川东地区中寒武统高台组蒸发岩特征和沉积模式  

Evaporite Characteristics and Sedimentary Model of the Middle Cambrian Gaotai Formation in the Eastern Sichuan Basin

作　　者：王纪煊 胡忠贵[1,2] 李世临[3] 蔡全升[1,2] 郭艳波[3] 左云安[3] 庞宇来[3] Wang Jixuan;Hu Zhonggui;Li Shilin;Cai Quansheng;Guo Yanbo;Zuo Yun’an;Pang Yulai(School of Geosciences,Yangtze University,Wuhan 430100,China;Sedimentary Basin Research Center,Yangtze University,Wuhan 430100,China;Chongqing Gas District,PetroChina Southwest Oil&Gasfield Company,Chongqing 400021,China)

机构地区：[1]长江大学地球科学学院,武汉430100 [2]长江大学沉积盆地研究中心,武汉430100 [3]中国石油西南油气田公司重庆气矿,重庆400021

出　　处：《吉林大学学报（地球科学版）》2024年第3期784-799,共16页Journal of Jilin University：Earth Science Edition

基　　金：国家科技重大专项(2016ZX05007-002)。

摘　　要：为明确川东地区中寒武统高台组蒸发岩特征与发育模式,综合野外观察、岩心描述、薄片鉴定、测井及地震资料,在对高台组蒸发岩的岩性及成因类型进行分析的基础上,讨论其沉积模式以及与油气的关系。研究结果表明:1)蒸发岩主要为含膏白云岩类、石膏岩和膏盐岩,存在清水和浑水两种蒸发岩岩性组合序列,蒸发岩厚度具有由西向东逐渐增厚的特点,沉积中心分别位于建深1井区—巫溪一线和太和1井区—石柱一线,蒸发岩盖层以“宽广圆环状”覆盖川东大部分地区;2)蒸发岩在干旱炎热的古环境、障壁滩形成的封闭环境、海水的周期性波动以及物源补给的共同作用下形成清水潟湖和浑水潟湖,即源控多潟湖成因环境;3)高台组蒸发岩厚度与龙王庙组储层的分布存在一定的负相关关系,即厚层蒸发岩控低含气储层,薄层蒸发岩控高含气储层;4)蒸发岩为盖层的储盖组合包括浑水潟湖成因的岩下储层和清水潟湖成因的岩间储层,薄层蒸发岩岩下储层含气规模较大,岩间储层的非均质性较强,厚度较薄,总体上呈中—低孔低渗的特征,研究区发育3个天然气有利勘探区带,分别位于北部、中部以及南部地区,是川东地区潜在的后备勘探领域。In order to clarify the sedimentary characteristics and development model of evaporite in the Gaotai Formation in eastern Sichuan basin,the sedimentary model of evaporite and its relationship with oil and gas are discussed based on field observation,core description,thin section identification,well logging and seismic data.The results show that:1)The evaporites are mainly gypsum dolomite,gypsum rock and gypsum-salt rock,and there are two kinds of evaporite lithologic assemblage sequence:Gypsum lagoon and mixed lagoon.The evaporite thickness gradually increases from the west to the east.The sedimentary centers are located in the Wuxi line of Jianshen 1 Well area and the Shizhu line of Taihe 1 Well area,respectively.2)Evaporite was formed in gypsum lagoon and mixed lagoon under the combined action of arid and hot paleoenvironment,closed environment formed by barrier beach,periodic fluctuation of seawater and provenance recharge,that is,sourcing-controlled multi-lagoon genetic environment.3)There is a negative correlation between the thickness of Gaotai Formation evaporite and the distribution of Longwangmiao Formation reservoir,that is,thick evaporite controlled the low gas reservoir,thin evaporite controlled the high gas reservoir.4)The reservoir cap assemblages with evaporative rocks as cap formations include subrock reservoirs of mixed lagoon and interrock reservoirs of gypsum lagoon.The subrock reservoirs of thin evaporative rocks have large gas bearing scale,and the interrock reservoirs are of strong heterogeneity and thin thickness,showing the characteristics of medium-low porosity and low permeability in general.Three favorable exploration zones for natural gas are developed in the study area.They are located in northern,central and southern regions,respectively,and are potential reserve exploration areas in the eastern Sichuan basin.

关 键 词：蒸发岩 川东地区 高台组 清水潟湖 浑水潟湖 沉积模式 

分 类 号：P618.13[天文地球—矿床学]