渝东北A地区龙马溪组页岩储层特征研究

发布时间：2018-01-21 22:35

  本文关键词： 渝东北 龙马溪组 页岩气 储层特征　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：综合露头、岩心的宏观描述,薄片鉴定、扫描电镜的微观观察,以及物性、有机地球化学与含气性等实验分析,对渝东北A地区龙马溪组页岩储层特征进行了研究。为了对页岩储层进行精细研究,将龙马溪组分为龙一段与龙二段,并且将龙一段分为了龙一1与龙一 2两个亚段,进一步将龙一1亚段分为了 a、b、c、d四个小层,本论文主要对龙马溪组底部龙一段富有机质页岩进行研究。研究区页岩TOC介于0.15%～11%之间,平均可达3%,TOC含量呈正态分布,在2%～6%之间分布最大,纵向上龙一 1亚段a小层TOC向上呈减少的趋势,在平面上TOC由西北向东南呈逐渐降低的趋势。通过邻区干酪根类型推断研究区主要为Ⅰ型干酪根,少数为Ⅱ1型干酪根,具有较好的生烃能力。镜质体反射率以及岩石热解分析都表明研究区大部分区域有机质处于过成熟阶段,平面上从北到南Ro呈增加的趋势。研究区主要发育4种岩性,分别为页岩、含粉砂页岩、粉砂质页岩与凝灰质页岩。页岩主要分布在龙一 1亚段a小层与c小层,含粉砂页岩主要分布在龙一1亚段a、b、c小层,粉砂质页岩与凝灰质页岩主要分布在龙一1亚段d小层与龙二段,从龙一1亚段a小层向上页岩颜色逐渐变浅,粉砂含量逐渐增多,页岩品质变差。岩石矿物成分以石英和粘土为主,且在纵向上龙一1亚段a小层向上石英含量逐渐减少,而粘土含量逐渐增多,碳酸盐矿物较少,普遍含有黄铁矿,粘土矿物主要为伊利石、绿泥石与伊/蒙混层。对页岩脆性指数研究表明,纵向上脆性指数总体较高且龙一1亚段a小层向上脆性指数呈降低的趋势。研究区孔隙度整体较低,介于0.53%～7.46%之间,整个龙一1亚段平均孔隙度仅为1.69%。纵向上龙一1亚段a小层向上孔隙度呈逐渐减小的趋势,页岩渗透率测试值普遍较低,最小值为0.0000098mD,最大值为5.144mD,且测试出的渗透率高值一般是由于裂缝发育造成的。研究区页岩储渗空间由裂缝、矿物基质孔隙与有机质孔组成,识别出构造缝、层间页理缝、层面滑移缝、成岩收缩微裂缝4种裂缝类型,并对矿物基质孔隙与有机质孔隙在扫描电镜下的形态特征进行了观察与描述。研究区页岩样品含气量介于0.17m3/t～5.66m3/t之间,纵向上从龙一1亚段a小层向上呈减小的趋势,且龙一1亚段整体含气量较高,各个小层平均值均大于3m3/t,而到了龙一 2亚段含气量显著降低,平均仅为0.58m3/t,分析认为含气量主要受TOC与孔隙度影响,而受矿物组成的影响有限。以TOC、孔隙度、含气量与脆性指数为储层分类评价参数,对X2井进行了储层评价,结果表明该井主要为Ⅲ类储层,Ⅰ类储层与Ⅱ类储层分布较少且厚度较薄,总的来说X2井储层品质较差。
[Abstract]:Comprehensive outcrop, core macroscopical description, thin slice identification, scanning electron microscopic observation, and physical properties, organic geochemistry and gas-bearing experimental analysis. The shale reservoir characteristics of Longmaxi formation in A area of northeast Chongqing were studied. In order to study the shale reservoir in detail, Longmaxi formation was divided into long 1 member and long 2 member. The first segment was divided into two subsections, Long-1 and Long-2, and further divided into four layers. In this paper, the organic shale of Longyi member at the bottom of Longmaxi formation is studied. The TOC of shale in the study area is between 0.15% and 11%, and the average content of TOC is normal distribution. The distribution was the largest between 2% and 6%, and the TOC of submember a of Long-1 submember showed a decreasing trend in the longitudinal direction. The TOC decreased gradually from northwest to southeast on the plane. The main type of kerogen was type I kerogen and a few type 鈪，

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