiary karst morphological units,karst residual hills and karst shallow depressions.Due to the differential dissolution characteristics of shallow depressions on karst slopes,they can also be further divided into steep slope shallow depressions and gentle slope shallow depressions,with residual hills,underground rivers,and sinkholes developed within the karst shallow depressions.The development of karst paleogeomorphology can be identified by the upward and downward characteristics of reflection events,the development of karst breccia,the flattening profile of seismic layers,RGB frequency fusion,and waveform changes.(3)The distribution of karst morphological units of Carboniferous in the study area is controlled by re‐gional tectonics.Shallow depressions and residual hills are mostly elliptical or irregularly elongated in a northwest-southeast direction,and the distribution of underground rivers is consistent with the long axis direction of shallow depressions.Karst morphological units controlled the thickness of strata and the development of dis‐solved pores.The residual thickness of the residual hills is relati

关 键 词：岩溶古地貌 浅洼 残丘 岩溶斜坡带 地震正演模拟 RGB分频融合 岩溶角砾岩 黄龙组 石炭系 川东五百梯地区 

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]