Effect of CO_(2)flooding in an oil reservoir with strong bottom-water drive in the Tahe Oilfield,Tarim Basin,Northwest China

The dissolution and diffusion of CO_(2)in oil and water and its displacement mechanism were investigated by laboratory experiment and numerical simulation for Block 9 in the Tahe oilfield,a sandstone oil reservoir with strong bottom-water drive in Tarim Basin,Northwest China.Such parameters were analyzed as solubility ratio of CO_(2)in oil,gas and water,interfacial tension,in-situ oil viscosity distribution,remaining oil saturation distribution,and oil compositions.The results show that CO_(2)flooding could control water coning and increase oil production.In the early stage of the injection process,CO_(2)expanded vertically due to gravity differentiation,and extended laterally under the action of strong bottom water in the intermediate and late stages.The CO_(2)got enriched and extended at the oil-water interface,forming a high interfacial tension zone,which inhibited the coning of bottom water to some extent.A miscible region with low interfacial tension formed at the gas injection front,which reduced the in-situ oil viscosity by about 50%.The numerical simulation results show that enhanced oil recovery(EOR)is estimated at 5.72%and the oil exchange ratio of CO_(2)is 0.17 t/t.

Analysis of Tectonic Conditions for Strong Earthquakes and Prediction of Seismic Risk of Seismogenic Fault Zones in the Northern Part of North China

The tectonic conditions for strong earthquakes are complicated in various aspects.The genetic conditions for strong earthquakes were studied from the angle of various disciplines.About 20 conditions belonging to different fields have been described by predecessors.In this paper,the authors try to study and evaluate all the tectonic condition factors for strong earthquakes by the methods of fuzzy mathematics and hierarchical analysis.Taking the northern part of North China as an example,the authors make a comprehensive digital analysis of all the quantitative and semi-quantitative tectonic factors.The credibility values of all strong earthquakes with different magnitudes are given after statistical analysis and calculation.Forty-one fault zones in the study region are quantitatively analyzed,and the potential seismogenic fault zones,maximum magnitude,and risk of earthquake occurrence in the near future are assessed.The result of synthetic evaluation,based on all tectonic conditions of different

Characteristics and main controlling factors of helium resources in the main petroliferous basins of the North China Craton

At present, the main controlling factors of helium accumulation is one of the key scientific problems restricting the exploration and development of helium reservoir. In this paper, based on the calculation results of He generation rate and the geochemical characteristics of the produced gas, both the similarities and differences between natural gas and He resources in the Bohai Bay, Ordos and the surrounding Songliao Basin are compared and analyzed, discussing the main controlling factors of helium resources in the three main petroliferous basins of the North China Craton. It is found that the three basins of Bohai Bay, Ordos and Songliao have similar characteristics of source rocks, reservoirs and cap rocks, that's why their methane resource characteristics are essentially the same. The calculated ~4He generation per cubic metamorphic crystalline basement in the three basins is roughly equivalent, which is consistent with the measured He resources, and it is believed that the ~4He of radiogenic from the crust is the main factor controlling the overall He accumulation in the three basins;there is almost no contribution of the mantle-derived CH_4, which suggests that the transport and uplift of mantle-derived ~3He carried by the present-day magmatic activities along the deep-large faults is not the main reason for the mantle-derived ~3He mixing in the basins. Combined with the results of regional volcanic and geophysical studies,it is concluded that under the background of the destruction of North China Craton, magma intrusion carried a large amount of mantle-derived material and formed basic volcanic rocks in the Bohai Bay Basin and Songliao Basin, which replenished mantle-derived ~3He for the interior of the basins, and that strong seismic activities in and around the basins also promoted the upward migration of mantle source ~3He. This study suggests that the tectonic zone with dense volcanic rocks in the Cenozoic era and a high incidence of historical strong earthquakes history may be a potential area for helium resource exploration.

Statistical analysis on temporal-spatial correlativity within temporal doublets of strong earthquakes in North China and its vicinity

In order to unify the time and the space attributes into temporal-spatial distance, the temporal-spatial proportional coefficient fTS is proposed in this paper. In accordance with the new distance concept, the temporal-spatial correlativity within temporal doublets of strong earthquakes in North China and its vicinity since AD 1500 has been analyzed. The computation results indicate that doublets of strong earthquake can be divided into two groups when fTS is endowed with 10 km/a in the new distance formula. The temporal-spatial distance between two points of doublet generally cannot exceed 140 km when two strong quakes in doublet have some causative relation. And those doublets with temporal-spatial distance exceeding 280 km are probably independent seismic events in doublets. This character can be the reference to the migration law summarization and trend prediction.

Spatial-temporal Divergence Characteristics and Driving Factors of Green Economic Efficiency in the Yangtze River Economic Belt of China

The spatial and temporal variation of green economic efficiency and its driving factors are of great significance for the construction of high-efficiency and low-consumption green development model and sustainable socio-economic development.The research focused on the Yangtze River Economic Belt(YREB)and employed the miniumum distance to strong efficient frontier DEA(MinDs)model to measure the green economic efficiency of the municipalities in the region between 2008 and 2020.Then,the spatial autocorrelation model was used to analyze the evolution characteristics of its spatial pattern.Finally,Geodetector was applied to reveal the drivers and their interactions on green economic efficiency.It is found that:1)the overall green economic efficiency of the YREB from 2008 to 2020 shows a W-shaped fluctuating upward trend,green economic efficiency is greater in the downstream and smallest in the upstream;2)the spatial distribution of green economic efficiency shows clustering characteristics,with multi-core clustering based on‘city clusters-central cities'becoming more obvious over time;the High-High agglomeration type is mainly clustered in Jiangsu and Zheji-ang,while the Low-Low agglomeration type is clustered in the western Sichuan Plateau area and southwestern Yunnan;3)from input-output factors,whether it is the YREB as a whole or the upper,middle and lower reaches regions,the economic development level,labor input,and capital investment are the leading factors in the spatial-temporal evolution of green economic efficiency,with the com-prehensive influence of economic development level and pollution index being the most important interactive driving factor;4)from so-cio-economic factors,information technology drivers such as government intervention,transportation accessibility,information infra-structure,and Internet penetration are always high impact influencers and dominant interaction factors for green economic efficiency in the YREB and the three major regions in the upper,middle and lower reaches.Accordingly,the article puts forward relevant policy re-commendations in terms of formulating differentiated green transformation strategies,strengthening network leadership and informa-tion technology construction and coordinating multi-factor integrated development,which could provide useful reference for promoting synergistic green economic efficiency in the YREB.

The Statistical Analysis of Migration of Strong Earthquakes─Taking the North China Region as an Example

The migration of strong earthquakes is an important research topic because the migration phenomena reflect partly the seismic mechanism and involve the prediction of tendency of seismic activity. Research on migration of strong earthquakes has mostly focused on finding the phenomena. Some attempts on getting regularity were comparatively subjective. This paper suggests that there should be indices of migration in earthquake dataset and the indexes should have statistical meaning if there is regularity in the migration of strong earthquakes. In this study, three derivative attributes of migration, i.e., migration orientation, migration distance and migration time interval, were statistically analyzed. Results in the North China region show that the migration of strong earthquakes has statistical meaning. There is a dominant migration orientation (W by S to E by N), a dominant distance (≤100km and on the confines of 300～700km), and a dominant time interval (≤1a and on the confines of 3～4a). The results also show that the migration will differ slightly with different magnitude range or earthquake activity phase.

Recurrence anomaly of ground water behavior before strong earthquakes in North China

By analyzing the relationship between ground water behavior and strong seismic activity during the past more than 20 years in North China, we have found similar water level descending variation of a part of wells in the short-term stage before several strong earthquakes. The characteristics of anomaly are: at the beginning, water level dropped abruptly or accelerated to drop; then it turned to slow rising with a smaller amplitude than that of descending; earthquakes occurred during the slow-rising process of water level, and at that time or before earthquake occurrence, water level rose with a large amplitude. Among more than 100 wells in North China, the descending anomalies were not recorded for many times, but similar variation processes of water level were noted at different wells before several strong earthquakes, which proves that seismic precursory anomalies of ground water are of certain recurrence features, occurring repeatedly before different strong earthquakes. Therefore, it is necessary to study the genesis of this type of anomaly and its relationship with strong seismic activity.

Analysis of the VWP Product Characteristics in One Strong Rainstorm Process

[Objective] The aim was to study the characteristics in VWP period characteristics in one strong rainstorm process.[Method] Based on the previous studies,the VWP product characteristics in early period of strong rainstorm,during the development and the end period in Hunan Province on April 8,2008 were studied.[Result] Before the occurrence of rainstorm,the destruction of low layer 'ND' layer indicated the increase of water vapor content layer.The intrusion of cold and dry air in the middle layer led to unstable layer;during the maintaining period of rainstorm,the strong vertical shear in the low layer led to the occurrence of strong rainstorm.The cold air in the boundary layer penetrated and led the rainstorm to the most prevailing stage.There was hailstorm on the ground.Before the disappearance of rainstorm(after 17:59),the entire wind field changed into consecutive 'ND' layer and it suggested that the strong convective cloud was far away from the location of radar,and indicated the end of rainstorm.[Conclusion] The study provided reference and basis for the pre-warning of rainstorm for temporary reporter.

Rational Identification of Lightning Derivative Disasters by Strong Convective Weather Monitoring Data in Southern China——A Case Study in Guangzhou Development Region

Analytic method and identification direction for rational identification of lightning derivative disasters by strong convective weather monitoring data in southern China were introduced. Taking identification cases of lightning disaster in Guangzhou Development Region as the background,according to the characteristics in the region that large high-precision enterprises were more,lightning derivative disasters occurred frequently in thunderstorm season,and the actual situation that time of the affected enterprise applying for lightning disaster scene identification lagged,combining Technical Specifications of Lightning Disaster Investigation（ QX / T103-2009）,qualitative analysis method of lightning derivative disaster was put forward under the weather condition of strong convection in southern China by using weather monitoring data（ Doppler sounding radar data,lightning positioning monitoring data,atmospheric electric field data,rainfall data,wind direction and force）,and was optimized by technical means（ ＂ metallographic method＂ and ＂ remanence law＂）. The research could put forward efficient and convenient analytical thinking and method for lightning derivative disaster,and further optimize accuracy and credibility of lightning disaster investigation.

Media Response to Health Emergencies:An Analysis of International Newspapers Coverage of Early Days of COVID-19 Breakout in China

This study investigated the dominant perception triggered among the foreign residents in China by international newspapers’coverage of early months of COVID-19 outbreak in China.In total,12 leading newspapers from USA,UK,Malaysia,Nigeria,Australia,and Tanzania,with two selected from each country;and 10 samples are taken from each newspaper,totalling 120 samples.Two focus groups of seven members each were created and each of the groups separately discussed the samples listing their perception of the newspapers’articles.A control group of 13 participants was also created.Also,the views of 247 foreigners resident in China during the outbreak were sampled.Results from the study showed that in the early months of COVID-19 newspapers from USA,UK,and Australia sensationalized most of their news while some of their reports showed some political slant.However,most news reports from Nigeria,Tanzania,and Malaysia were less sensational.The results from the study and control groups were also backed by the results from the survey sample where most of the respondents said the news reports created fear and panic among them while containing less educative information.This study recommends prioritization of media social responsibility in the coverage of health emergencies.

Discussion of Some Problems in the Research into the Seismotectonics of Strong Earthquakes on the North China Plain

The tectonic characteristics and research problems of five earthquakes with M≥7.0 on the North China Plain over the last 300 years are addressed in the paper, including the cognition that there were no ground fractures in the 1966 Xingtai earthquake, the question caused by the thrust activity of the seismic fault of the Tangshan Earthquake and the discussion of the seismotectonic environment of the 1830 Cixian earthquake and the 1937 Heze earthquake. The author thinks that the main reason for the problems in research of strong earthquake tectonics in the region is that the status of activity of the main tectonics during the Late Quaternary are unknown. This affects the founding of discrimination criteria for seismotectonics of strong earthquakes on the North China Plain. Discriminating the Holocene active faults from the large number of faults is the most effective method for seismic hazard assessment in the area in future.

Study of Finite Element Modeling of Strong Earthquake Activities and Its Preliminary Application—Taking Southwest China as an Example

Based on research result concerning the preparation and activity of strong earthquakes in groups and using the finite element method, a finite element dynamic model for Southwest China is established in this paper. Using this model, the stress adjustment in the whole of the Southwest China region in response to the stress change due to strong earthquake occurrence is studied. The preliminary result shows that many strong earthquakes occurred in areas where the stress heightened after the last strong earthquake. So, the finite element model set up in this paper is useful for judging the regions where strong earthquakes are likely to occur in future.

To Create a Big andl Strong Shipbuilding of China

Reality:A Big Gap Exists with StrongShipbuilding Countries We cad clearly see,though greatachievements have been made.China’sshipbuilding industry still has a large gapwith the ship building powers like Japanand South Korea. The gap is not onlyreflected in"quantity"(refer to the per-centage of delivery tonnage in the

The influence of different underlying surface on sand-duststorm in northern China

In this paper, a quantitative research on the relationship between different underlying surface and sand-dust storm has been made by using 40 years meteorological data of five different types of underlying surface in northern China, which include farmland, grassland, sandland, gobi and salt crust. These metrological data comprise sand-dust storm days and strong wind days. By analyzing, we can find that there are certain correlations between the days of sand-dust storm and strong wind for different underlying surface, which has great influence on sand-dust storm. But there are pronounced differences in different types of underlying surface. The sand-dust storm days of grassland, gobi and salt crust, with smaller interannual variation are obviously less than strong wind days. On the other hand, the sand-dust storm days of farmland and sandland increase evidently, even in many years, are much more than strong wind days. The differences are mainly induced by the influencing mechanism of different underlying surface on sand-dust storm. Grassland, gobi and salt crust with stable underlying surface are not prone to sand-dust storm under strong wind condition. Whereas, the underlying surface of farmland and sandland is unstable, that is easy to induce sand-dust storm under strong wind condition.

Attenuation characteristics of ground motions in northern China

Four recently developed attenuation models are calibrated by using a very limited amount of strong motion data recorded in China.The research shows that the attenuation characteristics of the earthquake shaking in northern China are similar to those in the western US.The supporting evidence includes Q factors,preliminary results of kappa values,stress drop, shear wave velocity profile in the shallow earth crust,areas enclosed by the isoseismals of Modified Mercalli Intensity V.From these comparison,s of different attenuation models,it is recommended that the Crouse and McGuire spectral attenuation model could possibly be used for northern China.

The Study on the Interannual Variation and the Mechanism of the South China Sea Monsoon

By using the USA NCAR / NCEP reanalysis data, the characteristics of climatic elements and the temporal and spatial structures of precipitation in the strong and weak years of the SCS monsoon are analyzed, the mechanism of the interannual variation of the SCS monsoon is discussed. It is found that the climatic elements in SCS have great differences, and there are great differences in the spatial and temporal structures of the precipitation anomalies between the strong and weak monsoon years. The variation of climatic elements in the south of Indochina Peninsula in April is a good index of the strength of the SCS monsoon. There is a good connection between the SCS monsoon and the sea surface temperature. The SCS monsoon is weak in the EL Nino years, and strong in the La Nina years. The strength of the SCS monsoon depends on the local heating differences between the eastern continent of China and the western Pacific. It depends on the intensity and the position of the western Pacific Subtropical High. The western Pacific Subtropical High is weak and eastward in the strong monsoon years, and the case is reversed in the weak monsoon years.

The regional characteristics of seismic activity in China

In this paper, the regional characteristics of seismicity of strong earthquakes in 27 seismic provinces in the wholeChina were discussed. It is divided into b kinds of regions on the basis of analyzing the earthquake's annual average rate of M≥6, b-value and the maximum magnitude in history in those provinces. Among them, the seismicactivity in the eastern part of Taiwan seismic province is the highest, where the annual average rate of earthquake occurrence vM≥6 is more than 1. The second kind region includes Pamir, south and north Tianshan, Yunnan-Sichuan, west Kunlun, Himalaya and western part of Taiwan etc. 9 seismic provinces, vM≥6 are 0. 12 -0. 34. The third kind of regions contains 10 seismic provinces, such as 4 provinces in North China, northeastborder of Qingzang (Qinghai-Xizang) plateau, Gobi-Altay and the outside southeast coast province etc., wherevM≥6=0. 032-0. 08, the maximum earthquakes of Mmax≥8 were recorded in the history in most seismicprovinces of the region, only a few seismic provinces recorded Mmax=7.3-7. 5. The fourth kind of regions include 6 seismic provinces, such as the northeast China, the middle and lower reaches of the Yangtze River and South China etc., where, vM≥6=0. 01-0. 03, the largest earthquake recorded in the history is Mmax<7. Thefifth kind of regions is the one with the lowest seismic activities, Mmax=53/4 be recorded as the maximum magnitude there. The regional characteristics of the strong earthquake activity have close relationship with tectonicmovement of the surrounding plate and of the introplate block.

The Analysis on the Temporal and Spatial Variation of Strong Precipitation Caused Flood and Agricultural Disaster Loss in Huaihe River Basin of Anhui Province during Meiyu Period of 2007

[Objective] The research aimed to analyze temporal and spatial variation of strong precipitation caused flood and agricultural disaster loss in Huaihe River basin of Anhui Province during Meiyu period of 2007.[Method] On the basis of rainfalls of each station in Huaihe River basin of Anhui,rainfall data during Meiyu period of 2007 and flood disaster data in the same period,the temporal and spatial distribution characteristics of strong precipitation caused flood during Meiyu period of 2007 and its harm on agriculture were analyzed.The variation rule,distribution characteristics of strong precipitation during Meiyu period in Huaihe River basin of Anhui and its relationship with agricultural disaster loss were discussed.[Result] During Meiyu period of 2007 in Huaihe River basin of Anhui,the rainstorm was more,and the rainfall was large.The precipitation variation showed 'three-peak' trend.Rainfall in Huaihe River basin during Meiyu period of 2007 was greatly more than that homochronously in Yangtze River basin.The rain area over 400.0 mm during Meiyu period mainly located in Huaihe River basin,and the rain area over 600.0 mm mainly located from area along Huaihe River to central Huaibei.The rainfall during Meiyu period gradually decreased toward south and north by the north bank of Huaihe River as the symmetry axis.The rainfall in area along Huaihe River showed wavy distribution in east-west direction.The flood disaster loss index and disaster area of crops in Huaihe River basin of Anhui both increased as rainfall in Meiyu period.[Conclusion] The research provided theoretical basis for flood prevention,disaster reduction and agricultural flood-avoiding development in Huaihe River basin.

The characteristics of variation in inhomo geneity of temporalspatial distribution of short to imminent precursors before strong earthquakes

C_v is used in this paper to describe the variation in inhomogeneity of spatial and temporal distribution of precur sors. The inhomogeneous variation in the spatial and temporal distribution of the anomalies in water radon and electromagnetic waves before M_s≈6 earthquakes in northern North China is analyzed in detail. Results show that before a moderate to strong earthquake, the distribution of anomalies in water radon and electromagnetic waves changes inhomogeneously, i.e., C_v increases significantly. The inhomogeneity in spatial distribution of short-to- imminent precursors increases before a strong earthquake, which may relates to the enhancement of crustal strain field. The research will not only help us to know more about the process of seismogeny and to improve practical earthquake prediction, but also blaze a new way to do earthquake prediction with present precursor data.