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1.
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
2.
This article performed a series of parallel experiments with numerical modeling to reveal key factors affecting the gas adsorption capacity of shale, including shale quality, gas composition and geological conditions. Adsorption experiments for shales with similar OM types and maturities indicate that the OM is the core carrier for natural gas in shale, while the clay mineral has limited effect. The N2 and CO2 adsorption results indicate pores less than 3 nm in diameter are the major contributors to the specific surface area for shale, accounting for 80% of the total. In addition, micropores less than 2 nm in diameter are generated in large numbers during the thermal evolution of organic matter, which substantially increases the specific surface area and adsorption capacity. Competitive adsorption experiments prove that shale absorbs more CO2 than CH4, which implies that injection CO2 could enhance the CH4 recovery, and further research into N2 adsorption competitiveness is needed. The Langmuir model simulations indicate the shale gas adsorption occurs via monolayers. Geologically applying the adsorption potential model indicates that the adsorption capacity of shale initially increases before decreasing with increasing depth due to the combined temperature and pressure, which differs from the changing storage capacity pattern for free gases that gradually increase with increasing depth at a constant porosity. These two tendencies cause a mutual conversion between absorbed and free gas that favors shale gas preservation. During the thermal evolution of organic matter, hydrophilic NSO functional groups gradually degrade, reduce the shale humidity and increase the gas adsorption capacity. The shale quality, gas composition and geological conditions all affect the adsorption capacity. Of these factors, the clay minerals and humidity are less important and easily overshadowed by the other factors, such as organic matter abundance. 相似文献
3.
渝东南渝页1井下志留统龙马溪组页岩孔隙特征及其主控因素 总被引：2，自引：0，他引：2
富有机质黑色页岩的孔隙结构控制了页岩气的赋存状态和储气量。中国南方地区下志留统是页岩气发育的最重要层位之一。为研究页岩的孔隙特征及其主控因素,对以下志留统龙马溪组页岩气为勘探目标的渝页1井的岩心进行系统的采样,并进行了比表面和孔径、有机质成熟度(Ro)、显微组分、总有机碳(TOC)含量、全岩X射线衍射和粘土矿物含量等一系列分析测试。结果显示,黑色页岩的孔径主要分布于2~5 nm,即以中孔隙为主;中孔体积占总体积的70%左右,微孔体积和宏孔体积分别占10%和20%左右。页岩孔隙结构(微孔体积、中孔体积和宏孔体积)和组成(碎屑矿物成分、粘土矿物成分、TOC和Ro)的相关关系分析表明：粘土矿物对微孔体积和中孔体积都具有控制作用,并且对中孔体积的控制作用更加显著;陆源碎屑含量的增加有利于宏孔体积的增加;有机质成熟度较高时和高成熟度有机碳含量都与宏孔隙体积呈正相关,这可能与高成熟有机质中nm级显微裂缝的发育导致宏孔体积增加有关。 相似文献
4.
有机储集空间是页岩的重要储集类型, 但对处于生油窗内的湖相页岩是否发育有机储集空间却缺少研究.系统采集处于生油窗范围内不同演化程度的湖相页岩样品, 利用氩离子抛光样品制备技术, 分别使用Quanta200扫描电镜及EDAX能谱仪联机和JSM-6700f冷场发射扫描电子显微镜对湖相页岩进行微观特征观察和岩石组分分析, 背散射图像和二次电子图像均显示, 页岩内大量发育呈暗色条带状的有机质-粘土-碳酸盐和有机质-粘土-硫酸盐混合体.该混合体内极易发育孔隙, 从2 500~4 000 m, 该类孔隙连续分布, 当埋深小于3 600 m时, 这类孔隙的尺度一般为微米级, 但随着演化程度增高纳米孔隙增加, 并且呈密集分布.混合体内孔隙的发育分别与页岩含油饱和度迅速增高及游离有机酸含量的增加同步, 该类孔隙的发育不仅仅取决于生烃作用, 它的形成是生烃转化和有机酸溶蚀共同作用的结果.上述结果表明, 在生油窗范围内湖相页岩中, 有机质与无机矿物作为整体共同演化且相互作用, 在生烃与溶蚀叠合作用下形成了丰富的有机质-矿物混合体内储集空间, 该储集类型对陆相页岩油气赋存具有重要意义. 相似文献
5.
6.
Tectonic and climate control of oil shale deposition in the Upper Cretaceous Qingshankou Formation (Songliao Basin, NE China) 总被引：4，自引：0，他引：4
Jianliang Jia Zhaojun Liu Achim Bechtel Susanne A. I. Strobl Pingchang Sun 《International Journal of Earth Sciences》2013,102(6):1717-1734
Oil shales were deposited in the Songliao Basin (NE China) during the Upper Cretaceous period, representing excellent hydrocarbon source rocks. High organic matter (OM) contents, a predominance of type-I kerogen, and a low maturity of OM in the oil shales are indicated by bulk geochemical parameters and biomarker data. A major contribution of aquatic organisms and minor inputs from terrigenous land plants to OM input are indicated by n-alkane distribution patterns, composition of steroids, and organic macerals. Strongly reducing bottom water conditions during the deposition of the oil shale sequences are indicated by low pristane/phytane ratios, high C14-aryl-isoprenoid contents, homohopane distribution patterns, and high V/Ni ratios. Enhanced salinity stratification with mesosaline and alkaline bottom waters during deposition of the oil shales are indicated by high gammacerane index values, low MTTC ratios, high β-carotene contents, low TOC/S ratios, and high Sr/Ba ratios. The stratified water column with anoxic conditions in the bottom water enhanced preservation of OM. Moderate input of detrital minerals during the deposition of the oil shale sequences is reflected by titanium concentrations. In this study, environmental conditions in the paleo-lake leading to OM accumulation in the sediments are related to sequence stratigraphy governed by climate and tectonics. The first Member of the Qingshankou Formation (K2qn1) in the Songliao Basin, containing the oil shale sequence, encompasses a third-order sequence that can be divided into three system tracts (transgressive system tract—TST, highstand system tract—HST, and regressive system tract—RST). Enrichment of OM changed from low values during TST-I to high-moderate values during TST-II/III and HST-I/II. Low OM enrichment occurs during RST-I and RST-II. Therefore, the highest enrichment of OM in the sediments is related to stages of mid-late TST and early HST. 相似文献
7.
有机质孔隙是页岩储集空间的重要组成部分,具有强烈的非均质性,阻碍对页岩储层质量的正确认识和评价,其本质是受有机显微组分类型及其在生烃过程中孔隙演化的影响。本文采用场发射扫描电镜和荧光显微镜定位观察手段实现特定显微组分孔隙发育特征的表征,结合Image J图像处理技术,对不同演化阶段的显微组分进行定量化统计,总结不同有机显微组分的孔隙演化规律。研究结果表明:固体沥青孔隙度随着成熟度的升高呈现先增加后减小的趋势,在固体沥青反射率SBR_O介于1.6%～2.0%时,固体沥青孔隙最为发育,而以SBR_O=2.0%为界,固体沥青孔隙度开始减小。镜质体和惰质体的孔隙发育规律相似,随着成熟度增加,总体表现出先减小而后微弱增加的趋势。在生油窗阶段,镜质体和惰质体孔隙度最小,无机矿物和固体沥青的充填使胞腔孔隙损失达90%以上,而进入高成熟阶段,固体沥青孔隙的发育使原始胞腔孔隙得到一定程度的恢复,成为镜质体和惰质体残余孔隙的主要贡献者,贡献率达56.73%和100%,可见固体沥青孔隙对页岩储层储集空间的重要性。综合沉积成岩作用和生烃作用,页岩储层在未成熟阶段和高成熟阶段晚期孔隙最为发育,前者有机质以原始胞腔孔隙为主,后者以固体量孔隙为主。明确有机显微组分孔隙演化规律为页岩有利储层预测和页岩气生产开发储层改造提供参考。 相似文献
8.
The accumulation and productivity of shale gas are mainly controlled by the characteristics of shale reservoirs;study of these characteristics forms the basis for the shale gas exploitation of the Lower Cambrian Niutitang Formation(Fm),Southern China.In this study,core observation and lithology study were conducted along with X-ray diffraction(XRD)and electronic scanning microscopy(SEM)examinations and liquid nitrogen(N_2)adsorption/desorption and CH_4 isothermal adsorption experiments for several exploration wells in northwestern Hunan Province,China.The results show that one or two intervals with high-quality source rocks(TOC2 wt%)were deposited in the deep-shelf facies.The source rocks,which were mainly composed of carbonaceous shales and siliceous shales,had high quartz contents(40 wt%)and low clay mineral(30 wt%,mainly illites)and carbonate mineral(20 wt%)contents.The SEM observations and liquid nitrogen(N_2)adsorption/desorption experiments showed that the shale is tight,and nanoscale pores and microscale fractures are well developed.BJH volume(V_(BJH))of shale ranged from 2.144×10~(-3) to 20.07×10~(-3) cm~3/g,with an average of11.752×10~(-3) cm~3/g.Pores mainly consisted of opened and interconnected mesopores(2–50 nm in diameter)or macropores(50 nm in diameter).The shale reservoir has strong adsorption capacity for CH_4.The Langmuir volume(V_L)varied from1.63 to 7.39 cm~3/g,with an average of 3.95 cm~3/g.The characteristics of shale reservoir are controlled by several factors:(1)A deep muddy continental shelf is the most favorable environment for the development of shale reservoirs,which is controlled by the development of basic materials.(2)The storage capacity of the shale reservoir is positively related to the TOC contents and plastic minerals and negatively related to cement minerals.(3)High maturity or overmaturity leads to the growth of organic pores and microfractures,thereby improving the reservoir storage capacity.It can be deduced that the high percentage of residual gas in Niutitang Fm results from the strong reservoir storage capacity of adsorbed gas.Two layers of sweet spots with strong storage capacity of free gas,and they are characterized by the relatively high TOCcontents ranging from 4 wt%to 8 wt%. 相似文献
9.
以湘中坳陷涟源凹陷上二叠统龙潭组和大隆组海陆过渡相泥页岩为研究对象,重点选取12块典型泥页岩钻井岩心样品开展有机碳含量、岩石热解、X射线衍射、密度法孔隙度、高压压汞、二氧化碳和氮气吸附等测试分析,利用氩离子抛光-场发射扫描电镜（FE-SEM）观察了泥页岩孔隙特征,通过定性描述和定量测定相结合的方法研究了海陆过渡相泥页岩纳-微米级孔隙结构特征及孔隙发育影响因素.研究结果表明:龙潭组和大隆组泥页岩有机碳含量均较高,热演化程度处在凝析油和湿气生成阶段早期,对应Ro为1.22%~1.43%;泥页岩孔隙类型主要为粒间孔、粒内孔、有机孔和微纳米缝.龙潭组与大隆组样品在孔隙形态、孔隙大小和影响因素上均有差异:龙潭组样品氮气吸附滞回环开口宽,有机孔形态多为圆形和椭圆形,孔径较大;大隆组样品氮气吸附滞回环开口窄,有机孔形态多为不规则状,孔径较小;龙潭组泥岩和大隆组泥页岩样品有机碳含量与黏土矿物含量呈正相关关系,2套样品的微孔孔隙积体与有机碳和黏土矿物含量均呈正相关性;龙潭组样品介孔+宏孔的孔隙体积与有机碳和黏土矿物含量呈正相关性,与石英+长石含量呈负相关性;大隆组样品中的碳酸盐矿物对其孔隙性有明显影响,大隆组样品介孔+宏孔孔隙体积与有机碳、黏土矿物和石英+长石含量相关性不明显. 相似文献
10.
页岩的微观孔隙结构对其甲烷吸附性能及页岩油气潜力具有重要影响,前人研究主要集中在海相页岩。该文以四川
盆地川西坳陷上三叠统须家河组五段为例,开展了陆相页岩的探索研究。首先通过低温氮气吸附实验对页岩样品的微观孔
隙结构特征进行了研究,计算了页岩的比表面积、孔径分布、孔体积和平均孔径等孔隙结构参数;然后通过高压甲烷等温
吸附实验,研究了页岩样品的甲烷吸附特征;最后探讨了页岩微观孔隙结构特征对甲烷吸附性能的影响。结果表明,须五
段页岩平均孔径为7.81~9.49 nm,主体孔隙为中孔,也含有一定量的微孔和大孔,孔隙形状以平行板状孔为主,含有少量
墨水瓶形孔。页岩比表面积高出常规储层岩石许多,有利于气体在页岩表面吸附存储,孔径在2~50 nm的中孔提供了主要
的孔体积,构成了页岩中气体赋存的主要空间。在85℃条件下,页岩甲烷吸附的兰氏体积为1.21~4.99 m3/t,不同页岩样品
之间的吸附性能差异明显。页岩的兰氏体积与比表面积之间呈现良好的正相关关系,比表面积与黏土矿物含量呈正相关,
而与总有机碳含量关系不明显。页岩的兰氏体积与微孔和中孔体积之间都具有良好的正相关关系,微孔体积和中孔体积与
总有机碳含量之间存在一定的正相关关系,但是正相关性的程度没有微孔体积和中孔体积与黏土矿物含量之间的关系强
烈。陆相页岩有机质热演化程度相对较低,因此有机孔发育有限：但另一方面同时黏土矿物含量较高,所以其内部发育大
量微孔和中孔,从而构成可观的比表面,影响甲烷吸附能力。 相似文献
11.
运用X射线衍射技术,对柴北缘中侏罗统46块岩心泥页岩样品和15块露头泥页岩样品进行了定性和定量分析。结果表明研究区泥页岩矿物成分中黏土矿物含量最高,介于33%~79.7%之间,平均54.3%;其次为石英,含量介于14.5%~57.8%之间,平均35.4%;碳酸盐矿物含量较少,总量一般介于0~13%之间,个别样品大于15%,露头样品与岩心样品矿物成分有差别。黏土矿物组合特征反映出研究区进入中成岩阶段,对应有机质演化的成熟阶段,具有适宜页岩油气形成的成熟度条件。扫描电镜显示,研究区泥页岩发育3种孔隙类型。与海相页岩相比,柴北缘中侏罗统泥页岩黏土矿物含量高但敏感性矿物含量低,石英、长石等脆性矿物含量偏低但达到湖相泥页岩开发标准,脆性指数平均为42.6%,整体上具有较好的脆性和可压性,有利于该区湖相页岩的压裂改造。 相似文献
12.
虽然页岩气的勘探已经在北美以及中国取得了突破,但是对页岩中孔隙空间的形成与发育仍然存在较大的争议,页岩中是否存在有效的孔隙,这些孔隙与气体的赋存有何联系都需要解答。本文对不同地区、不同岩石类型以及不同热成熟度的页岩进行微观分析,对比前人的研究,同时结合四川盆地龙马溪组页岩的实际分析数据,将页岩划分为富有机质页岩和含粉砂质泥页岩。富有机质页岩中有机质纳米孔是主要的孔隙类型,同时也是气体聚集与吸附的主要空间,有机质孔隙度与有机质含量、热成熟度密切相关;含粉砂质泥页岩中以粒间、粒内溶蚀孔为主,由于有机质含量较少,因而受热成熟影响很小。对页岩的孔隙形成机理分析发现,富有机质页岩孔隙度与有机质含量呈正相关,特别是与初始有机碳含量密切相关,因此恢复初始有机碳的含量是评价页岩含气量与含气性的关键。在热演化程度较低时（Ro < 0.6%）,页岩中有机质孔隙不发育,页岩几乎不含气;随着热演化程度升高（Ro = 0.8%）,页岩微孔隙发育,此时页岩以吸附气为主;随着热演化程度增大（Ro > 1.2%）,微孔逐渐向中孔和宏观孔转化,总的比表面积减小,页岩中游离气含量开始增加,吸附气含量减少。 相似文献
13.
HAN Hui DAI Jie GUO Chen ZHONG Ningning PANG Peng DING Zhengang CHEN Jianping HUANG Zhenkai GAO Yuan LUO Jinyu LI Qirui ZHANG Zhaokun 《《地质学报》英文版》2021,95(2):585-601
To investigate pore characteristics and the factors controlling lacustrine shales,geochemical,mineralogical and petrophysical experiments were performed on 23 shale samples from the Qingshankou Formation of the Songliao Basin,China.A comparison of mercury injection capillary pressure (MICP) and low-temperature N2 adsorption pore-size distribution showed that MICP has a higher pore-size distribution (PSD) line in its overlapping pore diameter range,which may be elevated by the higher pressure of MICP.Therefore,in the overlapping range,low-temperature N2 adsorption data were preferred in pore characterization.Negative correlations were observed between pore volumes and TOC content,indicating organic matter pores are not well-developed in the studied samples.This may be related to their low grade of maturity and type I kerogens.There existed negative relationships between pore volumes and S1,which illustrated that liquid hydrocarbons occupied some pore space.Micropore volume had a better correlation with S1 than mesopore and macropore volumes,which suggests that liquid hydrocarbons preferentially occur in micropores.No obvious relationships between pore volumes and quartz or feldspar were observed,while pore volumes increased with the increasing clay mineral content.These relationships indicate that intraparticle pores in clay minerals represent the principal pore type. 相似文献
14.
柴北缘盆地YQ-1井中侏罗统石门沟组泥页岩纳米孔隙特征及影响因素 总被引：1，自引：0，他引：1
柴达木北缘(柴北缘)盆地侏罗纪是典型的陆相湖沼盆地,是目前具有页岩气潜力的盆地之一。本文运用氮气吸附、有机碳含量、有机质成熟度、全岩X衍射分析等方法,对柴北缘鱼卡地区YQ - 1井中侏罗统石门沟组泥页岩的纳米孔隙特征及控制因素进行研究。结果表明,石门沟组泥页岩纳米孔隙结构复杂,根据吸附回线及孔径分布特征可划分为两类,第一类以一端不透气性孔和开放性平行板状狭缝孔为主,孔径主要集中在3～5 nm范围内,呈单峰状分布;第二类则以一端不透气性孔和开放性倾斜板狭缝孔为主,孔径主要分布在3～5 nm和8～14 nm范围内,呈双峰状分布。孔径小于50 nm的微孔和介孔是比表面积和孔体积的主要贡献者;黏土矿物含量与微孔、介孔、总孔体积呈正相关;在较低的成熟度制约下,泥页岩有机质孔隙基本不发育,有机质丰度较高的石门沟组上段H9泥页岩TOC含量与微孔、介孔、总孔体积呈负相关性,有机质丰度较差的下段H8泥页岩TOC含量与孔体积相关性则不甚明显;孔隙结构及孔径分布受沉积环境水动力条件影响;黏土矿物是石门沟组泥页岩纳米孔隙的主要提供者,是孔隙发育的主控因素,TOC含量与沉积环境也会对泥页岩孔隙发育产生一定影响。 相似文献
15.
M. Khanehbad R. Moussavi-Harami A. Mahboubi M. Nadjafi 《Geochemistry International》2012,50(9):777-790
The Sardar Formation (Carboniferous) has a lithological variation that is characterized by sandstone, shale and limestone members. Shales of the Sardar Formation from the east central Iran have been analyzed for major elements and a number of trace elements. The shales of Sardar Formation are rich in quartz minerals and clay minerals of the bulk minerals. Clay minerals of shales are composed of illite, kaolinite and slightly montmorillonite. SiO2 versus K2O/Na2O diagram shows these shales plotted in the passive continental margin or cratonic field. Geochemical data suggest high acidic source rocks similar to granite and intermediate igneous rocks. CIA and ICV suggest semi-humid climatic conditions during depositions and indicate high chemical weathering in the source area. The geochemical parameters such as V/Cr, Ni/Co and Cu/Zn ratios indicate that these shales were deposited in oxic environment. 相似文献
16.
以"沉积控相,相控储层"为研究思路,基于野外露头剖面实测与室内实验测试,以及前人的研究成果,探讨渝东北地区上奥陶统五峰组-下志留统龙马溪组沉积环境对页岩气储层的控制作用。研究表明,渝东北地区五峰组-龙马溪组富有机质泥页岩主要发育于滞留浅海陆棚相中,沉积中心页岩厚度可达70~80m,有机碳含量(TOC)最高可达7.56%,平均3.09%。静水缺氧还原沉积环境岩石类型主要以富含有机质的含碳质含粉砂泥(页)岩、含碳质含硅质泥(页)岩、含硅质泥(页)岩、含碳质泥(页)岩、含粉砂泥(页)岩及硅质泥(页)岩为主。页岩矿物成分以石英(平均达62.76%)和黏土矿物(平均达22.61%)为主。缺氧还原环境下沉积的大量黄铁矿形成的黄铁矿晶间孔、黏土矿物层间微孔隙、有机质生烃形成的微孔隙以及脆性矿物控制形成的微裂缝为页岩气提供了良好的储集空间。沉积环境控制的储层发育特征的研究可为页岩展布、有机质丰度、储集空间及其之后有利区评价等研究提供基础。 相似文献
17.
页岩储层孔隙结构是评价页岩气资源潜力的基础。本文基于有机碳含量、沥青反射率、X射线衍射、场发射扫描电镜(FE-SEM)及低温氮气吸附等方法,探讨鄂西地区震旦系陡山沱组页岩沉积组成、孔隙结构及其控制因素。结果表明:(1)陡山沱组为硅质和钙质页岩,TOC介于3.29%～6%,主要为I型干酪根,处于高-过成熟阶段;(2)陡山沱组页岩有机孔发育程度较低,无机孔提供主要储集空间,包括脆性矿物和黏土矿物的粒间孔、层间孔和部分溶蚀孔,以及少量微裂缝;(3)孔径分布范围为1.1～284nm,总孔体积平均为0.034ml/g,微孔、介孔和大孔体积分别为0.005ml/g、0.023ml/g和0.006ml/g,以介孔为主;(4)陡山沱组页岩TOC与孔体积无明显相关性,表明有机孔对孔体积贡献较小。硅质矿物和黏土矿物含量与页岩孔体积正相关性较好,表明矿物组成是陡山陀组页岩孔隙发育的主要控制因素。鄂西地区陡山沱组页岩具有良好的物质条件、生烃条件和页岩气储集空间,是潜在的页岩气勘探开发层系。 相似文献
18.
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
19.
泥页岩中有机质孔隙是有机质向烃类转化的产物,也是烃类重要的纳米级赋存空间。以我国不同沉积相泥页岩（鄂尔多斯盆地延长组、四川盆地东南缘龙马溪组和牛蹄塘组、南华北盆地山西组）为研究对象,通过有机地球化学和微区分析等手段对有机质孔隙发育特征及影响因素进行了精细表征和深入探讨。结果表明:TOC与孔隙参数的相关性随热成熟度的增加展现出规律性变化,表明热演化是有机质孔隙发育的主要驱动因素。除热成熟度外,四组样品中有机质孔隙的发育特征受多种因素影响:延长组有机质孔隙处于形成阶段,多数有机质不发育孔隙,孔隙的形成主要受有机质类型和显微组分的影响。龙马溪组有机质孔隙普遍发育,为孔隙发育的高峰阶段,有机—无机相互作用制约着孔隙的结构和形貌特征。牛蹄塘组因排烃作用较为完全而处于孔隙收缩阶段,已有较多有机质孔隙被压实而消失,孔隙形态主要受控于微裂隙和有机质—黏土复合体的发育情况。山西组因过高的热演化程度引起有机质结构塌陷,且保存条件极差,处于孔隙的转化和消失阶段;有机质孔隙的发育情况与有机质类型和内部结构直接相关,并受保存条件的严重影响。相关结论有助于深刻理解页岩油气资源赋存富集机理,促进页岩油气资源的勘探开发。 相似文献
20.
ZHANG Xu LIU Chenglin LI Bing WU Linqiang GUI Herong WANG Ziling ZHANG Zhihui LIANG Dexiu 《《地质学报》英文版》2020,94(2):337-351
The Songliao Basin is one of the most important petroliferous basins in northern China. With a recent gradual decline in conventional oil production in the basin, the exploration and development of unconventional resources are becoming increasingly urgent. The Qingshankou Formation consists of typical Upper Cretaceous continental strata, and represents a promising and practical replacement resource for shale oil in the Songliao Basin. Previous studies have shown that low-mature to mature Qingshankou shale mainly preserves type Ⅰ and type Ⅱ1 organic matter, with relatively high total organic carbon(TOC) content. It is estimated that there is a great potential to explore for shale oil resources in the Qingshankou Formation in this basin. However, not enough systematic research has been conducted on pore characteristics and their main controlling factors in this lacustrine shale reservoir. In this study, 19 Qingshankou shales from two wells drilled in the study area were tested and analyzed for mineral composition, pore distribution and feature evolution using Xray diffraction(XRD), scanning electron microscopy(SEM), low-pressure nitrogen gas adsorption(N2-GA), and thermal simulation experiments. The XRD results show that clay, quartz, and feldspar are the dominant mineral constituents of Qingshankou shale. The clay minerals are mostly illite/smectite mixed layers with a mean content of 83.5%, followed by illite, chlorite, and kaolinite. There are abundant deposits of clay-rich shale in the Qingshankou Formation in the study area, within which many mineral and organic matter pores were observed using SEM. Mineral pores contribute the most to shale porosity;specifically, clay mineral pores and carbonate pores comprise most of the mineral pores in the shale. Among the three types of organic matter pores, type B is more dominant the other two. Pores with diameters greater than 10 nm supply the main pore volume;most are half-open slits and wedge-shaped pores. The total pore volume had no obvious linear relationship with TOC content, but had some degree of positive correlation with the content of quartz + feldspar and clay minerals respectively. However, it was negatively correlated with carbonate mineral content. The specific surface area of the pores is negatively related to TOC content, average pore diameter, and carbonate mineral content. Moreover, it had a somewhat positive correlation with clay mineral content and no clear linear relationship with the content of quartz + feldspar. With increases in maturity, there was also an increase in the number of carbonate mineral dissolution pores and organic matter pores, average pore diameter, and pore volume, whereas there was a decrease in specific surface area of the pores. Generally, the Qingshankou shale is at a low-mature to mature stage with a TOC content of more than 1.0%, and could be as thick as 250 m in the study area. Pores with diameters of more than 10 nm are well-developed in the shale. This research illustrates that there are favorable conditions for shale oil occurrence and enrichment in the Qingshankou shale in the study area. 相似文献