Water organisation at the solid–aqueous solution interfaceOrganisation de l'eau à l'interface solide–solution aqueuse

The aim of this review is to examine the present knowledge about water structure close to an interface or confined in porous spaces. First, the structure of liquid water is briefly described. Though its understanding remains incomplete, it appears that it is largely dominated by the hydrogen bond network and its dynamical evolution. The presence of any ‘foreign’ substance in water perturbs such a structure by changing at least locally the hydrogen bond network. For this reason, the presence of a solid interface significantly modifies the structure of the first adsorbed layers. Whatever the support, it is now clearly evidenced that structural perturbations are limited to distances lower than 10–15 Å from the interface. The nature, energetic heterogeneity and hydrophilicility/hydrophobicity of the solid surface influence the arrangement of water molecules. This surface organisation must definitely be considered when studying adsorption phenomena at the solid–aqueous solution interface. The relevance of such problems to geosciences is illustrated by a few situations in which water structure plays a prominent role. To cite this article: L.J. Michot et al., C. R. Geoscience 334 (2002) 611–631.     

Locating a Community Recycling Center within a Residential Area: A Belgian Case Study

This article demonstrates the operation of a simple optimal location‐allocation technique for solving the problem of locating one or several community recycling center(s) within a residential area. The article attempts to measure both transportation and externality costs in comparable units, and to incorporate them into the model. A sensitivity analysis of the results at the level of the nuisance provides further insight into the operation of the model and the relative importance of the quantification of pollution in applied location‐allocation problems.     

地震储层表征:在模拟储层的三维地震响应时考虑盖层、地震勘探布局和储层物性的敏感度(英文)

根据三维地震地质模型对地震数据进行模拟是从勘探到生产的周期内决策过程中的一个不可或缺的组成部分。虽然对于在储层内的动力过程和地震地质的模型表述已经取得很大进展,但如何从这些模型得到地震数据的精确模拟仍面临很多挑战。通常是在地球模型范围内根据物性用一维褶积方法来模拟地震数据。然而这个过程一般不考虑地震勘探布局和盖层对地震信号的影响。我们审视了为什么这些因素会制约三维地球模型的有效性,并考虑了为什么需要把盖层和地震勘探布局对三维覆盖和分辨率的影响加进模拟过程之中。我们提出了一种新方法,把建立物性模型和一种新的地震模拟技术结合起来,给出一个工作流程;利用这个流程,勘探工作者可以很快模拟出三维的PSDM数据,这些数据加进了盖层和地震勘探布局对覆盖及分辨率的影响。我们利用从远离挪威海岸的一个油田得到的数据,在考虑覆盖和分辨率效应的地震数据模拟之前,对岩石物性做了一些扰动,然后进行地震数据模拟,以此来说明如何可以用这种方法提高三维地球模型的精确性和增进我们对储层的了解。     

On the use of long-term observation of water level and temperature along the shore for a better understanding of the dynamics: example of Toulon area,France

Ocean Dynamics - A dense network of instruments has been deployed within harbors along the Mediterranean coast, in the Toulon Metropole area, between the Hyères islands and the Sanary Bay in...     

Weathering of Oil in a Surficial Aquifer

The composition of crude oil in a surficial aquifer was determined in two locations at the Bemidji, MN, spill site. The abundances of 71 individual hydrocarbons varied within 16 locations sampled. Little depletion of these hydrocarbons (relative to the pipeline oil) occurred in the first 10 years after the spill, whereas losses of 25% to 85% of the total measured hydrocarbons occurred after 30 years. The C_6‐30 n‐alkanes, toluene, and o‐xylene were the most depleted hydrocarbons. Some hydrocarbons, such as the n‐C_10–24 cyclohexanes, tri‐ and tetra‐ methylbenzenes, acyclic isoprenoids, and naphthalenes were the least depleted. Benzene was detected at every sampling location 30 years after the spill. Degradation of the oil led to increases in the percent organic carbon and in the δ ¹³C of the oil. Another method of determining hydrocarbon loss was by normalizing the total measured hydrocarbon concentrations to that of the most conservative analytes. This method indicated that the total measured hydrocarbons were depleted by 47% to 77% and loss of the oil mass over 30 years was 18% to 31%. Differences in hydrocarbon depletion were related to the depth of the oil in the aquifer, local topography, amount of recharge reaching the oil, availability of electron acceptors, and the presence of less permeable soils above the oil. The results from this study indicate that once crude oil has been in the subsurface for a number of years there is no longer a “starting oil concentration” that can be used to understand processes that affect its fate and the transport of hydrocarbons in groundwater.     

Fault throw determination using 4 component VSP: Aigion fault (Greece) case study

The present paper presents the results of a technique based on Vertical Seismic Profiling (VSP) to quantify the offset of a fault in a context where seismic reflection profiles do not image any reflectors. The case study is located in Greece, in the Aigion area, on the south border of the Corinth Gulf. The Aigion fault, oriented East–West, and dipping at 60°N, has been intersected by the scientific well Aig-10 at 760 m in depth, but some uncertainty remained concerning its exact offset since the depth of the pre-rift sequence is open to debate due to the lack of subsurface data. The pre-rift consists of a Mesozoic low-porosity series (carbonates and radiolarite), while the syn-rift consists of poorly compacted conglomerates and turbidites.

Seismic diffractions on fault edges are expected to be present along the fault surface. We find that a few diffracted events are effectively recorded in P and S wave mode by the 4 components of the VSP survey, and critically refracted arrivals along the Aigion fault plane. These singular events have been used in order to refine the fault geometry and to determine its throw. Additionally, results from a 2D finite difference elastic seismic model of a single fault step geometry have been closely examined in order to illustrate the generation of the singular seismic events observed on the field data, such as P-wave and S-wave refracted and diffracted events, and support their interpretation with higher confidence. As a result, the seismic arrival patterns from full waveform seismic modelling confirm the characterisation of the main fault geometry (mainly its throw: about 200 m) in the well vicinity derived from the actual analysis of the 4 Component Aigion VSP data.