模拟退火方法在三维速度模型地震波走时反演中的应用

采用块状建模以及三角形拼接的界面描述方式,并通过立方体速度网格线性插值获得块体内部的速度分布。正演过程中采用逐段迭代射线追踪方法计算三维复杂地质模型中的射线走时,并采用模拟退火方法进行了三维模型中的地震波走时反演研究。模型测试结果表明,使用的射线追踪和走时反演算法有效。     

Hydrological system analysis and modelling of the Kara River basin (West Africa) using a lumped metric conceptual model

This paper discusses the analysis and modelling of the hydrological system of the basin of the Kara River, a transboundary river in Togo and Benin, as a necessary step towards sustainable water resources management. The methodological approach integrates the use of discharge parameters, flow duration curves and the lumped conceptual model IHACRES. A Sobol sensitivity analysis is performed and the model is calibrated by applying the shuffled complex evolution algorithm. Results show that discharge generation in three nested catchments of the basin is affected by landscape physical characteristics. The IHACRES model adequately simulates the rainfall–runoff dynamics in the basin with a mean modified Nash-Sutcliffe efficiency measure of 0.6. Modelling results indicate that parameters controlling rainfall transformation to effective rainfall are more sensitive than those routing the streamflow. This study provides insights into understanding the catchment’s hydrological system. Nevertheless, further investigations are required to better understand detailed runoff generation processes.

EDITOR M.C. Acreman; ASSOCIATE EDITOR N Verhoest     

Coupling snow accumulation and melt rate modules of monthly water balance models with the Jazim monthly water balance model

Several models for simulation of water balance processes in semi-arid mountainous basins were developed by coupling different modules of existing water balance models (WBM). Snow accumulation and snowmelt rate relationships extracted from the McCabe-Markstrom, Guo, Rao-Al Wagdany and WASMOD-M WBMs, originally developed for basins with humid climate, were coupled with the Jazim WBM, primarily developed for arid basins. Karaj Basin, central Iran, with snowy autumn–winter and dry summer periods, was selected to assess model performance. The model parameters were optimized using a genetic algorithm (GA). All coupled models performed better than the non-modified (original) WBMs in the study basin. The coupled Jazim–McCabe-Markstrom model provided the best performance in simulating low and high monthly flows. It estimated the snowmelt runoff values more accurately than other proposed coupled models because the linear relationships used in the snow module of the McCabe-Markstrom model are more compatible with snow variations in the Karaj Basin.     

A conceptual hydrogeological model of ophiolitic aquifers (serpentinised peridotite): The test example of Mt. Prinzera (Northern Italy)

The main aim of this study is the experimental analysis of the hydrogeological behaviour of the Mt. Prinzera ultramafic massif in the northern Apennines, Italy. The analysed multidisciplinary database has been acquired through (a) geologic and structural survey; (b) geomorphologic survey; (c) hydrogeological monitoring; (d) physico‐chemical analyses; and (e) isotopic analyses. The ultramafic medium is made of several lithological units, tectonically overlapped. Between them, a low‐permeability, discontinuous unit has been identified. This unit behaves as an aquitard and causes a perched groundwater to temporary flow within the upper medium, close to the surface. This perched groundwater flows out along several structurally controlled depressions, and then several high‐altitude temporary springs can be observed during recharge, together with several perennial basal (i.e., low altitude) springs, caused by the compartmentalisation of the system because of high‐angle tectonic discontinuities.     

基于反应位移法的复杂软土盾构隧道横断面抗震分析

采用反应位移法,利用ABAQUS软件建立梁-弹簧有限元模型,进行复杂软土场地中盾构隧道横断面抗震分析,并结合天津滨海Z2线软土盾构隧道进行计算。研究表明,在地震作用下,最大弯矩值和剪力值一般出现在拱肩位置,最大轴力值一般出现在拱腰附近;处于复杂地层附近的隧道结构内力值较大,应加强该位置处的抗震构造措施或在选线时尽量避免复杂场地。本文对复杂软土场地中盾构隧道横断面抗震设计具有一定参考价值。     

川西坳陷新页HF-1井须五段泥页岩吸附气含量主控因素及其定量预测模型

页岩气是一种重要的非常规天然气,其中相当一部分的天然气以吸附态存在。吸附气含量是页岩气资源评价和目标区优选的关键性参数,也是评价页岩是否具有经济开采价值的一个重要标准。为了探讨川西坳陷新页HF-1井须五段泥页岩吸附气含量主控因素,选取了该井须五段泥页岩样品进行同一温度下的等温吸附实验,获得页岩等温吸附特征曲线及Langmuir体积和Langmuir压力值,分析压力对页岩吸附气含量的影响程度,利用Langmuir模型计算地层压力条件下的吸附气含量。利用实验数据分析了新页HF-1井须五段泥页岩吸附气含量与比表面积、孔隙度、密度、成熟度、湿度和压力各单因素之间的相关关系,然后运用SPSS软件对吸附气含量的几个影响因素进行了主成分分析。结果表明：比表面积、湿度和压力是影响新页HF-1井须五段泥页岩吸附气含量的主要因素。最后建立了同时考虑这3个主控因素的页岩吸附气含量计算新模型。通过新模型可以计算出新页HF-1井须五段未知泥页岩的吸附气含量,计算结果与实测值之间相关系数高,结果准确可靠,是一种评价等温条件下页岩吸附气含量的好方法,对页岩吸附气含量评价具有一定的指导意义。     

西藏多龙矿集区拿若铜（金）矿床成矿元素空间分布规律及地球化学勘查模型

拿若铜(金)矿床是多龙矿集区内继多不杂斑岩铜(金)矿、波龙斑岩铜(金)矿之后又一取得重大找矿突破的大型斑岩型矿床。作者以矿区探矿工程分析数据为基础,研究各成矿元素空间分布规律。成矿元素在垂向上的分带特征不明显,在平面上分带特征较显著,表现为自矿区中心ZK0001,向南西方向具有Cu+Au-Cu(Au、Ag)→Cu(Ag、Au)-Cu(Ag)的分带特征。同时,矿区土壤地球化学测量显示,从0线开始至31线(北东→南西)具有Mo、Cu→Mo(Cu、Au)→Cu、Au(Ag、Mo、Pb)→Pb→Pb、Zn分带特征,显示物质来源和热源位于0线附近,成矿流体是以0线、7线一带向四周运移,并具有从北东向南西方向运移的特点。通过矿床地质特征、元素分带特征研究,建立了矿区地球化学勘查模型。     

区划方法在无资料地区水文预报中的应用研究

区划方法是目前国际上解决无资料地区水文预报问题的常用方法,是近20年水文学界热点问题之一。本文通过介绍当前国际应用区划方法解决无资料地区水文预报问题的研究进展、存在问题和应用前景,为国内无资料地区水文模拟研究提供借鉴和参考。文章将区划方法分为3类:临近流域替代法、水文相似流域替代法和回归法。通过文献梳理及案例分析,本文指出各类方法的问题、适用范围及不同资料条件下方法选择。最后,通过对国际上无资料地区水文预报的总结分析,提出我国无资料地区研究亟待解决的5个问题。     

Petrophysical software for interpreting integrated well-logging data based on spectrometric gamma-logging

This paper discusses modern techniques of identification of reservoir rocks of complex mineral composition in low-thickness layers. The principal purpose of the study is the elaboration of an optimal set of petrophysical investigations used for interpretation of well-logging (WL) data. The solution of the problem lies in generating a mineral-component model of sediments and in finding a range of admissible values of every macro component and its petrographic parameters.     

利用地震模拟技术研究逆断层的断点位置

在地震资料解释阶段,可根据解释结果进行正演模拟,以验证解释结果的可靠性,并通过模型正演方式了解地下波场的细微变化,提高解释精度。依据内蒙古鄂托克前旗沙章图矿区DF2逆断层的赋存形态,建立的地质模型,并围绕其逆断层的断点位置、埋深、地层速度等,对各种接收排列进行射线追踪实验。通过改变开动的道数、道距及偏移距,观察各种参数下射线追踪的分布情况及模拟时间剖面的面貌。正演结果表明利用射线模型追踪的模拟地震反射剖面与实际时间剖面完全吻合,其确定的逆断层断点位置及断面倾角合理。