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951.
Well placement optimization with the covariance matrix adaptation evolution strategy and meta-models
The amount of hydrocarbon recovered can be considerably increased by finding optimal placement of non-conventional wells.
For that purpose, the use of optimization algorithms, where the objective function is evaluated using a reservoir simulator,
is needed. Furthermore, for complex reservoir geologies with high heterogeneities, the optimization problem requires algorithms
able to cope with the non-regularity of the objective function. In this paper, we propose an optimization methodology for
determining optimal well locations and trajectories based on the covariance matrix adaptation evolution strategy (CMA-ES)
which is recognized as one of the most powerful derivative-free optimizers for continuous optimization. In addition, to improve
the optimization procedure, two new techniques are proposed: (a) adaptive penalization with rejection in order to handle well
placement constraints and (b) incorporation of a meta-model, based on locally weighted regression, into CMA-ES, using an approximate
stochastic ranking procedure, in order to reduce the number of reservoir simulations required to evaluate the objective function.
The approach is applied to the PUNQ-S3 case and compared with a genetic algorithm (GA) incorporating the Genocop III technique
for handling constraints. To allow a fair comparison, both algorithms are used without parameter tuning on the problem, and
standard settings are used for the GA and default settings for CMA-ES. It is shown that our new approach outperforms the genetic
algorithm: It leads in general to both a higher net present value and a significant reduction in the number of reservoir simulations
needed to reach a good well configuration. Moreover, coupling CMA-ES with a meta-model leads to further improvement, which
was around 20% for the synthetic case in this study. 相似文献
952.
班怒带西段尕尔穷铜金矿两套侵入岩源区及其地质意义——来自Hf同位素特征的指示 总被引:1,自引:0,他引:1
尕尔穷铜金矿位于班公湖—怒江缝合带西段南缘的措勤—申扎火山岩浆弧内,为与侵入岩有关的矽卡岩型-破碎带型铜金(铁)矿床。在已有石英闪长岩LA-ICP-MS锆石U-Pb测年的基础上,进一步对其进行锆石Hf同位素研究,同时对最新勘查成果显示具有一定成矿潜力的花岗斑岩进行LA-ICP-MS锆石U-Pb定年和Hf同位素研究,确定了两套侵入岩的形成顺序;结合前人总结的岩石地球化学特征,利用Hf同位素对其岩浆源区进行示踪。结果显示:花岗斑岩锆石206Pb/238U年龄加权平均值为(83.2±0.7)Ma,较石英闪长岩晚4 Ma左右,其初始176Hf/177Hf值为0.282 235~0.283 073,εHf(t)值为-17.2~12.5;石英闪长岩锆石初始176Hf/177Hf值为0.282 800~0.283 015,εHf(t)值为3.5~10.5。结合二者地球化学特征显示:石英闪长岩和花岗斑岩可能是同一岩浆系统不同分异阶段的产物,前者主要起源于具有幔源印记的初生地壳,而花岗斑岩具有和石英闪长岩相似的岩浆源区,但明显混入上地壳基底物质;暗示晚白垩世班怒带西段南缘内随着南羌塘—三江复合板片与冈底斯—念青唐古拉板片之间的弧-陆碰撞,先成的具有幔源印记的初生地壳重熔形成岩浆,随着碰撞的继续和岩浆的上涌分异,部分上地壳受挤压或热效应进一步重熔并参与岩浆系统中,由早至晚形成了由幔源特征向幔-壳混合源特征源区逐渐转变的花岗岩演化系列。尕尔穷铜金矿是起源于具有幔源印记的初生地壳的花岗岩的成矿专属性表现。 相似文献
953.
Jinzhu Ma Feng Pan Jiahua He Lihua Chen Sujing Fu Bing Jia 《Environmental Earth Sciences》2012,66(7):1769-1782
The possible sources of water pollution and the evolution of water quality in the Malian River Basin of China’s Longdong Loess Plateau were studied based on chemical analysis. Concentrations of major chemicals in the river were related to the distance downstream from the source of the river and the surface water in the upstream had good quality, while the river from Southern Huanxian County to Qingcheng County was seriously polluted. Groundwater quality was generally good in the phreatic aquifer beneath the loess plateau, with bicarbonate and calcium dominant, but salinity was high and petroleum pollution was present in many parts of the study area. Both surface water and groundwater quality have declined rapidly during the past 20 years, leading to much of the water unsafe to drink and unsuitable for use in irrigation. The substances released into the water included industrial wastes, domestic sewage, organic and inorganic fertilizers, and pesticides, as well as a range of other substances that are harmful to humans. However, petroleum contamination caused by the oil industry in the Longdong oilfield is the largest source of pollution that infiltrates surface water and groundwater, leading to deterioration of water quality. It is recommended that oilfield management must be improved and the petroleum products and wastes must be disposed carefully to reduce the risk of further spills and pollution. 相似文献
954.
Liming He Jing M. Chen Shaoliang Zhang Gustavo Gomez Yude Pan Kevin McCullough Richard Birdsey Jeffrey G. Masek 《International Journal of Applied Earth Observation and Geoinformation》2011
Forest disturbances such as harvesting, wildfire and insect infestation are critical ecosystem processes affecting the carbon cycle. Because carbon dynamics are related to time since disturbance, forest stand age that can be used as a surrogate for major clear-cut/fire disturbance information has recently been recognized as an important input to forest carbon cycle models for improving prediction accuracy. In this study, forest disturbances in the USA for the period of ∼1990–2000 were mapped using 400+ pairs of re-sampled Landsat TM/ETM scenes in 500m resolution, which were provided by the Landsat Ecosystem Disturbance Adaptive Processing System project. The detected disturbances were then separated into two five-year age groups, facilitated by Forest Inventory and Analysis (FIA) data, which was used to calculate the area of forest regeneration for each county in the USA. 相似文献
955.
基于最小二乘法道路平面曲线拟合 总被引:2,自引:0,他引:2
结合最小二乘法的基本原理,利用其进行道路平面曲线拟合,实例表明,与三次样条函数设计计算结果接近,同样能满足路线设计要求,且简化了计算过程,在平面设计工作中具有很强的实用性。 相似文献
956.
957.
June-Yi Lee Bin Wang Q. Ding K.-J. Ha J.-B. Ahn A. Kumar B. Stern O. Alves 《Climate Dynamics》2011,37(5-6):1189-1203
The retrospective forecast skill of three coupled climate models (NCEP CFS, GFDL CM2.1, and CAWCR POAMA 1.5) and their multi-model ensemble (MME) is evaluated, focusing on the Northern Hemisphere (NH) summer upper-tropospheric circulation along with surface temperature and precipitation for the 25-year period of 1981–2005. The seasonal prediction skill for the NH 200-hPa geopotential height basically comes from the coupled models’ ability in predicting the first two empirical orthogonal function (EOF) modes of interannual variability, because the models cannot replicate the residual higher modes. The first two leading EOF modes of the summer 200-hPa circulation account for about 84% (35.4%) of the total variability over the NH tropics (extratropics) and offer a hint of realizable potential predictability. The MME is able to predict both spatial and temporal characteristics of the first EOF mode (EOF1) even at a 5-month lead (January initial condition) with a pattern correlation coefficient (PCC) skill of 0.96 and a temporal correlation coefficient (TCC) skill of 0.62. This long-lead predictability of the EOF1 comes mainly from the prolonged impacts of El Niño-Southern Oscillation (ENSO) as the EOF1 tends to occur during the summer after the mature phase of ENSO. The second EOF mode (EOF2), on the other hand, is related to the developing ENSO and also the interdecadal variability of the sea surface temperature over the North Pacific and North Atlantic Ocean. The MME also captures the EOF2 at a 5-month lead with a PCC skill of 0.87 and a TCC skill of 0.67, but these skills are mainly obtained from the zonally symmetric component of the EOF2, not the prominent wavelike structure, the so-called circumglobal teleconnection (CGT) pattern. In both observation and the 1-month lead MME prediction, the first two leading modes are accompanied by significant rainfall and surface air temperature anomalies in the continental regions of the NH extratropics. The MME’s success in predicting the EOF1 (EOF2) is likely to lead to a better prediction of JJA precipitation anomalies over East Asia and the North Pacific (central and southern Europe and western North America). 相似文献
958.
北京一次冬季回流暴雪天气过程的数值分析 总被引:6,自引:0,他引:6
回流天气是华北地区冬、春、秋季节产生降雨(雪)的主要天气类型,预报员常常因对回流天气系统结构特征认识不足和诊断失误而导致预报的失败,是降雨(雪)预报的难点和重点。利用北京地区高分辨率快速循环同化中尺度数值预报系统(BJ-RUC)对2010年1月2—3日一次典型的回流暴雪天气过程进行模拟,分析数值模式的模拟能力,研究各层主要影响系统结构特征及形成暴雪的关键性条件,探讨典型回流暴雪天气过程的形成机理。主要结论为:数值模式对此次暴雪过程的近地面回流冷空气、中低层低值系统及变化特征、主要降雪时段和降雪量模拟效果较好,对降雪落区的模拟存在一定偏差。低层回流偏东风遇到地形后引起垂直运动主要在低层800 hPa以下,所产生的降雪量不大,而其与上游850~700 hPa低涡系统发展东移其前部的上升运动汇合所形成的大范围、深厚、强烈的上升运动是产生明显降雪的关键性条件。上游低涡系统前部西南暖湿气流相对应的大湿度区移近是产生较强降雪的重要条件。持续的低层回流冷空气湿度较大,对于低层大气起到水汽输送的作用。回流冷空气使低层大气维持长时间的水汽输送并与其上层东移的大湿度区相结合,增加湿层厚度,有利于降雪持续而形成较强降雪。降雪开始时间和降雪强度的变化与对流层中下转偏南风的时间和偏南风风速增大有关。 相似文献
959.
960.
选取了汶川地震主震后的2008年5月12日——2009年8月31日, 震级为3.0le;MSle;5.0的余震4240次.利用波形互相关方法得到其P波到时,用双差定位方法对其进行定位,最终得到了2441次重新定位的结果.统计定位误差(两倍标准偏差)在E-W方向为0.4 km,N-S方向为0.4 km,垂直方向为0.7 km.定位结果表明,汶川地震的余震深度集中在10——20 km,震中分布与龙门山中央断裂带的走向关系密切.沿龙门山断裂的地震分布具有明显的分段性,西南段呈水平带状分布,东北段接近垂直分布,且在北川附近存在深度突变.这与龙门山断裂的地震在西南段多表现为逆冲,东北段多表现为走滑的现象相吻合.在深度剖面上地震的空间分布存在分立的特征,通过对比前人在此地区浅层的地震剖面资料, 发现地震空间分布与已探知的浅部断层有较好的对应关系. 相似文献