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基于聚焦离子束-扫描电镜方法研究页岩有机孔三维结构 总被引：6，自引：3，他引：3
页岩中纳米级有机孔的大小直接影响页岩气含气量,其连通性亦对气体运移和开采至关重要。本文选择漆辽地区龙马溪组富有机质页岩,利用聚焦离子束-扫描电镜(FIB-SEM)在纳米尺度上(10 nm)进行有机孔结构的三维重构。研究结果表明:(1)FIB-SEM方法适用于微米级页岩的纳米(3 nm)孔隙结构特征研究。(2)蜂窝状有机孔发育均匀,孔径集中于10~200 nm,连通性较差;界面有机孔孔径集中于200~300 nm,局部连通性较好。(3)页岩总孔隙度与有机质含量成正比。研究认为,对于以有机孔为重要储集空间的页岩,有机质分布越集中,连续性越好,研究孔隙度的表征单元体尺度越小。 相似文献
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中国南方下寒武统牛蹄塘组页岩是目前页岩气勘探的主要目的层位之一,然而在渝东北地区其勘探效果不尽如人意,原因在于其孔隙结构特征并未清楚.采用聚焦离子束扫描电子显微镜、纳米C和气体吸附实验等方法对渝东北地区下寒武统牛蹄塘组页岩微纳米孔隙结构进行了定量表征.结果表明,牛蹄塘组页岩的微纳米孔隙类型主要为无机质孔隙,包括粒间孔和粒内孔,而N2吸附滞后环类型属于4型,对应孔隙类型为单边狭缝型孔隙;牛蹄塘组页岩的平均总孔体积为0.0317mL/g,平均总比表面积为34.7m2/g.牛蹄塘组页岩过高的演化程度导致有机质孔隙不发育,进而导致其微纳米孔隙具有较差的连通性;中孔贡献了绝大部分的孔体积,而微孔则贡献了相对较多的比表面积. 相似文献
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In order to evaluate the shale microscopic pore characteristics more economically and effectively in limited circumstances, the pore characteristics of Longmaxi Formation in Pengshui area, Sichuan Basin, were qualitatively observed and analyzed with Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) with argon ion polishing method at the same time. Pore quantitative information were extracted from shale SEM and FESEM images with the help of a professional image analysis software IamgeJ2x, and combined with statistical methods, the whole pore size distribution as well as shale pore fractal dimension and the relevance between fractal dimension and organic matter content, mineral composition and pore adsorption capacity and the corresponding pore structure characteristics of Longmaxi Formation in Pengshui area were analyzed. The study shows that under SEM, there are mostly micro pores of Longmaxi Formation in Pengshui area. The main pore types include intergranular pore, clay mineral layer pore, intragranular pore and micro cracks, etc. Through argon ion polishing FESEM, there mainly develop nanoscale pores. The main pore types contain organic pore, inorganic mineral pore (pyrite intergranular pore, intragranular pore, clay mineral layer pore and intergranular pore, etc.) and micro cracks. The use of both of the two methords is more advantageous to qualitatively analyze shale pore. The whole pore size distribution of shale pore has four main peaks and the main distribution range is 3~10 nm, 10~40 nm, 100~400 nm, 1~4 μm, respectively. The shape factor of shale organic matter pore is distributed between 0.9~1 and inorganic mineral pore is distributed between 0.5~0.7. It shows that the organic matter pore is circular, nearly circular and inorganic mineral pore shape is triangle, polygon, slit shape and so on. The inorganic mineral pore shape is relativly complex because of the different pore causes. The shale pore of Longmaxi Formation in Pengshui area conforms to the fractal features, and the organic pore fractal dimension is smaller than that of inorganic mineral pore, showing that the organic matter pore structure is relatively simple. There is a certain relevance between fractal dimension and organic matter content, mineral composition, porosity, and adsorbed gas content. With the increase of the organic matter content, the shale pore fractal dimension increase, the pore structure characteristics become complicated. With the shale pore fractal dimension increasing, the biggest gas adsorption quantity increases and the ability of pore adsorption strengthens. 相似文献
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页岩孔隙结构及差异性是页岩含气性和产能评价的基础性问题.针对川东南彭水地区五峰组与龙马溪组页岩的孔隙结构已有若干研究成果,然而在页岩孔隙结构差异性和有机孔定量特征方面还缺乏研究.利用低温低压氮气吸附测定和氩离子抛光-场发射扫描电镜（FE-EM）技术,对页岩样品纳米孔隙进行了二维观察与统计以及分形特征计算,研究了3nm至几百nm页岩孔径范围的孔隙结构及其差异性.研究区五峰组-龙马溪组页岩有机孔十分发育;氮气吸附测定页岩孔隙形状包含开放型圆筒状、层状结构狭缝状和墨水瓶状等;扫描电镜观察有机孔形态主要有近圆形、椭圆形和多角形等.五峰组和龙马溪组页岩孔隙结构具有明显的差异性,主要体现在孔径大小、形态和数量上.氮气吸附测定表明,五峰组页岩孔隙比表面积和总孔容较龙马溪组大,微孔所占总孔的比例也较高;五峰组页岩孔径相对龙马溪组更细窄.扫描电镜二维图像观察与统计结果表明,五峰组有机孔径以小于3nm为主,形态以多角形为主;龙马溪组有机孔径以小于0nm为主,形态多呈近圆形和椭圆形.五峰组页岩的分形维值大于龙马溪组页岩,说明前者孔隙复杂程度较高. 相似文献
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页岩中的有机质孔隙对烃类气体的赋存至关重要。为了明确渝东南下志留统龙马溪组页岩的有机质孔隙发育特征,使用聚焦离子束氦离子显微镜(FIB-HIM)技术进行观察。FIB-HIM具有极高的分辨率,分辨精度可达到亚纳米级,能够有效识别直径为0~20 nm的孔隙。结果表明:龙马溪组页岩的焦沥青内部发育大量的有机质孔隙,孔隙直径大,连通性好,大量较小直径的孔隙嵌套在直径较大的有机质孔隙中,增加了页岩有机质孔隙系统的比表面积和孔隙连通性,有利于烃类气体在页岩有机质孔隙内的赋存及有效渗流。龙马溪组页岩的固体干酪根内部有机质孔隙的发育特征与焦沥青相比存在较大差别,固体干酪根内部发育的有机质孔隙数量少,孔隙直径小,连通性差,孔隙多呈孤立状存在于固体干酪根内部。 相似文献
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渝东南地区是我国页岩气勘探开发的重点地区.以彭水地区彭页1井龙马溪组泥页岩为研究对象,结合钻井资料、全岩分析、薄片观察、扫描电镜、核磁共振与氮气吸附等实验,对页岩岩矿特征、有机地球化学、储层特征与含气性进行系统分析.研究表明：彭页1井龙马溪组泥页岩厚度约80 m,脆性矿物含量高,以石英为主,约占48%,其次为长石与碳酸盐矿物;黏土矿物占29%,以伊利石为主,占黏土矿物总量的65%,与美国Barnett页岩矿物成分及含量相近,有利于后期压裂.该井区页岩有机质类型为II2型,TOC为1%～3%,平均1.84%,成熟度2.5%～4.4%.储集空间多为纳米级—微米级孔隙,有机质孔和粒间孔为主,可见粒内溶蚀孔、微裂隙、黏土矿物层间孔和少量晶间孔,平均孔隙度2.43%,孔径以微小孔为主,介于2～80 nm,渗透率主要集中在0.005～0.01 mD,含气性中等—偏低,解析气量平均1.15 m3/t,饱和吸附量（VL）平均2.56 m3/t,均低于Barnett页岩和焦页1井的含气量,有机质丰度、储层孔隙度是该区页岩含气量的主控因素,其次还受脆性矿物和黏土矿物含量影响. 相似文献
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A key target of shale gas exploration and production in China is the organic-rich black shale of the Wufeng Formation-Longmaxi Formation in the Sichuan Basin and its periphery. The set of black shale contains abundant graptolites, which are mainly preserved as flattened rhabdosomes with carbonized periderms, is an important organic component of the shale. However, few previous studies had focused on the organic matter (OM) which is derived from graptolite and its pore structure. In particular, the contributions of graptolites to gas generation, storage, and flow have not yet been examined. In this study, focused ion beam-scanning electron microscope (FIB-SEM) was used to investigate the characteristics of the graptolite-derived OM and the micro-nanopores of graptolite periderms. The results suggested that the proportion of OM in the graptolite was between 19.7% and 30.2%, and between 8.9% and 14.4% in the surrounding rock. The total organic carbon (TOC) content of the graptolite was found to be higher than that of the surrounding rock, which indicated that the graptolite played a significant role in the dispersed organic matter. Four types of pores were developed in the graptolite periderm, including organic gas pores, pyrite moulage pores, authigenic quartz moldic pores, and micro-fractures. These well-developed micro-nano pores and fractures had formed an interconnected system within the graptolites which provided storage spaces for shale gas. The stacked layers and large accumulation of graptolites resulted in lamellation fractures openning easily, and provided effective pathways for the gas flow. A few nanoscale gas pores were observed in the graptolite-derived OM, with surface porosity lie in 1.5%–2.4%, and pore diameters of 5–20 nm. The sapropel detritus was determined to be rich in nanometer-sized pores with surface porosity of 3.1%–6.2%, and pore diameters of 20–80 nm. Due to the small amount of hydrocarbon generation of the graptolite, supporting the overlying pressure was difficult, which caused the pores to become compacted or collapsed. 相似文献
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利用扫描电镜对湘西北下古生界下寒武统牛蹄塘组和下志留统龙马溪组的黑色页岩样品进行了观察,进一步分析了黑色页岩中的微观孔隙类型、特征及其形成演化过程。区内两套黑色页岩内部发育多种储集空间类型,可概括分为3大类:矿物基质孔、有机质孔、微裂缝,其中矿物基质孔又可细分为粒间骨架孔、凝絮成因孔、溶蚀孔和基质晶间孔,有机质孔主要包括生物骨架孔和生烃残留孔。原始的沉积环境与成岩过程决定了泥页岩中的孔隙和微裂缝系统,不同的成岩阶段控制着页岩中孔隙结构的演化过程,进而影响着页岩气的赋存状态。泥页岩中这种复杂的微观孔隙网络系统为油气储集提供了有效空间,也为页岩气的渗流提供了主要通道,对页岩气的成藏和开发有重要意义。 相似文献
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页岩微观孔隙结构是影响页岩气储层储集能力的重要因素。为评价川南地区下寒武统筇竹寺组页岩性质,基于井下
岩心样品、钻井资料,运用普通扫描电镜和氩离子抛光-场发射扫描电镜观测、Image J2x软件分析、低温CO2和N2 吸附、
高压压汞实验方法,对川南地区筇竹寺组页岩气微观孔隙成因类型、孔隙结构特征及其影响因素进行了研究。研究结果表
明,川南地区下寒武统筇竹寺组页岩孔隙度为0.25%~5.80%,平均为2.49%;发育多种成因类型微观孔隙,以粒间孔为
主,粒内孔、有机质孔和微裂缝次之,页岩微观孔隙总面孔率为3.58%~5.92%;川南地区筇竹寺组页岩总孔容为（2.86~
12.55）×10-3 mL/g,总比表面积为2.727~21.992 m2/g,孔径主要分布于0.30~1.00 nm、2.5~4.7 nm和55~70 nm这三个区间,微
孔（<2 nm）和介孔（2~50 nm）是筇竹寺组页岩气储集空间的主体,孔隙结构形态主要为圆孔、楔形孔、平板狭缝型孔和混合
型孔结构。页岩孔隙度及总比表面积与TOC、脆性矿物含量呈正相关关系,页岩微孔孔容及比表面积与TOC呈正相关关
系,页岩孔隙度、总孔容及总比表面积与R0、粘土矿物含量呈负相关关系。 相似文献
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利用扫描电镜对湘西北下古生界下寒武统牛蹄塘组和下志留统龙马溪组的黑色页岩样品进行了观察,进一步分析了黑色页岩中的微观孔隙类型、特征及其形成演化过程。区内两套黑色页岩内部发育多种储集空间类型,可概括分为3大类:矿物基质孔、有机质孔、微裂缝,其中矿物基质孔又可细分为粒间骨架孔、凝絮成因孔、溶蚀孔和基质晶间孔,有机质孔主要包括生物骨架孔和生烃残留孔。原始的沉积环境与成岩过程决定了泥页岩中的孔隙和微裂缝系统,不同的成岩阶段控制着页岩中孔隙结构的演化过程,进而影响着页岩气的赋存状态。泥页岩中这种复杂的微观孔隙网络系统为油气储集提供了有效空间,也为页岩气的渗流提供了主要通道,对页岩气的成藏和开发有重要意义。 相似文献
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通过薄片分析、扫描电镜及氩离子抛光技术,对渝东南下古生界含气页岩中的孔隙类型及特征进行了分类观察、描述,结合有机碳含量、X衍射、岩石物性、氮气吸附及甲烷等温吸附实验测试,分析了页岩气储层中各类孔隙的储气贡献,探讨这些孔隙对页岩中烃类运移的影响。研究认为,有机质孔隙、颗粒内孔、粒间孔隙及微裂隙是页岩气储层孔隙的4种类型,有机质表面的分散状孔隙多为nm级,石英碎屑可形成粒内或粒间孔隙,黄铁矿颗粒内部小晶体排列分布产生孔隙空间,黏土絮状沉淀形成片粒状结构孔隙,微裂隙普遍发育在页岩基质中,可达mm级。不同类型的孔隙能够为页岩气的赋存提供不同尺度的储集空间,页岩吸附含气量与表征孔隙特征的参数(TOC、BET比表面积、BJH总孔体积)具有显著的正相关关系。微裂隙与粒间孔隙对页岩中烃类的运移最有利。 相似文献
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场发射扫描电镜及PerGeos系统在安页1井龙马溪组页岩有机质孔隙研究中的联合应用 总被引：3，自引：3，他引：0
安页1井是中国地质调查局在我国南方盆地外围武陵山复杂构造区实施并取得页岩气突破的一口地质调查参数井。本文以安页1井龙马溪组富有机质页岩为研究对象,利用场发射扫描电镜,研究了上扬子地区盆地外围龙马溪组富有机质页岩储集空间类型,并将Per Geos数字岩石处理系统引入有机质孔隙定量分析,定量刻画了有机质微纳米孔隙结构及发育特征。研究认为:有机质孔隙是安页1井龙马溪组富有机质页岩最主要的储集空间,形态上表现为填隙于自生硅质中的有机质发育着均匀海绵状孔隙结构,或与黏土矿物交互生长的有机质发育着气泡状孔隙结构,这两类不同赋存形态的有机质的孔隙均极为发育。通过Per Geos数字岩石系统处理,揭示了两类有机质孔隙孔径发育呈现双众数分布,其中海绵状结构的有机质孔隙孔径众数为5~10 nm,气泡状结构的有机质孔隙孔径众数为51~100 nm,有机质孔隙主要介于中孔~宏孔范畴。安页1井龙马溪组有机质孔隙的大量发育,指示了盆地外围的龙马溪组页岩经历了较强烈的生烃过程并具有较好的储集能力,具备良好的开发潜力。 相似文献
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为了评价陆相页岩气储层的储集空间和储气能力,以鄂尔多斯盆地延长探区上三叠统延长组长7段、长9段页岩为研究对象,运用电子扫描显微镜、高压压汞、低温CO2和N2气体吸附等实验方法,对陆相页岩气储层孔隙类型特征、孔隙结构及其影响因素进行研究。结果表明：(1)延长探区上三叠统延长组陆相页岩发育多种类型微观孔隙,以粒间孔和粒内孔为主,少量晶间孔和溶蚀孔,有机质孔发育较少,为陆相页岩气赋存提供了储集空间;(2)延长组页岩中介孔(2～50 nm)贡献了其主要的孔容和比表面积,占总孔容的7437%,占总比表面积的6440%,且长9段页岩的总孔容和总比表面积均大于长7段页岩;(3)延长组页岩孔隙结构以狭缝型孔和板状孔为主,孔径主要分布在04～09 nm、3～25 nm和5～200 μm区间段内,延长组页岩平均孔径为853 nm,且长7段页岩平均孔径大于长9段页岩;(4)页岩有机碳含量、有机质成熟度及矿物成分含量共同影响着延长组页岩孔隙的发育,其中矿物成分含量是以介孔孔隙为主的延长组页岩孔隙发育的主控因素,有机碳含量及成熟度的增加主要对页岩中微孔孔隙的发育起到积极作用。 相似文献
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页岩气储集空间与储层矿物特征关系密切,以四川盆地东缘龙马溪组页岩为研究对象,利用矿物组成、微量元素、地球化学等测试结果,结合低温氮气吸附法和高分辨率成像技术,采用多元统计分析方法,建立了页岩孔容预测方程,并分析孔隙分布特征和影响因素。结果表明,龙马溪组中部和底部页岩组分含量差异较大,生物成因的自生石英发育是龙马溪组底部石英含量高的主要原因;页岩纳米级孔隙以2~5 nm为主,对孔容贡献率介于64.2%~70.1%;建立的页岩组分含量与孔容的预测模型高度显著。脆性矿物孔、黏土矿物片间孔及其粒内孔是富黏土矿物页岩的主要孔隙类型,孔隙呈微缝状,小于2 nm孔隙不发育;有机质含量是富有机质页岩孔容大小的主控因素,有机质孔的面孔率介于8.8%~12.5%;有机质含量及成熟度是小于2 nm微孔发育的主控因素,大于50 nm孔隙的发育则受控于黏土矿物、石英及长石含量。 相似文献
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In organic-rich gas shales, clay minerals and organic matter (OM) have significant influences on the origin, preservation, and production of shale gas. Because of the substantial role of nanoscale pores in the generation, storage, and seepage of shale gas, we examined the effects of clay minerals and OM on nanoscale pore distribution characteristics in Lower Paleozoic shale gas reservoirs. Using the Niutitang and Longmaxi shales as examples, we determined the effects of clay minerals and OM on pores through sedimentation experiments. Field emission–scanning electron microscopy combined with low-pressure N2 adsorption of the samples before and after sedimentation showed significant differences in pore location and pore size distribution between the Niutitang and Longmaxi shales. Nanoscale pores mostly existed in OM in the Longmaxi shale and in clay minerals or OM–clay composites in the Niutitang shale. The distribution differences were attributed largely to variability in thermal evolution and tectonic development and might account for the difference in gas-bearing capacity between the Niutitang and Longmaxi reservoirs. In the nanoscale range, mesopores accounted for 61–76% of total nanoscale pore volume. Considerably developed nanoscale pores in OM were distributed in a broad size range in the Longmaxi shale, which led to good pore connectivity and gas production. Numerous narrow pores (i.e., pores?<?20 nm) in OM–clay composites were found in the Niutitang shale, and might account for this shale’s poor pore connectivity and low gas production efficiency. Enhancing the connectivity of the mesopores (especially pores?<?20 nm and those developed in OM–clay composites) might be the key to improving development of the Niutitang shale. The findings provide new insight into the formation and evolutionary mechanism of nanoscale pores developed in OM and clay minerals. 相似文献
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渝东南地区龙马溪组高演化页岩微纳米孔隙非均质性及主控因素 总被引：1，自引：0，他引：1
对页岩气赋存的主要场所页岩孔隙的研究是解决页岩气赋存和保存机理的关键,但目前缺少有效的手段去定量刻画高演化页岩微纳米孔隙的非均质性特征。通过低压N2吸附/解吸、高压压汞、场发射扫描电镜(FE-SEM)等实验,运用分形维数对渝东南地区龙马溪组高演化页岩微纳米孔隙非均质性进行了定量分析。结果表明：高演化页岩的微纳米级孔隙非均质性极强。中孔(2.0~50.0 nm)中2.0~4.5 nm 的孔隙分形维数平均2.853 4,4.5~50.0 nm 的孔隙分形维数平均2.7367,这种极强非均质性主要受有机质控制。总有机碳(TOC)含量大于1.7 %时,有机质孔在中孔中占主导地位,粘土矿物含量的增加会在一定程度上增加中孔的非均质性。宏孔(＞50.0 nm)分形维数平均2.8441,非均质性较强,主要受石英和碳酸盐等脆性矿物控制,随着碳酸盐矿物含量的增大,非均质程度增加,有机质对页岩宏孔的非均质性影响不明显。 相似文献