Sand Accumulation Research Articles

Physical modelling of cyclic loading-induced footing settlement with nearby pit excavation

A series of physical model tests and cyclic triaxial tests were conducted on a dry sand to investigate the effects of excavating an adjacent pit on the settlement behaviour of a footing under cyclic loading. The excavation was simulated by moving a retaining wall between loading cycles in the physical model tests. The excavation-induced stress disturbance on soil elements was modelled by reducing cell pressure between loading cycles in triaxial tests. The results indicate that nearby excavation leads to a reduction in lateral stress in ground, and therefore increases the settlement of footing in the subsequent loading cycles. However, there is no clear relationship between the settlement increment and the magnitude of wall movement, when the lateral movement of the wall is within the range of 0.1–0.37% of the wall height. The lateral excavation does not have a great impact on the influence zone of the footings under cyclic loading. An empirical model was proposed to estimate the cyclic loading-induced strain accumulation of sand with the consideration of lateral unloading effects between loading cycles. After being validated using cyclic triaxial test results, the proposed model was employed to predict cyclic loading-induced settlement of the footing before and after the excavation.

Closure of Khor Al Balid and Khor Rori harbours/estuaries with coastal uplift and aridity in the 12th – 15th c. CE and evidence for an extreme overwash event in the 18th – 19th c. CE: Implications for ancient port sites in southern Oman

Ancient maritime trading ports along the southern coast of Oman have been the target of archaeological excavations for several decades. Though historical chronologies are well-researched, information from a paleoenvironmental perspective is lacking and can provide a more complete understanding of site development. This study investigates the timing of coastal sand barrier accumulation in the natural harbours at Khor Al Balid and Khor Rori, which had considerable effects on the populations at the ancient cities of al–Balīd and Sumhuram, respectively. Six cores from Khor Al Balid and four cores from Khor Rori were analyzed using sedimentological, microfossil (foraminifera and testate amoebae), geochemical (μXRF), and radiocarbon dating methods. Marine proxies (e.g., Amphistegina spp., C. pseudolobatulus, E. limbatum, Sr, Ca/Si) and lagoon proxies (e.g., T. macrescens, T. inflata, C. constricta and C. aculeata, Ti/Ca, Fe/Ca) were used to identify Marine Sand, Brackish Lagoon/Marsh, and Freshwater facies. Results indicate that the eastern arm of Khor Al Balid closed off from the sea around the 12th century CE and that the western arm closed around the 15th century CE. Siltation of harbours and the formation of sand barriers may have contributed towards site abandonment. Previous archaeological findings suggest that al-Balīd was able to continue with maritime trade activities along the southern seaside edge of the city for several centuries after siltation of Khor Al Balid, possibly with the help of dredging. An extreme overwash event was recorded in almost all cores across both sampling sites, suggesting that a very large cyclone or a tsunami hit the southern Oman coast sometime around the 18th–19th century CE. This event, as well as continuous coastal sand accumulation, may have contributed to the decline and abandonment of Khor Al Balid and highlights the impacts that large storm/wave events have on archaeological site preservation.

The secret of nabkha development–From the inspective of surface wind erosion and sand accumulation

Nabkhas can effectively reduce wind speed and intercept sand, slowing down the rate of land desertification and playing an important role in the stability of the oasis ecosystem and the conservation of biodiversity. The purpose of this study is to explore the evolutionary mechanism of nabkha development and wind erosion and sand accumulation of different nabkhas during nabkha development in the oasis region. Five typical nabkhas (Nitraria tangutorum, Haloxylon ammodendron, Krascheninnikovia ceratoides, Kalidium foliatum and Artemisia desertorum nabkhas) were selected. Morphological indicators and surface wind erosion and sand accumulation during nabkha development were investigated. Our results confirmed that from the nascent stage to the stable stage, the length, width and height of five nabkhas showed a significant correlation. As nabkha develops, the different parts of nabkha were mainly sand accumulation occurred first on the apex part, then on the windward slope and finally on the leeward slope. When the lateral area of the nabkha was close to the semi-ellipsoidal shape, the nabkha reach the stable stage. The sand accumulation height of Nitraria tangutorum nabkhas is the highest. Haloxylon ammodendron nabkha is able to intercept sand sources from multiple directions due to the pike-shaped branching structure. Kalidium foliatum nabkhas have a high sand accumulation height in the pre-developmental stage. Krascheninnikovia ceratoides and Artemisia desertorum nabkhas are morphologically irregular with limited sand accumulation height. The results indicate that the surface wind erosion and sand accumulation changes during the development of nabkhas were mainly related to the interaction between vegetation growth and nabkha formation.

Swash-Zone Formula Evaluation of Morphological Variation in Haeundae Beach, Korea

In this study, a swash-zone model, using Larson and Wamsley formula (LW07), was combined into the Telemac-2D model system to examine the performance of modeling swash-zone processes through comparisons with field observation data. The experimental site was the Haeundae Beach in South Korea where Typhoon Phanfone occurred in October 2014, and bathymetric surveys were performed before and after the typhoon. Hydrodynamic data were also measured to validate the modeled data. The performance of LW07 was tested by running the model in two modes, with and without LW07. First, the model was run to simulate the shoreline response to an imaginary coastal breakwater. The result showed a clear discrepancy between the two modes as the sediments were considerably cumulated behind the breakwater in the case with the swash-zone formula (LW07) in the wide range along the shoreline behind the breakwater, indicating that the sediments more actively and rapidly responded to the shadowing by the breakwater with LW07. The model was also run for a realistic case from August to October 2014, which included the typhoon’s period during 2–6 October. The results showed that the morphological changes at both ends of the beach in the swash zone were simulated with higher accuracy with LW07, supporting the effectiveness of LW07 in simulating the short-term morphological changes induced by the typhoon attack. In particular, the successful simulation of the sand accumulation at the end sides of the beach’s swash zone indicates that LW07 was effective in estimating not only the cross-shore transport but also longshore transport, which was likely due to the characteristics of LW07 that calculated sand transport in both directions. The enhanced modeling performance with LW07 was likely due to the adjustment of the sediment transport rate to the instantaneous changes in the local beach slope, which could successfully control the erosion/accretion process in the swash zone more realistically.

Interactions between foredune morphologies and vegetation: Exploring the occurrence of arbuscular mycorrhizal fungi

Vegetation is a key trait for understanding the foredune morphologies. However, the rhizosphere in coastal dunes imposes high levels of water and nutrient stress on plants. In these conditions, arbuscular mycorrhizal fungi (AMF) are prominent root symbionts that play a crucial role in improving to abiotic stress and promoting plant growth. On the south coast of the state of São Paulo, foredunes were studied for their floristic composition, relative frequency of AMF and grain size of rhizosphere. Foredune was classified regarding the morphology as terrace, ridge I, and ridge II. The terrace has a low height (<0.5 m) and is composed of native species canopies low (<0.2 m) and high (0.5–1.5 m) characterized by AMF colonization close to 60%. In contrast, ridge I showed wavy crests that were about 1 m high and ∼30 m wide, with a predominance of plant species with low canopy and 68% AMF colonization. The morphology ridge II reaches the greatest height (3 m), to the detriment of a smaller width (up to 15 m) and the plants present high canopy (>0.5 m) with close to 75% AMF. The increase of the relative frequency AMF from the terrace to ridges I and II may indicate that the increase of sand accumulation with continuous burial of roots is rather positive to plant growth. Yet, varied canopy heights of the plants species control the verticalization and horizontalization of the foredune. Low-canopy species, gradually slow down wind flow, causing spatialized deposition and widening. Conversely, species with highest canopies swiftly reduce wind flow due to the density of their aerial portion (leaves), resulting in deposition just below their structure fostering foredune vertical growth.

Field monitoring of alluvium accumulation in the riverine floodplain of the Oka River, European Russia

Sedimentation traps were used to assess the annual surface renewal dynamics of the low floodplain of the Oka River (a major tributary of the Volga River in central European Russia). Trap-mats and platforms made of crushed bricks were installed in positions near the meandering and relatively straight riverbed, in different sedimentation environments. Stationary research in 2014–2020 covered a section of the bottom of the Oka River valley with a length of more than 400 km along the main channel. The graphical-analytical processing of field data using Ferret's Triangles and sedimentation diagrams showed that transport and deposition of suspended sediment dominated in the accumulation of 87% of alluvium samples. The formation of ripples was not recorded, which was lithologically reflected in the horizontal layering of the new sediment. The determination of the granulometric composition of the removed sediment and their thickness on the traps showed the absence of statistically significant differences according to the Kruskal–Wallis test between the data samples from the trap-mats and trap-platforms. The reference to the daily calendar of synoptic mechanisms according to the classification of Dzerdzeevsky contributed to the identification of meteorological prerequisites for the variation of the hydrograph curve of the Oka River in its middle reaches. Prolonged floods caused by the premature arrival of spring lead to massive deposition of silt and clay particles even on sandbanks. On the other hand, short (15–35 d) March floods and abnormal high water in June, caused by Atlantic cyclone intrusions, can stabilize sand accumulation on the riverine floodplain. The thickest sediment layers on the traps were obtained in 2018 after a very cold March and a powerful April flood, and the overall distribution of alluvium thickness and its particle size distribution also depends on the morphology of the riverine relief. The siltation is caused by the accumulation of silts; the most finely dispersed sediment was deposited in those facies environments for which siltation was also characteristic in historical times.

Plug Your Way Through Downhole Restrictions

_ Unable to successfully deploy plug-and-perf bottomhole assemblies (BHA) to the desired depth has resulted in significant nonproductive time (NPT) in unconventional completions. These instances of NPT are primarily attributed to casing deformation, rather than plug presets. To address these downhole restrictions, frac plugs with smaller outer diameters (OD) were introduced for stage isolation. This reduction in plug OD minimizes the risk of getting stuck in tight spaces, but it also compromises pressure ratings. This raises the risk of skidding (slip losses, anchoring) and leads to increased fluid usage for pumpdown. These challenges not only risk well productivity, but also escalate completion time and costs. For a comprehensive solution, a smaller-OD frac plug is necessary to pass through tight spots, while maintaining anchoring, sealing, and reducing required pumped-fluid volume. The Gap The annular clearance between the plug OD and casing inner diameter (ID) significantly influences plug-and-perf operations. A smaller gap leads to advantages such as lower expansion rates for isolation, better anchoring, and reduced pumped-fluid volume, but it also heightens the risk of obstructions. Conversely, a larger gap requires higher expansion rates for isolation, resulting in weaker anchoring, lower pressure rating, and increased fluid consumption, but reduces the likelihood of obstructions. In some frac operations, higher pressure is needed to break down the formation; thus, frac plugs with higher pressure ratings (smaller gap) are commonly favored. For instance, in 5.5-in., 20-lb/ft casing, typical frac plugs have an average OD of 4.4 in., an expansion rate of 8–12%, and a pressure rating of 10,000 psi. In many 5.5-in., 20 lb/ft casedhole completions across the US and parts of China, the annular clearance between casing ID and frac plug OD is approximately 0.2 in. on the x-axis and 0.4 in. on the y-axis (Fig. 1). In this confined space, encountering debris, sand accumulation, or a deformed section during pumpdown can obstruct or fully trap the plug. To mitigate these uncertainties, smaller-OD plugs are used for such “emergency” scenarios. Smaller-OD plugs have improved chances of navigating through tight spots, but they necessitate higher expansion rates for isolation, resulting in lower pressure ratings. For example, in 5.5-in., 20 lb/ft casing, reduced OD plugs have an average OD of 3.8 in., an expansion rate of 20–25%, and a pressure rating of 5,000 psi. They are more likely to fail due to their pressure limitations and use more fluid for pumpdown. In cases where the use of normal-OD plugs is not feasible, opting for smaller-OD plugs, even though they might have a higher risk of failure, can be a valuable last resort. This approach is sometimes favored over entirely skipping the problematic stages without any form of stimulation.

Grain-size and geochemical investigations on the Novyi Tik site (NW Ukraine) and their significance for understanding the local sedimentary environment in the Pleistocene

&#x0D; &#x0D; &#x0D; Grain size and geochemical composition of the loess-palaeosol sequences are important evidence of the sedimentary environment in the Pleistocene, which enables to revela- tion of the sedimentation rates, the origin of deposits, and the sources of material that contributed to the loess accumulation and pedogenesis. The Kd index (10-50 μm / &lt;5 μm), and the Ti/Zr, Ti/Nb and Ce/Y ratios considered to be indicators of aeolian silt accumulation, whereas the ratio of physical sand to physical clay have been suggested to reveal the relationship between sedimentation and pedogenesis. The grain size and geochemical analysis were applied at the Novyi Tik section (Volyn’ Upland), which is characterized by detailed stratigraphy and lateral diversity of palaeosols and deposits. Based on grain size and geochemical data from the section, four main units have been distinguished, which represent periods with similar sedimentary environment such as MIS 10-7, MIS 6, MIS 5 and MIS 4-2. During MIS 9 and 7, pedogenesis pre- vailed with a slight sedimentary contribution; during short-term cooling, thin loess beds were formed. High loess accumulation rates occurred during MIS 6, however, the source of aeolian dust material was different from those to other loess units. At the end of MIS 6, a period of dynamic sedimentation began, which resulted in the sandy grain-size composition of soils and non-soil deposits of MIS 5. The highest sedimentation rates presumably occurred during the stadials, therefore the soils could inherit the grain-size composition of the parent material. Moreover, during MIS 5 in the valley of the Styr River, episodes of aeolian sand accumulation could take place, since the sandy grain-size composition of soils of that time is widespread throughout the basin of the modern Khrinnyky reservoir. At the end of MIS 5, abrupt changes occurred in the sedimentary environment: sand sedimentation almost ceased and a period of aeolian silt accumulation began, and proceeded until the Holocene.&#x0D; &#x0D; &#x0D;

Study of the blocking mechanism in gravel packing based on CFD-DEM

Gravel packing sand control (GPSC), as the optimization of mechanical sand control technology, is widely used in the deep water completion and sand control of loose sandstone heavy oil reservoirs and highly argillaceous. To explore the blocking mechanism of GPSC, the influence of its structural parameters on the blocking of GPSC is investigated. This paper establishes a particle element model based on computational fluid dynamics-discrete element method coupling using the discrete element method and establishes a fluid flow model combined with computational fluid dynamics to realize their full coupling solution. And sand control experiments were carried out using a micro visual sand control simulation device to verify the blocking model. The blocking mechanism is analyzed from the microscopic point of view, and then, the influence of sand control structure parameters on the blocking in GPSC design is evaluated. The results show the following: (1) the blocking process of GPSC can be divided into three stages: an initial stage, sand accumulation stage, and equilibrium stage. (2) There are two main types of gravel packing blockage. The first type of blocking is blocking on the surface of the gravel layer. Sand particles on the surface of gravel layer mainly exist in the form of large particle size blocking gravel pores and sand particles bridging each other. The second type of blockage is the blockage inside the gravel layer. Sand particles mainly exist in the form of internal mud cakes and adsorption on gravels inside the gravel layer. (3) To ensure the sand control performance of the gravel layer, the gravel layer thickness is designed between 23 and 28 mm. The displacement or pressure of the on-site packing pump should be increased to ensure that the gravel layer packing solidity ranges between 59% and 62%. In the design of GPSC, it should be ensured that the median particle size of gravel is 5–6 times the median particle size of sand. This study provides an effective technical reference for the design of gravel structural parameters in on-site gravel packing completion sand control.

Effect of Sand and Dust Shading on the Output Characteristics of Solar Photovoltaic Modules in Desertification Areas

Photovoltaic power generation is rapidly developing as a kind of renewable energy that can protect the ecological environment. The establishment of photovoltaic power stations in desertification areas can play a very important role in desert windbreaks and sand fixation as well as improve the ecological environment. The realization of the effective integration of photovoltaics and deserts can have multiple benefits for the economy, society, and ecology. However, the deposition of sand and dust caused by environmental factors in desertification areas can seriously affect the power generation efficiency of PV modules. In this study, the output characteristics of photovoltaic modules were tested under three wind speed conditions (5 m/s, 10 m/s, and 15 m/s), with different sand densities, sand particle sizes, and inclination angles. The experimental study showed that the module’s output power gradually decreased with an increase in the density of accumulated sand; the sand accumulation density on the surface of the photovoltaic module increased from 0 to 40 g/m2, and the maximum output power decreased by 32.2%. As the sand particle size increased, the maximum output power of the module rose and was gradually stabilized in the three wind speed groups. As the sand particle size increased, the maximum output power of the module increased and gradually stabilized in the three wind speed groups. When the wind speed was 15 m/s, the component output power of the angle had the largest drop; the tilt angle was 60° when the relative output power rate reached the minimum (i.e., 86.5%); that is, there was electrical energy loss of approximately 13.7%. The sand particle size and accumulated sand density were the control variables related to the module temperature and the transmittance of the proportion of the impact of the module filling factor differences. According to the curve analysis of the filling factor in different sand accumulation densities, the filling factor first increased and then decreased. In this test, the filling factor at the sand accumulation density of 35 g/m2 (module temperature valley) reached the peak value. The change trend for the component filling factor under different sand particle sizes fluctuated.

Flume experiments in the development of crevasse-splay deposits: transition from asymmetric to symmetric geometry

Abstract Crevasse-splay deposits play an important role in the reconstruction of the magnitude of past flood events and in understanding the behavior of river systems. Despite the extensive studies conducted on the geometry and facies of crevasse-splay deposits, their spatiotemporal developmental processes have remained insufficiently understood. In this study, scaled flume experiments were conducted to study the relationship between the developmental processes of crevasse splays and their characteristics. An experimental flume was set up in a tank to simulate the 2019 Chikuma River flooding event in central Japan. To model the overbank flow, an opening was created on the side of the flume’s wall through which the flow flooded onto a horizontal acrylic plate. The sediment used in the experiments consisted of particles with grain sizes of approximately 0.3 and 0.1 mm, which were determined to be equivalent to bedload gravel and suspended sand in a real-scale river using dimensional analysis. The results of the experiments revealed three important findings: 1) Crevasse-splay deposits initially developed an asymmetric shape extending downstream of the main river channel but gradually showed a symmetric geometry. The river mainstream initially influenced the direction of the inundation flow, but channel bifurcations after the deposition of the sediment piles later changed the geometry of splays into a more symmetric shape. 2) Crevasse-splay deposits developed in two distinct regions (proximal and distal splay), corresponding to sediment transport by bedload and suspended load, respectively. These two regions are commonly observed in the actual field scale. 3) The original overbank flow was a sheet flow without channels, which caused coarse-grained sediments to be spread over a wide area. Subsequently, the accumulation of coarse sands in the developed channel interiors resulted in the buildup of finer-grained sediments upstream of the proximal splay. Thus, the proximal splay deposits became slightly coarse downstream, whereas they rapidly became fine at the boundary with the distal splay. These findings indicate that the characteristics of crevasse-splay deposits vary with the landform’s development stage, thus providing a basis for interpreting their depositional facies.

Utilization of waste foundry sand and fly ash in the production of steel fibre reinforced concrete

As the main raw materials for concrete preparation, natural sand and cement are in increasing demand. Meanwhile, the large accumulation of waste foundry sand (WFS) and fly ash (FA) seriously pollutes the environment. The research on the application of waste materials in concrete preparation has become a hotspot for scholars. This study attempts to respectively use WFS and FA to substitute natural sand and cement in the preparation of steel fibre reinforced concrete (SFRC). 3-factor, 3-level orthogonal experiment was designed, and the study variables include the WFS substitution rate (20%, 40%, and 60%), FA substitution rate (10%, 20%, and 30%), and SF content (1%, 2%, and 3%). The workability, dry density and mechanical properties of concrete were tested and discussed. Range analysis and variance analysis were used to analyse the effect of various factors on the different properties of concrete. Efficacy coefficient method was used to specifically determine the optimum substitution rate of waste materials for raw materials. Additionally, microanalysis was carried out to investigate the influencing mechanism of waste materials on the properties of concrete. It was observed that the workability of concrete deteriorated with the addition of waste materials, while the change of mechanical properties closely correlated with the content of waste materials. The workability and compressive strength were most significantly affected by the WFS content, while the density, tensile strength, flexural strength and elastic modulus were most significantly affected by the SF content. The mechanical properties of concrete were optimum at 34%, 20% and 2.3% of WFS, FA and SF content respectively. In this case, the compressive strength, split tensile strength, flexural strength and elastic modulus increase by 28.8%, 33.5%, 33.8% and 17.7% respectively compared to the control concrete. Microanalysis proved that moderate amount of WFS and FA could increase the beneficial pores, decrease the harmful pores, and reduce the porosity of concrete, but excessive WFS (60%) and FA (30%) would inhibit the hydration process and enlarge the porosity of concrete. This study demonstrates the feasibility of the application of WFS and FA in SFRC preparation, contributing to overcoming the pollution of waste material accumulation and alleviating the shortage of natural resources.

Yardang-controlled dune morphology and dynamics in the Qaidam Basin: Insight from remote sensing and numerical simulations

The yardang-dune coexistence and the control of yardangs on dune formation reveal the joint action of wind erosion and deposition. Yardangs exhibit distinctive characteristics of streamlining and clustering, which apply unique and complicated impacts on the wind field and sand transport. However, previous studies lack systematic investigation on how yardangs exert control over dune morphology, and the intricate wind dynamics and mechanisms involved remain unclear. In this study, the “yardang-controlled dune” is systematically illustrated, supported by thorough studies of the yardang-controlled dune morphology and dynamics. Through the monitoring of the 6722 km2 dunes in the Qaidam Basin (QB), three typical yardang-dune coexistence patterns are identified and summarized: Pattern I-windward dune, crescentic dunes form on the upwind sides of the sparsely arranged yardangs; Pattern II-corridor dune, crescentic dunes form beside the narrowly arranged yardangs in the corridors and migrate; Pattern III-leeward dune, linear dune forms on the downwind side from isolated yardang tail. Computational fluid dynamics (CFD) modeling is used to analyze the dynamics and mechanisms of the three patterns and the corresponding real yardang topographies. CFD simulations show that with the control of yardangs, the winds in the locations corresponding to the dunes have significantly low velocities, leading to the wind entrainment decrease, sand accumulation and subsequent dune formation. CFD also reveals that the aspect ratios of yardangs control the formations of wind shadows and linear dunes on the yardang tails. The simulation results agree well with the actual landforms observed in the QB of the three patterns. Additionally, the dune leeward slope width and migration velocity statistics based on remote sensing provide further support for the observations and simulations. This study sheds light on the intricate influences of yardangs on wind deposition, underscoring their role in shaping the landform of dunes.

A Study on the Depositional Law of Road Cutting in the Tengger Desert

In this study, the characteristics of wind-blown sand in the hinterland of the Tengger Desert and the regularity of sand deposition in road cutting are studied by combining a field test and numerical simulation. Firstly, the meteorological observation system is used to obtain the long-term monitoring of the Tengger Desert hinterland, and the perennial wind speed, wind direction, and strong wind period are obtained. Then, a three-dimensional ultrasonic anemometer and stepwise sand accumulation instrument are used to measure the transient wind-blown sand velocity and density at the top of the cutting slope, which provide the basis and verification for the numerical simulation. Finally, Fluent software (2020R2) is used to establish two numerical models with and without grading. Based on Euler’s two-fluid theory and fluctuating-wind user-defined functions, the movement of wind-blown sand in the cutting section of the desert hinterland is simulated, and the regularity of sand accumulation in the cutting section is obtained. The main conclusions are as follows: (1) The strong wind period in the hinterland of the Tengger Desert in 2021 mainly occurs from April to August, and the mainstream wind direction is concentrated in the WSW and SW directions. (2) The sand in the hinterland of the Tengger Desert is mainly medium–fine, and the particle size range is mainly concentrated at 0.075–0.250 mm, accounting for 98.2% of the total sand; the curve of the wind-blown sand density with height is oblique and L-shaped. (3) The method of grading excavation is beneficial to reduce the sand accumulation rate on the road’s surface.

Automated Work Flow for Sand Prediction, Monitoring Improves Operational Efficiency

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 22989, “An Automated Work Flow of Simplified Representative Elementary Volume Approach to Sand Prediction and Control Monitoring Using Web-Based Interfaces To Reference With Operational Efficiency Improvement in Zawtika Field, Myanmar,” by Supha-Kitti Dhadachaipathomphong, Prapong Sooksawat, and Pooritat Toprasert, PTTEP, et al. The paper has not been peer reviewed. Copyright 2023 International Petroleum Technology Conference. Reproduced by permission. _ The objective of the study described in the complete paper is to increase operational efficiency by using a sand-prediction model to estimate sand production per well based on current operating conditions and to calculate a sand-operating envelope for each well to guide planning and management. The authors found that the simplified representative elementary volume (SREV) approach to sand prediction and control monitoring (SPCM) resulted in an improvement in operational efficiency by reducing time spent on manual analysis and decision-making through dashboards with predictive results. The reader is encouraged to review the complete paper, which contains detailed work flows that include associated equations and steps. Study Objective - Implement SREV approach - Use a sand-prediction model to estimate sand production per well based on current operating conditions - Estimate sand accumulation from the wellhead to the inlet separator dynamically - Predict wall thickness of the main flowlines from the wellhead to the production and test manifold - Forecast sand production when considering changes in reservoir conditions - Use an automated work flow to run the network model and obtain flow conditions, generate the well’s sand-prediction model based on well design and reservoir information, and calibrate the well’s sand-production models based on the latest validated test or sensor data - Implement Web-based interfaces Study Area The Zawtika gas field is in the Gulf of Moattama, Myanmar. A total of 123 wells and 11 platforms was used in the study. Some wells suffer from sand production because the sands are unconsolidated or weakly consolidated from Pliocene to Pleistocene geologic sequences. Sand production causes severe problems such as reduced well productivity and gas potential and damage to surface equipment such as choke, pipeline, and production systems.

Oscillatory and accumulative motions of sand particles around a vertical pile subjected to lateral vibrations

We conducted a two-dimensional experiment to investigate sand particle motions around a laterally vibrated pile structure. By recording and processing data of sand particle motions using particle image velocimetry and Particle Tracking Velocimetry, we have revealed and explained the mechanism of oscillatory and accumulative motions of sand particles at two different time scales. Our findings suggest that the velocity magnitudes of sand accumulation motions, or convection, are minimal compared to the sand oscillatory motions.

Numerical Simulation and Parameter Optimization of a New Reed–Nylon Net Combined Sand Fence

This paper introduces a kind of double-row reed–nylon net combined sand barrier. Using the computational fluid dynamics (CFD) method and the Euler–Euler double-fluid model, the new sand fences’ windproof effect and airflow features are simulated under different porosities and spacings, and the optimal configuration parameters are selected. The new sand fence has better windproof performance and practical significance than double-row reed and double-row nylon net fences. The new sand fences with a porosity of 0.3–0.4 and spacing of 28 H provide a longer protection range and a better wind protection effect. Considering the serious sand damage in China’s Taklamakan Desert, the new fences’ impact on sand buildup is examined. The combined sand fences have powerful sand blocking and accumulation effects, even though there is only a small quantity of sand accumulation on the leeward side of the second row. The sand particles primarily settle between sand fences in the center and rear areas. The combination of sand fences made of different materials combines the advantages of both, improves the construction efficiency and service life, and provides a more economical and efficient sand barrier arrangement for the arrangement of wind and sand-blocking facilities around railroads and highways in desert areas.

Performance of solar roof top panels with disparate particulate accumulation: Exergy analysis on an indoor lab study.

Deployment of solar photovoltaic panels are significantly rising to tackle adverse effects of climate change however, factors affecting output need to be categorized in addition to latitude angle and space. It is important to consider the atmospheric impact which can drastically change output power of solar panels. This study covers dust accumulation of soil, sand and ash at variable weights to foresee its effects on panel power output. Mixtures of these particles at multiple constituents were also analyzed. Experimental results indicated that clean panel gives maximum power output of 21.37W and exergy efficiency of 7.96% whereas ash accumulation showed worst results of 2.88W power output and 1.07% exergy efficiency at 700W/m2 and 50g dust accumulation. Other parameters like energy destruction, exergy losses and sustainability index were also analyzed. Trends have been illustrated in graphs along with the change in solar intensity and dust accumulations.

Exploring Controls on Coastal Dune Growth Through a Simplified Model

AbstractProcess‐based morphodynamic models can be useful in understanding coastal dune responses to disturbances, as well as possible evolutionary patterns. To this aim, we employ Duna, a simplified 1D morphodynamic model, to assess the influence of dune morphology (height and slope) on sand transfer and deposition across the dune profile for different beach widths and wind incidence angles through idealized experiments. Simulations of real conditions show good model performance, both in wind flow reproduction and in topographic change along the dune profiles tested. The idealized experiments show that wind speed increases and sand accumulation decreases logarithmically with dune height and linearly with stoss slope along the dune profile. Fetch and cosine transport limiting parameters are reflected in the sand accumulated windwards from the toe, while sand transfer to the dune appears controlled by multiple factors; the higher the dune and/or the narrower the beach, the likelier that maximum accumulation occurs under oblique winds. Results point to two different types of evolution for high dunes. Either the vegetation is dense enough to maintain the stoss position, in which case vertical growth near‐ceases and seaward progradation is promoted, or the stoss is eroded and landward retreat dominates, in which case sand transfer to the crest and lee continues as a mixture of low input from the beach and recycled sand from the stoss.

SPATIO-TEMPORAL VARIATION OF AEOLIAN SHOREWARD SAND TRANSPORT MEASURED USING NEAR-CONTINUOUS LASER SCANNING

A beach in Mariakerke-Bad (Belgium) was monitored in 2017-2018 for more than a year with a near-continuous laser scan system. From a total of 8500 scans 7700 hourly scan epochs were used to study the spatio-temporal shoreward sand transport at the beach. In order to account for weather influences and other possible disturbances of the scan-system, a time-dependent correction method was applied to reduce rotation errors up to 0.2 degrees in the point cloud orientation (around the zero point of the laser scanner) reducing height errors on the beach to the order of centimeters. Cross shore analysis of the beach profile shows that shoreward transport occurs at most times during the year with an accumulated maximum of 17m3/m throughout the measurement period and maximum transport rates of 0.6 m3/m/day. However most of the shoreward sand transport is redistributed seawards again due to beach shaping leaving a total of about 2 m3/m a year which is below the average values found along the Belgium coast. The spatio-temporal behavior of the shoreward sand transport has been studied with the 4D-OBC analysis technique which identified accumulations of sand in the full 4D point cloud dataset. A total of about 3600 4D-OBC accumulation events were identified and most found accumulations on the beach can be associated with natural (aeolian) processes. Also, accumulations appear to occur during the whole year which is consistent with the previous cross-shore analysis.