高温-超压-高CO_(2)背景下致密砂岩储层成岩作用特征——以莺歌海盆地LD10区新近系梅山组——黄流组为例  

Diagenesis characteristics of tight sandstone reservoirs with high temperature,overpressure and high CO_(2) content:A case study of Neogene Meishan-Huangliu Formation in LD10 area,Yinggehai Basin

作　　者：杨楷乐 何胜林 杨朝强 王猛 张瑞雪 任双坡 赵晓博 姚光庆[4,5] YANG Kaile;HE Shenglin;YANG Zhaoqiang;WANG Meng;ZHANG Ruixue;REN Shuangpo;ZHAO Xiaobo;YAO Guangqing(Zhanjiang Branch of CNOOC(China)Co.,Ltd.,Zhanjiang 524057,Guangdong,China;Hainan Branch of CNOOC(China)Co.,Ltd.,Haikou 570311,China;Jianghan Oil Production Plant,Sinopec Jianghan Oilfield Company,Qianjiang 433124,Hubei,China;Key Laboratory of Tectonics and Petroleum Resource,Ministry of Education,China University of Geosciences(Wuhan),Wuhan 430074,China;School of Earth Resources,China University of Geosciences(Wuhan),Wuhan 430074,China)

机构地区：[1]中海石油(中国)有限公司湛江分公司,广东湛江524057 [2]中海石油(中国)有限公司海南分公司,海口570311 [3]中国石化江汉油田分公司江汉采油厂,湖北潜江433124 [4]中国地质大学(武汉)构造与油气资源教育部重点实验室,武汉430074 [5]中国地质大学(武汉)资源学院,武汉430074

出　　处：《岩性油气藏》2023年第1期83-95,共13页Lithologic Reservoirs

基　　金：中海石油(中国)有限公司湛江分公司项目“乐东10区沉积模式及储层非均质性研究”(编号:CCL-2019-ZJFN0734)资助。

摘　　要：利用薄片鉴定、扫描电镜、阴极发光及碳氧同位素分析等手段,对莺歌海盆地LD10区新近系梅山组—黄流组高温-超压-高CO_(2)背景下的储层成岩作用特征及其对孔隙的影响进行了系统研究。研究结果表明:(1)莺歌海盆地LD10区新近系梅山组—黄流组储层发育重力流沉积,岩性以中—细粒长石岩屑石英砂岩为主,储层物性以特低—低孔、特低渗特征为主。(2)压实、胶结和溶蚀作用是研究区主要的成岩作用类型。超压对黏土矿物的转化及石英次生加大具有明显抑制作用,并在一定程度上保护了原生孔隙。富含CO_(2)的高温流体不仅造成了黏土矿物的异常转化,同时促进了溶蚀作用发生,增加了次生孔隙。(3)研究区黄二段储层的成岩演化序列为:菱铁矿胶结→石英次生加大→绿泥石胶结→长石淋滤溶蚀→高岭石形成→早期方解石胶结→早期白云石胶结→长石溶蚀→方解石溶蚀→伊利石大量生成→晚期铁方解石、铁白云石形成。(4)总体上,压实作用使孔隙度减少了45.30%~62.93%,胶结作用使孔隙度减少了1.65%~35.01%,溶蚀作用使孔隙度增加了0.72%~8.00%。其中,黄流组中下部砂岩储层受到了超压保护和CO_(2)溶蚀作用的双重影响,物性较好,钻井过程中应考虑高CO_(2)风险。By means of thin section identification,scanning electron microscopy,cathodoluminescence,and carbon and oxygen isotope analysis,the diagenesis characteristics and their influence on pores of Neogene MeishanHuangliu Formation under the background of high temperature,overpressure and high CO_(2)content in LD10 area of Yinggehai Basin were studied.The results show that:(1)The reservoirs of Neogene Meishan-Huangliu Formation in LD10 area of Yinggehai Basin are developed with gravity flow.The lithologies are mainly medium-fine feldspathic lithic quartz sandstones,and the reservoir physical properties are mainly characterized by ultra-low porosity and ultra-low permeability.(2)Compaction,cementation and dissolution are the main diagenesis types in the study area.Overpressure can obviously inhibit the transformation of clay minerals and the secondary enlargement of quartz,which can protect the primary pores to a certain extent.The high-temperature fluid rich in CO_(2)not only causes the abnormal transformation of clay minerals,but also promotes the dissolution to increase the secondary pores.(3)The diagenetic sequence of the second member of Huangliu Formation is summarized as siderite cementation→secondary enlargement of quartz→chlorite cementation→early stage feldspar dissolution→kaolinite formation→early stage calcite cementation→early stage dolomite cementation→feldspar dissolution→calcite dissolution→massive illite formation→late stage iron calcite and iron dolomite formation.(4)In general,compaction reduces the porosity by 45.30%-62.93%,and cementation reduces the porosity by 1.65%-35.01%,while dissolution increases the porosity by 0.72%-8.00%.The sandstone reservoir in the middle and lower part of Huangliu Formation is affected by overpressure and CO_(2)dissolution,with good physical properties,so high CO_(2)risk should be considered during drilling.

关 键 词：致密砂岩储层 高温-超压-高CO_(2) 成岩演化 梅山组—黄流组 新近系 LD10区 莺歌海盆地 

分 类 号：TE121.1[石油与天然气工程—油气勘探] P618.13[天文地球—矿床学]