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1.
Weathering rates of silicate minerals observed in the laboratory are in general up to five orders of magnitude higher than
those inferred from field studies. Simple calculations show that even if the field conditions were fully simulated in standard
laboratory experiments, it would be impossible to measure the slow rates of mineral dissolution that are observed in the field.
As it is not possible to measure the dissolution rates under typical field conditions, one should extrapolate the available
data to the field conditions. To do this, a rate law for the dissolution of plagioclase in the field was formulated by combining
the far from equilibrium dissolution rate of weathered natural oligoclase at 25°C with the effect of deviation from equilibrium
on dissolution rate of fresh albite at 80°C. In contrast to the common view that laboratory experiments predict dissolution
rates that are faster than those in the field, the simulation based on this rate law indicates that laboratory dissolution
experiments actually predict slower rates than those observed in the field. This discrepancy is explained by the effect of
precipitation of secondary minerals on the degree of saturation of the primary minerals and therefore on their dissolution
rate. Indeed, adding kaolinite precipitation to the simulation significantly enhances the dissolution rate of the plagioclase.
Moreover, a strong coupling between oligoclase dissolution and kaolinite precipitation was observed in the simulation. We
suggest that such a coupling must exist in the field as well. Therefore, any attempt to predict the dissolution rate in the
field requires knowledge of the rate of the secondary mineral precipitation. 相似文献
2.
南海A区某开发气田为岩性一断圈气藏,受断层影响,为多个小型断块气藏的集合,每块气水界面不统一,气藏情况复杂。常规的AVO反演技术往往只能定性地识别含气性,无法定量地识别储层的含水饱和度。为了满足气田合理高效开发的需求,查清每块气藏的气水充注程度,在高分辨率三维地震资料中,采用了EEI反演技术来预测储层的含水饱和程度。研究结果表明,在该区运用EEI反演技术得到的EEI属性,能有效地识别出含水饱和度低于60％的气层,研究成果对气田进入开发后期调整井布署、提高采收率具有不可替代的作用。 相似文献
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Doklady Earth Sciences - The original materials obtained, along with the literature data (hydrochemical contrasting halos), make it possible to predict a new (Tarakon) gold ore field within the... 相似文献
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利用积累的磁照图——S_q曲线,通过计算机进行S-q图象编整处理后作对比分析,对局部磁异常(S_q时段)变化进行探讨,总结地震孕育过程震磁效应的相关性,更好地为地震预报提供依据。 相似文献
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针对构造裂缝产状演化规律难以准确定量表征的问题,通过确定研究区裂缝力学性质、岩石力学参数,在恢复古构造形态的基础上,对裂缝形成时期古应力场数值模拟后选择适用性的岩石破裂准则,预测裂缝形成时期的产状分布。提出了造缝期应力场预测古裂缝产状,后期构造活动改造裂缝产状的思路,即通过早期岩层、晚期岩层的三维空间变化规律,建立了不同构造活动时期对应的裂缝空间转换理论模型,利用推导的数学算法,定量分析裂缝的演化规律,进而提高了现今裂缝产状的预测精度。最后,以铜城断裂带东翼阜二段储层为例进行了构造裂缝演化规律定量描述工作,结合构造演化,将阜二段储层构造裂缝演化分为阜宁运动晚期裂缝形成发育、戴南运动期裂缝继承发展、三垛运动期裂缝差异分离3个阶段。 相似文献
7.
Yuanzhong Lu Shuxin Yang Lianwang Chen Jianshe Lei 《Journal of Asian Earth Sciences》2011,40(4):990-1001
Strong earthquakes that occurred in the Chinese continent are usually characterized by grouped activity, long-distance jumping migration, and different main activity areas formed in different times. In the present study, a three-dimensional (3-D) finite element model was set up for the Chinese continent involving surface topography, major active fault zones and initial stress field to study the mechanism of the long-distance jumping migration of main active areas for the strong earthquakes that occurred in the Chinese continent. A number of numerical simulation experiments have been made by introducing the birth and death of element groups under different boundary loading configurations. Our results show that (1) in an environment where always exists an initial stress field in the Earth’s crust, the areas where strong earthquakes have occurred (taken as a killed element in the model) have no longer abilities to concentrate the stress largely enough and can cause the stress adjustment by an order of MPa in a large area, which may be one of the main factors affecting the long-distance jumping migration of the follow-up strong earthquakes, and (2) it is hard to accurately predict where the follow-up strong-earthquakes will occur because it could be affected by many factors such as the loading manner, geological structure, active fault zones, initial stress field, or stress field adjustment induced by strong earthquakes, but in an active period of earthquakes, the major activity area migration of strong earthquakes may be affected largely by the boundary loading configurations. These results suggest that it is helpful to predict a trend of the strong earthquake migration by investigating various kinds of boundary loading manners and the relationship between stress field adjustment induced by strong earthquakes and the regions where the strong earthquakes occurred. 相似文献
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矿物原位LA-ICPMS微量元素分析及其在矿床成因和预测研究中的应用进展 总被引：5，自引：4，他引：1
随着激光剥蚀电感耦合等离子质谱技术(LA-ICPMS),短波近红外光谱分析技术(SWIR)以及其它微区分析技术的飞速发展,矿物原位微量元素组成的相关研究已成为地球科学领域的热点。目前国内外的研究主要集中在利用矿物微量元素组成来反演成矿流体的性质和演化规律,示踪成矿物质的来源,约束岩石和矿床的成因,并进行成矿带的识别和矿化中心的预测,特别是近十多年,在应用矿物微量元素组成特征进行矿床预测和勘探方面取得了巨大的进展。本文简要综述了国际上该领域近年来上述有关方面的研究现状和取得的主要进展,并重点总结和论述了部分重要矿物的原位微量元素研究在成矿预测应用方面所取得的最新成果,包括:(1)通过对岩浆成因矿物,如斜长石、锆石、磷灰石和磁铁矿等元素组成研究进行成矿潜力的判别;(2)通过热液蚀变矿物,如绿帘石,绿泥石,磁铁矿和明矾石等的元素组成来预测矿化中心的方向和位置,同时进行含矿性和成矿潜力的判别。文章认为,随着微区分析技术的飞速发展,矿物原位微量元素组成的研究已成为地球科学领域特别是矿床学和勘查学的研究热点。继续加强矿物原位LA-ICPMS微量元素分析技术及相关基础研究,进一步探索和应用不同矿物微量元素组成特征来建立精确的勘探指针,有效指导深部矿床勘查,是下一步的主要发展方向。 相似文献
10.
Complexation of metal ions by organic matter is frequently considered to play a part in metal ion dissolution in natural waters. A field study of a relatively unperturbed stream, high in organics, associates this with the fraction related to soil organic acids (humic acids). The association might have two origins. The first is complexation. However, well known sequences of complexing tendency do not predict the behaviour. A better theory uses the additional factor of the reducing capacity of dissolved organic matter toward Fe(III) and Mn(IV). 相似文献
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The resource of the gas from coal and coal measures deep in Songliao Basin hasbeen drawing more and more attention to.It is necessary to find out the evolution regulari-ty of the geothermal field of the basin in addition to a series of geological studies in orderto predict its resources because the ancient geothermal field of the basin is one of themain factors controlling the generation,evolution and disappearance of oil and gas.Inthe recent twenty years,it is generally believed that vitrinite reflectance is the best quanti-tative marker for the ancient geothermal field.In the present paper,a systematic studyof the vitrinite reflectance value of Songliao Basin and its influence factors is made by mul-tiple statistical analysis so as to reconstruct the evolutional process of the Moho and thecorresponding geothermal field.Then,an overall prediction is made of the vitrinitereflectance and the distribution of J_3-K_1 fault basin group at the bottom of SongliaoBasin,which provides the evidence for the furth 相似文献
13.
Using energy and entropy constraints applicable to the Earth's core, the heat flow at the core–mantle boundary (CMB) needed to sustain a given total dissipation in the core can be computed. Reasonable estimates for the present Joule dissipation in the core gives a present heat flow of 6 to 10 TW at the CMB. Palaeointensity data acquired from rocks younger than 3.5 Ga provide support that the Joule dissipation in the core before inner core crystallization was between today's value and four times lower than today. Prior to inner core crystallization (around 1 Ga), the magnetic field was maintained by thermal convection driven by core cooling, and our calculations of the two extreme cases predict that the heat flow at the CMB at that time was either 14 to 24 TW in the case of constant dissipation, or essentially the same as today in the lower field intensity case. 相似文献
14.
四川盆地富顺-永川地区五峰组—龙马溪组应力场模拟及裂缝发育区预测 总被引：1，自引：1，他引：0
岩石中构造裂缝主要受控于地层所处的区域构造应力场,地应力对油气的运移、成藏和分布有着重要的作用。通过应用ANSYS有限元数值模拟方法对四川盆地富顺-永川区块的五峰组-龙马溪组进行应力场模拟及分析研究、应用构造曲率法中的三点法对该层段页岩进行张裂缝发育情况预测研究、综合模拟结果与曲率计算数据对目的区域目的层段进行裂缝发育强度综合预测研究,结果表明富顺-永川区块五峰组-龙马溪组应力高值沿背斜走向分布的规律明显,研究区的东部及西南部的背斜应力值较其他区域背斜高;曲率高值沿背斜走向分布的规律明显,研究区东部及西南部背斜曲率值较其他区域背斜高;在现今应力的作用下,研究区背斜处裂缝发育程度较高,向斜处裂缝发育程度较低,研究区东部及西南部背斜裂缝发育程度较其他区域高。 相似文献
15.
铁路碎石道碴层通风阻力参数试验研究 总被引：3，自引：1，他引：2
铁路碎石道碴层能被看作高渗透率的多孔介质,由于其具有较好的通风特性,它的存在改变了寒区铁路路基的顶部热交换条件,对路基温度场产生不可忽视的影响.为了能够实现对寒区铁路路基温度场的更合理预测,基于对铁路碎石道碴层传热和通风特性的研究现状,通过风洞试验对铁路碎石道碴层的通风特性及通风阻力参数进行了试验研究.试验中选用的铁路碎石道碴平均粒径为4.2cm,孔隙率为0.433,对不同空洞风速条件下铁路碎石道碴层中的压力梯度和渗流速度进行了测试分析.结果表明:铁路碎石道碴层中空气渗流速度随着压力梯度的增大而增大,其内部压力梯度与渗流速度之间存在良好的二次非线件关系.通过计算得到铁路碎石道碴层的渗透率和惯性阻力系数,为寒区铁路路基热稳定性的数值研究提供了参数依据. 相似文献
16.
Two numerical models, one for the vadose zone and the other for the aquifer system, are utilized to predict nitrate pollution
potential in groundwater. Transport by dispersion and convection of mobile species of nitrogen, ammonium ion exchange, first
order nitrogen transformations, and nitrogen plant uptake are included in the formulation for the vadose zone. Transport of
nitrate in the aquifer is assumed to be affected only by dispersion-convection phenomena. Justifications for one-dimensional
conceptualization of flow in the vadose zone and two-dimensional representation for the aquifer, under various field conditions,
are presented. To illustrate the concept, a simple hypothetical problem is solved. The approach presented here provides an
efficient means of long-term simulation of large-scale field problems. 相似文献
17.
R.J. Muir 《Geology Today》2015,31(6):232-236
Current desktop technology is largely mouse‐driven, but many analysts predict that in less than five years we will have a professional workforce that have only experienced learning in a touchscreen environment. Midland Valley have developed a digital mapping tool for smartphones called FieldMove Clino, which has been downloaded more than 20 000 times over the past year. The free version offers an effective way of introducing students to digital field mapping. However, many geoscience departments and teachers of field mapping have yet to make the switch from traditional paper‐based methods to digital technology. This article aims to answer some of the frequently asked questions about digital field mapping and outlines some of the advantages for improving field skills and geological thinking in students. 相似文献
18.
为解决琼东南盆地深水区物源问题,将非线性技术应用于陵水17-2气田物源分析,即利用自然伽马测井曲线的分形维数进行沉积物源方向分析。该技术有效避免了由于风化、搬运、沉积等作用而导致的重矿物组分变化问题,在琼东南盆地深水区黄流组沉积物源分析的应用中取得了良好效果,开辟了深水区物源分析的新思路。同时针对深水区复杂储层特征,为有效预测油气层评价中储层参数如孔隙度、渗透率等,文中基于非线性理论,采用多重分形模型对琼东南盆地深水区黄流组储层参数进行预测,并与实钻结果进行对比,结果表明,采用物性参数-面积(PP-A)分形模型计算得到的范围包含了实钻结果,可以根据该参数预测未知区域储层参数,从而为油气藏评价提供依据;而采用分形滤波技术(S-A)得到的结果更接近实际情况,这说明S-A法能在PP-A法的基础上更深层次地预测储层参数,从而得到更准确的信息。多重分形法可以准确有效地获取无井点处的参数估计值,其精度和预测能力都能达到少打井、少投资和早见效的目的。 相似文献
19.
Utilizing computational neural networks for evaluating the permeability of compacted clay liners 总被引：1，自引：0，他引：1
The design of lined waste-storage facilities is significantly influenced by the permeability of the liner. The permeability of compacted clay liners, in turn, is influenced by factors such as clay type and composition, compaction type and effort, and operating conditions. The complexity of the permeation process makes it difficult to predict analytically the permeability from these factors. As a result, empirical regression models are frequently used to predict permeability. In this paper, permeability prediction models are developed using computational neural networks (CNNS). The developed CNN models are used to predict the permeability of compacted clay for a known set of soil properties and field and laboratory conditions. Moreover, the models are used to determine the relative importance of the various input parameters to the model output. Also, a comparison between regression models and neural networks for predicting permeability is presented and the advantages of utilizing CNN methodology over regression techniques in model development are highlighted. 相似文献
20.
乌干达K油田位于Albert盆地,由于钻井数较少,地震资料品质差,沉积储层空间分布预测存在严峻挑战.根据岩心、测井、古生物、重矿物、粒度分析等资料综合分析后认为,乌干达K油田属滨浅湖环境,发育受边界断层控制的近源扇三角洲沉积,物源方向位于油田东南部,以低能长期的水下分流河道牵引流搬运为主.在沉积主控因素定量分析的基础上,将可容纳空间变化、物源供应及沉积物搬运等参数定量表征,并在年代地层框架约束下,通过正演模拟,再现地质历史时期地层沉积演化过程,建立了三维储层砂岩分布概率模型,进一步认识了研究区各层砂体的空间分布特征.将沉积演化模拟的砂岩分布结果转化为三维地质建模的定量控制条件,对沉积相模型进行约束,建立了更符合沉积认识的高精度相控地质模型,实现了扇三角洲储层砂体定量预测与表征. 相似文献