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1.
1.IntroductionAnimportantaspectofthestudyoftheGGT(i.e.GlobalGeoscienceTransect)istoreconstructthehistoryoftheterranesthattheGGTrunsacross(Mongeretal.,1985).Becausethesedimentsaretheproductsofvariousgeologicaleffectsinthegeologicalhistory,wecanreconst…  相似文献   

2.
冰川冻土分会发出为“全球冻土数据库(GGD)”征集数据的紧急通知国际冻土协会(IPA──InternationalPermafrastAssociation)正在筹建全球冻土数据库(GGD──GlobalGeocryologicalDatabase)...  相似文献   

3.
1.IntroductionThesystematictheoryinRockMasEngineeringGeologyistheRockMasEngineeringGeomechanicsestablishedbyGuDezhen(1979).He...  相似文献   

4.
1.IntroductionFig.1. RegionalgeologyoftheeasternLiaoningSouthernJilinarea(AfterZhang,1984)  ThePaleoproterozoicvolcanicsedimentarysequence,i.e.,theSouthLiaoheGroupandNorthLiaoheGroup,extendsbetweentwoArchaeancratons(Fig.1).Abundantmineralresources…  相似文献   

5.
笔者系统研究了广西六景中泥盆统民塘组底部的硅化腕足化石,描述了31个属种,其中新属、新亚属各1个,新种20个,划分出Geranocephalus-Pentamerela(下部)动物群和Stringocephalus-Changtanela(上部)两个动物群。着重对Geranocephalus-Pentamerela动物群的特征与时代进行了讨论,其时代具浓厚的艾菲尔晚期的色彩。该动物群属老世界区的一部分,与美国内华达同期动物群有密切的亲缘关系,同时与欧洲(如德国、捷克以及乌拉尔地区)也有一定相似性,然而从种群而言,它是一个斩新的动物群。提出Geranocephalus不是Subrensel-landia与Stingocephalus之间的中间形态,而是Renselandia与Stingocephalus之间的中间形态,很可能Geranocephalus就是Stingocephalus的先躯,它代表Rensselandia向Stingocephalus演化过程中的一个重要阶段。  相似文献   

6.
王红梅 《贵州地质》1996,13(3):220-224
通过对罗甸Meng江中三叠统许满组成4件睡形刺样品的处理分析,发现了一批牙形刺化石,经研究,这些牙形刺分属8属6种和6个未定种,并自上而下建立了两个牙形刺带:(2)Neogondolella excelsa-Gladigondolellatethydis带及(1)Neogondolella constricta带。  相似文献   

7.
FrequencyEffectsofFineThinLayer¥ZhangShuangxi(EepartmentofGeophysics,ChinaUniversityofGeosciences,Wuhan430074)YuanTao;ZhangWe...  相似文献   

8.
EarthScience-JournalofChinaUniversityofGeosciencesAbstracts(Volume18,1993)¥//GareiencebankingOnsystemahcviewinpaleontologyalx...  相似文献   

9.
新疆塔里木盆地北部石炭纪孢子带及其地质意义   总被引:2,自引:0,他引:2  
高联达  何卓生 《甘肃地质》1999,8(1):14-27,T002
塔里木盆地北部石炭纪孢子花粉非常丰富,属种众多,保存完美,经研究共计有74属,231种。根据孢子花粉演化及其在地层中的分布规律,自上而下划分出9个孢子带:9Proprisporiteslaevigatus-Grumosisporitesvarioreticulatus(LV)带8Belisporitesnitidus-Murosporacandiplicata(NC)带7Raistrickianigra-Schulzosporacampyloptera(NC)带6Lycosporapusila(PU)带5Schopfitesclaviger-Aurorasporamacra(CM)带4Spelaeotriletespretiosus-Raistrickiaclavata(PC)带3Spelaeotriletesbalteatus-Rugosporapolyptycha(BP)带2Kraeuselisporiteshibernicus-Umbonatisporitesdistinctus(HD)带1Valatisporitesverucosus-Retusotriletesincohatus?  相似文献   

10.
杜煜 《贵州地质》1996,13(3):276-279
矿床坑道涌水量的预测杜煜(贵州地质矿产勘查开发局104地质大队)OnPredictionofGushingWaterYieldinMineGalleries¥DuYu(GeologicalParty104,GuizhouBureauofGeology...  相似文献   

11.
长江源生态环境问题与可持续发展对策   总被引:7,自引:0,他引:7  
长江源自然环境严酷,以草原退化、森林萎缩、水土流失、气候暖旱化、冰川退缩、雪灾频繁为代表的生态环境退化正在进行。宜采用保护、恢复和改善林草植被系统来对其进行综合整治。  相似文献   

12.
改进的重力模拟退火反演研究   总被引:14,自引:0,他引:14  
通过对模拟退火方法中常用的VFSA算法的分析,针对其在模型扰动及退火计划上存在的缺陷,针对性地作了更合理的改进VFSA算法,提高了VFSA算法的计算速度与稳健性,并结合重力反演过程中对模型的修正,克服了常规重力反演方法所存在的等值效应。研究中还把重力正演计算的单元体改为垂直侧边梯形单元,并合单同一层位的垂直侧边梯形单元成为一大单元再作计算,加快了正反演计算速度并提高了正反演精度。通过模型试验及实际资料的处理,验证了作者所提出的改进的模拟退火重力反演方法的有效性。  相似文献   

13.
模拟退火优化算法的冻土热传导参数反分析   总被引:1,自引:0,他引:1  
文斌  吴青柏  蒋观利  张鹏 《岩土力学》2013,34(8):2401-2408
土体热参数是寒区工程温度场预测和稳定性分析至关重要的参数。根据冻土温度场计算的特点,建立冻土一维相变热参数估计模型,采用非线性有限元法得到土体温度场,基于一种非常快速的模拟退火(VFSA)算法对热参数进行反分析。考虑各个参数的敏感度因子和土体分层情况,将热参数分组、分步进行反演,克服参数较多反演困难的缺陷。以青藏公路多年冻土区监测断面下土体反分析为例,反演分析冻土路基下部不同土层的导热系数、体积热容量和孔隙率等参数。最后,运用参数反演结果对温度场进行预测,经检验和与实测地温对比,表明参数反分析结果可靠,有较高的精度,该方法可用于实际工程。  相似文献   

14.
On optimization algorithms for the reservoir oil well placement problem   总被引:1,自引:0,他引:1  
Determining optimal locations and operation parameters for wells in oil and gas reservoirs has a potentially high economic impact. Finding these optima depends on a complex combination of geological, petrophysical, flow regimen, and economical parameters that are hard to grasp intuitively. On the other hand, automatic approaches have in the past been hampered by the overwhelming computational cost of running thousands of potential cases using reservoir simulators, given that each of these runs can take on the order of hours. Therefore, the key issue to such automatic optimization is the development of algorithms that find good solutions with a minimum number of function evaluations. In this work, we compare and analyze the efficiency, effectiveness, and reliability of several optimization algorithms for the well placement problem. In particular, we consider the simultaneous perturbation stochastic approximation (SPSA), finite difference gradient (FDG), and very fast simulated annealing (VFSA) algorithms. None of these algorithms guarantees to find the optimal solution, but we show that both SPSA and VFSA are very efficient in finding nearly optimal solutions with a high probability. We illustrate this with a set of numerical experiments based on real data for single and multiple well placement problems.  相似文献   

15.
A very fast simulated annealing(VFSA) global optimization is used to interpret residual gravity anomaly.Since,VFSA optimization yields a large number of best-fitted models in a vast model space;the nature of uncertainty in the interpretation is also examined simultaneously in the present study.The results of VFSA optimization reveal that various parameters show a number of equivalent solutions when shape of the target body is not known and shape factor 'q' is also optimized together with other model parameters.The study reveals that amplitude coefficient k is strongly dependent on shape factor.This shows that there is a multi-model type uncertainty between these two model parameters derived from the analysis of cross-plots.However,the appraised values of shape factor from various VFSA runs clearly indicate whether the subsurface structure is sphere,horizontal or vertical cylinder type structure.Accordingly,the exact shape factor(1.5 for sphere,1.0 for horizontal cylinder and 0.5 for vertical cylinder)is fixed and optimization process is repeated.After fixing the shape factor,analysis of uncertainty and cross-plots shows a well-defined uni-model characteristic.The mean model computed after fixing the shape factor gives the utmost consistent results.Inversion of noise-free and noisy synthetic data as well as field data demonstrates the efficacy of the approach.  相似文献   

16.
The resolution of self-potential anomalies due to closely spaced multiple sheet-like bodies by the potential difference and potential gradient is studied in this paper. Self-potential anomalies due to several synthetic models were inverted through a very fast simulated annealing (VFSA) global optimization. Increase in depth to the top, polarization constant and depth extent of the body decreases resolution at a particular target separation. It has been observed that depth to the top and separation between two targets play an important role in the resolution. Vertical sheets at equal depth can be resolved in the potential difference measurement only if they are separated by at least four times their depth, while they can be resolved in the gradient method, if they are separated by twice the depth. Resolution using potential difference becomes more difficult for dipping sheets, although the potential gradient method can resolve them efficiently. Efficacy of potential gradient data in the inversion is demonstrated in the study using synthetic data as well as field measurement from South Purulia Shear Zone related with uranium investigation.  相似文献   

17.
直流电测深法与中心回线瞬变电磁法联合反演   总被引:2,自引:0,他引:2  
分析了直流电测深法(VES)与中心回线瞬变电磁法(TEM)对地层的响应特征,结果显示:TEM对低阻层反应灵敏,而VES对高阻层具有较高的分辨能力。基于TEM与VES对地层响应特征互补的特点,尝试将TEM与VES数据进行联合反演,模型试算结果表明,联合反演的效果明显比单一方法反演的效果好。  相似文献   

18.
板状体磁异常数据反演的PSO算法   总被引:3,自引:2,他引:1  
粒子群优化(PSO)算法是根据鸟群觅食过程中的迁徙和群集模型而提出的用于解决优化问题的算法,是一类随机全局优化技术,它通过粒子间的相互作用搜索复杂空间中的最优区域,其优势在于效率高,且又简单易实现。本文讨论了PSO算法用于板状体磁异常数据反演的方法,并与遗传算法(GA)进行了比较。理论和实测磁异常数据反演的结果表明,PSO算法具有更高的找寻最优解效率,是一种很有潜力的位场反演工具。  相似文献   

19.
为了适当地完成储层表征的过程,一个有效的方法就是把现场所有可以利用的信息融合成一个一致性的模型。在实际生产中实现这种融合并非简单的任务,所以有必要运用如地震反演等特殊方法。应用地震反演可以使测井数据和地震数据的有效结合成为可能,并且可以得到一个模型,该模型在预测过程中可通过流体数字模拟来验证。地震反演可以通过多种方法进行,主要分为两大类:一类是确定性方法(其代表是回归反演和约束稀疏脉冲反演),另一类是随机方法(其代表是地质统计学反演)。在本次研究中,通过随机反演结果和确定性反演结果的对比展示了随机反演是如何改进储层表征过程的。事实上,随机反演,可以运用较高的采样率(和储层模型的网格大小相接近),来产生一个更可靠的模型。随机反演的另一个好处就是随机方法可产生一些基本的统计测量值来改进解释精度,并且在储层表征过程中能生成大量的实现,从而使储层模型的不确定性研究成为可能。  相似文献   

20.
一个基于模拟退火法的陆面数据同化算法   总被引:15,自引:3,他引:15  
陆面数据同化系统是近年来兴起的新领域。我们发展了一个实验型的陆面数据同化方案,它使用一种启发式优化算法——模拟退火法极小化目标泛函。与变分法和Kalman滤波方法比较,这一算法具有独立于目标泛函的优点,可处理模型和观测算子的非线性和不连续性。使用GAME—Tibet实验中的土壤水分观测值进行单点数值实验,成功地将土壤水分观测同化到陆面过程模型SiB2中。结果表明,与不进行同化相比,土壤水分的估计值有较大改善。  相似文献   

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