溶胀——研究石油初次运移的新途径   总被引：1，自引：1，他引：0  

蔡玉兰  张馨  邹艳荣 《地球化学》2007,36(4):351-356

用不同方法确定了扒搂沟煤型干酪根的溶胀比,计算模拟了石油的初次运移.结果显示,溶胀比决定了源岩的留烃潜力;石油的初次运移受源岩溶胀比和生烃能力的控制.Ⅲ型干酪根只有少量液态烃排出,除受Ⅲ型干酪根留烃能力制约外,还与生成液态烃的数量有关.溶胀实验可以确定和模拟源岩的留-排烃能力,是研究石油初次运移及其质量分馏的新途径.  相似文献   

Gas-generation potential of shales in small and medium-sized basins: a case study from the Xuanhua Basin,north China     

J. L. Liu  Z. Li  M. H. Chang  S. Wang  L. Chen 《Australian Journal of Earth Sciences》2020,67(3):411-424

Abstract

Small- and medium-sized basins are widely distributed, and some contain commercial gas reservoirs demonstrating their gas-generation potential. The Xuanhua Basin, which is a small-sized coal-bearing basin in north China, includes a promising target for shale-gas exploration in the Xiahuayuan Formation. In this study, we used this basin as a case study to assess the critical geochemical features for small or medium-sized basins to form commercial gas reservoirs. Total organic carbon (TOC) analysis, Rock-Eval pyrolysis, microscopic observation of macerals, vitrinite reflectance measurement and kerogen stable carbon isotope analysis were performed to characterise the organic geochemistry of the Xiahuayuan shales. The original total organic carbon (TOC_o) content and hydrocarbon-generative potential (S_2o) were reconstructed to further evaluate the gas-generation potential of these shales. In addition, geochemical data of shales from other similar-sized basins with gas discoveries were compared. The results showed that the kerogen from the Xiahuayuan Formation is Type III (gas-prone), and macerals are dominated by vitrinite. TOC values showed a strong heterogeneity in the vertical profiles, with most higher than 1.5?wt%. The measured R_o values ranged from 1.4 to 2.0%. However, thermal maturity was not correlated with the present-day burial depth with higher maturity in the wells closest to the diabase intrusion centre. The remaining generation potential (S₂) averaged 0.91?mg HC/g rock, equal to 1.4?cm³ CH₄/g rock, and the average amount of hydrocarbon generated was 4.33?cm³ CH₄/g rock. In small and medium-sized basins, the TOC content of commercially developed gas shales ranged from 0.5 to 2.5?wt%, organic matter was mainly humic (gas-prone), and the burial depth was generally shallow. Biogenic gas reservoirs for commercial exploitation tend to have larger shale thicknesses (120–800?m) than thermogenic gas reservoirs (60–90?m).

1. The Xiahuayuan Formation is a good gas-source rock with gas-prone kerogen type, relatively high TOC values and moderate thermal maturity.

2. The average amount of hydrocarbon generated from the Xiahuayuan shales is about 4.33?cm³ CH₄/g rock, indicating a potential to form a shale gas reservoir.

3. Owing to the influence of diabase intrusions, the Xiahuayuan shales have entered the dry gas window at relatively shallow-buried depths.

4. Small- and medium-sized basins have the potential to generate commercial gas reservoirs with the generated volume mainly a product of the thickness and maturity of black shales.

  相似文献   

四川盆地龙潭组高热演化烃源岩有机质生源及沉积环境探讨   总被引：4，自引：0，他引：4  

朱扬明  顾圣啸  李颖  郝芳  邹华耀  郭彤楼 《地球化学》2012,(1):35-44

四川盆地龙潭组烃源岩R°值主要变化在2.0％～3.0％范围,干酪根H/C原子比值多数集中在0.3～0.5之间,有机质热演化达到过成熟阶段.它们的各类饱和烃生物标志物组成和分布大都发生了异常变化,限制了其地球化学应用.其芳烃组分和干酪根碳同位素及S、N元素组成还包含着标志有机质生源及沉积环境的信息.川东南地区近海湖沼相含...  相似文献   

Origin of crude oils from oilfields in the Zagros Fold Belt,southern Iraq: Relation to organic matter input and paleoenvironmental conditions     

《Marine and Petroleum Geology》2016

Crude oil samples from Cretaceous and Tertiary reservoir sections in the Zagros Fold Belt oil fields, southern Iraq were investigated using non-biomarker and biomarker parameters. The results of this study have been used to assess source of organic matter, and the genetic link between oils and their potential source rocks in the basin. The oils are characterized by high sulphur and trace metal (Ni, V) contents and relatively low API gravity values (17.4–22.7° API). This indicates that these oils are heavy and generated from a marine source rock containing Type II-S kerogen. This is supported by their biomarker distributions of normal alkanes, regular isoprenoids, terpanes and steranes and the bulk carbon isotope compositions of their saturated and aromatic hydrocarbons. The oils are characterized by low Pr/Ph ratios (<1), high values of the C₃₅ homohopane index and C₃₁-22R/C₃₀ hopane ratios, relatively high C₂₇ sterane concentrations, and the predominance of C₂₉-norhopane. These biomarkers suggest that the oils were generated predominantly from a marine carbonate source rock, deposited under reducing conditions and containing plankton/algal and microorganisms source input. The presence of gammacerane also suggests water column stratification during source rock deposition.The biomarker characteristics of the oils are consistent with those of the Middle Jurassic Sargelu carbonate as the effective source rock in the basin. Biomarker maturity data indicate that the oils were generated from early maturity source rocks.  相似文献   

The Original Organism Assemblages and Kerogen Carbon Isotopic Compositions of the Early Paleozoic Source Rocks in the Tarim Basin, China     

HU Guang  MENG Qingqiang  WANG Jie  Tengger  XIE Xiaomin  LU Longfei  LUO Houyong  LIU Wenhui 《《地质学报》英文版》2018,92(6):2297-2309

Original organisms are the biological precursors of organic matter in source rocks. Original organisms in source rocks are informative for oil-source rock correlation and hydrocarbon potential evaluation, especially for source rocks which have high-over level of thermal maturity. Systematic identification of original organism assemblages of the Lower Paleozoic potential source rocks and detailed carbon isotopic composition of kerogen analyses were conducted for four outcrop sections in the Tarim basin. Results indicated that the original organism assemblages of the lower part of the Lower Cambrian were composed mainly of benthic algae, whereas those of the Upper Cambrian and the Ordovician were characterized by planktonic algae. Kerogen carbon isotopic data demonstrated that the δ13Ckerogen values of source rocks dominated by benthic algae are lower than ?34‰, whereas the δ13Ckerogen values of source rocks dominated by planktonic algae are higher than ?30‰ in general. We tentatively suggested that the carbon species those are utilized by algae and the carbon isotopic fractionation during photosynthesis are the major controls for the δ13Ckerogen values in the Lower Paleozoic source rocks in the Tarim basin. Correlating the δ13C values of oils exploited in the Tarim basin, the original organism assemblages, and δ13Ckerogen values of source rocks, it implied that the Lower Paleozoic oils exploited in the Tarim basin should be sourced from the source rocks with original organism assemblages dominated by planktonic algae, and the hydrocarbon sourced from the Cambrian benthic algae should be of great exploration potential in future. Original organism assemblages in source rocks can provide important clues for oil-source rocks correlation, especially for the source rocks with high thermal maturity.  相似文献   

塔里木盆地烃源岩中有机显微组分的超微特征   总被引：1，自引：0，他引：1       下载免费PDF全文

刘大锰  金奎励 《地球科学》1996,21(1):79-83,T001

采用扫描电镜（ＳＥＭ）及透射电镜（ＴＥＭ）对塔里木盆地烃源岩中干酪根的超微组分和超微结构以及笔石，沥青的超微特征分别进行了研究，研究结果表明，（１）扫描电镜可以区分干酪根的类型；（２）在ＴＥＭ下，发现塔里木下古生界岩中存在两类超微组分即超微细菌体和超微藻类体，且超微细菌体的发现可以为该区下古生界原油含蜡量高提供证据；（３）笔石在ＴＥＭ下显示清晰的网状结构，沥青大多呈团凝状，凝块状，无任何结构显示，  相似文献   

Electron-probe microanalysis of light elements in coal and other kerogen     

R. M. Bustin  M. Mastalerz  M. Raudsepp 《International Journal of Coal Geology》1996,32(1-4)

Recent advances in electron microprobe technology including development of layered synthetic microstructures, more stable electronics and better matrix-correction programs facilitated routine microanalysis of the light elements in coal. Utilizing an appropriately equipped electron micro-probe with suitable standards, it is now possible to analyze directly the light elements (C, O and N, if abundant) in coal macerals and other kerogen. The analytical results are both accurate compared to ASTM methods and highly precise, and provide an opportunity to access the variation in coal chemistry at the micrometre scale. Our experiments show that analyses using a 10 kV accelerating voltage and 10 nA beam current yield the most reliable data and result in minimum sample damage and contamination. High sample counts were obtained for C, O and N using a bi-elemental nickel-carbon pseudo-crystal (2d = 9.5 nm) as an analyzing crystal.Vitrinite isolated from anthracite rank coal proves the best carbon standard and is more desirable than graphite which has higher porosity, whereas lower rank vitrinite is too heterogeneous to use routinely as a standard. Other standards utilized were magnesite for oxygen and BN for nitrogen. No significant carbon, oxygen or nitrogen X-ray peak shifts or peak-shape changes occur between standards and the kerogen analyzed. Counting rates for carbon and oxygen were found to be constant over a range of beam sizes and currents for counting times up to 160 s. Probe-determined carbon and oxygen contents agree closely with those reported from ASTM analyses. Nitrogen analyses compare poorly to ASTM values which probably is in response to overlap between the nitrogen K α peak with the carbon K-adsorption edge and the overall low nitrogen content of most of our samples.Our results show that the electron microprobe technique provides accurate compositional data for both minor and major elements in coal without the necessity and inherent problems associated with mechanically isolating macerals. Studies to date have demonstrated the level of compositional variability within and between macerals in suites of Canadian coals.  相似文献   

塔里木盆地下古生界高成熟干酪根生烃潜力的评估   总被引：1，自引：0，他引：1  

范善发  周中毅  解启来  潘长春  钱吉盛  陈一平 《地球化学》1996,(5)

塔里木盆地下古生界海相高成熟生油岩干酪根仍具有一定的生烃潜力，其产烃率－温度－时间关系研究表明，在最近１－２Ｍａ内凹陷区奥陶系生油岩向邻近的隆起区提供了大量烃类。  相似文献   

不同成因原油全扫描定量荧光特征及其影响因素          下载免费PDF全文

李素梅  庞雄奇  孙爱艳 《地质学报》2007,81(2):230-235

为揭示不同成因类型原油的三维全扫描荧光特征及其主控因素,对50个不同成因类型的原油的三维荧光特征进行了分析。原油样品代表了未熟—低熟至高成熟度范畴原油、淡水与咸水湖相、沼泽相成因原油、高蜡低硫与低蜡高硫油、常规油与重质油等类型。结果表明,分析原油三维荧光谱图及其定量参数有所差异。原油的荧光强度随芳烃含量增加而增加,沼泽相高蜡油荧光强度总体高于湖相原油;荧光强度随成熟度增加而降低、荧光主峰波长随成熟度增加而变短,反映芳烃总量与相对高分子量芳烃丰度具有降低趋势。稠油的荧光谱图不同于常规油,具有波长分布范围宽、主峰不明显等特征。成熟度、母源岩有机质类型与生源、次生改造等多种因素对原油的三维荧光特征有控制作用。  相似文献   

惠民凹陷上古生界烃源岩的生烃动力学研究   总被引：1，自引：0，他引：1  

赵青芳  耿安松  熊永强  张海祖  耿新华  刘金钟 《矿物岩石地球化学通报》2007,26(2):191-196

以化学动力学方法定量评价烃源岩是近些年发展起来的一种新方法。本文采用金管-高压釜封闭体系研究了惠民凹陷上古生界烃源岩(碳质泥岩)生烃动力学,取得了热解产物C1和C2～C5烃类气体组分生成动力学参数,结合Kinetics生烃动力学专用软件计算,模拟了具体地质条件下的成烃规律。结果表明,生成CH4所需活化能较高,分布范围较宽;随着碳数的增加(C2～C5),所需活化能与甲烷相反。结合惠民凹陷埋藏史与受热史,烃源岩发生过二次生烃过程,模拟计算结果与实际地质背景相吻合,指出古地温演化模式对烃源岩的生烃行为有重要的影响。生烃动力学参数为计算含油气盆地烃源岩油气生成量提供了科学依据。  相似文献