储层岩石电性特征的逾渗网络模型研究(英文)

建立能够反映储层孔隙结构、流体特征的逾 渗网络模型,通过数值模拟研究了储层孔隙尺寸、 孔隙形状、连通性、微孔隙的发育状况等对I-Sw曲 线影响的定性规律,研究了地层水矿化度对岩石电 阻率的影响。分析讨论了不同因素对电阻率影响的 相对强度。最后,通过曲线拟合定量地研究了不同 因素对I-Sw曲线的影响规律。研究表明,在上述影 响因素中连通性和微孔隙对I-Sw曲线的影响很大, 其它因素的影响强度较小。地层水矿化度对岩石电 阻率绝对值的影响很大。“非阿尔奇”现象普遍存在, 在低渗透(低连通性)储层岩石中更为明显。     

Thermodynamic conditions of framework grain dissolution of clastic rocks and its application in Kela 2 gas field

Feldspar and clastic debris are the most important constituent framework grains of sedimentary clastic rocks and their chemical dissolution plays an essential role in the formation and evolution of the secondary pore in the reservoir rocks. On the basis of thermodynamic phase equilibrium, this study investigates the chemical equilibrium relationships between fluid and various plagioclase and K-feldspar in diagenesis of the sediments, particularly, the impact of temperature and fluid compositions (pH, activity of K+, Na+, Ca2+ and so on) on precipitation and dissolution equilibria of feldspars. Feldspar is extremely easily dissolved in the acid pore water with a low salinity when temperature decreases. The dissolution of anorthite end-member of plagioclase is related to the Ca content of the mineral and the fluid, higher Ca either in the mineral or in the fluid, easier dissolution of the feldspar. Moreover, the dissolution of albite end-member of plagioclase is related to Na of both the mineral and fluid,     

鄂尔多斯盆地南部的黄土塬区地震资料处理与解释,第一部分:地震资料处理

Branching river channels and the coexistence of valleys, ridges, hiils, and slopes＇as the result of long-term weathering and erosion form the unique loess topography. The Changqing Geophysical Company, working in these complex conditions, has established a suite of technologies for high-fidelity processing and fine interpretation of seismic data. This article introduces the processes involved in the data processing and interpretation and illustrates the results.     

Converted-wave seismology in anisotropic media revisited,Part I: Basic theory

We have developed new basic theories for calculating the conversion point and the travel time of the P-SV converted wave (C-wave) in anisotropic, inhomogeneous media. This enables the use of conventional procedures such as semblance analysis, Dix-type model building and Kirchhoff summation, to implement anisotropic processing, and makes anisotropic processing affordable. Here we present these new developments in two parts: basic theory and application to velocity analysis and parameter estimation. This part deals with the basic theory, including both conversion-point calculation and moveout analysis. Existing equations for calculating the PS-wave (C-wave) conversion point in layered media with vertical transverse isotropy (VTI) are strictly limited to offsets about half the reflector depth (an offset-depth ratio, xlz, of 0.5), and those for calculating the C-wave traveltimes are limited to offsets equal to the reflector depth (x/z=l.0). In contrast, the new equations for calculating the conversion-point extend into offsets about three-times the reflector depth (x/z=3.0), those for calculating the C-wave traveltimes extend into offsets twice the reflector depth (x/z=2.0). With the improved accuracy, the equations can help in C-wave data processing and parameter estimation in anisotropic, inhomogeneous media. This work is funded by the Edinburgh Anisotropy Project (EAP) of the British Geological Survey. First author: Xiangyang Li, Mr. Li is currently a professorial research seismologist (Grade 6) and technical director of the Edinburgh Anisotropy Project in the British Geological Survey. He also holds a honorary professorship in multicomponent seismology at the School of Geosciences, University of Edinburgh. He received his BSc(1982) in Geophysics from Changchun Geological Institute, China, an MSc (1984) in applied geophysics from East China Petroleum Institute (now known as the China University of Petroleum), and a PhD (1992) in seismology from the University of Edinburgh. During 1984–1987, he worked as a lecturer with the East China Petroleum Institute. Since 1991, he has been employed by the British Geological Survey. His research interests include seismic anisotropy and multicomponent seismology.     

Analysis of Short-Period Rayleigh Waves Recorded in the Bohemian Massif Area During Celebration 2000 Experiment

The aim of this paper is to show the application of short-period surface waves recorded during deep seismic sounding experiment for constraining shallow velocity structure of the crust. Phase velocity of fundamental mode Rayleigh waves, observed along the CELEBRATION 2000 experiment profile CEL09, were obtained by a p-ω method and has been subsequently inverted for one-dimensional shear velocity models for the top 2 km. Multiple filter technique applied to one shot gather was used to carry out a joint inversion of phase and group velocity data and to provide γ_R data to be used for Q_β inversion. Validity of obtained V_S and Q_β models was confirmed by the reflectivity method. Noticeably, no clear dispersive wawes were observed in the Tepla-Barrandian Unit. Quasi-2D model based on the individual 1D V_S models is well correlated with the surface geology. Lower V_S are observed in the Saxothuringian Zone in comparison to the Moldanubian Zone. In the vicinity of the Central Bohemian and Moldanubian Plutons, the near-surface V_S values are relatively low, but below 1 km depth, they are higher than in surrounding areas. We interpret it as the result of the weathering and cracks within the granitoid rocks.     

Retrospective Assessment of Bottom Deposits in Kondopoga Bay,Lake Onega

Long-term observations of the chemical composition of bottom sediments in Kondopoga Bay, Lake Onega, are considered. The present-day state of bottom sediments is characterized, and regularities of variations in the composition and properties of sediments occurring in the zone of influence of wastewaters from a pulp and paper plant (PPP).     

Assessing the Comparability of Ammonium,Nitrate and Sulfate Concentrations Measured by Three Air Quality Monitoring Networks

Airborne fine particulate matter across the United States is monitored by different networks, the three prevalent ones presently being the Clean Air Status and Trend Network (CASTNet), the Interagency Monitoring of PROtected Visual Environment Network (IMPROVE) and the Speciation and Trend Network (STN). If combined, these three networks provide speciated fine particulate data at several hundred locations throughout the United States. Yet, differences in sampling protocols and samples handling may not allow their joint use. With these concerns in mind, the objective of this study is to assess the spatial and temporal comparability of the sulfate, nitrate and ammonium concentrations reported by each of these networks. One of the major differences between networks is the sampling frequency they adopted. While CASTNet measures pollution levels on seven-day integrated samples, STN and IMPROVE data pertain to 24-hour samples collected every three days. STN and IMPROVE data therefore exhibit considerably more short-term variability than their CASTNet counterpart. We show that, despite their apparent incongruity, averaging the data with a window size of four to six weeks is sufficient to remove the effects of differences in sampling frequency and duration and allow meaningful comparison of the signals reported by the three networks of concern. After averaging, all the sulfate and, to a lesser degree, ammonium concentrations reported are fairly similar. Nitrate concentrations, on the other hand, are still divergent. We speculate that this divergence originates from the different types of filters used to collect particulate nitrate. Finally, using a rotated principal component technique (RPCA), we determined the number and the geographical organization of the significant temporal modes of variation (clusters) detected by each network for the three pollutants of interest. For sulfate and ammonium, the clusters’ geographical boundaries established for each network and the modes of variations within each cluster seem to correspond. RPCA erformed on nitrate concentrations revealed that, for the CASTNet and IMPROVE networks, the modes of variation do not correspond to unified geographical regions but are found more sporadically. For STN, the clustered areas are unified and easily delineable. We conclude that the possibility of jointly using the data collected by CASTNet, IMPROVE and STN has to be weighed pollutant by pollutant. While sulfate and ammonium data show some potential for joint use, at this point, combining the nitrate data from these monitoring networks may not be a judicious choice.     

Analysis of Many-Year Variations in River Runoff into the Arctic Ocean

Statistical analysis of long-term hydrological observations has shown that the interannual variations in the total river runoff into the Arctic Ocean can be considered as a stationary process. Similar are the variations in the annual runoff of the Ob, Lena, and rivers of the northwestern Asia. However, some components of the total runoff into the Arctic Ocean feature distinct and fairly complicated disturbances in the homogeneity of runoff variations. For example, variations in the annual runoff of the Yenisei River have a distinct nonmonotonic trend: the runoff systematically decreased till the late 1950s and increased since the late 1960s. The rivers of the European part of the Arctic Ocean drainage basin featured a decrease in the amplitude of variations in runoff during the past decades. Rivers of the northwestern America and northeastern Asia featured a regular increase in the amplitude of runoff variations and their autocorrelation since the late 1960s.