顶空气相色谱法测定海水二甲基硫和浮游植物细胞二甲基硫丙酸的研究   总被引：12，自引：2，他引：12  

王永华  焦念志 《海洋与湖沼》1996,27(1):46-50

建立了顶空ＧＣ／ＦＰＤ测定海水中二甲基硫（ＤＭＳ）和浮游植物细胞中二甲基硫丙酸（ＤＭＳＰ）的方法，并研究盐度、温度、气液相比ＤＭＳ诸因素对ＤＭＳ顶空灵敏度的影响。该法对ＤＭＳ测定的相对标准偏差均小于６％，平均回收率为１０６％，最低检出限为２０ｎｇ／Ｌ。细胞ＤＭＳＰ先经碱作用转化为ＤＭＳ，在５０℃下作用时间不少于６ｈ，峰高与浓度的双对数线性相关系数大于０．９９。对１９９４年冬、１９９５年夏采自胶州湾  相似文献   

Investigation of gas content of organic-rich shale:A case study from Lower Permian shale in southern North China Basin,central China     

Wei Dang  Jin-Chuan Zhang  Xuan Tang  Xiao-Liang Wei  Zhong-Ming Li  Cheng-Hu Wang  Qian Chen  Chong Liu 《地学前缘(英文版)》2018,9(2):559-575

Measuring gas content is an essential step in estimating the commerciality of gas reserves. In this study,eight shale core samples from the Mouye-1 well were measured using a homemade patented gas desorption apparatus to determine their gas contents. Due to the air contamination that is introduced into the desorption canister, a mathematical method was devised to correct the gas quantity and quality.Compared to the chemical compositions of desorbed gas, the chemical compositions of residual gas are somewhat different. In residual gas, carbon dioxide and nitrogen record a slight increase, and propane is first observed. This phenomenon may be related to the exposure time during the transportation of shale samples from the drilling site to the laboratory, as well as the differences in the mass, size and adsorptivity of different gas molecules. In addition to a series of conventional methods, including the USBM direct method and the Amoco Curve Fit(ACF) method, which were used here for lost gas content estimation, a Modified Curve Fit(MCF) method, based on the 'bidisperse' diffusion model, was established to estimate lost gas content. By fitting the ACF and MCF models to gas desorption data, we determined that the MCF method could reasonably describe the gas desorption data over the entire time period, whereas the ACF method failed. The failure of the ACF method to describe the gas desorption process may be related to its restrictive assumption of a single pore size within shale samples. In comparison to the indirect method, this study demonstrates that none of the three methods studied in this investigation(USBM, ACF and MCF) could individually estimate the lost gas contents of all shale samples and that the proportion of free gas relative to total gas has a significant effect on the estimation accuracy of the selected method. When the ratio of free gas to total gas is lower than 45%, the USBM method is the best for estimating the lost gas content, whereas when the ratio ranges from 45% to 75% or is more than 75%, the ACF and MCF methods, are the best options respectively.  相似文献   

Multi-factor sensitivity analysis on the stability of submarine hydrate-bearing slope     

《China Geology》2018,1(3):367-373

There are many factors affecting the instability of the submarine hydrate-bearing slope (SHBS), and the interaction with hydrate is very complicated. In this paper, the mechanical mechanism of the static liquefaction and instability of submarine slope caused by the dissociation of natural gas hydrate (NGH) resulting in the rapid increase of pore pressure of gas hydrate-bearing sediments (GHBS) and the decrease of effective stress are analyzed based on the time series and type of SHBS. Then, taking the typical submarine slope in the northern South China Sea as an example, four important factors affecting the stability of SHBS are selected, such as the degree of hydrate dissociation, the depth of hydrate burial, the thickness of hydrate, and the depth of seawater. According to the principle of orthogonal method, 25 orthogonal test schemes with 4 factors and 5 levels are designed and the safety factors of submarine slope stability of each scheme are calculated by using the strength reduction finite element method. By means of the orthogonal design range analysis and the variance analysis, sensitivity of influential factors on stability of SHBS are obtained. The results show that the degree of hydrate dissociation is the most sensitive, followed by hydrate burial depth, the thickness of hydrate and the depth of seawater. Finally, the concept of gas hydrate critical burial depth is put forward according to the influence law of gas hydrate burial depth, and the numerical simulation for specific submarine slope is carried out, which indicates the existence of critical burial depth.  相似文献   

川东南丁山地区龙马溪组页岩裂缝特征及对含气性的影响   总被引：1，自引：0，他引：1       下载免费PDF全文

范存辉 钟 城秦启荣  胡东风李 虎 朱梦月 何 顺 《地质科学》2018,(2):487-509

川东南丁山地区是近年来四川盆地页岩气勘探开发的热点区域,裂缝的发育对页岩含气性及保存条件有重要的影响。综合运用野外露头、岩心、测井资料,结合岩石脆性矿物含量、岩石力学参数等数据,深入分析龙马溪组页岩裂缝发育特征和控制因素,并探讨了裂缝发育对含气性的影响。结果表明,丁山地区龙马溪组页岩裂缝主要以构造成因的剪切缝为主,裂缝优势方位共6组,主要包括4组平面剪切缝和2组剖面剪切缝,其发育主要受2个方向、3个阶段的构造应力场影响而成;裂缝延伸稳定,平均密度小,宽度小,充填程度高,主要被方解石和黄铁矿等充填。裂缝受控因素主要包括古构造应力场、构造部位、脆性矿物组分、岩石力学性质等;断层对裂缝发育具有明显的控制作用,其中断层两盘均存在裂缝发育程度急剧下降的临界范围,临界范围内裂缝发育程度高,超过此临界范围,裂缝发育程度变差且变化趋于平缓;不同期次的裂缝中,形成时间晚、规模过大、充填程度不高、与现今地应力方向一致或呈低角度相交的裂缝易造成页岩气的散失,对提高页岩含气性不利;龙马溪组岩石脆性矿物含量高,脆性指数属中等偏上程度,有利于构造缝发育且可压性较好。随着距齐岳山断裂距离的适当增加,龙马溪组页岩埋藏深度适中,地层压力增大,抗压强度增强高,脆性指数适中,构造保存条件变好,有利于不同方位的裂缝发育和页岩含气量的增加,位于该区域的DY2井与DY4井均位于该有利区域,含气性良好。研究结果对下一步深化页岩气勘探开发具有重要指导作用。  相似文献   

常见稀有气体采样容器研究进展及意义     

宋宏  李立武  汤庆艳  鲍坚  苏天宝  张家和  许仕海  郑国东  李中平 《地质科学》2022,57(1):274-293

稀有气体是地学研究的重要手段之一,在研究成矿流体来源、壳幔相互作用过程中具有重要的研究意义,其组成及同位素比值是研究天体和地质体来源、成岩机理及各种地质和物理化学过程的关键,可作为地球化学示踪剂。如何有效地在大气圈、水圈和岩石圈进行稀有气体同位素样品的提取,是气体同位素研究急需解决的基础科学问题,所以气体采样容器和取样技术显得尤为重要。本文在文献调研的基础上,对常见的采样容器的优缺点进行对比,并总结了不同采样容器对稀有气体取样的优劣性。常见的气体采集容器包括不锈钢瓶、铜管、玻璃瓶、气体采样袋、注射器等,而稀有气体的采集容器常为不锈钢瓶和铜管等;通过对比表明不锈钢瓶具有耐高温、耐高压、抗强腐蚀、不易燃、不易爆等特点和优越性,在气体样品采集和运输过程中稳定性最好,实验效果也最好;铜管采样效果和密封性好,但操作较为复杂;玻璃采样容器效果次之;石英玻璃瓶虽然操作简便,但是运输保存不便;气体采样袋和注射器的采集和运输储存效果较差。因此建议稀有气体样品采集使用不锈钢瓶和铜管以及钠钙材质的玻璃瓶,不建议将石英材质玻璃容器以及注射器和气袋作为稀有气体的采样工具。该工作可为气体地球化学的研究提供新的参考。  相似文献   

Paleo-oil reservoir pyrolysis and gas release in the Yangtze Block imply an alternative mechanism for the Late Permian Crisis     

《地学前缘(英文版)》2022,13(2):101324

The causes of the global mass extinction that occurred around the Permian–Triassic boundary have been widely studied through the geological record and in various locations. The results show that volcanic activity was a key factor in initiating the crisis during the Late Permian. Compared to other thermal events triggered by volcanic activity, pyrolysis of petroleum in Pre-Permian reservoirs has rarely been suggested as a significant source of the greenhouse gases that caused the mass extinction. In this study, geochemical analysis is carried out of a huge paleo-oil reservoir in the Yangtze Block (YB), South China. The detection of mineral inclusions and pyrobitumens is evidence of rapid pyrolysis of accumulated oil in the Ediacaran reservoir. New evidence from hydrothermal minerals and the presence of domain mesophase in the pyrobitumen suggest that the pyrolysis process occurred abruptly and that greenhouse gases were rapidly released through venting pipes. The dating of such a complex geological event in this old and deeply buried reservoir is inevitably difficult and potentially unreliable. However, cross-validation of the multiple evidence sources, including hydrothermal minerals and domain mesophase, indicates that the rapid oil pyrolysis must have been driven by a major thermal event. Reconstruction of burial and thermal histories suggests that the thermal event was most likely to have been triggered by the Emeishan Large Igneous Province (ELIP), which was in a period of significant volcanic activity during the Late Permian. Massive volumes of gases, including methane, carbon dioxide, and possibly hydrogen sulfide, were released, causing a significant increase in greenhouse gases that may have contributed to global warming and the resulting mass extinction during the Late Permian Crisis (LPC).  相似文献   

Experimental investigation of hydrate formation in water-dominated pipeline and its influential factors     

Li Huang  Jia-le Kang  Xiao-dong Shen  Jian-ye Sun  Qing-guo Meng  Qiang Chen  Gao-wei Hu  Chang-ling Liu  Neng-you Wu 《China Geology》2022,5(2):310-321

Blockage in water-dominated flow pipelines due to hydrate reformation has been suggested as a potential safety issue during the hydrate production. In this work, flow velocity-dependent hydrate formation features are investigated in a fluid circulation system with a total length of 39 m. A 9-m section pipe is transparent consisted of two complete rectangular loops. By means of pressurization with gas-saturated water, the system can gradually reach the equilibrium conditions. The result shows that the hydrates are delayed to appear as floccules or thin films covering the methane bubbles. When the circulation velocity is below 750 rpm, hydrate is finally deposited as a “hydrate bed” at upmost of inner wall, narrowing the flow channel of the pipeline. Nevertheless, no plugging is observed during all the experimental runs. The five stages of hydrate deposition are proposed based on the experimental results. It is also revealed that a higher driving pressure is needed at a lower flow rate. The driving force of hydrate formation from gas and water obtained by melting hydrate is higher than that from fresh water with no previous hydrate history. The authors hope that this work will be beneficial for the flow assurance of the following oceanic field hydrate recovery trials.©2022 China Geology Editorial Office.  相似文献   

若尔盖铀矿田方解石稀土元素与碳氧同位素地球化学特征及其意义   总被引：1，自引：0，他引：1  

陈友良  魏佳  叶永钦  宋昊  孙泽轩 《地球科学进展》2012,27(10):1061-1067

方解石是若尔盖铀矿田与成矿最为密切的脉石矿物之一。方解石的REE地球化学特征研究表明,产于地层中的方解石、矿区中的方解石和含矿方解石具有明显不同的稀土元素组成特征,分别具有轻稀土富集右倾型、重稀土富集左倾型和相对平坦型的3种稀土配分模式。其中产于地层中的方解石明显继承了地层中岩石的稀土元素特征,而含矿方解石表现出与矿石稀土元素相似的特征。碳氧同位素显示地层中的方解石为海洋沉积碳酸盐岩的碳氧同位素组成特征;矿区方解石脉、含矿方解石脉的碳同位素组成明显表现为地幔来源的特点;而矿区方解石脉的氧同位素组成具明显的深部来源特征,含矿方解石脉的氧同位素组成表明在成矿过程中有大气降水的混入。若尔盖铀矿田的方解石主要为热液成因,其矿床成因类型属于典型的热液矿床,成矿流体主要来源于地幔。  相似文献   

河南濮城油田沙二上2+3砂层组末端扇沉积特征及剩余油分布          下载免费PDF全文

李红南  于文文  刘伟 《沉积与特提斯地质》2012,32(4):29-33

本文以濮城油田沙二上2+3砂层组为例,分析了末端扇储层的沉积特征,建立了末端扇沉积模式,确定了剩余油分布.末端扇储层分为近端亚相、中部亚相和远端亚相,中部亚相的分流河道微相是主要储集砂体.剩余油平面上主要集中在分流河道侧翼过渡区及近水道漫溢、远水道漫溢和分散的井网难控制的小透境体中,垂向上集中在正韵律顶部和反韵律底部等物性差的地方.二砂组主要富集在S23、S24小层的近气顶区,三砂组主要富集在S34、S35小层的濮53、文17断块构造高部位及注采不完善的地区.  相似文献   

Estimation of viscoelastic attenuation of real seismic data by use of ray tracing software: Application to the detection of gas hydrates and free gas     

Fateh Bouchaala  Claude Guennou 《Comptes Rendus Geoscience》2012,344(2):57-66

Analysis of P wave velocity profiles and seismic data recorded over the 2002 Hydratech cruise conducted in the Storegga region, North of Norway, has shown the existence of anomalies (a velocity decrease) in some layers of the medium. An elastic propagation model is not sufficient to explain clearly these anomalies, since the viscoelastic attenuation, represented by the quality factor Q_P, is sensitive to physical phenomena of geological media. The combination of the quality factor profile with the velocity profile leads to realistic explanations of these anomalies. In this article, we explain the procedure which we developed for determining the Q_P profile from the P wave velocity profile and the seismic data recorded during Hydratech cruise. Both the Q_P and velocity profiles indicate anomalies in the same layers. Based on previous studies, we interpret that these anomalies are being due to existence of gas hydrates and free gas within these layers.  相似文献