致密砂岩储层CO2驱油特征的核磁共振实验研究

利用核磁共振技术对致密砂岩储层不同渗透率级别基质岩心和裂缝基质岩心不同驱替压力下CO2驱油特征进行了研究,简述核磁共振原理及实验方法。表明:致密砂岩储层特低、超低渗透基质岩心在初始CO2驱替压力下,岩心毛细孔隙和微毛细孔隙区间的油不同程度被采出,随着CO2驱替压力增大,特低、超低渗透基质岩心毛细孔隙区间油的采出程度不断增加且累积采出程度不同。裂缝致密砂岩储层岩心,裂缝和毛细孔隙区间的油在初始CO2驱替压力下,岩心裂缝中的油及毛细孔隙中的部分油被驱替出来,CO2驱替压力提高毛细孔隙、微毛细区间油的采出程度和累积采收程度较小。致密砂岩储层特低、超低渗透基质岩心和裂缝致密砂岩储层岩心,随着CO2驱替压力增大毛细孔隙区间的部分剩余油成正比增加进入到微毛细孔隙区间改变储层剩余油分布。核磁共振技术能够深入研究致密砂岩储层CO2不同驱替压力阶段,岩心裂缝、毛细孔隙区间、微毛细孔隙区间油的采出程度和剩余油分布情况,对于研究致密砂岩储层微观驱油机理具有较重要的价值。     

Satellite Earth Observations Support CTBT Monitoring: A Case Study of the Nuclear Test in North Korea of Oct. 9, 2006 and Comparison with Seismic Results

The Comprehensive Nuclear-Test-Ban Treaty prescribes the use of seismic stations and arrays as the main measure for verification of Treaty compliance. Since the inception of the Treaty, a vast amount of open source earth observation satellite data has become available. This paper investigates the potential for combining seismic and satellite data for more effective monitoring and response. With data acquired before, during and after the alleged North Korean underground nuclear test on October 9, 2006, wide area change detection techniques using medium resolution optical/infrared satellite sensors are combined with localized high-resolution imagery to attempt to pinpoint the test location within the area identified by the seismic measurements. Problems associated with the timeliness, degree of coverage and ambiguity of the remote sensing data are pointed out, however it is generally concluded that their integration into the CTBT regime would valuably complement the existing seismic observation network.     

Charakterisierung von Al(III)-Spezies in basischen Aluminiumchlorid-Flockungsmitteln mittels Ferronreaktion bzw. 27Al-Kernresonanzspektroskopie Characterization of Al(III) Species in Basic Aluminium Chloride Flocculants by Means of Ferron Method and 27 Al Nuclear Magnetic Resonance

Flocculant processes as a treatment step in water and wastewater purification technology are of increasing importance. Partially neutralized aqueous aluminium chloride solutions — the basic aluminium chlorides — are often used as flocculants in water conditioning. The present paper describes the reactions which appear in these solutions by their dilution, the identification of occurring cationic aluminium species, and the relations between the composition of the solutions and their efficiency as flocculants. The solutions were quantitatively analyzed using ²⁷Al NMR and the ferron method; the latter method offers a simple and inexpensive alternative for identification and quantification of aluminium cations and can facilitate investigations of the Al speciation at concentrations too low for analysis by NMR. The distribution of aluminium cations in basic aluminium chloride solutions changes drastically by the dilution while applied as flocculants because the equilibrium strongly depends on the concentration. The dynamic changes following the dilution of partially neutralized solutions were investigated simply by mixing a solution with water and immediate analysis by the ferron method. It could be shown that rearrangement reactions occur in the system, partially overlapping each other, the oligomeric cations seem to be especially instable. Furthermore, a partial change from octahedral to tetrahedral coordination of the aluminium in the species can be observed. At extremely low aluminium concentration as in the case of application of the basic aluminium chloride solutions for flocculation, monomeric and especially transition polymeric and polymeric aluminium cations, respectively, appear. The ratio of these cations to each other also depends on the time up to the flocculation. Accordingly, these cations especially the different polymeric aluminium species seem to be important for the efficiency of the basic aluminium chlorides as flocculants in water conditioning.     

Monitoring Quiescent Volcanoes by Diffuse CO2 Degassing: Case Study of Mt. Fuji, Japan

Since the 8th century, more than seventeen eruptions have been recorded for the Mt. Fuji volcano, with the most recent eruption occurring in 1707 (Hoei eruption). For the past 300 years the volcano has been in a quiescent stage and, since the early 1960s, has exhibited neither fumarolic nor thermal activity. However, the number of low-frequency earthquakes with a hypocentral depth of 10–20 km increased significantly beneath the northeastern flank of Mt. Fuji in 2000–2001, suggesting a possible resumption of magmatic activity. In this study, diffuse CO₂ efflux and thermal surveys were carried out in four areas of the volcano in 2001–2002 in order to detect possible signs of the upward movement of deep magma. At all survey points, the CO₂ efflux was below the detection limit with the exception of a few points with biological CO₂ emission, and ground temperatures at a depth of 20–30 cm were below ambient, indicating no surface manifestations of gas or heat emission. Should magma rise into the subsurface, the diffuse CO₂ efflux would be expected to increase, particularly along the tectonically weakened lineation on the Mt. Fuji volcano, allowing for the early detection of pre-eruptive degassing.     

Determination of Polar Organic Pollutants in Aqueous Samples of Former Ammunition Sites in Lower Saxony by Means of HPLC/Photodiode Array Detection (HPLC/PDA) and Proton Nuclear Magnetic Resonance Spectroscopy ( 1H-NMR)

Leachate, ground-, and surface water from former ammunition sites and areas which are known to be contaminated by nitroaromatic compounds in Lower Saxony (Germany) were investigated in order to identify and quantify acidic nitroaromatic compounds (e.g., nitrobenzoic acids, aminonitrobenzoic acids, nitrophenols, and nitrocresols). Acidic and neutral nitroaromatic compounds were enriched by solid-phase extraction (SPE) on a polystyrenedivinylbenzene copolymer and routinely screened for acidic compounds by means of HPLC/photodiode array detection (HPLC/PDA). Qualitative and quantitative results obtained in this way were corroborated by proton nuclear magnetic resonance spectroscopy (¹H-NMR). Validation data for the quantification procedure using this technique are given. The results show that all samples contaminated with 2,4,6-trinitrotoluene (TNT) and related compounds are also contaminated by acidic nitroaromatic compounds (e.g., 2,4-dinitrobenzoic acid, 3,5-dinitrophenol, and especially with 2-amino-4,6-dinitrobenzoic acid) in the μg/L range. This current work shows that 1 H-NMR allows the quantitative determination of protoncarrying analytes in mixtures after solid-phase extraction down to the upper ng/L range after addition of an internal standard to the SPE extract. This is even possible when reference compounds are not commercially available.     

Simple Methodology for Estimating the Groundwater Recharge Potential of Rural Ponds and Lakes Using Remote Sensing and GIS Techniques: a Spatiotemporal Case Study of Roorkee Tehsil,India

Water Resources - Groundwater resources are depleting at an alarming rate all over the world. Therefore, ensuring water security is the foremost priority of every nation. This paper presents a...     

汶川地震滑坡危险性评价——以武都区和文县为例

利用GIS技术详细研究汶川地震在甘肃省陇南市武都区和文县触发的滑坡地质灾害的分布规律及其与地震烈度、地形坡度、断层、高程、地层岩性的相关关系,采用基于GIS的加权信息量模型的崩塌滑坡危险性评价方法,对研究区的地震滑坡危险性进行学科分析。结果表明：极高危险区在高程上主要分布在集水高程区,高度危险区主要沿白水江、白龙江等主干河流两侧极高易发区的边界向两侧扩展,轻度和极轻度危险区面积占比较小,主要分布在低烈度、活动断裂不发育、人类活动微弱的高海拔地区,另外国道G215沿极高危险性区域分布明显;利用危险性等级分区结果统计人口公里格网数据,得到武都区和文县潜在影响人口,发现研究区约78万人将受到地震滑坡灾害的潜在影响。     

Delineation of Shallow Subsurface Structure by Azimuthal Resistivity Sounding and Joint Inversion of VES-TEM Data: Case Study near Lake Qaroun, El Fayoum, Egypt

An azimuthal resistivity survey was conducted at the transition zone between the desert area and the cultivated land near Lake Qaroun, Egypt. This area has been affected by an east-west trending fault system as indicated from the surface geology. Apparent resistivity values were plotted along azimuth on a polar diagram. Resistivity anomalies, for most of the AB/2 values with long axes strike in a direction parallel to the contact between the desert and cultivated lands, indicate the presence of electrical macro-anisotropy, mainly due to the faulting effect, at this area. Vertical electrical soundings (VES) and transient electromagnetic (TEM) measurements were conducted at eight stations along a line that crosses the boundary between the desert and cultivated land. Joint inversion of VES-TEM data was successfully used for identification of the subsurface lithostratigraphic succession and demonstrated the effect of the fault zone on the investigated subsurface medium. Apparent anisotropy coefficients at all current electrode spacings were calculated, plotted against AB/2 values and compared with the geoelectrical cross section. The effect of the fault zone was detected at AB/2 spacings equal to 100 m and extended downward and is largely related to the depth of the fault, as indicated in the constructed cross section.     

Detection of Aseismic Slip on an Inland Fault by Crustal Movement and Groundwater Observations: A Case Study on the Yamasaki Fault, Japan

To understand the detailed process of fault activity, aseismic slip may play a crucial role. Aseismic slip of inland faults in Japan is not well known, except for that related to the Atotsugawa fault. To know whether aseismic slip does not occur, or is merely not detected, is an important question. The National Institute of Advanced Industrial Science and Technology constructed an observation site near Yasutomi fault, a part of the Yamasaki fault system, and has collected data on the crustal strain field, groundwater pressures, and crustal movement using GPS. In a departure from the long-term trend, a transient change of the crustal strain field lasting a few months was recorded. It indicated the possibility of an aseismic slip event. Furthermore, analyses of data from the extensometers at Yasutomi and Osawa observation vaults of Kyoto University, as well as GPS data from the Geographical Survey Institute (GEONET), revealed unsteady crustal strain changes. All data could be explained by local, left-lateral, aseismic slip of the order of 1 mm in the shallow part of the Yasutomi fault.