Search

Abstract Study on the microscopic structure of saline–alkali soil can reveal the change of its permeability more deeply. In this paper, the relationship between permeability and microstructure of saline–alkali soil with different dry densities and water content in the floodplain of southwestern Shandong Province was studied through freeze–thaw cycles. A comprehensive analysis of soil samples was conducted using particle-size distribution, X-ray diffraction, freeze–thaw cycles test, saturated hydraulic conductivity test and mercury intrusion porosimetry. The poor microstructure of soil is the main factor that leads to the category of micro-permeable soil. The porosity of the local soil was only 6.19–11.51%, and ultra-micropores (

Recent developments of crowd analysis and behaviour prediction have attracted much attention. Crowd counting, as the essential and challenging task in crowd analysis, is riddled with many issues, such as large scale variations, serious occlusion, and so on. In this study, a self‐attention‐based multi‐scale cascaded network called SAMC‐Net to estimate density map for crowd counting, especially for high congested scene, is proposed. The proposed SAMC‐Net consists of two components: a classification sub‐network for density estimation and an end‐to‐end multi‐scale convolution neural network for crowd counting. In order to reduce the negative effect of multi‐scale issue on crowd counting task, the main network is designed as a multi‐scale structure similar to U‐Net. In order to enhance the crowd feature representation, this study proposes a self‐attention‐based crowd feature extraction way and uses it in the proposed SAMC‐Net. Extensive experiments demonstrate the feasibility, effectiveness and robustness of the proposed SAMC‐Net.

Abstract Oil–water two-phase flow in horizontal oil-producing wells with low velocity and high water cut generally presents the phenomenon that the underlayer shows water flow and the upperlayer presents oil flow or a dispersion of oil in water flow. And existing ring-shaped conductance water cut meter cannot obtain the online and real-time response values corresponding to oil field water conductivity in the calculating water holdup procedure. To tackle this issue, this paper designs a mini-conductance probe array (MCPA). In order to further investigate the ability of the total flow rate of the allowable measurement fluid and the parameters valuing of the water cut in horizontal segregated flow, this paper also analyzes the performance of MCPA with different structure parameters in terms of the spatial sensitivity distribution characteristics. Firstly, the geometry model and mathematical model of MCPA are designed, and the MCPA simulation model is analyzed by using the finite element method. Then, the optimum structure parameter results of the sensors are obtained through analyzing the spatial sensitivity distribution characteristics of MCPA in consideration of different distance between the two electrodes and different inner diameters. Lastly, the MCPA different parameters are developed, and experiments are carried out in horizontal multiphase flow experiment facility to analyze spatial sensitivity distribution characteristics of MCPA with different inner diameters on the basis of optimum parameters. Experimental results demonstrated that MCPA with a larger inner diameter would have high measurement accuracy in variation range of water cut, and has a high adaptability in horizontal oil-producing wells with relatively high flow rate and different flow conditions.

This paper studied conductance-based method for water cut measurement to dynamically monitor the horizontal oil-producing wells. Existing conductance tools cannot obtain the response values corresponding to the water phase in horizontal wells due to the characteristics of the ring-shaped electrode structure and the horizontal well structure. In order to tackle this issue, this paper designed a novel Combined Conductance Sensor (CCS), which mainly consists of the Ring-Shaped Conductance Probe (RSCP) and the novel Clock-like Conductance Probe Array (CCPA). Specifically, we first established the structure model of CCS, optimized the geometry of CCPA by analyzing the uniformity of electric field distribution generated by the exciting electrodes of CCPA and then analyzed the local sensitivity field region of the optimized CCPA. Then we studied the flow pattern distribution of the horizontal oil-water two-phase flow and analyzed the response characteristics and the linear relation between RSCP and CCPA. In addition, this research developed the CCS-based tool and conducted the experiments about different inclined angles in horizontal and slightly inclined pipes. Extensive experiments demonstrated that the developed CCS can cover the three-quarter scale of water cut measurement(25%-100%) in horizontal and slightly inclined pipes, and the experimental results verified the validity of CCS for the water cut measurement. Comparing to the existing methods, the proposed CCS is more suitable for water cut measurement with the advantages of simple structure and low cost for the horizontal oil wells with the characteristics of the low production, which could be used widely in the actual logging.

This paper proposes an automatic scale-adaptive approach with attention mechanism-based crowd spatial information addressing the crowd counting task, i.e. a novel cascaded crowd counting network. The proposed network is composed of a classification sub-network to estimate crowd scales and the main network to predict the corresponding density maps. First, the image serves as the input of the classification network and the main network. Second, according to the estimated crowd scale results, the main network structure is adjusted; simultaneously, the feature in the intermediate layer of the classification network is added stepwise into the main crowd counting network. Then, the semantic feature of the classification network is converted into the crowd spatial information mask via the proposed spatial attention conversion module, and the crowd spatial information mask is weighted into the specific feature of the main network. Last, the crowd density map and the crowd counting result are obtained. The experiments on challenging Mall, the Shanghaitech_A and Shanghaitech_B datasets prove the effectiveness, feasibility, and robustness of the proposed method, and the ablation study demonstrates the structure rationality of the proposed network.

In the process of production logging interpretation, a water cut is one of the key factors to obtain the oil phase content in the oil well. In order to measure the water cut of the horizontal oil⁻water two-phase flow with low yield, the response characteristics of the combined capacitance sensor (CCS) are investigated under different flow patterns. Firstly, the measuring principles of coaxial, cylindrical, and CCS are introduced in detail. Then, according to the different flow pattern conditions of the horizontal oil⁻water two-phase flow, the response characteristics of the CCS are simulated and analyzed using the finite element method. Additionally, compared with the other two sensors, the advantages of the CCS are verified. Finally, the temperature and pressure calibration experiments are carried out on the CCS. The horizontal oil⁻water two-phase flow patterns in a low yield liquid level are divided in detail with a high-speed camera. Dynamic experiments are carried out in a horizontal pipe with an inner diameter of 125 mm on the horizontal oil⁻water two-phase flow experimental equipment. The simulation and experimental results show that the CCS has good response characteristics under different working conditions.

Oil-water two-phase flow is widespread in petroleum industry processes. The study of oil-water two-phase flow in horizontal pipes and the liquid holdup measurement of oil-water two-phase flow are of great importance for the optimization of the oil production process. This paper presents a novel sensor, i.e., a mini-conductance probe (MCP) for measuring pure-water phase conductivity of oil-water segregated flow in horizontal pipes. The MCP solves the difficult problem of obtaining the pure-water correction for water holdup measurements by using a ring-shaped conductivity water-cut meter (RSCWCM). Firstly, using the finite element method (FEM), the spatial sensitivity field of the MCP is investigated and the optimized MCP geometry structure is determined in terms of the characteristic parameters. Then, the responses of the MCP for the oil-water segregated flow are calculated, and it is found that the MCP has better stability and sensitivity to the variation of water-layer thickness in the condition of high water holdup and low flow velocity. Finally, the static experiments for the oil-water segregated flow were carried out and a novel calibration method for pure-water phase conductivity measurements was presented. The validity of the pure-water phase conductivity measurement with segregated flow in horizontal pipes was verified by experimental results.

Soil salinization is an issue of global concern. Despite recent evidence indicates that application of sediments into saline-alkali soil in Yellow River Delta as an additive can increase crop yield, its effects on soil structure and infiltration remain uncertain. In this study, the comprehensively analyses were conducted on the soil infiltration and microstructure of the soil treated with three sediment application layers (surface layer at 0-15 cm, lower layer at 15-30 cm, and plough layer at 0-30 cm) and four sediment incorporation rates (0, 2%, 5% and 10%), using soil column simulation experiment. Results indicated that the dredged Yellow River sediments can improve the infiltration capacity of saline-alkali soil; and the infiltration capacity increased with the rising sediment incorporation rate under the given application pattern. Compared with the control, applying dredged Yellow River sediments at 10% rate at lower layer and plough layer significantly facilitated the soil infiltration of the saline-alkali soil. Soil macro-porosity for T2, T5 and T10 was 26%, 52% and 158% more than that for the control, respectively. This phenomenon was attributed to the increased soil macro-porosity, due to the improved soil microstructure with the incorporation of sediment into the saline-alkali soil. Moreover, the cumulative infiltration was fitted better with Kostiakov infiltration model than Horton and Philip models. [ABSTRACT FROM AUTHOR]

To understand the water-salt transport process of saline soils in the Yellow River Delta region under traditional hydraulic remediation measures and to determine its engineering parameters, in this study, laboratory investigations were made to measure the soil salt content using three remediation practices under simulated rainfall conditions. The results indicated that under the rainfall intensity of 100 mm/h, 6-8 h are needed when the soil salt content tends to be constant. The distribution of the salt content presents a typically symmetrical shape regardless of the position of the saline soil relative to the concealed pipe, the open ditch, and the vertical shaft. The two-parameter exponential function indicates the relationship between the soil desalination rate and the horizontal distance from the pipe, the ditch or the shaft. The maximum spacing to build the salt drainage engineering of the concealed pipe, the open ditch or the vertical shaft in the laboratory is 4.79 m, 2.88 m, and 2.19 m, respectively. The effectiveness of salt drainage for coastal saline soils can be ranked from largest to smallest as the concealed pipe, the open ditch and the vertical shaft. The findings provide an experimental basis and reference for the application of hydraulic measures to remediate saline soils in this region. [ABSTRACT FROM AUTHOR]

Recent developments of crowd analysis and behaviour prediction have attracted much attention. Crowd counting, as the essential and challenging task in crowd analysis, is riddled with many issues, such as large scale variations, serious occlusion, and so on. In this study, a self-attention-based multi-scale cascaded network called SAMC-Net to estimate density map for crowd counting, especially for high congested scene, is proposed. The proposed SAMC-Net consists of two components: a classification sub-network for density estimation and an end-to-end multi-scale convolution neural network for crowd counting. In order to reduce the negative effect of multi-scale issue on crowd counting task, the main network is designed as a multi-scale structure similar to U-Net. In order to enhance the crowd feature representation, this study proposes a selfattention- based crowd feature extraction way and uses it in the proposed SAMC-Net. Extensive experiments demonstrate the feasibility, effectiveness and robustness of the proposed SAMC-Net. [ABSTRACT FROM AUTHOR]

In order to accurately measure the flow rate under the low yield horizontal well conditions, an auto-cumulative flowmeter (ACF) was proposed. Using the proposed flowmeter, the oil flow rate in horizontal oil–water two-phase segregated flow can be finely extracted. The computational fluid dynamics software Fluent was used to simulate the fluid of the ACF in oil–water two-phase flow. In order to calibrate the simulation measurement of the ACF, a novel oil flow rate measurement method was further proposed. The models of the ACF were simulated to obtain and calibrate the oil flow rate under different total flow rates and oil cuts. Using the finite-element method, the structure of the seven conductance probes in the ACF was simulated. The response values for the probes of the ACF under the conditions of oil–water segregated flow were obtained. The experiments for oil–water segregated flow under different heights of the oil accumulation in horizontal oil–water two-phase flow were carried out to calibrate the ACF. The validity of the oil flow rate measurement in horizontal oil–water two-phase flow was verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]