24 resultados para Limestone

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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An internally circulating fluidized bed (ICFB) was applied to investigate the behavior of chlorine and sulfur during cofiring RDF and coal. The pollutant emissions in the flue gas were measured by Fourier transform infrared (FTIR) spectrometry (Gasmet DX-3000). In the tests, the concentrations of the species CO, CO2, HCl, and SO2 were measured online. Results indicated when cofiring RDF and char, due to the higher content of chlorine in RDF, the formation of HCl significantly increases. The concentration Of SO2 is relatively low because alkaline metal in the fuel ash can absorb SO2. The concentration of CO emission during firing pure RDF is relatively higher and fluctuates sharply. With the CaO addition, the sulfur absorption by calcium quickly increases, and the desulfuration ratio is bigger than the dechlorination ratio. The chemical equilibrium method is applied to predict the behavior of chlorine. Results show that gaseous HCl emission increases with increasing RDF fraction, and gaseous KCl and NaCl formation might occur.

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Our analysis of approximately 40,000 km of multichannel 2-D seismic data, reef oil-field seismic data, and data from several boreholes led to the identification of two areas of reef carbonate reservoirs in deepwater areas (water depth >= 500 in) of the Qiongdongnan Basin (QDNB), northern South China Sea. High-resolution sequence stratigraphic analysis revealed that the transgressive and highstand system tracts of the mid-Miocene Meishan Formation in the Beijiao and Ledong-Lingshui Depressions developed reef carbonates. The seismic features of the reef carbonates in these two areas include chaotic bedding, intermittent internal reflections, chaotic or blank reflections, mounded reflections, and apparent amplitude anomalies, similar to the seismic characteristics of the LH11-1 reef reservoir in the Dongsha Uplift and Island Reef of the Salawati Basin, Indonesia, which house large oil fields. The impedance values of reefs in the Beijiao and Ledong-Lingshui Depressions are 8000-9000 g/cc x m/s. Impedance sections reveal that the impedance of the LH11-1 reef reservoir in the northern South China Sea is 800010000 g/cc x m/s, whereas that of pure limestone in BD23-1-1 is > 10000 g/cc x m/s. The mid-Miocene paleogeography of the Beijiao Depression was dominated by offshore and neritic environments, with only part of the southern Beijiao uplift emergent at that time. The input of terrigenous sediments was relatively minor in this area, meaning that terrigenous source areas were insignificant in terms of the Beijiao Depression: reef carbonates were probably widely distributed throughout the depression, as with the Ledong-Lingshui Depression. The combined geological and geophysical data indicate that shelf margin atolls were well developed in the Beijiao Depression, as in the Ledong-Lingshui Depression where small-scale patch or pinnacle reefs developed. These reef carbonates are promising reservoirs, representing important targets for deepwater hydrocarbon exploration. (C) 2008 Elsevier Ltd. All rights reserved.

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In practice,many fracture reservoir was found,which has giant potential for exporation. For example,in limestone fracture reservoir,igneous rock fracture reservoir and shale fracture reservoir ,there are high yield oil wells found. The fracture reservoir has strong anisotropy and is very difficult to explore and produce.Since 1990’s,the techniques that use structure information and P-WAVE seismic attributes to detect fracture developed very rapidly,include stress and strain analysis,using amplitude,interval velocity,time-difference,azimuthal AVO analysis etc. Based on research and develop these advanced techniques of fracture detect,this paper selected two typical fracture reservoir as target area,according to the characters of research area,selected different techniques to pridect the fracture azimuth and density of target,and at last ,confirmed the favored area. This paper includes six parts:the first chapter mainly addresses the domestic and international research actuality about the fracture prediction and the evolement in ShengLi oil field,then according to the temporal exploration requirement,a research route was established; Based on the close relationship between structural fracture and the geotectonic movement and the procedure of rock distortion,the second chapter research the structural fracture predicting technique which is realized by computing the strain in every geotectonic movement ,which is by use of the forward and inversion of the growing history of structure; The third chapter discussed many kind of traditional techniques for fracture reservoir prediction,and point out their disadvantages.then research and develop the coherence volume computing technique which can distinguish from faults,the seismic wave absorbing technique,and other fracture predicting technique which is by use of seismic attributes ,such as azimuthal AVO FVO etc; The fourth chapter first establish the geological and petrophysical model by use of the existed log and drill well information, then research the variation of amplitude and seismic wave which is caused by fractures.based on it , the fracture predicting technique which is by use of variation of azimuthal impedance is researched;The fifth chapter is a case study,it selects shale fracture reservoir in LuoJia area as target,selects several kind of techniques to apply ,at last ,the fracture distribution of target reservoir and favored area were gotten;the sixth chapter is another case study,it selects limestone fracture reservoir in BoShen6 buried hill as target,selects several kind of techniques to apply,similarly favored area were gotten. Based on deeply research and development of the new techniques for fracture reservoir exploration, This paper selects two fracture reservoirs the most typical in ShengLi as targets to be applied ,good results show up a good application way ,which can be used for reference for future fracture exploration,and it can bring materially economic and social benefit.

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The distribution in outcrop of carbonate rocks in China is about 3.44×106km2 and accounts for over one third of the total area of the country, mainly in the Yangtze valley and the Yungui tableland ,and there is a great plenty of Water and hydropower resources in these carbonate area. A large number of projects will be built in order to develop the Water and hydropower resources. They are facing amount of complicated problems of karsts, specially the problem of the depths of karsts below water, which is a key problem that hasn’t been solved well theoretically. So, systematically research in quantitative analysis of the problem is necessary, which is very important to solve the inconsistency between current theories and facts, and is helped to foresee the depth of karsts below water and decrease the expense of the engineering. For the problem mentioned above, the thesis makes a detailed research on the length of corrosion of karsts water, based on the kinetics of corrosion, and founds the primary theory about the processes of four typical geologic elements, which are single fracture, single conduit, porous limestone and fractured limestone. And it has done a deep research upon the characterties and kinetics of corrosion of the four typical geologic elements by simulation using the programme edited by the author. The thesis also makes a discussion on the general model and process of the form of caves by using the founded theory. According to the characteristic of Water Resource and Hydropower engineering, the thesis creates three representative flow-dissolution models for three types of common geologic conditions under the induction of the theory kinetics of corrosion of karsts water. It has done quantitative research upon the process of dissolution and brought out primary theory about quantitative analysis of the depth of karsts below water as well. It found that the depth of karsts below water relates to the specific geologic conditions and the time of dissolution by simulation based on typical parameters and deep analysis of the result. That is to say there are karsts caves in any depths in flow areas of groundwater in specific geologic conditions and appropriate time. The thesis also discourses three basic problems that frequently encountered in the reconnaissance of Water Resource and Hydropower engineering, which are karsts base level, essential conditions of karsts, the comparability of caves and terrace, and indicates the importance of time in karsts. Finally, as an application, the karsts of the scheming Qianzhong water resource engineering is analyzed by the primary theory founded of quantitative analysis. The result of the application comes to a conclusion that the theory accords with the facts properly.

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Abstract The karsrt erosion engineering geology became a highlight problem in recent years, in particularly, the karst erosion of marlite of Badong formation made the rock mechanics weaken in Three Gorges Reservoir area, which reduces the safety of slope. During the immigrant construction, many high slopes have been formed, whose instabilities problems pose serious threats to the safety of the people and properties. The accidents of the slope failure take place now and then. By testing, it has been found that the karst erosion pattern and dissolution rate of marlite are not weaker than that of the pure limestone. Furthermore, owning to the weathering and unloading, the karst erosion of the marlite will reach certain depth of the slope, which is named infiltrated karst erosion. The karst erosion made the rock mass quality of slope or foundation worse in a large scale. The karst erosion geological disasters, taken place or not, has become the main restrictive factors to the social stability and economic development. Thus the karst erosion process and mechanism of marlite of Badong formation are studied as the main content of this dissertation. The weakening characteristic of rock mass mechanics parameters are studied along with the rock mass structure deformation and failure processes in the course of the karst erosion. At first, the conditions and influencing factors of the karst erosion are analyzed in the investigative region, on the basis of different karst erosion phenomenon of the marlite and different failure modes of slope. Then via indoor the karst erosion tests, it is analyzed that the karst erosion will change the rock mass composition and its structure. Through test, the different karst erosion phenomena between micro and macro have been observed, and the karst erosion mechanism of the marlite has been summarized. Damage theory is introduced to explain the feature of dissolution pore and the law of crack propagation in the marlite. By microscope and the references data, it can be concluded that the karst erosion process can be divided into rock minerals damage and rock structural damage. And the percent of karst erosion volume is named damage factor, which can be used to describe the quantify karst erosion degree of marlite. Through test, the rock mechanical properties in the different period of karst erosion are studied. Based on the damage mechanics theory and the test result, the relation between the karst erosion degree of marlite and weakening degree of mechanical properties is summarized. By numerical simulations, the karst erosive rock mass mechanics is verified. The conclusion is drawn as below: to the rock mass of marlite, the karst erosion damage made mechanics parameters variation, the deformation modulus, cohesion, and inter friction angle reduce as the negative exponent with the increasing of the karst erosion volume, however, the Poisson ratio increases as the positive exponent with the karst erosion volume increasing. It should be noticed that the deduced formulations are limited to the test data and certain conditions. It is suitable to the rock mass parametric weakening process after the karst erosion of marlite in Three Gorges Reservoir area. Based on the failure types of marlite slope in the field, the karst erosion and weathering process of rock mass are analyzed. And the evolution law of deformation and failure of the marlite mass is studied. The main failure feature of the marlite slope is the karst erosive structure subsidence mode in Three Gorges Reservoir area. The karst erosive structure subsidence mode is explained as follows: the rock mass undergoes the synthetic influence, such as weathering, unloading, corrosion, and so on, many pores and cavities have been formed in the rock mass interior, the rock mass quality is worsen and the rock mass structure is changed, and then the inherent structure of rock mass is collapsed under its gravity, therefore, the failure mode of compaction and subsidence take place. Finally, two examples are used to verify the rock mass parameters in Three Gorges Reservoir area, and the relationship between the marlite slope stability and the time of karst erosion is proposed.

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Luo Ning ( Mineralogy, Petrology, Deposit Mineralogy) Directed by Fu Liyun With the increase of the level of exploration and development, North China field, as one of the maturing fields in the east, has gradually turned their prospecting targets to frontiers such as deep zones, lithologic hydrocarbon reservoirs, low permeable layers, special lithostromes, etc, which propose new challenges to mating technique of exploration engineering. In it, the special lithostrome of clay carbonate in Shu-Lu cave in Middle Flank exploration area locates in Es_3 generating rock. The area distribution is large, formation thickness is over 100 meters, the oil accumulation condition is excellent, prognostic reserves is over 80,000,000 tons, but how to effectively stimulate the special low permeable and fractured reservoir has become the bottle neck problem of stimulation and stable yields. In this thesis, through comprehensive evaluation and analysis of lithology, lithomechanics, hydrocarbon reservoir characteristics, the characteristics of fluid flow through porous medium and the stimulation measures in the past, we acquire new cognition of clay carbonate reservoirs, in addition, the research and application of first hydraulic fracturing has gained positive effect and formed commensurable comprehensive reservoir evaluation technique and mating engineering technique of hydraulic fracturing. The main cognitions and achievements are as follows: 1.Study of geological information such as lithololy analysis and nuclear magnetic logging, etc, indicates that clay carbonate formation of Shu-Lu cave is anisotropic, low permeable with high shale content, whose accumulation space gives priority to microcracks. 2.The analysis of lithomechanics of clay carbonate indicates that the hardness is moderate, Young’s modulus is between that of sandstone and limestone, clay carbonate presents plastic property and its breakdown pressure is high because of the deep buried depth. 3.The analysis of the drillstem test curves indicates that the flow and build-up pressure curve of clay carbonate of Shu-Lu cave mainly has three types: formation contamination block-up type, low permeable type, formation energy accumulation slowness type; the reservoir characteristics presents double porosity media, radial compounding, uniform flow vertical fracture, isotropy, moniliform reservoir type. The target well Jingu 3 belongs to moniliform reservoir type. 4.Through recognition and re-evaluation of the treatment effect and technologic limitations of acidizing, acid fracturing and gelled acidizing in the past, based on the sufficient survey and study of hydraulic fracturing home and abroad, combined with comprehensive formation study of target well, we launched the study of the optimization of hydraulic fracturing technique, forming the principal clue and commensurable mating technology aimed at clay carbonate formation, whose targets are preventing leak off, preventing sand bridge, preventing embedment, controlling fracture height, forming long fracture. 5. Recognition of stimulation effect evaluation.

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The black rock series of the Upper Ordovician - Lower Silurian in Yangtze area are important source rocks and have exceptional characteristics of sediment, biology, element geochemistry, carbon and oxygen isotope, organic geochemistry and etc. These characteristics are the reflection of important geology events. Due to scarce system research, many problems that relate to the development mechanism of source rocks are not solved. And this restricts the exploration of Oil and gas in South China. In this paper, author studied the palaeo-climate, palaeo-structure and palaeo-environment of the Upper Ordovician - Lower Silurian in Yangtze area by sedimentology, palaeobiology and geochemistry, especially the element geochemistry and isotope geochemistry. The environment model of source rocks is established and some conclusions are drawn. The Upper Ordovician - Lower Silurian sediment types in Yangtze area are mostly black shales, next, mudstone, shell limestone and siltystone. During the Late Ordovician and Earily Silurian periods, a series of big upheaval and depressed are distributed in Yangtze area, and the strata pattern of interphase upheaval and depressed led to Yangtze palaeosea isolated with outside sea. So the stagnant and anoxic environment that are the favorable factor of rich organic black shales sediment is formed in Yangtze area. That Chemical Index of Alteration (CIA) values of the lower Wufeng formation and Longmaxi formation exhibits moderate chemistry weathering suggests they were deposited under the circumstances of the warm and humid climate. However, the large difference of the CIA values of N.extraordinarius-N.ojsuensis biozone suggests that climate is changeful. Therefore, there were two different kinds of climates in the course of the deposition of the Wufeng formation and Longmaxi formation. During the Late Ordovician - Earily Silurian periods, in Yangtze palaeosea, the surface water which is full of rich nutriment and abundant bacterium - algae has high palaeo-productivity that is obvious difference in the different space – time. The content of sulphate changes gradually from the surface water columns to the deep water columns. That is, salinity in the surface water columns is serious low and the salinity in deep water columns is normal. Salinity delamination is favor of the forming of deep anoxic environment. During Wufeng period, the oxidated and low sulfate environment exists in the upper Yangtze palaeosea, while the anoxic and normal salinity environment occurs in the lower Yangtze palaeosea. During the Late Wufeng and Guanyinqiao periods, the steady anoxic environment is replaced by oxidated environment. During the Longmaxi period, layered and anoxic environment recur. In Yangtze area, studies of δ13C of sedimentary organic carbon show a positive δ13C excursion up to 4‰ in the Guanyinqiao stage and then, acute negative excursion in the earily Longmaxi stage. These organic carbon isotopes curve are not only efficient measure of carving up strata borderline, but also reflected the change of originality productivity. These organic carbon isotopes curves showed the process of the enhanced embedding of the global organic carbon. Anoxic event is the main factor of increasing organic carbon embedding speed. And the reduced organic carbon embedding in Hirnantian stage is due to the water column with abundant oxygen. The δ34S values are gradually positive excursion from P.pacificus biozone to N.extraordinarius biozone, and reach the maximum in the Upper Hirnantian stage. Then, the δ34S values are negative excursion. The excursions of δ13C and δ34S reflect the acute change of environment. The formation of source rocks is largely dependent on the nature of organisms from which kerogen is derived and the preservation conditions of organic matter, which are fundamentally dependent on a favourable combination of various elements in which organisms live and are subsequently buried. These elements include palaeoclimate, palaeostructure and palaeoenvironmental conditions. Based on above mentioned circumstance, the coupling connection of source rock and the palaeoclimate, and of palaeostructure and palaeoenvironmental conditions are confirmed, and the “anoxic-marginal depression-photosynthesis” environemental model is established. It is indicated that anoxic played important role in production of organic matter. The produced organic matter was accumulated in marginal depression of the Yangtze area. The photosynthesis is favor of the high productivity. Source rocks have a good perspective, like that of “hot shale” deposited in North Africa.