滑模施工中滑升偏差的防治及纠正   总被引：1，自引：0，他引：1  

金仁和  李明瑛  梁锐 《测绘科学》2005,30(5):77-78

本文以采用无井架液压滑升模板工艺的某沿海石化公司(原油车间三、四部炉)120m高的钢筋混凝土烟囱施工为例,分析了滑模施工中出现偏差的原因,并针对不同现象的偏差介绍了不同的纠偏的方法,提出了有效的内外相结合的控制方法和预防措施。通过频繁而定时的测量检查,及时发现不同程度偏差,并进行纠偏,可以确保高耸结构滑模施工的按质按时进行。  相似文献   

塔北雅克拉地区油气藏上方"烟筒效应”的磁学与矿物学证据   总被引：4，自引：0，他引：4       下载免费PDF全文

刘庆生  徐忠祥  侯卫国 《地球科学》1996,5(1)

依据位于塔北雅克拉油气田内的沙田井、沙七井、沙十五井及位于油水边界的沙六井岩屑与岩心的磁学（包括磁化率、磁滞回线及热磁分析）与矿物学（包括重矿物、电子探针及扫描电子显微镜）的综合分析测试结果，获得了已知油气井内生、储、盖层与地表第四纪土壤中与烃运移相关的蚀变矿化作用（即烟筒效应）的物质证据．本区位于油气藏上方的蚀变矿化作用以磁铁矿化与菱铁矿化作用为主；而位于油水边界处的沙六井则以磁铁矿化与黄铁矿化为主．随着地层深度的减小，虽然“烟筒效应”的强度明显减北，但在地表仍可检测到明显的磁学与矿物学异常．综合磁学与矿物学研究结果表明，本区岩屑中发现的球粒状磁铁矿是“烟筒效应”的产物，它是与烃运移相关的次生低温磁性矿物重要的形貌特征  相似文献   

华北中元古代硫化物黑烟囟发现的初步报道   总被引：19，自引：1，他引：19  

李江海  冯军等 《岩石学报》2003,19(1):167-168

海底黑烟囟为当代海洋地质调查的重要发现，对于揭示地史时期块状硫化物的成矿过程中以及生命起源具有重要意义。本文初步报道在冀东中元古代块状硫化物矿床中首次发现保存完好的黑烟囟构造，它们保留了成矿流体运移的通道构造，围绕通道构造还显示良好的矿物分带现象。完全可以与现代海底黑烟囟对比，黑烟囟的发现证明了该区硫化物矿床的形成与海底喷流过程密切相关。  相似文献   

Growth history of hydrothermal chimneys at EPR 9―10°N: A structural and mineralogical study     

PENG Xiaotong  ZHOU Huaiyang 《中国科学D辑(英文版)》2005,48(11)

Based on structural and mineralogical characteristics of four hydrothermal chimney samples collected by submersible Alvin, growth history and formation environment of hydrothermal chimney at EPR 9―10°N are established. It is shown that there occur two types of hydrothermal chimney with different deposition environments at EPR 9―10°N according to differences in their shape, structure and mineral assemblage: type I chimney forms in an environment with high temperature, low pH and strong reducing hydrothermal focus flow and type II chimney forms in a relatively low temperature, high pH and rich Zn hydrothermal environment. Growth of type I chimney begins with the formation of anhydrite. Subsequently deposition of Cu-Fe-Zn sulphide in various directions of chimneys decides the final structure of this type of chimney. According to observation and analysis of mineral assemblages, the formation process of type I chimney could be divided into three stages from early, middle to late. Changes of temperature and major chemical reaction type in the process of hydrothermal chimney formation are also deduced. Different from type I chimney, quenching crystalline of pyrite and/or crystalline of sphalerite provide the growth foundation of type II chimney in the early stage of chimney formation.  相似文献   

防止烟囱、水塔爆破倾倒时后座现象的技术   总被引：1，自引：0，他引：1       下载免费PDF全文

陈连成 《探矿工程》1995,(6):42-43

引起烟囱水塔等细高型建筑物爆破损倒时的后座现象的两大因素，即爆破切口长度和切口形状。并在控爆实践中提出有效防止后座现象的确定方法和计算公式。  相似文献   

Natural gas sources, migration and accumulation in the shallow water area of the Panyu lower uplift: An insight into the deep water prospects of the Pearl River Mouth Basin, South China Sea   总被引：2，自引：0，他引：2  

Honghan Chen  Changmin Chen  Xiong Pang  Jiahao Wang  Wanzhong Shi 《Journal of Geochemical Exploration》2006,89(1-3):47

Although no drilling has been carried out in the deep water area of the Baiyun sag in the Pearl River Mouth Basin, South China Sea, the successful exploration for natural gas in the shallow water area of the Panyu lower uplift allows an insight into the prospectivity of the adjacent deep water fan system of the Baiyun sag. The Paleogene gas kitchen in the Baiyun sag provided both oil-derived gas and coal-derived gas. Fluid inclusion measurements and 2D numeric modelling of formation pressure indicate four episodes of hydrocarbon charge since the third release of the overpressure system. Seismic wipeout zones manifest several types of gas chimney which could play a role in vertical migration conduits to feed the natural gases into the deep water fan system. There would be, therefore, a low risk for hydrocarbon exploration in the deep water fan system.  相似文献   

深穿透地球化学迁移机理与方法技术研究新进展   总被引：2，自引：0，他引：2  

唐金荣  吴传璧  施俊法 《地质通报》2007,26(12):1579-1590

系统地论述了近年来国际勘查界在深穿透地球化学迁移机理与方法技术方面的新进展。重点介绍了元素垂向迁移的新模型和新理论,包括"还原囱"模型、"雷暴电池"模型、泵压效应机制等。叙述了国内外深穿透地球化学的研究成果,主要包括加拿大矿业研究组织(CAMIRO)资助的国际合作项目、澳大利亚景观环境与矿产勘查联合研究中心(CRC LEME)的试点研究及其他国家的研究工作。在此基础上,对影响选择性提取技术的关键因素进行了探讨,认为选择性提取技术的战略选择和对单一"目标矿物"的选择性提取比较复杂,在一定程度上受土壤形成过程及其理化性质如pH、Eh等因素的影响,此外还与提取液的浓度、采样深度和提取条件与过程的控制等有关。  相似文献   

The seismic property of reef flat in the Changxing-Feixianguan Formation, Northwest Sichuan Province, China     

Liu Shu  Tang Jianming  Guo Xusheng  Zhao Shuang 《Frontiers of Earth Science》2007,1(3):358-365

The development of a carbonate reservoir is dominated by its primary sedimentary environment. Generally, a good reservoir must be the oolite of a bank or bioclastics of an organic reef in a marginal mesa, which must deposit on the slope of the mesa. Therefore, the analyses of sequence stratigraphy are the key for predicting the presence of carbonate reservoirs. A typical sequence pattern can be seen in the Puguang gas field. As an independent lithological body, the mechanical property of a reef flat is very different from the surrounding rock, causing stress to concentrate. Stress centralization will, in turn, cause a lot of fractures and faults to develop, and ultimately, result in a gas chimney, which is a seismic smear zone beneath or above the reef flat. Known gas fields, such as the puguang gas field, also possess gas chimneys. Sequence stratigraphy patterns in the marginal mesa and gas chimney near the reservoir are very obvious in all known fields in southeast and east Sichuan Province. By analyzing the seismic features of all known gas fields, a model to predict carbonate reservoirs has been set up. Using this prediction model, we have found that there is a typical reef flat of the marginal mesa in the Malubei structure of Tongnanba structural belts whose sequence stratigraphy pattern is very much like that of the Puguang gas field; and in the Cangxi-Jiulongshan structure, there is another reef flat which is symmetrical to the Malubei reef. The Cangxi reef flat possesses the largest platform edge shallow facies domestically found, and has a typical prograding sequence. Its gas chimney is very obvious too. Because the Cangxi reef flat is in the very vicinity of the hydrocarbon kitchen and the depression is much bigger than that of the Puguang gas fields, we predict that there may be a gigascopic gas field in Cangxi County. There may also be a large gas field in the Malubei structure. Translated from Oil & Gas Geology, 2006, 27(3): 332–339 [译自: 石油与天然气地质]  相似文献   

World's largest known Precambrian fossil black smoker chimneys and associated microbial vent communities, North China: Implications for early life     

Jianghai Li  Timothy M. Kusky   《Gondwana Research》2007,12(1-2):84

Black smoker chimneys and biological vent communities have been identified at many sites on the deep seafloor, particularly along oceanic spreading centers. We report the largest and oldest known, microbe-rich sub-meter-sized black smoker chimneys and mounds from a 1.43 billion-year old sulfide deposit in a continental graben in northern China. These chimneys are especially well preserved, with characteristic morphology, internal textures and internal cylindrical mineralogical zonation. Four main types of chimneys are distinguished on textural and mineralogical criteria, exhibiting either Zn–Fe-sulfide or Pb–Zn–Fe-sulfide internal cylindrical mineralogical zones. The chimneys mark vent sites in submarine grabens indicating focused flow-venting processes. The fossil chimneys have mineralogical and geological evolutionary features similar to their counterparts on the modern seafloor and other submarine hydrothermal vents. Black smoker vent fluids and seafloor tectonism played important roles for formation of the massive sulfide deposits in the Mesoproterozoic.We also report the first known, remarkably diverse assemblage of fossil microbialites from around and inside Precambrian vent chimneys, demonstrating that Proterozoic life flourished around submarine hot vents and deep within the chimney vent passages. Filamentous, spherical, rod, and coccus-shaped fossil microbes are preserved preferentially on sulfide precipitates. Based on the depth and setting of the fossil biota, the organisms that produced the microbialites were likely sulfate-reducing chemosynthetic and thermophyllic microbes. Textural and mineralogical evidence shows that biomineralization processes enhanced chimney growth and sulfide precipitation.Close association of microorganisms with sulfide chimneys in modern deep-sea hydrothermal vents and younger ophiolites has sparked speculation about whether life may have originated at similar vents. However, little is known about fossil equivalents of vent microfossils and black smoker chimneys from Earth's early evolution. The fossilized microorganisms from the Gaobanhe black smoker chimney sulfide deposits include thread-like filaments with branching and twisted forms and preserved organic carbon, representing fossilized remnants of microbial mats metabolized at high temperatures characteristic of venting fluids. The preservation of fossil microorganisms provides evidence that microbial populations were closely associated with black smoker chimneys in Earth's early history. The microbial population clearly constitutes the site for mediating mineral formation. These ancient microbial fossils lead to a much better understanding of early life on the deep seafloor. The discovery of the Mesoproterozoic microfossils within black-smoker hydrothermal chimneys indicates that hydrothermal activity around sea-floor vents supported dense microbial communities, and supports speculation that vent sites may have hosted the origin of life.  相似文献   

Dissociation of gas hydrates by hydrocarbon migration and accumulation-derived slope failures: An example from the South China Sea     

《地学前缘(英文版)》2022,13(2):101345

The mechanism of slope failure associated with overpressure that is caused by hydrocarbon migration and accumulation remains unclear. High-resolution seismic data and gas hydrate drilling data collected from the Shenhu gas hydrate field (site SH5) offer a valuable opportunity to study the relations between submarine slope failure and hydrocarbon accumulation and flow that is associated with a ～2 km-diameter gas chimney developed beneath site SH5 where none gas hydrates had been recovered by drilling and sampling despite the presence of distinct bottom simulating reflectors (BSRs) and favorable gas hydrate indication. The mechanism of submarine slope failure resulted from buoyancy extrusion and seepage-derived deformation which were caused by overpressure from a ～1100 m-high gas column in a gas chimney was studied via numerical simulation. The ～9.55 MPa overpressure caused by hydrocarbons that migrated through the gas chimney and then accumulated beneath subsurface gas hydrate-bearing impermeable sediments. This may have resulted in a submarine slope failure, which disequilibrated the gas hydrate-bearing zone and completely decomposed the gas hydrate once precipitated at site SH5. Before the gas hydrate decomposition, the largely impermeable sediments overlying the gas chimney may have undergone a major upward deformation due to the buoyancy extrusion of the overpressure in the gas chimney, and slope failure was initiated from plastic strain of the sediments and reduced internal strength. Slope failure subsequently resulted in partial gas hydrate decomposition and sediment permeability increase. The pressurized gas in the gas chimney may have diffused into the overlying sediments controlled by seepage-derived deformation, causing an effective stress reduction at the base of the sediments and significant plastic deformation. This may have formed a new cycle of submarine slope failure and finally the total gas hydrate dissociation. The modeling results of buoyancy extrusion and seepage-derived deformation of the overpressure in the gas chimney would provide new understanding in the development of submarine slope failure and the link between slope failure and gas hydrate accumulation and dissociation.  相似文献