摘要
为了研究川中东北部中侏罗统沙溪庙组致密油储层中自生绿泥石的产出状态、成因及对储层的影响,利用偏光显微薄片、矿物X射线衍射、电子探针、扫描电镜等实验分析数据,对其进行了系统分析。结果表明,川中东北部自生绿泥石为富铁的铁镁过渡型绿泥石,颗粒包膜绿泥石形成于同生期—早成岩A期;孔隙衬垫是绿泥石的主要产状,形成早成岩A期;孔隙充填状绿泥石主要形成于中成岩A2期。自生绿泥石形成所需的Fe,Mg来源于岩浆岩岩屑、黑云母等水化水解和溶蚀,以及邻近地层的泥岩中黏土矿物转化释放层间吸附的Fe,Mg离子。绿泥石形成机制有3种:①同生期—早成岩A期,硅酸盐矿物水化水解以及富Fe,Mg流体中蒙脱石向绿泥石的转化;②早成岩A期,邻近泥岩中蒙脱石向伊利石转化提供充足的Fe,Mg离子;③中成岩A2期,与有机酸脱羧形成的碳酸对硅酸矿物的溶蚀以及高岭石(或伊利石)向绿泥石的转化有关。绿泥石衬垫可提高砂岩的抗压强度,有利于孔隙和喉道的保存;适宜厚度(>7μm)的绿泥石衬垫可有效抑制石英次生加大和充填;绿泥石衬垫发育的储层有利于原生孔隙的保存,使孔隙水能够与围岩颗粒发生进一步的反应,保证后期溶蚀作用的进行。因此,绿泥石衬垫对研究区致密油储层的形成具有积极作用。
In order to study the occurrence,genesis and influence of authigenic chlorite in the tight oil reservoirs of Middle Jurassic Shaximiao Formation in NE of central Sichuan Basin,the experimental data such as polarized microscopic slice,mineral X-ray diffraction,electron probe and scanning electron microscopy were used to sys‐tematically analyze the authigenic chlorite.The results show that the authigenic chlorites in the study area are iron-magnesium transitional chlorites rich in iron.The granular-coated chlorite was formed in the syngenetic-early diagenetic A stage,the pore liner was the main occurrence of chlorite,which was formed in the early diagenetic A stage,and the pore-filled chlorite was mainly formed in the middle diagenetic A2 stage.The Fe and Mg required for the formation of authigenic chlorite were derived from hydration hydrolysis and dissolution of magmatic rock cuttings and biotite,and Fe and Mg ions adsorbed by the clay mineral conversion release layer in mudstone adja‐cent to the stratum.There are three kinds of formation mechanism of chlorite:(1)in the syngenetic-early diage‐netic A stage,symbiotic hydration hydrolysis of silicate minerals and montmorillonite conversion to chlorite in Fe and Mg fluids;(2)in the early diagenetic A stage,the conversion of montmorillonite to illite in adjacent mudstones provided sufficient Fe and Mg ions;(3)in the middle diagenetic A2 stage,it was related to the disso‐lution of silicate minerals by carbonic acid formed by decarboxylation of organic acids and the conversion of ka‐olinite(or illite)to chlorite.The chlorite liner can improve the compressive strength of sandstone and facilitate the preservation of pores and throat.The chlorite liner with suitable thickness(>7μm)can effectively inhibit the secondary expansion and filling of the quartz.The reservoir with chlorite liner developed is conducive to the pres‐ervation of primary pores,enabling pore water to react further with the surrounding rock particles to ensure the dissolution of the later st
作者
吴家洋
吕正祥
卿元华
杨家静
金涛
WU Jiayang;LYU Zhengxiang;QING Yuanhua;YANG Jiajing;JIN Tao(College of Energy Resource,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Exploration Department,PetroChina Tarim Oilfield Company,Korla 836000,Xinjiang,China;Research Institute of Exploration and Development,PetroChina Southwest Oil and Gas Field Company,Chengdu 610041,China)
出处
《岩性油气藏》
CSCD
北大核心
2020年第1期76-85,共10页
Lithologic Reservoirs
基金
中国石油天然气股份有限公司重大专项“四川盆地侏罗系石油勘探开发关键技术研究”（编号：2012E-2601-02）资助
关键词
致密油
自生绿泥石
储层物性
沙溪庙组
侏罗系
四川盆地
tight oil
authigenic chlorite
reservoir physical properties
Shaximiao Formation
Jurassic
Sichuan Basin
