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11.
This paper investigates whether diagenetic alterations in sandstones and resulting changes in reservoir quality are influenced by depositional environments and sequence stratigraphy. The study focusses on the Cretaceous U and T sandstone members of the Napo Formation in the Oriente Basin of Ecuador. The sandstones were deposited in fluvial, transitional and marine environments, and comprise Lowstand (LST), Transgressive (TST) and Highstand Systems Tract (HST) deposits. The data were obtained by detailed petrographic observations supported by microprobe, stable isotope, and fluid inclusion analyses. The sandstones consist of fine- to medium-grained quartzarenites and subarkoses. Diagenetic events include cementation by chlorite, early and late kaolinite/dickite, early and late carbonates (siderite, Fe-dolomite/ankerite), and quartz. Early (eogenetic) processes included formation of chlorite grain coatings, kaolinite pore filling, and siderite (SI) cementation. Chlorite is absent in TST sandstones but was found frequently in LST-HST sandstones. Early kaolinite is not present in LST sandstones but occurred frequently in LST-HST sandstones. The distribution of mesogenetic cements relative to sequence stratigraphy is different in the U and T units. In the U sandstones, calcite is frequent in LST deposits and absent in the LST-HST. Fe-dolomite/ankerite is abundant only in the TST. S2 siderite is present in the TST and LST, but absent in the LST-HST. Quartz cement and kaolinite/dickite are equally distributed in all systems tracts. In the T sandstones Fe-dolomite/ankerite is only abundant in the TST, whilst calcite, quartz and dickite have similar distributions in all the systems tracts. The distribution of kaolinite cement is interpreted to be the result of relatively more intense meteoric-water flux occurring during sea-level fall, whereas chlorite cement may have formed through burial diagenetic transformation of precursor clays e.g. berthierine which was precipitated in mixed marine-meteoric waters in tidal channel and estuarine environments. Chlorite cement in the T and U sandstones appears to have retarded development of quartz overgrowths, and 12–13% primary porosity is retained. The T sandstones (LST-HST) contain up to 4% chlorite cement. Little evidence for chemical compaction was found with the exception of occasional concave-convex grain contacts. Eogenetic siderite appears to have helped to preserve reservoir quality through supporting the sandstone framework against further compaction, but mesogenetic calcite has considerably reduced primary porosity. Eogenetic siderite (SI) was partly replaced by later carbonate cements such as late siderite (S2) and Fe-dolomite. Although there appears to be a relationship in the Napo Formation between the occurrence of siderite SI and sequence stratigraphy, the relationship may change when original volumes of siderite are considered. There is likewise partial replacement of early kaolinite and recrystalization to dickite which masks the amount of original early kaolinite. Since the amount of early kaolinite could not be confirmed, the relationship to sequence stratigraphy is tentative. Only chlorite seems to have a clear relationship to sequence stratigraphic framework in the Napo Formation. The high intergranular volume (IGV) of the sandstones indicates that cementation played a more important role than mechanical and chemical compaction in both Napo Formation sandstone members. Later dissolution of feldspar grains and siderite cements was the main process of secondary porosity development (up to 11% in the U sandstones).  相似文献   
12.
奥连特盆地主要生烃灶位于盆地西南部,但目前已发现油藏主要分布在盆地北部地区,油气成藏特征独特。以盆地油气运移及成藏特征为基础,分析了T区已发现油田的油藏地质特征及油气分布规律,认为油源断层控制着有利成藏区的分布,构造和沉积体系联合控制着油气成藏的有利位置,断层、构造及沉积体系展布为T区油气成藏的主控因素,并以此为基础进一步指出了该地区下步勘探方向。  相似文献   
13.
Water management studies often overlook community diversity, different stakeholders’ values, and frames to claim water rights. Using a political-ecology approach, this article examines an irrigation system in Ecuador’s highlands via Fraser’s principles of justice (recognition, representation, redistribution). Large flower companies and indigenous smallholders frame their arguments differently to legitimize water allocation claims. Framing is effective when it resonates with other stakeholders’ values. Some unexpected findings are explained: most of the water is still used by large companies since communities took control; rules regarding water use differ greatly among sectors in the system; and small flower producers have been appearing recently.  相似文献   
14.
为进一步查清厄瓜多尔境内地表水资源的时空分布特性,为其水资源综合利用提供基础数据,选择该国流量系列相对完整、质量较好、空间分布具有代表性且控制条件较好的水文站作为计算地表水资源量的主要依据站,绘制了地表径流量等值线图、计算了区域地表水资源量、分析了地表水资源量时空分布。研究结果表明:厄瓜多尔全国多年平均地表水资源量为3 617.47亿m~3,折合年径流深1 457 mm。全国9个DH中,多年平均径流量最大的为DH Napo,年径流量为1 321.54亿m~3,占全国的36.5%,径流量最小的为DH Manabi,年径流量为62.70亿m~3,仅占全国的1.7%。  相似文献   
15.
ABSTRACT

This article compares public–private partnerships dedicated to improving forestry management to protect water in the Paute River basin in Ecuador (FONAPA) and the Verde River basin in Arizona (the Four Forest Restoration Initiative). Both programmes create incentives for improved forestry management and suggest lessons for water management in general but may face legal challenges that require reforms. While there is scope for mutual learning between the programmes, such cross-fertilization is inhibited by differences in the legal status of water and forest resources in the two systems.  相似文献   
16.
This paper describes the current energy sector in Ecuador, its present structure, the oil industry, subsidies, and renewable energy, focusing on the evolution and reform of the electricity sector. Currently, 86% of the primary energy originates from nonrenewable sources. In 2005, the gross electricity generation was 15 127 GWh (45.5% hydropower, 43.11% thermal, and 11.39% imported). Ecuador is the fifth largest oil producer in South America but lacks sufficient oil refining capacity. Reserves of natural gas (NG) are small, and most of NG is produced from oil fields without energy recovery. Several projects are underway to increase the utilization of NG and renewable energies to meet Ecuador commitments to the Kyoto Protocol.  相似文献   
17.
通过对区域构造演化及地层沉积特征分析,揭示了厄瓜多尔Oriente盆地烃源岩和储层主要存在于裂后热沉降阶段发育的白垩系地层中,圈闭发育于白垩系末至新近纪前陆盆地阶段。烃源岩条件较好,两个生排烃灶区位于盆地西南和西北部,西北部灶区油气生成和运移时间早;从盆地西部到东部,储层发育的层位由老到新;生储盖组合有利。圈闭类型以4种背斜构造为主。根据油气地质条件和圈闭类型差异,盆地划分为西、中、东3个油气构造带,分别具有不同的成藏模式。  相似文献   
18.
We present a land-use allocation model that evaluates the impact of payments for ecosystem services such as biodiversity conservation on land-use patterns. In a non-linear optimisation procedure, land use is allocated at farm level, taking into account risk behaviour, and spatial as well as temporal variability of net revenues of land-use alternatives, using a spatial resolution of 29 m × 29 m. The model is applied to a study area of 30 km × 34 km in western Ecuador, considered a hotspot for biodiversity. In this coffee growing region, agroforestry systems with shade-coffee are important for biodiversity conservation at the landscape level, but under pressure due to low revenues. Through scenario analyses, we analyse the effects of price premiums per kg, payments per ha, and price buffering for coffee, as well as incentives leading to coffee yield increases, and payments per ha of forest remnants. We compare different risk aversion levels of the involved agents. We conclude that payments per ha are more efficient to maintain or increase coffee areas than payments per kg. Price buffering may be the most cost-effective way to support coffee production, especially at high-risk aversion levels. Significant yield increases are necessary to make coffee more attractive compared to the other alternatives. Relatively low payments per ha of forest can significantly increase forested land. Risk behaviour turns out to be an important factor when determining the possible effect of payments for ecosystem services. We conclude that the model is a versatile tool to support planning of payments for conserving ecosystems.  相似文献   
19.
The larvae of three races of Heliconius erato were fed various species of Passiflora containing varying levels of cyanoglucosides. The mortality rate of larvae and pupae rose when larvae were fed species of Passiflora capable of releasing larger quantities of cyanide. When larvae were fed species of Passiflora with these properties, the resulting adult butterflies also released higher levels of cyanide. This may serve as a defense mechanism. The compounds responsible for the release of cyanide were not evenly distributed throughout the adult butterfly’s body. The thorax contained the highest concentration of cyanogenic substances, followed by the head, wings, and abdomen. The younger tissues of Passiflora plants had higher levels of cyanide-releasing compounds than stems and mature leaves. Cyanogenic glycoside distribution within the plants is consistent with optimal allocation theory. The levels of cyanide-releasing substances in plants varied depending on the season.  相似文献   
20.
Modern cities are constantly growing and evolving. This expansion of urban development bleeds into the surrounding landscapes, causing the displacement and disturbance of native plant and animal species to remote areas where topography limits human access. As a result, metropolitan areas often become gray places with low biodiversity, elevated temperatures, poor air quality, flood issues, and lack of a local identity. Quito, Ecuador is one of the cities facing this important challenge. Perched high in the Andes, Quito is a place of great biodiversity, nevertheless the constructed landscapes are dominated by introduced species due to colonization and to the lack of availability of native species in the nursery trade. This article walks through the creation of a native nursery in Quito and the implementation of initial trial plots, a green roof, and a garden. It explains the discoveries made during the process and provides directions for future goals to reintroduce native plant species into urban environments and contemporary landscapes in order to create more sustainable cities. The goal is to help people reconnect with their natural heritage and to learn about native plants to ensure the continuity of ancestral knowledge of the natural world for future generations.  相似文献   
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