Geostatistical seismic Amplitude‐versus‐angle inversion

Seismic inversion plays an important role in reservoir modelling and characterisation due to its potential for assessing the spatial distribution of the sub‐surface petro‐elastic properties. Seismic amplitude‐versus‐angle inversion methodologies allow to retrieve P‐wave and S‐wave velocities and density individually allowing a better characterisation of existing litho‐fluid facies. We present an iterative geostatistical seismic amplitude‐versus‐angle inversion algorithm that inverts pre‐stack seismic data, sorted by angle gather, directly for: density; P‐wave; and S‐wave velocity models. The proposed iterative geostatistical inverse procedure is based on the use of stochastic sequential simulation and co‐simulation algorithms as the perturbation technique of the model parametre space; and the use of a genetic algorithm as a global optimiser to make the simulated elastic models converge from iteration to iteration. All the elastic models simulated during the iterative procedure honour the marginal prior distributions of P‐wave velocity, S‐wave velocity and density estimated from the available well‐log data, and the corresponding joint distributions between density versus P‐wave velocity and P‐wave versus S‐wave velocity. We successfully tested and implemented the proposed inversion procedure on a pre‐stack synthetic dataset, built from a real reservoir, and on a real pre‐stack seismic dataset acquired over a deep‐water gas reservoir. In both cases the results show a good convergence between real and synthetic seismic and reliable high‐resolution elastic sub‐surface Earth models.     

Strategies to Make Methods Based on Flow Injection Analysis Greener

The implementation of flow injection analysis (FIA) systems and correlated techniques in the laboratory routine provides an increase of analytical throughput and the reduction of risks of analyte losses and contamination. Naturally, it contributes to the reduction of reagent consumption and minimization of waste generation. This paper presents and discusses an overview of the main strategies adopted to make methods based on FIA systems more environmentally friendly, and offers a review of these methods that covers the period from January 2002 to December 2019. Strategies based on reagent management (adoption of procedures without reagents, replacement of toxic reagents, recycling and reuse of reagents and, use of immobilized reagents), the online waste treatment, and the improvements of FIA systems (flow system configurations that avoid reagent wastage, use of green detectors, automation, and miniaturization) are approached in this perspective.     

Middle Terrace Deposits of the Tagus River in Alpiarça, Portugal, in Relation to Early Human Occupation

The stratigraphy and sedimentology of the Q3 middle terrace alluvial sequence in the lower Tagus river valley, Portugal, were studied near the village of Alpiarça, approximately 40 km upstream from the estuarine area. Two main stratigraphic units were recognized, separated by an important uncomformity. The Lower Gravels unit (LG) consists of intercalations of medium to coarse gravel deposits, mainly quartzitic, with coarse sandy matrix, organized in tabular bodies. The overlying Upper Sands unit (US) consists of tabular sandy channel deposits and overbank fines, the latter containing well-developed paleosols and backswamp deposits, showing a general aggrading trend, apparently with varying rates; available data indicate that deposition of the US took place under temperate climatic conditions. Within US deposits are several paleolithic archaeological sites, the lower ones in the alluvial stratigraphy being Middle Acheulian, whereas those embedded in overlying deposits are, from bottom to top, Upper Acheulian and Micoquian. Some of these sites have been recently excavated. The quartzite artifacts were apparently abandoned by early humans on the flood plain surface during deposition of the US unit and were subjected to limited reworking during their incorporation in the alluvium. TL/OSL dating of sandy-silty sediments, though imprecise, support archaeological evidence pointing to an age of 150,000 to 70,000 yr B.P. for the US unit.     

基于Fuller投影的六边形球面离散格网生成算法

随着云计算、航天遥感、地理信息、导航等技术的发展,用于空间信息剖分组织的全球多分辨率离散格网模型得到了长足发展。针对已有研究成果和当前研究现状,选取性能优异的六边形作为基本格网单元,Fuller多面体投影作为投影类型,提出了一种基于正八面体构建新型六边形球面离散格网的方法。全文系统地论述了此新型离散格网的生成算法并给出了相应实验结果,最后与基于Snyder等积多面体投影的格网进行比较,得出其特点和应用前景。     

贵州台江革一黔东统杷榔组沉积环境初探

贵州台江革一杷榔组出露完整、富含化石,其中—上部层位产有类群组合多样的杷榔动物群,为杷榔动物群的一个重要产地。本文通过详细的野外观察,结合生物化石保存情况及岩石薄片的分析结果,对革一杷榔组沉积环境及其海平面变化规律进行了综合分析,认为革一杷榔组的沉积位于盐度正常、较深水的陆棚环境,生物生活环境多为氧化—弱氧化环境,富含化石的层位经历了快速沉积事件,整组的沉积由底向上海水经历了由深至浅的变化过程,但其间经历2次小的波动,水体变深后变浅,并出现还原—氧化界面的波动 。     

Rotation of Tokamak Plasmas by Alfvén Waves

Externally excited Alfvén waves can generate the poloidal and toroidal rotation in the collisional (edge) and core (weakly collisional) tokamak plasma. The necessary value of these velocities to achieve the L-H transition, can be obtained by manipulating the value of an absorbed power. This rotation linearly depends on dissipated power, decreases in banana regimes and did not depend on toroidal magnetic field. In the plasma layer where the RF power is absorbed, the radial electric field also appears. There is the very satisfactory agreement between our theory and experimental results obtained on Phaedrus-T tokamak. The methods developed in this paper can be applied to other tokamaks with another kind of waves, which can be used to operate the plasma dynamics taking into account the appropriate dispersion relation for that type of waves.     

Effect of Induced Toroidal Rotation on Poloidal Rotation and Ion Heat Conductivity of Tokamak Edge Plasmas

The transport processes in edge (collisional) plasmas of tokamaks with smooth profiles of macroscopic plasma parameters and induced poloidal and toroidal plasma flows, are considered. The toroidal and poloidal velocities of particles, the radial electric field and the ion heat flux are derived. It is shown that forces, induced by radio frequency waves, plasma turbulence or neutral beam injection, can be used to control the poloidal and toroidal plasma velocities, as well as ion heat conductivity, in a wide range of these values.     

高潜水位矿区采煤沉陷地DEM的无人机构建方法

针对高潜水位矿区采煤沉陷地植被密度大、无人机摄影测量难以获取地面点云的问题,从采煤沉陷地地形特征出发,提出了一种基于断面式点云滤波和DEM模型修正的采煤沉陷地DEM构建方法,经分析,精度可达到1：500比例尺地形图要求,可以为采煤沉陷地损毁评价和土地复垦工作开展提供重要依据。     

Phytoremediation potential and morphological changes of plants growing in the vicinity of lead smelter plant

With the increasing industrialization, heavy metals concentration in soils has greatly increased. Phytoremediation is a low-cost, non-intrusive and aesthetically harmonious technology that uses plants to remediate contaminated sites by heavy metals. The aim of the study was to determine Cd, Pb and Zn concentration in the biomass of plant species growing on a multi-metal-contaminated site of lead smelter processing, to assess the workability of using these plants for phytoremediation purposes and highlight possible damage in morphological leaf changes. Two plant species, i.e., Ipomoea asarifolia and Urochloa decumbens and the associated soil samples were collected and analyzed Cd, Pb and Zn concentrations and then calculating the bioconcentration factor and translocation factor parameters for each element. Leaves and roots samples were observed by light microscopy. Metal concentrations varied greatly and majorly depend on site sampled, plant species and tissue. Cd, Pb and Zn in tissue ranged from 0 to 102.48, 0 to 381.04 and 12.84 to 295.02 mg Kg^?1. However, none of the plant showed potential for hyperaccumulation. Both plants showed bioaccumulation factor more than one, where it was 7.66 and 6.82 for Pb and Zn in U. decumbens, respectively. Translocation factor was calculated below one for both plants and all metals. Morphological studies revealed development of adaptive features that strengthen the U. decumbens to grow in contaminated soil. Our study suggests that I. asarifolia and U. decumbens have potential for phytostabilization at multi-metal-contaminated site.