川东下志留统特征及页岩气有利目标区优选评价
发布时间：2018-09-06 14:04
【摘要】：下志留统龙马溪组的富含有机质黑色页岩,普遍被认为是中上扬子地区最佳的页岩气研究对象。前人已对这套黑色页岩进行了系统的烃源岩分析,但针对川东地区龙马溪组的沉积特征和页岩气资源潜力评价的研究还比较薄弱,勘探程度较低。本文针对川东地区龙马溪组开展了野外露头剖面观察和采样,收集了区内及邻区已有剖面资料和钻井资料,并对黑色页岩进行了镜下薄片鉴定、有机地球化学、全岩X射线衍射、扫描电镜等室内测试分析,在此基础上系统研究了区内龙马溪组黑色页岩的沉积特征及页岩气评价参数,优选出页岩气有利目标区,并对有利目标区进行综合评价。研究区五峰组-龙马溪组沉积环境总体为陆棚环境,处于浅水陆棚与深水陆棚的交替期,可细分为五段:①涧草沟组(或临湘组)为灰质浅水陆棚沉积,②五峰组下部黑色页岩段为泥质深水陆棚沉积,③五峰组上部观音桥段为灰泥质浅水陆棚沉积,④龙马溪组下部为泥质深水陆棚沉积,⑤龙马溪组上部为砂泥质浅水陆棚沉积。平面展布上从酉阳黑水到巫溪田坝,沉积相从深水陆棚逐渐向半深海-深海盆地变化。沿此剖面两端向中心:龙马溪组泥页岩厚度逐渐变厚。研究区龙马溪组黑色页岩有机质类型以I型-II型为主;有机质丰度较高,黑色页岩TOC集中在1%~4%之间,平均值约1.7%;Ro值大于2.2%,一般在2.4%~4.3%,已处于过成熟演化阶段,核心地区的Ro≥3.6%(最大达4.3%)。TOC纵向上从五峰组到龙马溪组下段有逐渐降低的趋势,横向上TOC的展布与川东地区构造形迹相似,呈北东-南西向的浓集中心展布,向中心有页岩厚度变厚且有机碳质变大的趋势。研究区龙马溪组黑色页岩段矿物以石英矿物、粘土矿物为主,其次为黄铁矿、碳酸盐岩。粘土矿物含量平均分布在24.2%~60.6%,平均含量为44.14%,粘土矿物成分主要有伊蒙间层、伊利石和绿泥石,其中尤以伊利石含量最高。石英矿物平均分布在27.5%~60.9%,平均含量为40.01%。页岩BET比表面积为8.156m2/g~30.54m2/g,平均为14.796m2/g。研究区龙马溪组黑色页岩段孔隙度较低,主要集中在4%~8%,平均值为6.17%。微观孔隙为开放型,连通性较好。孔隙类型主要为粒间孔、粒内孔、有机质孔以及微裂缝。其中粒间孔分为粒间格架孔、粘土片间孔、粒缘孔、表生溶孔,粒内孔分为草莓状黄铁矿粒内晶间孔、粘土粒内孔以及成岩溶孔。依据页岩气有利目标区划分标准,综合分析泥页岩有效厚度、有机碳含量、有机质成熟度、页岩出露与埋深及有利构造等条件,在川东地区出圈定3个有利目标区并进行评价:分别是位于合江-习水一带的习水目标区、位于涪陵-石柱一带的石柱目标区、位于开县-巫溪一地的巫溪目标区。
[Abstract]:The black shale rich in organic matter in the Longmaxi formation of Lower Silurian is generally considered as the best shale gas research object in the middle and upper Yangtze area. The former has carried out systematic source rock analysis of the black shale, but the study on sedimentary characteristics of Longmaxi formation and evaluation of shale gas potential in east Sichuan is still weak and the exploration degree is relatively low. In this paper, the outcrop profile of Longmaxi formation in eastern Sichuan is observed and sampled, the existing profile data and drilling data are collected in the area and adjacent areas, and the black shale is identified by microscopic thin section, organic geochemistry, and organic geochemistry. On the basis of the whole rock X-ray diffraction and scanning electron microscope, the sedimentary characteristics and shale gas evaluation parameters of the black shale of Longmaxi formation are systematically studied, and the favorable target area of shale gas is selected. A comprehensive evaluation of the favorable target area is carried out. The sedimentary environment of Wufeng formation and Longmaxi formation in the study area is generally continental shelf environment, which is in the alternate period of shallow water shelf and deep water shelf, and can be subdivided into five sections: Wei 1 Jian Cao Gou formation (or Linxiang formation) as gray shallow water shelf deposit. (2) the black shale formation in the lower part of Wufeng formation is a muddy deep-water shelf sediment. The upper Guanyinqiao section of Wufeng formation is a shallow-water silty shelf sediment. The lower part of the Longmaxi formation is a muddy deep-water shelf deposit, the upper part of the Longmaxi formation is a sandy shallow-water shelf deposit. From Youyang Heishui to Wuxi Tianba, the sedimentary facies gradually changed from deep water shelf to semi-deep sea-deep sea basin. Along the two ends of this section, the shale thickness of Longmaxi formation becomes thicker and thicker. The organic matter type of black shale in Longmaxi formation in the study area is mainly type I -II, and the abundance of organic matter is relatively high, the TOC of black shale is concentrated in the range of 1% or 4%, the average value is about 1.7% and the Ro value is more than 2.2, and generally at 2.4% and 4.3%, it is already in the stage of over-maturation and evolution. In the core area, the Ro 鈮，
本文编号：2226578
[Abstract]:The black shale rich in organic matter in the Longmaxi formation of Lower Silurian is generally considered as the best shale gas research object in the middle and upper Yangtze area. The former has carried out systematic source rock analysis of the black shale, but the study on sedimentary characteristics of Longmaxi formation and evaluation of shale gas potential in east Sichuan is still weak and the exploration degree is relatively low. In this paper, the outcrop profile of Longmaxi formation in eastern Sichuan is observed and sampled, the existing profile data and drilling data are collected in the area and adjacent areas, and the black shale is identified by microscopic thin section, organic geochemistry, and organic geochemistry. On the basis of the whole rock X-ray diffraction and scanning electron microscope, the sedimentary characteristics and shale gas evaluation parameters of the black shale of Longmaxi formation are systematically studied, and the favorable target area of shale gas is selected. A comprehensive evaluation of the favorable target area is carried out. The sedimentary environment of Wufeng formation and Longmaxi formation in the study area is generally continental shelf environment, which is in the alternate period of shallow water shelf and deep water shelf, and can be subdivided into five sections: Wei 1 Jian Cao Gou formation (or Linxiang formation) as gray shallow water shelf deposit. (2) the black shale formation in the lower part of Wufeng formation is a muddy deep-water shelf sediment. The upper Guanyinqiao section of Wufeng formation is a shallow-water silty shelf sediment. The lower part of the Longmaxi formation is a muddy deep-water shelf deposit, the upper part of the Longmaxi formation is a sandy shallow-water shelf deposit. From Youyang Heishui to Wuxi Tianba, the sedimentary facies gradually changed from deep water shelf to semi-deep sea-deep sea basin. Along the two ends of this section, the shale thickness of Longmaxi formation becomes thicker and thicker. The organic matter type of black shale in Longmaxi formation in the study area is mainly type I -II, and the abundance of organic matter is relatively high, the TOC of black shale is concentrated in the range of 1% or 4%, the average value is about 1.7% and the Ro value is more than 2.2, and generally at 2.4% and 4.3%, it is already in the stage of over-maturation and evolution. In the core area, the Ro 鈮，
本文编号：2226578
本文链接：https://www.wllwen.com/kejilunwen/diqiudizhi/2226578.html
