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改良黄土强度特性与工程处置试验研究 总被引：1，自引：0，他引：1
本文针对山西朔州典型黄土,利用素黄土与石灰粉煤灰、石灰水泥、水泥粉煤灰三种改良黄土,进行了击实特性、抗剪强度特性及崩解特性试验研究,提出了黄土改良的最佳方案,并采用该方案对山西某煤矿电梯井填方段进行了数值模拟分析,验证了石灰粉煤灰改良黄土工程应用的可行性。试验结果表明:粉煤灰与黄土形成致密的混合结构,石灰的掺入,激活了粉煤灰的活性,发生了一系列的水化反应,使改良黄土的强度大大提高,改良黄土在物理力学性质方面有明显改善。 相似文献
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Jean‐Paul van Gestel Kevin D. Best Olav I. Barkved Jan H. Kommedal 《Geophysical Prospecting》2011,59(4):673-681
The frequent time‐lapse observations from the life of field seismic system across the Valhall field provide a wealth of information. The responses from the production and injection wells can be observed through time‐shift and amplitude changes. These observations can be compared to modelled synthetic seismic responses from a reservoir simulation model of the Valhall Field. The observed differences between the observations and the modelling are used to update and improve the history match of the reservoir model. The uncertainty of the resulting model is reduced and a more confident prediction of future reservoir performance is provided. A workflow is presented to convert the reservoir model to a synthetic seismic response and compare the results to the observed time‐lapse responses for any time range and area of interest. Correlation based match quality factors are calculated to quantify the visual differences. This match quality factor allows us to quantitatively compare alternative reservoir models to help identify the parameters that best match the seismic observations. Three different case studies are shown where this workflow has helped to reduce the uncertainty range associated with specific reservoir parameters. By updating various reservoir model parameters we have been able to improve the match to the observations and thereby improve the overall reservoir model predictability. The examples show positive results in a range of different reservoir modelling issues, which indicates the flexibility of this workflow and the ability to have an impact in most reservoir modelling challenges. 相似文献
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Three-dimensional seismic data and wireline logs from the western Niger Delta were analyzed to reveal the sedimentary and tectonic history of a major deltaic growth-fault depocenter comprising a kilometer-scale rollover anticline. The seismic units of the rollover show a non-uniform thickness distribution with their respective maximum near the main bounding growth-fault on the landward side of the system. This wedge-shaped sediment-storage architecture ultimately reflects the non-uniform creation of accommodation space in the study area that was controlled by 1) the differential compaction of the hanging-wall and footwall strata, 2) the lateral variation of fault-induced tectonic subsidence above the listric master fault, and possibly 3) local subsidence related to the subsurface movement of mobile shale reacting to loading and buoyancy. A sequential three-dimensional decompaction of the interpreted deltaic rollover units allowed to reconstruct and measure the compaction development of the rollover succession through time, documenting that sediment compaction contributed per depositional interval to between 25 and 35% of the generation of depositional space subsequently filled by deltaic sediments. The incremental decompaction of sedimentary units was further used to quantify the cumulative amount of accommodation space at and around the studied rollover that was created by fault movement, shale withdrawal, regional tectonic subsidence, isostasy and changes in sea level. If data on the regional subsidence and eustasy are available, the contribution of these basinwide controls to the generation of depositional space can be subtracted from the cumulative accommodation balance, which ultimately quantifies the amount of space for sediments to accumulate created by fault movement or shale withdrawal. This observation is important in that it implies that background knowledge on subsidence, stratigraphic age and sea-level changes allows to reconstruct and quantify fault movement in syn-tectonic deltaic growth successions, and this solely based on hanging-wall isopach trends independent of footwall information. 相似文献
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In this paper we describe a 3D control-volume finite-element method to solve numerically the coupled partial differential equations (PDEs) governing geological processes involved in the evolution of sedimentary basins. These processes include sediment deposition and deformation, hydrocarbon generation, multiphase fluid flow, and heat transfer in deforming porous media. 相似文献
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The morphology of Carbonate platforms may be influenced by tectonic activity and eustatic variations. 3D seismic data and satellite imagery are used in order to investigate the morphological similarities between present-day carbonates platforms, East of Borneo Island and Miocene carbonate platforms of the South China Sea. The morphological similarities exhibit platform fragmentation, that could be caused by subtle faulting, sufficient to drown reef rims; platform contraction, which is a result of back-stepping of the reef margin during a relative sea level rise and polygonal patterns in internal lagoons, described as mesh reefs in modern platforms and possibly interpreted as karst in Miocene platforms.Vertical movements may trigger the formation of new geomorphological conditions that modify the distribution of coral growth with respect to the new hydrodynamic conditions in space and time. These movements (uplift and tilting) reduce and localize the space necessary for the coral ecosystem, explaining the contraction leading to drowning of parts of and, ultimately, the whole platform. 相似文献
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Mechanical compaction is the main porosity-reducing process in sandstones, including high-reservoir-quality rigid-grain sandstones. For such sandstones, the extrapolation of theoretical or experimental compaction algorithms needs calibration with rocks having well constrained burial histories. Evaluating the compaction of these rocks is achieved by comparing current intergranular volume (IGV) with depositional IGV, which is strongly dependent on sorting. However, because sandstone sorting is difficult to measure accurately, its impact on depositional porosity and compaction state is largely underestimated. We use the quartzarenites of the Oligocene Carbonera Formation in the subsurface of the hydrostatically-pressured Llanos basin to illustrate the importance of sorting when evaluating the compaction of rigid-grain sandstones. IGV and sorting were measured in core samples using a combination of transmitted-light and cathodoluminescence images, resulting in improved accuracy over standard procedures. The compaction state of clean quartzarenites at given depths is best described using IGV-versus-sorting plots, which are used to derive compaction curves for specified sorting values. The IGV-versus-sorting trends are displaced to lower IGV values with increasing burial depth. The differences in IGV caused by differences in sorting exceed the differences in IGV resulting from 1000 m of burial, illustrating the high impact of sorting when evaluating compaction. Contrasting with published experimental results, the compaction of the Llanos basin ductile-grain-poor quartzarenites is independent of grain size, and grain rearrangement is the main compaction mechanism during the first ∼1.6 km of burial. Based on the Llanos data, we have generated IGV-versus-depth curves for clean pure quartzarenites of specific sorting, which can be used to predict their maximum primary porosity up to moderate burial depths. Differences with other published burial curves are probably related to unaccounted variations in sorting, ductile-grain content and framework-strengthening cements. However, the Llanos basin quartzarenites contain virtually no cements, explaining their high degree of compaction relative to other rigid-grain sandstones, and making them ideal to isolate the effects of compaction on the IGV of quartzarenites. The Llanos basin data suggest that, below ∼2.5 km of depth, clean well- to moderately well sorted quartzarenites continue reducing their IGV by mechanical compaction below the 26% limit, which should apply only to extremely well sorted, rigid grain, uncemented sandstones. 相似文献
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Geotechnical Properties of Low Calcium and High Calcium Fly Ash 总被引：1，自引：0，他引：1
In this paper, a comparative study has been made for physical and engineering properties of low calcium and high calcium Indian
fly ash. The grain size distribution of fly ash is independent of lime content. Fly ash particles of size >75 μm are mostly irregular in shape whereas finer fractions are spherical for low calcium fly ash. For high calcium fly ash, chemical
and mineralogical differences have been observed for different size fractions. Compared to low calcium fly ash, optimum moisture
content is low and maximum dry density is high for high calcium fly ash. Optimum moisture content is directly proportional
and maximum dry density is inversely proportional to the carbon content. The mode and duration of curing have significant
effect on strength and stress–strain behavior of compacted fly ash. The gain in strength with time for high calcium fly ash
is very high compared to that of low calcium fly ash due to presence of reactive minerals and glassy phase. 相似文献
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Compaction localization in the Earth and the laboratory: state of the research and research directions 总被引：1，自引：1，他引：1
Localized compaction in porous rocks is a recently recognized phenomenon that has been shown to reduce permeability dramatically.
Consequently, the phenomenon is relevant to a variety of technologies involving fluid injection or withdrawal. This article
summarizes current understanding of localized compaction and impediments to further progress. The article is based on discussions
at a small workshop on localized compaction sponsored by the Office of Science, U. S. Department of Energy. 相似文献