鄂尔多斯盆地镇泾区块延长组长81储层成岩作用特征及其对储集物性的影响

鄂尔多斯盆地镇泾区块上三叠统延长组长81储层具有成分成熟度低,结构成熟度中等到好的特点,岩性以岩屑长石砂岩和长石岩屑砂岩为主.长81砂岩属于特低孔特低渗储层,以次生溶蚀粒间孔为主要储集空间.目前储层正处于中成岩阶段A期,主要发育压实、胶结、溶解和交代4种成岩作用类型.机械压实作用是造成长81储层埋深小于2000 m砂岩...     

元坝气田长兴组储层特征与形成主控因素研究

本文以宏、微观资料相结合的方法,以优质储层发育与形成为主线开展了元坝气田长兴组礁滩储层发育特征研究。研究证明:(1)元坝气田长兴组礁滩储层岩石类型以亮晶生屑灰岩与亮晶生屑白云岩等颗粒岩为主,西部礁滩储层白云岩含量高于东部,长二段礁滩储层白云岩含量高于长一段浅滩储层;(2)储层类型以孔隙型为主,裂缝-孔隙型次之,储集空间包括晶间溶孔、晶间孔、粒间溶孔及裂缝;(3)元坝地区长兴组礁滩储层以Ⅱ、Ⅲ类为主,西部物性好于东部,长二段储层厚度远大于长一段。元坝地区长兴组储层受沉积相、构造活动及成岩作用等控制,受沉积前古地貌和燕山期后构造作用的双重控制,西部储层物性好于东部;3期破裂作用与3期溶蚀作用是形成储层的关键。     

Diagenetic Sequences Analysis of Fuyu Reservoir in

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Biomarker evidence for Botryococcus and a methane cycle in the Eocene Huadian oil shale,NE China

The saturated and unsaturated hydrocarbons of two samples (HD-19 and HD-21) from the same section of the Middle Eocene lacustrine Huadian oil shale in NE China were identified and shown to be mainly from algal and bacterial sources. Comparison of the two samples provided an opportunity to explore the contribution from telalginite to the hydrocarbon profiles. Cells identified from microscopy as Botryococcus in the telalginite of HD-21 were confirmed as belonging to the L race of B. braunii from the presence of monoaromatic lycopane derivatives and small amounts of several lycopadienes. Lycopane was abundant and was probably derived from biohydrogenation of lycopadienes and related lipids on the basis of δ¹³C values. Hopane distributions showed a dominance of those with the biological 17β,21β-stereochemistry, as expected for an immature shale, with low amounts of 17β,21α-hopanes (moretanes) and 17α,21β-hopanes. Two hopenes were also abundant and assigned as C₂₉ and C₃₀ neohop-13(18)-enes, which occurred together with the C₂₉ and C₃₀ hop-17(21)-enes. These had depleted carbon isotope values (−43.7‰ to −50.8‰), indicative of production by methane oxidizing bacteria (methanotrophs). The high proportion of hopanoids with carbon numbers < C₃₂ indicates extensive post-depositional diagenetic alteration of bacteriohopanepolyols as well as a direct input of C₃₀ hopanoids. The data clearly indicate that there was active utilization of methane in this lacustrine depositional setting, but isoprenoid hydrocarbon biomarkers for methanogens, such as pentamethylicosane (PMI) and squalane, were in surprisingly low abundance. It is possible that these bacterial contributions were present as polar lipids. The origins of an unusual C₃₈ isoprenoid alkane assigned as bipristane are uncertain, but may be from methanogens. Steranes and sterenes were relatively minor components, but abundant diasterenes and 4-methyldiasterenes were present, reflecting significant conversion of the original lipid composition by way of clay-catalysed diagenesis. The biomarker data suggest that the bottom waters in the original depositional environment had low O₂ content, but the sediments were probably neither sulfidic nor strongly reducing. The high content of organic matter in the shale likely reflects both high (but fluctuating) productivity due to eutrophic conditions in the overlying water and good preservation in the sediments.     

重庆南川地区中二叠统茅口组眼球状灰岩成因

中二叠世茅口组中-下部发育一种特殊的眼球状灰岩, 眼球部分通常为颜色较浅, 富含生屑颗粒的灰岩; 而眼皮部分通常为颜色较暗的泥灰岩。其成因一直存在分歧。本文通过对重庆南川大铺子剖面茅口组底部眼球状灰岩的野外观察和室内研究, 认为陆源输入的改变导致眼球和眼皮部分泥质含量的差异; 在成岩过程中, 碳酸盐沉积物为主的眼球部分因为胶结作用而没有被机械和压实作用破坏, 泥质含量较多的眼皮部分则受到强烈的压实。因此, 该地区眼球状灰岩的形成是沉积和成岩过程相互作用的结果, 为浅海陆棚沉积环境。     

杏子川油田长6储层成岩作用及对物性的影响

通过普通薄片、铸体薄片、X射线衍射、扫描电镜等多项测试方法,对鄂尔多斯盆地杏子川油田 W 区块长6储层的岩石学特征、孔隙结构、成岩作用进行分析与研究。结果表明：研究区长6储层岩性主要为细粒长石砂岩,颗粒分选性较好,胶结类型以接触式-孔隙式为主,少量镶嵌式胶结。储集空间类型以原生粒间孔、溶蚀粒间孔隙为主。砂岩储层成岩作用复杂,成岩现象丰富,对储集层物性影响显著。     

Diagenesis of organic matter in a 400 m organic rich sediment core from offshore Namibia using solid state 13C NMR and FTIR

Although rates and mechanisms of early diagenesis have been well studied, the effects of microbial metabolism on the molecular composition of the sedimentary organic matter (SOM) over long periods of time need more investigation. In this study, we characterize the early diagenesis of marine SOM from organic rich sediments of the Ocean Drilling Program site 1082 located off Namibia, in the vicinity of the Benguela coastal upwelling system. We used both Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (¹³C NMR) to assess the quantitative partitioning of the organic carbon into major compound classes (aliphatic, aromatic, ester, carboxylic, amide and carbons from carbohydrates). Then, we calculate the SOM composition in the main biomolecules (proteins, carbohydrates, lipids and lignin) on the basis of previous ¹³C NMR based estimates of the molecular composition of the organic mixtures. Results show that the SOM is still labile at 7 m below the seafloor (mbsf) and composed of about 25% proteins and 15% carbohydrates. With increasing depth, the protein content exponentially decreases to 13% at 367 mbsf, whereas the carbohydrate content decreases linearly to 11%. The lignin and lipid content consistently represent around 10% and 40% of the SOM, respectively, and show an increase with depth, due mostly to selective enrichment as the more labile components are lost by degradation. Thus, these components of the SOM are considered refractory at the depth scale considered. The calculated remineralization rates are extremely slow ranging from 5.6 mol C m⁻³ ky⁻¹ at the top of the core to 0.2 mol C m⁻³ ky⁻¹ according to the organic carbon flux to the seafloor. Knowing the labile carbon losses, we propose a method to calculate the initial TOC before the diagenesis took place.     

火山岩储层质量预测方法探讨——以松辽盆地徐家围子断陷为例

松辽盆地徐家围子断陷深层火山岩储层具有埋藏深、 温度高、 压力大、 物性差、 非均质性强的特征。为了预测火山岩储层类型和质量在平面上的变化规律,本文讨论了影响火山岩储层物性的主要地质因素。结果表明,火山岩的物性主要受火山岩相（组）和所处对应碎屑岩成岩阶段的影响。距火山口越远的火山岩相组的火山岩储层,其孔隙度和渗透率越低。火山岩工业气层主要分布在晚成岩阶段A期以前的火山岩储层中。在晚成岩阶段B期,只有少量低产气层。本文充分考虑徐家围子断陷火山岩相和成岩作用对火山岩储层物性的影响与控制,应用成岩模拟软件,预测了成岩阶段的横向展布,通过叠合营三段火山岩相图和成岩阶段预测图,预测了火山岩储层的类型和质量,目前已发现工业气流的井主要分布在断陷中部的Ⅱ、 Ⅲ类火山岩储层中。     

储层成岩产物对于油气运移的指示意义——以塔里木盆地群苦恰克构造带东河塘组为例

泥盆系东河塘组下段砂岩储层是塔里木盆地群苦恰克构造带内重要的勘探层系,有关储层内油气充注方向与富集规律的研究目前仍未有统一认识。研究层段内碳酸盐胶结物(主要为白云石和铁白云石胶结物)分布较为广泛,其中作为早成岩阶段产物的白云石胶结物的含量在平面上呈现出自东向西依次增加的趋势; 而铁白云石胶结物则以交代先期形成白云石胶结物的形式产出于中成岩阶段,略滞后于储层内的油气充注,其胶结程度在平面上呈现出自东向西依次减弱的分布规律。铁白云石胶结物作为反映储层内较强还原环境的指示性矿物,其在储层内的分布规律也承担着判明油气运移方向或富集规律的"责任",而其上述分布规律为研究区储层内油气自东向西充注提供了全新的判定依据。