川南—黔北地区龙马溪组页岩气地质条件分析

发布时间：2018-09-01 13:49

【摘要】：本论文以川南-黔北地区下志留统龙马溪组富有机质泥页岩段作为研究对象,在前人研究成果的基础上,搜集研究区内有关下志留统龙马溪组相关的地质资料,结合野外地质调查以及钻井岩芯的观察,对川南-黔北地区区域地质背景、沉积相、有机地化特征、富有机质泥页岩的厚度、埋深、脆性矿物含量、物性特征、含气性特征以及保存条件等几个重要条件进行分析,得出:沉降中心宜宾-泸州-合江-綦江等地区下志留统龙马溪组富有机质泥页岩的有机碳含量普遍大于5%,有机碳含量自沉降中心分别向北靠近川中隆起、向南靠近黔中隆起有机碳含量逐渐降低。深水陆棚区域内富有机质泥页岩有机碳含量较高;干酪根类型以I型、II1型为主,有机质成熟度在2.0%~3.3%之间;靠近隆起处为浅水陆棚沉积环境,有机碳含量较低普遍小于2%,干酪根类型以I型、II1型为主含部分II1型,有机质成熟度在1.0%~2.0%。川南-黔北地区下志留统龙马溪组富有机质泥页岩主要为海相沉积,分布稳定。区内在沉降中心宜宾-泸州-合江-綦江等地区富有机质泥页岩的厚度最大,可达百米以上,向北至自贡-内江-大足等地区,富有机质泥页岩的厚度降至60m左右,到达川中隆起富有机质泥页岩消失。向南至长宁-綦江等地区,富有机质泥页岩的厚度降至80m左右,至筠连-叙永-道真等地区,富有机质泥页岩的厚度降至60m,至威信-古蔺-习水-正安等地区,富有机质泥页岩的厚度降至40m左右,而靠近黔中隆起富有机质泥页岩的厚度逐渐消失。研究区内除靠近川中隆起与黔中隆起附近均具备成为页岩气有利区的条件。川南-黔北地区下志留统龙马溪组埋深主要分布在553~5000m,在沉降中心宜宾-泸州-合江-綦江附近埋深相对较深,在3000~4500m之间;在习水-正安附近埋深相对较浅,主要集中在1000~2000m,在黔中隆起附近威信、叙永、仁怀等地区,埋深降至1000~1500m;埋深有利区主要分布在威远-自贡-内江、长宁-兴文等地区,埋深集中在1500~3500m。川南-黔北地区下志留统龙马溪组富有机质泥页岩的矿物组成以脆性矿物为主,次为碎屑矿物及粘土矿物,石英、长石含量在34%~90%之间,平均为51.1%;碳酸盐矿物含量较少,在0~53%之间,平均为16.95%;纵向上龙马溪组自下而上脆性矿物含量逐渐降低,粘土矿物略显升高。研究区内下志留统龙马溪组富有机质泥页岩脆性矿物含量较高,具备良好的压裂潜力。川南-黔北地区下志留统龙马溪组富有机质泥页岩孔隙度在1.5%~10.1%之间,平均为4.16%;渗透率主要分布在0.0014×10-3~0.52×10-3μm2之间,平均渗透率为0.028×10-3μm2;孔喉直径主要分布在20~110nm;储集空间类型主要包括孔隙以及微裂缝两种,孔隙类型主要包括矿物颗粒间(晶间)微孔缝、矿物颗粒溶蚀微孔隙、有机质生烃形成的微孔隙以及基质溶蚀孔隙等。据长宁地区搜集的钻井资料可知,下志留统龙马溪组有300m左右的富有机质泥页岩,含气量在0.5~6.5m3/t之间,在2363~2396m之间含气量在3.5~6.5m3/t(威远仅2.8m3/t);道页1井在553~597m之间,现场含气性解析同样显示较好,总含气量在1.84~2.69m3/t之间,与Ohio、New Albany相近。通过与北美地区页岩气藏富集条件对比,研究区内下志留统龙马溪组具有良好的页岩气勘探潜力。川南-黔北地区有利区的分布主要是以沉降中心宜宾-泸州-合江-綦江等地区为中心,向北至威远-荣县-内江等地区;向南至筠连-威信-古蔺-习水-道真等地区。远景区主要分布在靠近川中隆起以及黔中隆起附近。
[Abstract]:In this paper, the Lower Silurian Longmaxi Formation rich in organic mudstone and shale in the southern Sichuan-northern Guizhou area is taken as the research object. On the basis of previous research results, the related geological data of Lower Silurian Longmaxi Formation in the study area are collected. Combined with field geological survey and drilling core observation, the regional geological background of the Southern Sichuan-northern Guizhou area is studied. Based on the analysis of sedimentary facies, organic geochemical characteristics, thickness, burial depth, brittle mineral content, physical characteristics, gas-bearing characteristics and preservation conditions, it is concluded that the organic carbon content of Lower Silurian Longmaxi Formation organic shale is generally more than 5% in Yibin-Luzhou-Hejiang-Qijiang sedimentation center. The organic carbon content of organic shale in deep-water shelf area is higher than that in central Guizhou uplift area; kerogen type is type I, type II1, and organic matter maturity is between 2.0% and 3.3%; near the uplift area is shallow shelf sedimentary environment, organic carbon content is higher. The organic matter maturity is 1.0%~2.0%. Lower Silurian Longmaxi Formation organic mudstone is mainly marine sedimentary, and its distribution is stable. From north to Zigong-Neijiang-Dazu and other areas, the thickness of organic mudstone shale is reduced to about 60 m, and the organic mudstone shale disappears in the central Sichuan uplift. At 60 m, the thickness of organic-rich mudstone shale decreased to about 40 m in Weixin-Gulin-Xishui-Zheng'an area, while the thickness of organic-rich mudstone shale gradually disappeared near the central Guizhou uplift. The burial depth is mainly distributed in 553-5000 m, and is relatively deep in the vicinity of Yibin-Luzhou-Hejiang-Qijiang River, which is between 3000-4500 M. The burial depth is relatively shallow near Xishui-Zheng'an, mainly concentrated in 1000-2000m, near Weixin, Xuyong, Renhuai and other areas in the central Guizhou uplift, and the burial depth is reduced to 1000-1500m. The burial depth of the Lower Silurian Longmaxi Formation in the Gong-Neijiang and Changning-Xingwen areas is 1500-3500 M. The mineral composition of the Lower Silurian Longmaxi Formation is mainly brittle minerals, followed by clastic minerals and clay minerals. The quartz and feldspar contents range from 34% to 90%, with an average of 51.1%; the carbonate minerals are less, ranging from 0% to 53%, with an average of 1.1%. The content of brittle minerals in Lower Silurian Longmaxi Formation is relatively high and has good fracturing potential. The porosity of Lower Silurian Longmaxi Formation is between 1.5% and 10.1%. The average permeability is 4.16%; the average permeability is 0.0014 0.52 6550 According to the drilling data collected in Changning area, the Lower Silurian Longmaxi Formation has about 300 m organic shale with gas content of 0.5-6.5m3/t, and gas content of 3.5-6.5m3/t between 2363-2396 m (Weiyuan only 2.8 m3/t), and Daoyao 1 well with gas content of 553-597 M. Compared with the enrichment conditions of shale gas reservoirs in North America, the Lower Silurian Longmaxi Formation in the study area has good shale gas exploration potential. As the center, north to Weiyuan-Rongxian-Neijiang and other areas; south to Yunlian-Weixin-Gulin-Xishui-Daozhen and other areas.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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