The determination of the optimal type and placement of a nonconventional well in a heterogeneous reservoir represents a challenging optimization problem. This determination is significantly more complicated if uncertainty in the reservoir geology is included in the optimization. In this study, a genetic algorithm is applied to optimize the deployment of nonconventional wells. Geological uncertainty is accounted for by optimizing over multiple reservoir models (realizations) subject to a prescribed risk attitude. To reduce the excessive computational requirements of the base method, a new statistical proxy (which provides fast estimates of the objective function) based on cluster analysis is introduced into the optimization process. This proxy provides an estimate of the cumulative distribution function (CDF) of the scenario performance, which enables the quantification of proxy uncertainty. Knowledge of the proxy-based performance estimate in conjunction with the proxy CDF enables the systematic selection of the most appropriate scenarios for full simulation. Application of the overall method for the optimization of monobore and dual-lateral well placement demonstrates the performance of the hybrid optimization procedure. Specifically, it is shown that by simulating only 10% or 20% of the scenarios (as determined by application of the proxy), optimization results very close to those achieved by simulating all cases are obtained. 相似文献
Investigation of deposits for traditional extraction activities (metals and coal) has generally been based on determining grade, or content, of the required material. In order to apply the grade concept to an ornamental rock such as slate, it is first necessary to define the variables that determine both the geotechnical recovery rate for the rock mass — which conditions the size of the extracted blocks – and the aesthetic features of the slate — which define the quality of the slabs as potential roofing material.
For this research, geotechnical and aesthetic data for a slate deposit were collected from 16 continuous core borehole samples. A fuzzy expert system was then developed using this data, defining the rock mass recovery rate and slab quality in accordance with the criteria of a slate expert, producing as a final output a zonation of the deposit in terms of top quality slate, medium quality slate or waste.
A mathematical model based on fuzzy logic was chosen due to the fact that the boundaries between different quality groups in a deposit are not clearly distinguished. Moreover, quality also depends on a company's infrastructures for transformation of the blocks, and also on its commercial strategies. 相似文献
The future availability and sustainability of fresh groundwater resources in the South West district of the national capital territory (NCT) Delhi, India, have been projected. Due to a rapid decline in groundwater level and quality, the district has been required by the Government of India to regulate development of groundwater resources. Shallow groundwater is mostly saline and water resources in the area are limited. The methodology applied here involves microzonation of the district in terms of thickness of fresh groundwater and then quantification of present and future availability of freshwater in different freshwater zones, including tentative timescales. The calculation method has been aided by data on historic trends in water level at representative groundwater monitoring stations, located either in fresh groundwater zones or near to them. It is estimated that the presently available 481 million m3 of resources will be reduced to 374 million m3 by year 2007 and to 303 million m3 by the year 2012, and by the year 2022 the district will have only 176 million m3 of available fresh groundwater resources. 相似文献
In Gaborone, as in other large cities in the developing world, individuals try to make a living by engaging in novel occupations
such as landfill scavenging. This paper reports on a research conducted in the Gaborone landfill, the largest in Botswana.
The study content-analyzed available literature from other countries. It also relied mainly on direct field observations.
The discussions on and answers to closed and interview schedules by stakeholders, affected- and- interested – persons, provided
the information on the threats and opportunities related to the landfill site and its informal management activities. This
on-going case study lends credence to the potential of scavenging in sustaining livelihoods among those who cannot secure
employment in the formal urban market. Scavenging tends to be useful although it may hazardous to the informal entrepreneurs.
Taking all the threats into consideration, the decommissioning and closure of the landfill seems inevitable, in spite of the
apparent short-term livelihood opportunities it provides to the informal sector. 相似文献
Slope movements together with intensive river erosion and the following accumulation are the leading processes in the landscape evolution in the area of Machu Picchu village (former Aguas Calientes), which is located close to the Machu Picchu Sanctuary. Debris flows affect not only the bottoms of valleys or canyons, but also debris fans at the termini of the drainage basins, which are heavily inhabited at some places. The most recent event in the Machu Picchu village occurred in April 2004, but several others were documented in a broader area in the last 50 years. The field inspections at Machu Picchu (May and September 2004; June and September 2005) together with oral testimony revealed the nature and behavior of the debris flow. Machu Picchu village can be assessed as a zone with high landslide risk in relation to its urban development. Despite that, the village recorded a rapid growth (threefold population increase) without urban control within the past two decades. Precipitation, which is the main triggering factor of the debris flows, and natural hazard management of the Machu Picchu village are discussed in this paper. 相似文献
A new approach to the method of artificial upraising of the water outlet point, for management and development of brackish karst springs, uses the MODKARST model. Brackish karst springs simulation can be used to estimate the necessary upraising of the spring elevation, so that sea-water intrusion is blocked. The consequent freshwater loss to the sea, due to this upraising, can also be estimated. The method has been applied to the periodically brackish karst Almiros spring at Heraklion of Crete, Greece. The spring simulation showed that the sea-water intrusion could be prevented through an artificial upraising of the water-outlet point, realized by the construction of a dam. The exact upraising has been estimated. Freshwater loss to the sea because of this upraising has also been estimated. The model could also be used as a tool for the management of the spring. For example, it was used to assess management options for the spring during the depletion period of the year 1994. The best scenario for the development of the spring during this period has been estimated. 相似文献
Aboriginal cultural heritage protection, and the legislative regimes that underpin it, constitute important mechanisms for Aboriginal people to assert their rights and responsibilities. This is especially so in Victoria, where legislation vests wide-ranging powers and control of cultural heritage with Aboriginal communities. However, the politics of cultural heritage, including its institutionalisation as a scientific body of knowledge within the state, can also result in a powerful limiting of Aboriginal rights and responsibilities. This paper examines the politics of cultural heritage through a case study of a small forest in north-west Victoria. Here, a dispute about logging has pivoted around differing conceptualisations of Aboriginal cultural heritage values and their management. Cultural heritage, in this case, is both a powerful tool for the assertion of Aboriginal rights and interests, but simultaneously a set of boundaries within which the state operates to limit and manage the challenge those assertions pose. The paper will argue that Aboriginal cultural heritage is a politically contested and shifting domain structured around Aboriginal law and politics, Australian statute and the legacy of colonial history. 相似文献