川中蓬莱—高磨地区震旦系灯二段泡沫绵层白云岩成因及地质意义  

Genesis and geological significance of foam-spongy dolomite in the second member of Sinian Dengying Formation in Penglai-Gaomo area,central Sichuan

作　　者：李凌[1,2] 邓禹 张新宇 罗文军 赵东方[1,2] 曾建军[1,2] 刘耘 谭秀成 LI Ling;DENG Yu;ZHANG Xinyu;LUOWenjun;ZHAO Dongfang;ZENG Jianjun;LIU Yun;TAN Xiucheng(State Key Laboratory of Reservoir Geology and Development Engineering,Southwest Petroleum University,Chengdu 610500,China;Key Laboratory of Carbonate Reservoir,Southwest Petroleum University,CNPC,Chengdu 610500,China;Development Division,Petrochina Southwest Oil and Gas Field Company,Chengdu 610000,China;Research Institute of Exploration and Development,Southwest Oil and Gas Field Company,Petrochina,Chengdu 610041,China)

机构地区：[1]油气藏地质及开发工程国家重点实验室·西南石油大学,成都610500 [2]中国石油集团有限公司碳酸盐岩储层重点实验室西南石油大学研究分室,成都610500 [3]中国石油西南油气田公司开发事业部,成都610000 [4]中国石油西南油气田分公司勘探开发研究院,成都610041

出　　处：《岩性油气藏》2025年第2期60-69,共10页Lithologic Reservoirs

基　　金：中国石油-西南石油大学创新联合体科技合作项目“深层/超深层碳酸盐岩天然气勘探开发基础理论与关键技术研究”(编号:2020CX010300)资助。

摘　　要：为明确四川盆地蓬莱—高磨地区震旦系灯二段泡沫绵层白云岩成因机理及地质意义,通过岩心、薄片资料,结合地球化学测试手段,分析了其岩石学特征、碳氧同位素特征、微量元素特征与稀土配分模式。研究结果表明:①川中蓬莱—高磨地区震旦系灯二段泡沫绵层白云岩具有颗粒状泡沫体,其外壁为环边状胶结,揭示其原岩为颗粒白云岩。②研究区灯二段泡沫绵层白云岩按宏观分布形态可以分为蜂窝状与格架状,均发育在高频旋回上部或顶部,宏微观特征与地球化学分析均表明这2类泡沫绵层白云岩受到了不同程度的大气淡水影响,揭示泡沫绵层白云岩的发育受早成岩期岩溶控制,且岩溶强度决定了形态类型,其中蜂窝状岩石所遭受的岩溶强度相对较小,格架状岩石所遭受的岩溶强度相对较大。③泡沫绵层白云岩经历了颗粒沉积—海底胶结—早期云化—早期大气淡水岩溶作用—后期胶结充填作用的成岩演化过程,其中早期大气淡水岩溶作用形成了粒内溶孔(铸模孔)及溶洞、溶缝、溶沟等储集空间。④泡沫绵层白云岩为颗粒原岩经溶蚀改造而成的成因机理揭示了研究区灯二段沉积以颗粒岩为主,沉积相以颗粒滩为主。In order to clarify the genetic mechanism and e geological significance of the foam-spongy dolomite of the second member of Sinian Dengying Formation(Deng2 member)in the Penglai-Gaomo area of Sichuan Basin,the petrological characteristics,carbon and oxygen isotope characteristics,trace element characteristics and rare earth partition model are analyzed by using core and thin section data combined with geochemical methods.The results shows that:(1)The foam-spongy dolomite of Deng2 member in the study area has granular foam body,and its outer wall is ringed and cemented,which reveals that its original rock is granular dolomite.(2)The foam-spongy dolomites can be divided into honeycomb and trell-shaped according to their macroscopic distribution,both of which develop at the upper or top of the high-frequency cycle.Macro and micro characteristics and geochemical analysis show that the two types of foam-spongy dolomites are affected by different degrees of atmospheric fresh water,revealing that the development of foam-spongy dolomites is controlled by karst in the early diagenetic stage,and karst strength determines the development type.The strength of honeycomb karst is relatively small,and the strength of lattice karst is relatively large.(3)The foam-spongy dolomite has undergone the diagenetic evolution process of particle deposition,submarine cementation,early cloud-forming,early atmospheric freshwater karstification and late cementation and filling,while early atmospheric freshwater karstification is useful to form ingrain solution holes(casting mold holes),karst caves,solution fractures,solution gullies of reservoir space.(4)The formation mechanism of foam-spongy dolomite is the transformation of granular original rock by dissolution,which reveals that the sedimentary facies of Deng2 member in the study area are mainly granular rock and granular beach.

关 键 词：泡沫绵层白云岩 早成岩期岩溶 环边胶结 高频暴露 颗粒滩 灯二段 震旦系 蓬莱—高磨地区 四川盆地 

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