Theoretical study on adsorption of Na+ and Na+(H2O)(n) (n=1-6) on a clean Si(111) surface

To model the adsorption of Na+ in aqueous solution on the semiconductor surface, the interactions of Na+ and Na+(H2O)(n) (n = 1-6) with a clean Si(111) surface were investigated by using hybrid density functional theory (B3LYP) and Moller-Plesset second-order perturbation (MP2) methods. The Si(111) surface was described with Si8H12, Si16H20, and Si22H21 Cluster models. The effect of the basis set superposition error (BSSE) was taken into account by applying the counterpoise (CP) correction. The calculated results indicated that the interactions between the Na+ cation and the dangling bonds of the Si(111) surface are primarily electrostatic with partial orbital interactions. The magnitude of the binding energies depends weakly on the adsorption sites and the size of the clusters. When water molecules are present, the interaction between the Nal and Si(I 11) surfaces weakens and the binding energy has the tendency to saturate. On a Si22H21 cluster described surface, the optimized Na+-surface distance for Na+(H2O)(5) adsorbed at on-top site is 4.16 angstrom and the CP-corrected binding energy (MP2) is -35.4 kJ/mol, implying a weakly adsorption of hydrated Na+ cation on clean Si(111) surface.

黄土-红粘土化学风化与晚新生代气候变化——甘肃平凉白水剖面为例

Late Cenozoic has witnessed a series of climate-environmental change which ends with a transitional shift from greenhouse to icehouse conditions. In last two decades, scientists began to employ the tectonic uplift and its weathering effect to interpret the climatic changes during the late Cenozoic. However, this endeavor has partly been restricted by the lacking of regional and global chemical weathering data. The loess-red clay deposit in the Loess Plateau may record the weathering features of the detritus material from the wide range upwind of the Loess Plateau. Therefore geochemistry of the loess-plaeosol and red clay sequences may provide insights into the regional chemical weathering regime and the connection between the chemical weathering and the late Cenozoic climate-environmental change Here we selected 319 samples from the Baishui section near the Pingliang City, Gansu Province, and analyzed them with X-ray fluorescence. Based on the result, we reconstruct the chemical weathering history of the Baishui section since 6Ma. We chose CIA as the proxy for chemical weathering intensity. The CIA ratio in soil units is higher than in adjacent loess horizons, but lower than in the red clay, in good agreement with the field observation. The CIA ratios of the Baishui section correlates well with the global ice volume fluctuations, indicating that the global cooling may contribute a lot to the chemical weathering variations in Chinese Loess Plateau. There are at least 3 million-year time scale variations that can be identified in the chemical weathering intensity curve, i.e., between 3.3 to 2.1 Ma, 1.7 to 0.9 Ma and from 0.9Ma. We think these may reflect the combined effect of the tectonic uplift and ice sheets on monsoon intensity. Other time scale variations can be also observed. In the period between 2.4 and 0.8 Ma, the CIA record display the 400,000 years cycle, which may be resulted from the Tibetan uplift during the Pliocene-early Pleistocene which have significantly amplified the monsoon response sensitivity to the orbital-scale variations in insolation. From 1.2 Ma, the 100,000 years period became intensifying, and particularly after 0.8 Ma, the earlier monsoon response at 400,000 year periodicity was overwhelmed by the ice sheet forcing at 100,000 year periodicity. These may indicate that the expansions of the Northern Hemisphere ice sheets may have crossed a threshold, which enforce the monsoon responding at the 100,000 year periodicity.

MB倒转在中国黄土中的记录及海陆对比

Chinese loess preserved in northwest and north China are famous for its fine grain size, high accumulate rate and high community and can be good archives for paleoclimate and paleomagnetic variation over the later Cenozoic, with which can be correlated well between marine sediments. Major geomagnetic chrons and long term paleoclimate changes in Quaternary are successfully extracted from Chinese loess-paleosols, as well as short-term geomagnetic excursions and climate instability of high resolution. Magneticstratigraphy based on paleogeomagnetic polarity reversal recorded in Chinese loess is a basic project in loess research since decades ago. True geomagnetic records and exact location of geomagnetic reversal boundary in section is the foundation of magneticstratigraphy. Matuyama-Brunhes (MB) reversal as the youngest one still remains divarication about exact location of its boundary (MBB). L8 and S8 of Luochuan and Xifeng located in the interior of Chinese Loess Plateau(CLP) and Mangshan in southeast part of CLP are chosen to make clear some problems which include magnetic mineral, process of MB reversal, location of MBB, downward displacement scale of magnetic reversal boundary, time lag of paleoclimate record by marine and loess, new correlation between Chinese loess and marine sediments. Rock-magnetic investigations carried on L8 and S8 show that the main mineral are ferrimagnetic assemblage consists of magnetite and maghemite in Luochuan and Xifeng, and magnetite in Mangshan, which all contains little hematite belongs to antiferromagnetic phases. The main carrier of nature remanet magnetism (NRM) is detrital magnetite with pseudo-single domain. Detailed paleomagnetic investigations display that there are several rapid reversals in direction during the process of MB reversal which started at the upper part of S8 and finished at the lower part of L8, and lasted about decades of centimeters to more than 100cm correspond to about 104 years. On the assumption that MBB is located in the middle part of the layer which recorded the very reversal, 11cm is considered as the scale of downward displacement for the MBB in Chinese loess after estimation through correlation between Luochuan and Mangshan records. So this study denies the theory of large scale displacement of MBB and large scale Lock-in depth of NRM acquired from Chinese loess. Time lag of paleoclimate records in terrestrial sediments and marine sediments is considered after reassessment of correlation between low field susceptibility of Chinese loess with marine oxygen isotope in benthic foraminifera. On the basis of traditional correlation between Chinese loess and marine oxygen isotope, this study document a new scheme which correlates L8 and S8 to MIS18 and MIS19, respectively.

黄铁矿热转变过程的岩石磁学研究

Pyrite is the most stable iron-sulfide in reduced environment, and plays an important role in geochemical iron-sulfur cycling of sediments. Thus, the presence of pyrite in sediments and rocks is an important indicator of sedimentary environments. Previous studies on the thermal products of pyrite showed that all of the products (e.g., pyrrhotite, magnetite, hematite) have strong capability of carrying remanence. To deepen our understanding of the environmental and paleomagnetic significances of pyrite, the mineral transformation processes of pyrite upon heating were systematically investigated in this study using intergrated rock magnetic experiments (in both argon and air atmospheres) and X-ray diffraction analysis. The room temperature susceptibility of the paramagnetic pyrite is about 2.68×10-5 SI. In argon atmosphere (reducing environment), pyrite was transformed into monoclinic stable single domain (SD) pyrrhotite above 440 C. The corresponding coercive force and remanence coercivity are about 20 mT and 30 mT, respectively. In contrast, in air atmosphere (oxidation environment), the intermediate thermal products of pyrite are magnetite and pyrrhotite, which were quickly further oxidated to SD hematite, which has coercivity of about 1400 mT. In addition, the hematite particles gradually grow from SD to PSD grain size region by multiple heating runs. The transformation processes of pyrite in oxidation atomosphere can be interpreted by three possible pathways: (1) pyrite→magnetite→hematite; (2) pyrite→pyrrhotite→magnetite→hematite; and (3) pyrite→pyrrhotite→hematite. Low-temperature magnetic experiments show no transitions for pyrite. Despite that low-temperature magnetic method is not suitable for identification of pyrite, it is clear in this study that the high-temperature thermomagnetic measurements (e.g.,  -T and J-T curves) are very sensitive to the presence of pyrite in sediments and rocks. Nevertheless, for the thermal treatment products, low-temperature magnetic measurements showed the 34 K transition of pyrrhotite and the 250 K Morine transition of hematite. Iron-sulfide has also been found on Martian meteorolites by other workers. Therefore, systematic study of rock magnetism of pyrite (and other iron-sulfides) and their products will have great significances for both paleomagnetism and planetary magnetism.

塔里木地块奥陶纪古地磁新结果及其构造意义

The Tarim Block is located between the Tianshan Mountains in the north and the Qinghai-Tibet Plateau in the south and is one of three major Precambrian cratonic blocks of China. Obviously, the Paleozoic paleogeographic position and tectonic evolution for the Tarim Block are very important not only for the study of the formation and evolution of the Altaids, but also for the investigation of the distributions of Paleozoic marine oil and gas in the Tarim Basin. According to the distributions of Paleozoic strata and suface outcrops in the Tarim Block, the Aksu-Keping-Bachu area in the northwestern part of the Tarim Block were selected for Ordovician paleomagnetic studies. A total of 432 drill-core samples form 44 sampling sites were collected and the samples comprise mainly limestones, argillaceous limestones and argillaceous sandstones Based on systematic study of rock magnetism and paleomagnetism, all the samples could be divided into two types: the predominant magnetic minerals of the first type are hematite and subordinate magnetite. For the specimens from this type, characteristic remanent magnetization (ChRM) could generally be isolated by demagnetization temperatures larger than 600℃; we assigned this ChRM as component A; whilst magnetite is the predominant magnetic mineral of the second type; progressive demagnetization yielded another ChRM (component B) with unblocking temperatures of 550-570℃. The component A obtained from the majority of Ordovician specimens has dual polarity and a negative fold test result; we interpreted it as a remagnetization component acquired during the Cenozoic period. The component B can only be isolated from some Middle-Late Ordovician specimens with unique normal polarity, and has a positive fold test result at 95% confidence. The corresponding paleomagnetic pole of this characteristic component is at 40.7°S, 183.3°E with dp/dm = 4.8°/6.9° and is in great difference with the available post-Late Paleozoic paleopoles for the Tarim Block, indicating that the characteristic component B could be primary magnetization acquired in the formation of the rocks. The new Ordovician paleomagnetic result shows that the Tarim Block was located in the low- to intermediate- latitude regions of the Southern Hemisphere during the Middle-Late Ordovician period, and is very likely to situate, together with the South China Block, in the western margin of the Australian-Antarctic continents of East Gondwana. However, it may have experienced a large northward drift and clockwise rotation after the Middle-Late Ordovician period, which resulted in the separation of the Tarim Block from the East Gondwanaland and subsequent crossing of the paleo-equator; by the Late Carboniferous period the Tarim Block may have accreted to the southern margin of the Altaids.

活动构造区区域地壳稳定性研究——以金沙江水电梯级工程规划区为例

The study of regional crustal stability of active tectonic region basically includes analysis of recent activity of Earth's crust, single factor assessment, study of complexity, and comprehensive assessment of crust stability. In this thesis, some work are made as follows: · Based on abundant data from gravity field, aeromagnetic survey, magnetism, magnetotelluric deep sounding, remote sensing and geotectonic as well as earthquakes observed in recent years around this region and adjacent zones, we can get a through understanding about the structural features and activity of the earth's crust in Chuan-Dian region. The results from explosion earthquake and telluric electromagnetic sounding are consistent with the structural features of the crust manifested by the geophysical field. The data of deep geologic structures are important for us to work out a vivid three-dimensional model of the earth's crustal structure of the Jinsha River region. According to a synthesis, the author of this thesis proposes some indicators for dividing the faulted blocks. It can also be inferred that the movement of the Chuan-Dian faulted block, which is the relatively active part of southwestern China, is controlled by the boundary faults, and the intensive activity and deformation are concentrated along the boundaries of the block. · Mainly discussing respectively the mechanism and laws of active faults, earthquakes, and geological hazards activity, and their influences on the stability and security of engineering, also trying to probe into the way to assess the risk of single factor in this section. Especially with the method of fractal geometry, the thesis has discussed how to study the complexity of each factor. These geologic hazards which are distributed at the uppermost part of the crust in this region form a typical mountainous set of the active tectonic areas. The results of survey show that some slopes are liable- to -sliding with a weak layer of low shear strength. Occurrences of landslides are to a great extent related to local geological structures, in particular active faults. This is why numerous landslides have occurred simultaneously around the epicenter of a strong earthquake or the center of a strong rainfall, which are related to active faults. · The analysis of the crustal stability is based on a regional grid division, and a fuzzy comprehensive analysis method is used to determine the grade of the quality in each grid. The evaluation factors and their weights are taken from the results of the hierarchical analysis. The evaluation indexes consist of qualitative and quantitative ones. The qualitative ones can be quantified through the experts weighing system, while the quantitative ones can be obtained from statistical analysis. For quality grades, four levels are used: stable, essentially stable, sub-stable, and unstable. The results of the evaluation on Jinshajiang region demonstrate that the crustal stability become distinctly worse in the areas controlled by active deep faults. Therefore, detailed investigations on the active faulting and geologic hazards, include earthquake activity are especially necessary for those areas adjacent to the deep fault belts. On the bases of the data available and the survey results, we have made a preliminary assessment for the construction conditions and adaptability of every planned site in the middle or lower reaches of Jinsha River. Finally, the thesis prospected the vista of the study of crustal stability.

陇西盆地晚第三纪风尘沉积的地层学研究

In Asia, the significant environment changes in Cenozoic include: uplift of Himalayas and Tibetan Plateau, formation Asian monsoon system, Aridification in Central Asia. One of major advances in recent studies of eolian deposit on the Loess Plateau is the verification of the eolian origin for the Late Tertiary Hipparion Red-Earth (also called red-Clay) underlying the Quaternary loess. Thus, the Late Tertiary eolian deposit, which has been proven a nearly continuous terrestrial record and sensitive to climate change, provides us an important archive to understand these above Cenozoic environment events. The deposit in eastern Loess Plateau has been extensively studied, while the property and age of deposit underlying the Quaternary loess in western plateau remains unclear. In this paper, detail investigations were made on the Sedimentology, geochemistry of Longxi section, a typical section in western Loess Plateau, to address its origin, and on micromammalian fossils and magnetostratigraphy to address its age. The main conclusions are presented as following: 1. The sedimentological and geochemical properties in Longxi section are highly similar to typical Quaternary eolian deposit in Loess Plateau. Nearly 100 paleosols are recognized in the field, and the grain size are very fine with the median grain size centered at 4～7μm. There is a good agreement of both major and trace element compositions between Longxi deposit and the Quaternary Loess. The REE distribution patterns of Longxi deposit and the Quaternary loess are remarkably similar in shape, with enrichment LREE and fairly flat HREE profiles and clear negative Eu anomaly. The mangnetic minerals in Longxi deposit are mainly magnetite, hematite and maghematite, which are similar to those of the Hipparion Red-Earth and Quaternary Loess. The major difference among them is that the samples from Longxi section contain more hematite. The characteristics of anisotropy of magnetic susceptibility (AMS) in Longxi deposit is highly consistent with that of Quaternary loess, while values of the major AMS parameters, e.g. anisotropy degree, magnetic foliation and lineation, are significantly lower than those of fluvial and lake deposits. These evidences indicate an eolian origin for the sediment. 2. An investigation of micromammalian fossils was firstly carried out for determining the approximate age of the sequence because of lack of materials for accurate isotope dating. Three fossil assemblages were obtained which indicate a chronological range from the Middle Miocene to Late Miocene. The magnetostratigraphical study suggests that it is a near continuous terrestrial record for the period from 13.23 to 6.23 MaB.P. The obtained chronology is highly consistent with fossils assemblages. This section is the oldest eolian deposit presently known in Loess Plateau. 3. The magnetic susceptibly value is high in paleosols than in surrounded weak-weathered layers, which suggests that it may be a climate index on orbital time scale. While it cannot be used as a proxy to address the long-term, change of climate on tectonic time scale, as content of the magnetic minerals is highly variable in different parts of the section. 4. The appearance of Middle Miocene eolian deposit in the Loess Plateau marks the strengthening of aridification of Central Asia. The high degree of similarity between the geochemical properties of Longxi eolian deposit, Hipparion Red-Earth and Quaternary loess a suggests that a rather similar source provenance. The dust accumulation rate (DAR) of Longxi section, which is widely used as a proxy to document the aridity in source areas in marine and terrestrial record studies, recorded the aridity condition in northwestern China over a period from Middle Miocene to Late Miocene. The DAR of the section shows that the continent aridity remains moderate and relative stable over that period.

13万年以来黄土高原东缘与捷克的风成沉积序列

The loess-paleosols in the Chinese loess plateau and Europe are the main eolian sediment sequences in mid-latitude area of north hemisphere. They record not only the paleoclimatic and paleoenvironmental processes since the last interglacial, but also the configuration of magnetic field during polarity transition. Comparisons of environmental magnetism, paleomagnetism and climate proxy analysis has been made for the loess/paleosol sequences in Datong and Czech Republic. The Datong loess/paleosol sequence is composed of the Holocene soil SO, the last glacial loess LI, the last interglacial soil SI and the upper penultimate loess L2. A basalt layer occurs in L2. The main magnetic minerals in LI and SI are magnetite, maghemite and ilmenite. The presence of local volcanic elastics in the loess and the characteristics of the magnetic minerals indicate that there are local materials in Datong loess, which differentiate the Datong loess from the central and eastern loess of the Chinese Loess Plateau. In addition, there are four polarity events in Datong loess, which are generally consistent with Gothenburg> Mono Lake, Laschamp and Blake events. Some signals of the East Asia monsoon were recorded in the Datong loess/paleosol sequences. Magnetic susceptibility, the content of >63um grains and the organic matter are used as climate proxies, which are similar to those of the typical eolian sediments in the loess plateau. In addition, it is possible that the Datong loess also recorded the Younger Dryas and the climatic fluctuations during the Holocene. The main magnetic minerals in the loess/paleosol at Znojmo section are magnetite, maghemite, hematite, pyrite, pyrrhotite and goethite. The morphology of these grains reveals that the iron sulfides originated from the eluvium loam above hypothetical ore deposits in the vicinity of the section or glaciofluvial sediments from nearby glacial margins. The pattern of the susceptibility variation at Dolni Vestonice section is coincident with that of the organic matter content. The grain size variation along the section recorded the climate instability since the last interglacial. The climate events in the Dolni Vestonice section may be correlated with the Heinrich events recorded in North Atlantic sediments, suggesting they controlled by the same marine-continent climate system.

砂砾岩储层流动单元四维模型研究

This article is an important part of "95" technological subject of SINOPEC. It has a large number of difficulties and workloads, and has significant theoretical meanings and practical value. The study area is composed of sandstone & conglomerate reservoir of alluvial fan & fan delta, which belong to Sha3 lower member and Sha4 upper member of lower tertiary of Yong'an Town Oilfield in Dongying Depression. The target stataum develops in the hanging wall of the synsedimentary fault in the scarp zone of Dongying Depression. The frequently intense movements result in the variation of sandstone and conglomerate reservoir and the evolution of the time and space of Sha3 lower member and Sha4 upper member in Yong'an Town Oilfield. As a result, it is difficult for the individual reservoir correlation at the root of fan, which bring about a tackle problem for the exploitation of oilfield. In this background, the research of fluid units will be more difficult. In this article, the new concepts, the new methods, and the new techniques of sedimentology, petroleum geology, reservoir geology, physics of crystal surface, dynamic & static state reservoir description and well logging geology are synthetically applied, and the computer technology are made full uses of, and the identifying, dividing and appraising of the two-formation-type sandstone & conglomerate reservoir fluid units of Sha3 lower member and Sha4 upper member systemically analyzed in Yong'an Town Oilfield, Dongying Depression. For the first time, the single-well model, the section model, the plane model, the nuclear magnetism log model, the microcosmic network model, the 4-D geology model and the simulation model of the two-formation-type reservoir fluid units of the of sandstone & conglomerate reservoir of Sha3 lower member and Sha4 upper member are established, and the formative mechanism and distributing & enrichment laws of oil-gas of the two type of sandstone and conglomerate reservoir fluid units are revealed. This article established the optimizing, identifying, classifying and appraising standard of the two-formation-type reservoir fluid units of the of sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member, which settles the substantial foundations for static state model of the fluid units, reveals the macroscopic & microcosmic various laws of geometrical static state of the fluid units, and instructs the oil exploitation. This article established static state model of the two-formation-type sandstone and conglomerate reservoir fluid units by using the multi-subject theories, information and techniques, and reveals the geometrical configuration, special distribution and the oil-gas enrichment laws of the sandstone and conglomerate reservoir fluid units. For the first time, we established the nuclear magnetism log model of the two-formation-type sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member, which reveals not only the character and distributing laws of the porosity and permeability, bat also the formation and distribution of the movable fluid. It established six type of microcosmic net model of the two-formation-type sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member in the working area by using the advanced theories, such as rock thin section, SEM, image analysis, intrusive mercury, mold, rock C.T. measure & test image etc., which reveals the microcosmic characteristic of porosity & throat, filterate mode and microcosmic oil-gas enrichment laws of the sandstone and conglomerate reservoir. For the first time, it sets up the 4-D model and mathematic model of the sandstone and conglomerate reservoir, which reveals the distributing and evolving laws of macroscopic & microcosmic parameters of the two-formation-type sandstone and conglomerate reservoir and oil-gas in 4-D space. At the same time, it also forecasts the oil-gas distribution and instructs the oilfield exploitation. It established reservoir simulation model, which reveals the filterate character and distributing laws of oil-gas in different porosity & throat net models. This article established the assistant theories and techniques for researching, describing, indicating and forecasting the sandstone and conglomerate reservoir fluid units, and develops the theories and techniques of the land faces faulted basin exploitation geology. In instructing oilfield exploitation, it had won the notable economic & social benefits.

大港千米桥地区综合地质地球物理研究

Qianmiqiao buried hill, which is a high-yield burial hill pool, was discovered at Dagang oilfield in 1998. To employ the integrated geological and geophysical research at Qianmiqiao area, it is very valuable and meaningful for the petroleum exploration of Bohai Bay Basin and even the whole country. Based on the previous results, this paper is carried out from the research on Huanghua depression, following the law, i.e. the deep part constrains the shallow, the regional constrains the local, takes the geophysical research in Qianmiqiao oilfield, discusses the formation history of burial hills, burial history, thermal history, the generated and expelling history of hydrocarbon, and migration characteristics, probes into the formation of burial hill pool. This paper uses the gravity and magnetic methods which are based on potential field, with natural sources, configures the inner structure of the earth according to the difference in the density and magnetism of the rock. The geophysical characteristics of Dagang oil field is that it is an area with positive Buge gravity anomal. The upheaval of Moho boundary is in mirror symmetry with the depression of the basin's basement. The positive and negative anomaly distributein axis symmetry, and the orientation is NNE. The thickness of the crust gradually reduces from west to east, from land to sea. The depth gradient strip of Curie surface is similar to Moho boundary, whereas their local buried depth is different. Local fractures imply that the orientation of base rock fractures is NNE-NE, and the base rock is intersected by the fractures of the same/ later term, whose orientation is NW, so the base rock likes rhombic mosaic. The results of tomography show that there exists significant asymmetry in vertical and horizontal direction in the velocity configuration of Huanghua depression. From Dezhou to Tianjin, there exits high-speed block, which extends from south to north. The bottom of this high-speed block is in good agreement with the depth of Moho boundary. Hence we can conclude that the high-speed block is actually the crystal basement. According to seismic data, well data and outcrop data, Huanghua depression can be divided into four structure layers, i.e. Pi,2-T, Ji,2-K, E, N-Q. Qianmiqiao burial hills undergo many tectonic movement, where reverse faults in developed in inner burial hill from Indosinian stage to Yanshanian stage, the normal faults extended in Himalayan stage. Under the influence of tectonic movements, the burial hills show three layers, i.e. the reverse rushing faults in buried hills, paleo-residual hill, and extended horst block. The evolution of burial hills can be divided into four stages: steady raising period from Calenonian to early Hercynian, rushing brake drape period from Indosinian to middle Yanshanian, block tilting period in early Tertiary, and heating depression period from late Tertiary to Quaternary. The basin modeling softwares BasinMod 1-D and Basin 2-D, which are made by PRA corporation, are used in this paper, according to the requirement, corresponding geological model is designed. And we model the burial history, thermal history, hydrocarbon generation and hydrocarbon expelling history of Qianmiqiao area. The results show that present bury depth is the deepest in the geological history, the sedimentary rate of Tertiary is highest and its rising rate of temperature rate is higher. During sedimentary history, there is no large erosion, and in the Tertiary, the deeper sediment was deposited in large space, therefore it is in favor of the conservation and transformation of oil and gas. The thermal research shows that the heat primarily comes from basement of the basin, present geotherm is the highest temperature in the geological history. Major source rock is the strata of ES3, whose organic is abundant, good-typed, maturative and of high-expulsive efficiency. The organic evolution of source rock of O has come to the overmature stage, the evolving time is long and the source rock can be easily destroyed. Therefore it is more difficult for the O formation source rock to form the huge accumulation of oil and gas than Es3 formation. In the research of oil assembling, we first calculated the characteristics of the fluid pressure of single well, then analyzed the distribution of the surplus fluid pressure of each formation and profile, and probe the first hydrocarbon migration situation and the distribution of pressure system of buried hill pool. In every formation, the pressure system of each burial hill has its own characteristics, e.g. high pressure or low pressure. In the research of secondary migration, the fluid potential is calculated while the relative low potential area is figured out. In Qianmiqiao area, the west margin faults have the low potential, and hence is the favorable reconnoiter belt.

凝析油气藏描述及开发对策研究-以莫北2油气藏为例

Gas condensate reservoir research involves not only structure sediment reservoir liquid properties characterization but also the change of the temperature field, the change of the pressure field, the change of liquid phase and the reservoir sensitivity. To develop the gas condensate reservoir effectively .we must depict the static properties of the oil and gas system ,build exact and comprehensive parameter field, predict the rule of dynamic change and do the necessary reservoir characterization development plan dynamic prediction direct production. The MoBei Oil and Gas Field is the first gas condensate reservoirs which is found by the Xinjiang Oil Field Company in ZhunGaEr basin belly.it has deserved some knowledge after prospect evaluation, the MoBei Oil and Gas Field start development ,it is one of the important development blocks of Xinjiang Oil Field Company productivity constuction. During its development , it gradually appears some problems, such as complex oil and gas phase, great change of reservoir stretch .uncertain reservoir type and scale, controling its development strategy and plan difficultly. To deserve the high efficient development and long-term stable production of the gas condensate reservoir, it is necessary to characterize it systematically and form a suit of scientific development strategy. This thesis take the MoBei zone SanGongHe sand group reservoir as research object, applied advanced log techniques ,such as the nulear magnetism log ,MDT testing .etc. After comprehensive research of loging geology information, set up a suit of methods to identify oil gas water layer .these methods can identify the gas-oil level and the oil-water level. On the basis of reasonable development object system, according fine structure interpretation and structure modeling. build any oil water column height of the reservoir accurately. Through carefully analysis of the basic theory and method of reservoir seism prediction. optimize a reservoir inversion method .technique. software fitting the research region aiming strata, set up the GR field, porosity field, Rt field, impedence field .permeability field and initial oil saturation field, generating the base of quantity reservoir characterization. Discussing the characteristic of reservoir fluid and the movement and reallocating of muti-phase fluid in reservoir. And according the material of 100 soviet gas condensate reservoir ,build the recognition method and mode of gas condensate reservoir. Building the 3D geology model ,carry on the static and production evaluation, propose the development strategy and improve plan , provide the base of increasing reserves and advancing production and enriching the prospect development theory of the gas condensate reservoi

中新世秦安黄土一古土壤序列记录的古气候变化周期

Analysis of periodic oscillations of climate is very important in understanding the behavior of the climate system. Milankovitch hypothesis, which holds that the glacial-interglacial climatic cycles during the Quaternary were primarily driven by variations in orbital parameters, has been supported by substantial geological evidence. Continuous long-term and high-resolution records are crucial to detect how variations of Earth's orbital parameters affected climate before the Quaternary when the boundary conditions were significantly different. Qinan loess formed in the Miocene is nearly continuous aeolian deposit in northern China. Previous study has established a constrained chronology, which provides a basis to examine long-term climatic variations. One of important issues to untangle the mechanisms behind major climate changes is the investigation of climate cycles recorded in Qinan loess. In this paper, two climatic proxies, magnetic susceptibility and redness, are analyzed for QA-I section to evaluate climate cycles using Maximum entropy spectral analysis and Blackman-Tuckey method. Main conclusions are presented as following: Results exhibit significant peaks at periods of 100 ka, 64 ka, 41 ka, 30 ka and 23 ka, but also 1000 ka, 600 ka and 400 ka. These peaks correspond to the dominant periods of the Earth's orbit parameters, which indicates that the formation of the aeolian sediment in northern China might be primarily driven by variations in orbital parameters. Fluctuations with different cycles respectively dominated in different periods. Major shifts in the dominant cycles occurred at 20.3, 19.0, 17.9, 15.2, 12.5 and 11.3 Myr ago. The transition that happened at 17.9 Myr ago was synchronous with the uplift of the Tibetan Plateau, while others at 15.2, 12.5 and 11.3 Myr ago were in good agreement with the timing of the development of Antarctic ice sheet. Therefore we inferred that these shifts might be related to changes in global ice volume and/or the Tibetan uplift. 3. The strong period of 100 ka is observed between 17.9 and 15.2, and 12.5 and 11.3 Myr ago. Ice sheet-climate models that have been used to explain the cause of the 100 ka period since the middle Pleistocene couldn't be responsible for driving the 100 ka climate cycle in the Miocene in Northern China because of the different boundary of climatic conditions between the Quaternary and Miocene. Further investigation is needed to understand how this cycle became dominant in Qinan loess records during these two time segments.

黄东海及朝鲜海峡冰后期陆架沉积物的环境磁学研究

There are four chapters in this dissertation. The first chapter briefly synthesizes the basic theories, methods and present-day applying situation of environmental magnetism. The second chapter probes into the magnetic mineral diagenesis in the post-glacial muddy sediments from the southeastern South Yellow Sea and its response to marine environmental changes, using the muddy sediment of Core YSDP103 formed in the shelf since about 13 ka BP. The third chapter illustrates the high-resolution early diagenetic processes by investigating the rapidly deposited muddy sediments during the last 6 ka in Cores SSDP-102 and SSDP-103 from the near-shore shelf of Korea Strait. The fourth chapter presents the results of detailed rock magnetic investigation of the surface sediments from the fine-grained depositional area on the outer shelf of the East China Sea in an attempt to provide environmental magnetic evidence for the provenance of the fine-grained deposit. Core YSDP103 was retrieved in the muddy deposit under the cold eddy of the southeastern South Yellow Sea, and the uppermost 29.79 m core represents the muddy sediments formed in the shelf since about 13 ka BP. The lower part from 29.79 to 13.35 m, called Unit A2, was deposited during the period from the post-glacial transgression to the middle Holocene (at about 6 ~(14)C ka BP) when the rising sea level reached its maximum, while the upper part above 13.35 m (called Unit Al) was deposited in a cold eddy associated with the formation of the Yellow Sea Warm Current just after the peak of post-glacial sea level rise. For the the uppermost 29.79 m core, detailed investigation of rock-magnetic properties and analyses of grain sizes and geochemistry were made. The experimental results indicate that the magnetic mineralogy of the core is dominated by magnetite, maghemite and hematite and that, except for the uppermost 2.35 m, the magnetic minerals were subject to reductive diagenesis leading to significant decline of magnetic mineral content and the proportion of low-coercivity component. More importantly, ferrimagnetic iron sulphide (greigite) is found in Unit A2 but absent in Unit Al, suggesting the control of marine environmental conditions on the magnetic mineral diagenesis. Magnetic parameters show abrupt changes across the boundary between the Unit Al and A2, which reflects a co-effect of environmental conditions and primary magnetic components of the sediments on the diagenesis. Alternating zones of high and low magnetic parameters are observed in Unit A2 of Core YSDP103, which is presumably due to periodic changes of the concentration and/or grain size of magnetic minerals carried into the study area. Cores SSDP-102 and SSDP-103, two studied sediment cores from the Korea Strait contain mud sequences (14 m and 32.62 m in thickness) that were deposited during the last 6,000 years. Analyses of grain sizes and geochemistry of the cores have demonstrated that the sediments have uniform lithology and geochemical properties, however, marked down-core changes in magnetic properties suggest that diagenesis has significantly impacted the magnetic properties. An expanded view of early diagenetic reactions that affect magnetic mineral assemblages is evident in these rapidly deposited continental shelf sediments compared to deep-sea sediments. The studied sediments can be divided into four descending intervals, based on magnetic property variations. Interval 1 is least affected by diagenesis and has the highest concentrations of detrital magnetite and hematite, and the lowest solid-phase sulfur contents. Interval 2 is characterized by the presence of paramagnetic pyrite and sharply decreasing magnetite and hematite concentrations, which suggest active reductive dissolution of detrital magnetic minerals, the absolute minimum abundance of magnetite is reached at the end of this interval. Interval 3 is marked by a progressive loss of hematite with depth, and at the base of this interval, 82% to 88% of the hematite component was depleted and the bulk magnetic mineral concentration was reduced to the lowest value in the entire studied mud section. Interval 4 has an increasing down-core enhancement of authigenic greigite, which is interpreted to have formed due to arrested pyritization resulting from consumption of pore water sulfate with depth. This is the first clear demonstration from an active depositional environment for a delay of thousands of years for acquisition of a magnetization carried by greigite. This detailed view of diagenetic processes in continental shelf sediments suggests that studies of geomagnetic field behavior from such sediments should be conducted with care. Paleoceanographic and paleoclimatic studies based on the magnetic properties of shelf sediments with high sedimentation rates like those in the Korea Strait are also unlikely to provide a meaningful signature associated with syn-depositional environmental processes. The rock magnetic properties of the surface sediments from the fine-grained depositional area on the outer shelf of the East China Sea, an area surrounded by sands, are investigated with a view to providing information on the sediment provenance. Multiple magnetic parameters such as magnetic susceptibility (%), anhysteretic remanent magnetization (ARM), saturation rernanent magnetization (SIRM), coercivities of SIRM (Her), and S ratios (relative abundance of low-coercivity magnetic minerals) are measured for all 179 surface samples, and partial representative samples are examined for their magnetic hysteresis parameters, temperature-dependence of magnetic susceptibility and x-ray diffraction spectra. Our research indicates that the magnetic mineralogy is dominated by magnetite with a small amount of hematite and is primarily of pseudo-single domain (PSD) to multidomain (MD) nature with a detrital origin. In the surface sediments, the granulometry of magnetic fractions is basically independent of grain sizes of the sediment containing the magnetic grains, and the composition of magnetic minerals remains almost homogeneous, that is, with a relatively constant ratio of low to high coercivity fraction throughout the area. The magnetic concentration in the study area generally decreases to the east or southeast accompanied by magnetic-particle fining to the east or to the northeast. The geographic pattern of magnetic properties is most reasonably explained by a major source of sediment jointly from the erosion of the old Huanghe River deposit and the discharge of the Changjiang River. The rock magnetic data facilitate understanding of the transport mechanism of fine-grained sediments in the outer shelf of the East China Sea.

准噶尔盆地低阻油藏实验研究及储层评价方法

Low resistivity reservoir is a special reservoir which is different from normal reservoir in identification and evaluation.Through core experiment and analysis, the achievement of which resistivity is resulted from clay additive electric conductivities and high bound water saturation in Junggar basin is gained. For accurately evaluating low resistivity, a good many of experiment have been completed, such as resistivity index and formation factor in hi^jher temperature and higher pressure, semi-permeability board, cation exchange, bound water, NMR (nucleus magnetism response), non-Nad water in different temperature and salinity, the experiments result show that lower resistivity has complex relation with these electric-parameters and chloric ion content in non-NaCl water.Based on comprehensive interpretation of NMR and normal resistivity data, the volume of moved water, bound water, moved oil and residual oil in the strata can be determined quantitatively and which have significant influence on reservoir recognition and perforation optimized.Experiment data (SEM mold, thin section, X ray diffraction, mercury penetration) can be used to analysis low resistivity forming and the relation between low resistivity and pore texture, to set up relation between porosity, permeability and petrophysical property. The reservoir was sorted, evaluated and described. The oil bedding in southern margin of Junggar basin is low porosity, low resistivity reservoir.Based on invasion theory of electric well-logging, modelling and inversion of resistivity well-logging are accomplished. For enhancing low resistivity resulted from higher bound water saturation and cation exchange, invasion period, invasion radius, the relation between fluid distribution in pore and response of laterolog logging have been studied. Virgin zone resistivity, invasion zone resistivity and invasion radius were inversed and which enhanced evaluation accuracy of reservoir. The method was used to process well-logging data in Luliang oilfield and southern margin in Junggar basin, and reservoir resistivity was enhanced effectively, appropriate oil saturation gained and it has better effect on oil exploration.

元谋地区晚新生代河湖相沉积物磁性地层学及古环境研究

Yuanmou area lies on the southeastern edge of the Tibetan Plateau, the middlesegment of Yunnan-Sichuan North-South Extending Tectonic Belt and the upper reaches of the Yangztze River, which is renowned for its thick late Cenozoic fluvial-lacustrine sequences that yield rich mammalian fossils including hominoid and early human. The sediments provides great potentials for understanding the relationships between uplift of the Tibetan Plateau, evolution of hominoids and other mammalian and evolution and formation of basins in Southwest China since late Miocene. However, lithostratigrphic and chronologic views on them are controversial and hinder further discussion of the relationships of them. To this end, we selected the Baozidongqing section and the Dapoqing section to carry out systematic lithostratigraphic, magnetostratlgraphic and environmental magnetism researches in this area.The Baozidongqing section was dated to about 10.95-7.17 Ma. The age estimation of the topmost hominoid-bearing layer was about 7.43-7.17 Ma. Rock magnetic results show that the dominant magnetic carrier is hematite, with minor amount of magnetite. Both the composition and concentration of magnetic minerals strongly correlate with the lithostratigraphy, indicating that Yuanmou basin is characterized by alternating of long-term torrid-humid climate and short-term dry-hot climate. But the pattern of these short-term hot-dry events, including both the lasting time and the frequency of their occurrence dramatically changed since -8.1 Ma. Our results infer that the drying process of the Asian west interior and a significant uplift of the Tibetan Plateau would have probably caused jointly the extinction of hominoids, or the emigration of hominoids from Yuanmou to adjacent relatively torrid-humid areas.The strata between the upper of the Dapoqing section, the Niujianbao Hill and Shangnabang area can be linked by three mark layers of conglomerate, which is rather continuous and coherent than physical disturbance by new tectonic activities. Rock magnetic studies indicate that hematite is the main magnetic carriers. The section is dated back to about 2.8-1.37 Ma. Its paleocurrent flowed northeastward, which was a close and stagnant river and swamp environment about 2.2 Ma ago. Then it ran northwestward and turned into an open overflown and braid river sedimentary face during 2.2 to 1.57 Ma. Since 1.57 Ma, the paleocurrent flowed intensely northwestern and about 1.37 Ma ago, it ended the basically continuous fluvial-lacustrine deposition.