bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of a geomagnetic induced current on a three-phase power transformer and power system
Authors: Adiba Zawawi Anis , Fadilah Ab Aziz Nur , Zainal Abidin Abd Kadir Mohd , Hashim Halimatun
Published: February 2021

A geomagnetic induced current (GIC), resulting from adverse space weather, has a low occurrence rate but the potential for high impact events. Such events can disrupt the operation of a power system, especially the power transformer as the current flows in the transmission lines and through the transformer ground points. It is a well-documented fact that a GIC can cause a significant threat to ground-based networks as the induced current can enter into the transmission system through the wye-grounded transformers. This paper presents a simulation of a GIC on an IEEE 9-bus test system under steady-state conditions using PSCAD/EMTDC software. The main focus of this paper is the effects of a GIC on a three-phase power transformer that includes half cycle saturation and reactive power consumption. Based on the simulation results under GIC conditions, the magnitude flux and magnetising current of the power transformer as well as reactive power consumption increase and may lead to power system instability.
Amateur satellite ground station: Troubleshooting and lesson learned
Authors: Ali F Z , Rahim S N M , Jusoh M H
Published: February 2021

Few troubleshooting steps have been taken during the non-operation period of UiTM ground station (UiTMSAT) where some of the main equipment and systems were malfunction. After few resolutions performed, the root cause of the defect was detected. The issue occurred due to the lighting strike that has transferred abundant amount of electricity to the devices in the monitor room. This paper explains the resolution steps that were taken to resolve the issue in the ground station. The maintenance is performed on radio, rotator controller, rotator interface, terminal node controller (TNC) and the software used for the satellite operation. The issues on the radio and rotator devices made some difficulties in using the operation software which are the SatPC and BIRDS operation software. Several attempts have been done and through this, many lessons were learned by the ground station operator. These lessons were shared to other BIRDS members during the ground station workshop at Kyushu Institute of Technology (KYUTECH), Japan.
Zenithal Sky Brightness Measurement at Selangor Observatory
Authors: Ngadiman N F , Shariff N N M , Hamidi Z S
Published: February 2021

The first continuous assessment of night sky brightness (NSB) at Selangor Observatory are presented. The brightness at night sky was monitored over 6 months in 2018, using portable light sensor called the Sky Quality Meter-type USB-Data Logging with a fixed position - pointing towards zenith. From the 179 records of night, the study shows that the average NSB readings at Selangor Observatory is 20.04 ± 0.18 magnitude per square arc second (MPSAS), after excluding the moonlight factor. Meanwhile, during the stable night sky conditions, the most recorded NSB value is 21.1 MPSAS with 0.78 MPSAS range and 21.03 MPSAS in average. Therefore, Selangor Observatory is still a relevant location for the implementation of astronomical work since it has a night sky within Bortle scale Class 4 to 5.
Energy transitions, air quality and health
Authors: Pereira Gavin , Bell Michelle L , Honda Yasushi , Lee Jong-Tae , Morawska Lidia , Jalaludin Bin
Published: February 2021

The way we produce and use energy is transforming. Policy in this area intersects decisions that affect climate change, air quality, and the economy. The exponential increase in use of fossil fuel and nuclear energy has now essentially replaced human and animal energy (McKinney 2019 Curr. Pollut. Rep.
5 394–406; Solomon and Krishna 2011 Energy Policy
39 7422–31). These transitions have contributed to notable gains, such as improvements in mortality rates attributable to improved heating, water quality and transportation (Rayner 2012 Ecological Public Health : Reshaping the Conditions for Good health/Geof Rayner and Tim Lang (Abingdon, Oxon: Earthscan); Rosen 2015 A History of Public Health (Jhu Press); Pain 2017 Nature
551 S134–7; Cutler and Miller 2005 Demography
42 1–22). However, such transitions have also been accompanied by health detriments. Improvements in transportation and occupational efficiencies have promoted lifestyle transitions that have contributed to the chronic disease epidemic (Heath 2009 Am. J. Lifestyle Med.
3 27S–31S). Certain energy-related accidents and waste products have been long-established as carcinogenic (Guizard et al 2001 J. Epidemiol. Community Health
55 469; Cardis and Hatch 2011 Clin. Oncol.
23 251–60) and potential precursors to genetic mutations (Beir 1990 Health Effects of Exposure to Low Levels of Ionizing Radiation (Washington, DC: National Academy of Sciences); Desouky
et al 2015 J. Radiat. Res. Appl. Sci.
8 247–54). Moreover, air pollution emissions are increasingly becoming recognised as a major contributor the global burden of disease, particularly cardiovascular and respiratory mortality (Cohen et al 2017 Lancet
389 1907–18). Although renewable energies can be perceived as ‘clean’, the shift to renewables has been relatively more recent and consequently, less is known about associated health impacts. The life course of renewable energy begins with the process of manufacturing renewable technologies, includes the means of transportation for the distribution and collection of these technologies as well as the disposal of their waste products and subsequent contamination. All of these stages have potential to involve direct chemical exposures through the groundwater, soil or air; and have potential to affect health through indirect pathways. A relatively understudied area, and the topic of this Focus Issue on Energy Transitions, Air Quality and Health, is the relevance of energy transitions and their associated environmental factors in a contemporary setting, how such factors affect health now, and will affect health in future.
Tail-behavior roadmap for sharp restart
Authors: Eliazar Iddo , Reuveni Shlomi
Published: February 2021

Many tasks are accomplished via random processes. The completion time of such a task can be profoundly affected by restart: the occasional resetting of the task’s underlying random process. Consequently, determining when restart will impede or expedite task completion is a subject of major importance. In recent years researchers explored this subject extensively, with main focus set on average behavior, i.e. on mean completion times. On the one hand, the mean approach asserts the centrality of ‘sharp restart’—resetting with deterministic (fixed) timers. On the other hand, a significant drawback of the mean approach is that it provides no insight regarding tail behavior, i.e. the occurrence likelihood of extreme completion times. Addressing sharp restart, and shifting the focus from means to extremes, this paper establishes a comprehensive tail-behavior analysis of completion times. Employing the reliability-engineering notion of hazard rate, the analysis yields a set of universal results that determine—from a tail-behavior perspective—when sharp restart will impede or expedite task completion. The universal results are formulated in terms of simple and explicit hazard-rate criteria. With these novel results at hand, universal average-&-tail classification manuals for sharp restart are devised. The manuals specify when the average and tail behaviors are in accord, and when they are in dis-accord. Notably, the manuals pinpoint general scenarios in which—rather counter-intuitively—sharp restart has an opposite effect on average behavior and on tail behavior: decreasing mean completion times while dramatically increasing the likelihood of extreme completion times; and, conversely, increasing mean completion times while dramatically decreasing the likelihood of extreme completion times.
A Comparative Study on the Readiness Parameters of Highway Construction Projects
Authors: Radzi A R , Rahman R A , Doh S I , Esa M
Published: February 2021

Successful highway projects could help contribute to a country’s economic development and growth. One of the factors that cause delays in highway projects is starting too early (i.e., premature start), and assessing the readiness of the project before construction could prevent it from happening. However, different types of highway projects can have various causes of delay. Therefore, having inappropriate readiness parameters can impair the process of assessing construction readiness. This study aims to compare the construction readiness parameters (CRPs) between different types of highway projects. To achieve that objective, questionnaire survey data from 105 industry practitioners with highway construction working experiences is analyzed using the analysis of variance (ANOVA), descriptive statistics, and mean score ranking technique. The results reveal 32 CRPs that are critical for both highway and expressway projects. Also, there are 6 CRPs that are only critical for highway projects. This study contributes to the current body of knowledge by illustrating any discrepancies of the readiness parameters between types of highway projects. The lessons from this study could help the industry to justify the usage of the parameters for assessing their highway projects in preventing premature starts.
Strategies for virtual teams in construction: Easiness-effectiveness analysis
Authors: Manea A A , Radzi A R , Rahman R A , Haron A T
Published: February 2021

Technology has contributed to the development of the construction sector. Scientific discoveries have resulted in the cooperation of a group of people from different geographic locations who depend on communication technologies (i.e., a virtual team). Virtual teams use advanced technology to fix communication issues and are considered as a practical, productive, and creative team concept. Thus, it is evident that the virtual team also needs to concern about improving construction efficiency. This study aims to define the strategies that maximize the effectiveness of virtual teams in the construction industry in Malaysia. To achieve the objective, a questionnaire survey was conducted with industry practitioners from the Malaysian construction industry. Data of 112 respondents were collected and analyzed. The results reveal that seven strategies are perceived by industry practitioners to be both the most effective and easiest in enhancing virtual teams. Conversely, ten strategies are either the most effective or easiest to be implemented. This research adds to the body of knowledge is in expanding the understanding of virtual teams in the construction industry in Malaysia, which could support industry practitioners in the decision-making process for improving virtual teams. The findings of this research would help increase the efficiency of the project teams in the construction industry.
Research on Voltage Control Method of Distributed Photovoltaic Distribution Network Considering Electric Vehicle Charging
Authors: Wang Zhi , Yu Lianghui , Ji Tongjun , Zeng Yuzhu , Ji Yongchao
Published: February 2021

A large number of distributed photovoltaic grid connected to the grid is the main reason for voltage overrun of low-voltage distribution network. Therefore, this paper proposes a voltage control method using electric vehicle (EV) and photovoltaic inverter. Firstly, the distributed control of photovoltaic inverter is adopted. The voltage is regulated by controlling the active power output and reactive power output of the photovoltaic inverter, and the utilization rate of each photovoltaic inverter is the same. If the voltage is not within the safety threshold or the spare capacity of the PV inverter is insufficient, the charging and discharging power control of the electric vehicle will be carried out, and the charging and discharging rate will be controlled according to the consistency target of the electric vehicle power utilization and the SOC local information. The low-voltage distribution system is built in Matlab/Simulink. The simulation results show that the proposed control method is feasible and effective, and the voltage overrun problem in this area is effectively solved.
The Research on comprehensive benefit Evaluation model of pumped storage power station based on improved G1-entropy weight method
Authors: Zhao Haiji , Wu Keming , Sun Mingze , Lv Changlin , Hou Kaiyuan , Peng Yongming
Published: February 2021

In this paper, the comprehensive benefit evaluation index system of pumped storage power station will be established from four aspects: operation effect, functional benefit, financial benefit and environmental benefit. The improved sequence relationship analysis method will be combined with entropy weight method, and TOPSIS will be used to establish comprehensive evaluation model to quantitatively evaluate the comprehensive benefit of pumped storage power station in the power system. Then, through the analysis of the results of typical case studies, it is concluded that the index to be strengthened and the index that has reached the standard for power station, which is convenient for targeted measures to improve the comprehensive benefits of the power station in the future.
Aggregation of Typical Diurnal Curves of Regional Distribution Based on FCM Algorithm
Authors: Liang Chao , Su Jinsheng , Zhao Hui , Zhao Dewei , Yang Jing , Liu Dunnan , Wang Lingxiang
Published: February 2021

In order to solve the influence of renewable energy output instability on distribution network planning and power contract decomposition, this paper proposes a typical daily curve aggregation method based on FCM algorithm for regional distribution of power types. In this paper, several kinds of polymerization optimization algorithms are compared and analysed. Then the calculation method of curve polymerization was designed based on the principle of FCM. Finally, the monthly photovoltaic power plant output curve of region A is aggregated by FCM algorithm to obtain the typical daily curve of that month. The results show that the power curve formation method proposed in this paper meets the planning demand of region A to the greatest extent and provides an effective technical means for curve decomposition.
Prospect of Typical Application of Integrated Energy System
Authors: Zhang Haijing , Wang Weishuai , Zhu Lingkai , Sun Zhuoxin , Ma Decao , Chen Wenjiao
Published: February 2021

Integrated energy system can break the pattern of unconnected and independent between traditional energy systems, which is of great significance in realizing the integration of multiple energy sources and promoting the efficient utilization of energy. This paper first introduces the concept of integrated energy system, and then according to the characteristics of integrated energy system in planning, design and operation optimization, summarizes the three-level application scenarios applicable to different spatial scales, and introduces some typical application scenarios in detail. At the same time, according to the existing integrated energy system demonstration projects, the application theory of specific scenarios is extended. Finally, combined with the national conditions and energy development status of China, the problems and development direction of the future development of the integrated energy system are proposed, and some suggestions and ideas are given for the energy utilization and planning and design, so as to provide reference for the follow-up research.
Review on the Superhydrophilic coating of Electric insulator
Authors: Guo Kai , Jiang Bo , Zhao Peng , Wu Yaping , Tian Shuang , Gao Zhiyue , Zong Lijun , Yao Shuo
Published: February 2021

In recent years, new preparation technologies of ultra-hydrophilic TiO2 films have emerged in an endless stream, such as spray pyrolysis, electrostatic spinning, spray printing, micro-arc oxidation, pulsed laser deposition, atomic force deposition, ion beam deposition, etc. These new preparation technologies are able to control the surface chemical composition and surface structure of the thin film more precisely and to prepare the ideal superhydrophilic TiO2 coating. Among them, the rf sputtering method has important research significance for the repair and maintenance of TiO2/SiO2 composite coating. Nano TiO2 has excellent photocatalytic activity and superhydrophilicity, making it an important material for the preparation of high self-cleaning superhydrophilic coatings. However, the application of TiO2 photocatalysis requires UV light, and there is less than 5% UV light in sunlight, so the application of TiO2 photocatalytic performance is greatly limited. In addition, the surface hydrophilicity of TiO2 under light also has great problems. Therefore, improving the surface hydrophilic durability of TiO2 has become a key research point.
Analysis and understanding of resistance in injection well testing
Authors: Tian Long
Published: February 2021

In this paper, the injection well test resistance is counted, and the adverse effects of wellbore blockage on stratified test are analyzed. The main sources of wellbore blockage are obtained, the corresponding treatment methods are worked out, and some understandings are put forward.
Evolution of Solar Photovoltaic Policies and Industry in China
Authors: Zhang Yueqi , Xie Pengcheng , Huang Ying , Liao Cuiping , Zhao Daiqing
Published: February 2021

China has experienced a rapid growth of both SPV manufacturing capacity and installed capacity in the last twenty-five years. However, this growth has followed a very erratic path. This study identifies policies issued through this period for a closer look on the impact of these policies to the solar photovoltaic (SPV) industry development in China. This paper examines five stages in China’s SPV policy from mid-1990s to 2019. Each stage has implemented different combinations of policy program. These changes in government policy and the effects to the SPV sector are attributed to three main sets of variables. First and foremost, the events that influence the policy and strategy priorities of Chinese government. Secondary factors include the government’s poor management of the policy impacts to the SPV manufacturing industry and the domestic SPV market at early days, as well as policymaking and problems coping within government. The subsidy, FIT policies and other programs had stimulated the deployment of SPV in a large scale but brings several problems such as subsidy reliance. The fundamental measure to improve SPV development into a grid parity era is the technological advancement of photovoltaic in efficiency and manufacturing.
Research on Surface Defect Detection of Solar Pv Panels Based on Pre-Training Network and Feature Fusion
Authors: Li Huohua , Fu Xiaogang , Huang Tairu
Published: February 2021

Aiming at the problems of the lack of sample size and the complexity of defect images in defect detection task, based on the idea of transfer learning and hierarchical feature fusion, this paper proposes a deep classification network model of improved vgg19 pre-training network by analyzing the basic principle of feature extraction of convolutional neural network and getting inspiration from feature pyramid network. Then, the model is trained by the small-scale defect images of solar pv panel. Finally, the solar pv panel data set containing four kinds of defects, including cracks, debris, broken gates and black areas, is selected to comprehensively verify the effectiveness of the improved network in the defect detection task. The experimental results show that the proposed method is superior to the classical vgg19 network model in four evaluation indexes, such as accuracy, precision, recall rate and F1 score.
A multi-task learning framework for multi-location short-term load prediction
Authors: Meng Zhaorui , Sun Jinhua
Published: February 2021

Short-term power load prediction is crucial to management of power system. The traditional load prediction methods are based on learning data from single location. However, load consumption is related among different locations. In this paper, we propose a novel approach to train load predictors for multi-locations in a collaborative way based on multi-task learning. Specifically, the load predictor in each location is splitted into two parts: a general one and a location-specific one. The general predictor is to capture information shared by various locations. And the location-specific predictor is to obtain location-specific information. In addition, a location similarity graph is built and incorporated into the model as regularization. Extensive experiment result shows that our approach outperformed single task learning method and another two multi-task learning methods in at least 80% of locations.
Urban integrated energy demand forecasting method considering multi-station fusion
Authors: Wu Haoyu , Ma Jiaxin , Zhang Chunyan , Zhou Hua , Bian Shimin , Zeng Ming
Published: February 2021

Under the background of energy reform, China’s energy-related industries actively innovate from the top to the bottom, vigorously promote the “Internet + Energy” strategy, and promote multi-station integration to deeply integrate energy, information communication and other pillar industries of the national economy to help China’s industrial upgrading and economic development. This paper proposes a method for forecasting urban comprehensive energy supply and demand that considers multi-station integration. Through the prediction and analysis of energy supply and demand under various scenarios of multi-station fusion, the comprehensive energy design scheme under different types of multi-station fusion scenarios is clarified to assist the early development of market developers and provide decision support for the promotion and application of comprehensive energy technology facing multi-station fusion.
Measurement of Noise Emission Level at Substation Boundary Based on Coherent Power
Authors: Li Linyong , Li Li , Li Duanjiao , Xiao Guofeng , Lin Qixiong , Fan Xiaopeng , Zou Zhuanglei , Peng Lei
Published: February 2021

According to the Chinese standard of GB 12348-2008, to determine the noise emission level at substation boundary, the noise level of substation boundary and the background should be measured separately. Then correct noise level at substation boundary utilizing measured background noise. However, the measured background noise is inaccurate due to the different acoustic environment. Therefore, the noise emission level at substation boundary applying this method often has a certain error. This paper proposes a method for separating transformer noise to calculate the noise emission level of transformers based on coherent power, which avoids the error caused by the inaccurate measurement of background noise.
Design of Reciprocating Wave Power Generation System
Authors: Ding Nan , Yang Junda , Cheng Hanxiang , Dai Qiangqin
Published: February 2021

The world’s energy structure, the main energy used by mankind is still oil, natural gas and coal and other non renewable resources. Therefore, renewable energy has a huge development prospect. Wave energy is a renewable energy with a high density. The system mainly depends on the wave energy in the ocean and provides a reciprocating wave power generation system. The influence of sea state on the dynamic characteristics of power tools is analyzed by using the knowledge of dynamics. The mechanical analysis of crank and connecting rod is carried out to understand its vibration characteristics, which provides necessary theoretical basis for power tools such as wave power generation system.
Research on the application of the frequency-phase controlled AC withstand technology in GIS
Authors: Zhang Peng , Liang Jianquan , Wang Yue , Zhang Dewen , Sun Wei , Zhang Jian
Published: February 2021

Gas insulated SWITCHGEAR has been widely used in modern power grid with increasingly tight land use due to its advantages such as small floor space, high integration, strong security, high reliability and small maintenance workload. For the extended high-voltage GIS equipment, field insulation AC voltage withstand test must be carried out before operation to verify whether the equipment is ready for operation. In the withstand voltage test, considering the possible breakdown of the original equipment during the withstand voltage between the tested, the original equipment must be cut off and grounded. However, with the continuous improvement of the reliability requirements of power supply, the power failure will cause great economic and political losses, which requires a technology that does not require the GIS bus to stop completely, namely frequency-phase controlled AC withstand test technology. In this paper, the test principle of the frequency-phase controlled AC withstand test technology is first analyzed, and then the test process of the frequency-phase controlled AC withstand technology is illustrated by an example, which provides a reliable scheme for the field test of GIS maintenance or expansion interval.
Influence of basalt fiber on mechanical properties of permeable cement stabilized macadam base
Authors: Li Chungang , Zhou Heng , Guo Chunmei
Published: February 2021

Different groups of permeable cement stabilized macadam specimens material test, which used different basalt fiber content were carried out, studying the influence of basalt fiber content on compressive strength and splitting strength of materials. The results showed that basalt fiber can improve the long term compressive strength and splitting strength of permeable cement stabilized macadam. When the basalt fiber content is 0.7 ‰ and the fiber length is 12 cm, the compressive strength and splitting strength of the specimen are improved best.
A novel optimization method based on interlayer equilibrium displacement for heterogeneous reservoir with high efficiency
Authors: Han Fengyang , Wang Min , Sun Hongxia , Tan Baoguo , Yao Yumin , Liu Zhifeng , Shi Anfeng , Wang Xiaohong
Published: February 2021

In order to formulate the optimal control scheme of injection and production rates for heterogeneous reservoir scientifically and effectively, so as to realize the efficient development of heterogeneous reservoirs, a production optimization method based on interlayer equilibrium displacement for heterogeneous reservoir is proposed. The proposed method decomposes the origin production optimization problem into multiple easy-to-solve sub-problems. Solving the sub-problems can obtain the approximate optimal solution of the origin production optimization problem at a small computational cost. Then use the approximate optimal solution as the initial solution, the number of iteration steps required for origin optimization problem will be greatly reduced. The proposed method is applied to an actual reservoir production optimization. The results show that the method can greatly shorten the calculation time and increase the calculation efficiency by 3 times while ensuring the optimization effect.
Study on benefit evaluation of developed oil and gas fields
Authors: Chen Yamei
Published: February 2021

With the development of economy and the fluctuation of international crude oil price, people are more and more concerned about the economic benefits of oilfield development. At present, most of the domestic oil fields have entered the middle and late stage of development. With the increase of water cut and decline of production, the economic benefits vary greatly, and some single Wells and block incomes are not enough to make up for their production costs. How to carry out economic evaluation, provide basis for production and operation decision, and seek the best economic benefit is the first problem that must be studied and solved in the development of oilfield quality benefit. Single well and block benefit evaluation system is applied in this article, combined with the most oil field in recent years, the crude oil output, production cost, sales income, etc. comprehensive analysis and evaluation has been developed single well, block, formulate corresponding measures and countermeasures, to guide the oilfield production and operation, inefficient, invalid next block and single well comprehensive treatment has a positive meaning.
Study on resource evaluation of coalbed methane in old gob area of Nanzhuang Coal mine
Authors: Ran Wang
Published: February 2021

Nanzhuang coal mine in Yangquan mining area has entered the dry period of coal resources, founded the mine gas extraction to reduce gradually, need to find a new source for the mine to provide continuous heating, industrial district and coalbed methane in the old mined-out area is clean and precious resources, has a very high use value, and the old goaf coal bed methane development cost is higher, so within the mining area before mining goaf estimation of coalbed methane resources and the development and utilization is of great significance. Based on founded 15# coal seam in Nanzhuang coal mine based on geological and production data, explores the specific geological conditions in Yangquan mining area resources assessment technological applications, according to the situation of 15 # coal seam in the indirect method is chosen as the calculation model for the evaluation of mined-out area resources, calculated founded 15 # coal seam mine goaf largest recoverable CBM resources up to 86.9938 million m3, that founded in mined-out areas is recoverable CBM resources, which provides theoretical basis for subsequent resources development.
Study on HPLC Fingerprint of Dendrobium Nobile Lindl. Flower Based on Chemometrics
Authors: Zhong Ke , Yang Tingting
Published: February 2021

Objective: TO establish HPLC fingerprin of Dendrobium nobile Lindl. (D. nobile Lindl.) flower. Method: Agilent SB-C18 (250×4.6mm, 5μm) chromatographic column was used, with the mobile phase of acetonitrile-0.1% phosphoric acid solution, the flow rate was 0.8mL/min, the wavelength was 254nm, and column temperature was 30°C. Similarity evaluation combined with cluster analysis (CA), principal components analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to evaluate the HPLC chromatographic fingerprint of 15 batches of D. nobile Lindl. flower. Result: The HPLC fingerprint of D. nobile Lindl. flower was obtained with 26 common peaks, and 3 of them were identifie, including protocatechuic acid, chlorogenic acid and rutin. The similarity of 15 batches of D. nobile Lindl. flower was between 0.866 ~ 0.989. By CA, PCA and OPLS-DA analysis, the 15 batches of samples were divided into 2 categories, and 14 components contributed most to the classification were obtained. Conclusion: The method is simple and reproducible, and could provide a reference for the quality evaluation of D. nobile Lindl. flower.
Transient simulation of dynamic buckle propagation of a shallow cylinder under external pressure with damping
Authors: Yan Sunting , Cheng Mao , Ling Zhangwei , Jin Zhijiang
Published: February 2021

This paper presents a finite element simulation of transient buckle propagation of shallow elastic cylinder under time dependent external pressure load considering the effect of damping. We conclude that by assigning transient pressure a value slightly smaller or larger than static buckle propagation pressure the buckle propagation directions can be reversed.
Well spacing optimization of hydrothermal doublet system
Authors: Wu Xiaohua , Ji Yonghong , Ma Hongyuan , Kong Jing , Liu Xiao , Jia Chao
Published: February 2021

It is of vital importance to study the influence of well spacing on geothermal system. A three-dimensional hydrothermal coupling model of doublet system is established with a geothermal system in Shandong province as background. Under different well spacing, temperature field distribution values are calculated by finite element software, low-temperature area developments are analysed and values of heat extraction ratio are compared. The results indicate that with a smaller well spacing, low-temperature area will develop faster, thermal breakthrough will happen earlier, and service life will be shorter. Moreover, the larger the well spacing is, the faster the growth rate of the heat extraction ratio is, and the higher final heat extraction ratio is. However, the final heat extraction ratio value become more and more close while the well spacing increase.
A Brief Discussion on the Research Status of Subsurface Drip Irrigation Technology in China
Authors: He Jing
Published: February 2021

Subsurface drip irrigation technology is a new water-saving irrigation technology formed by continuous improvement in the agricultural production process. At this stage of development, Subsurface drip irrigation technology has been extremely mature, from its theoretical basis to equipment production and on-site irrigation production.
Mechanism of advanced water injection and its application in Yuan A well area
Authors: Li Yingming
Published: February 2021

In order to explore an effective way to further increase the single well production and improve the development effect of low permeability fractured oilfield, it provides a new theoretical and practical basis for oilfield development in Taizhao area; Through the study of advanced water injection mechanism and field test in source A well area, an effective displacement pressure system is established in low permeability reservoir, which reduces formation damage caused by formation pressure drop and initial water cut of oil well, and optimizes the scheme by combining modeling and numerical prediction, water injection development adjustment and so on; Therefore, the output of the oilfield at the initial stage of production is increased; Good development results have been achieved in the early stage of production after 6 months’ advanced water injection in source A well area, and it is advisable to carry out advanced water injection for 6 months in the development of low permeability fractured oilfield.
Application and Evaluation of Ternary System Deep Profile Control Technology
Authors: Lu Yao
Published: February 2021

The development process of ASP flooding is strong in stages, and the contradictions in each injection stage are prominent. In the profile adjustment stage, there are still some wells and layers with poor plugging control effect, and the injection system is inefficient and ineffective, which not only causes the waste of high-cost injection system, but also can not effectively displace the remaining oil, which affects the expansion of swept volume and enhanced oil recovery. Therefore, deep profile control technology should be adopted to further assist profile control adjustment, but conventional profile control agents are not applicable due to the existence of alkali in ternary injection system. In this paper, the type of profile control agent suitable for ternary injection system is optimized by laboratory test, and the principle of well and layer selection is optimized. The profile control opportunity is summarized by comparing the profile control effects of four ternary industrial blocks. Through deep profile control technology, the inter-layer and intra-layer contradictions in an industrial block of ASP flooding were alleviated, and the utilization ratio of ASP system in reservoir production degree was effectively improved, and the development effect was improved.
Study on Development Characteristics of Low Permeability Oil-water Horizontal Well Area in the Same Layer
Authors: Wang Ning
Published: February 2021

According to the development practice of horizontal wells in Putaohua reservoir of low permeability oil-water block, this paper summarizes the development characteristics of the block. At the initial stage of production, the chloride ion value of the near-wellbore formation (i.e., the fluid produced at the initial stage of production) is corrected for the large-scale fractured horizontal wells according to the fracturing fluid that is not returned, so as to judge the water breakthrough property of high water-bearing wells. After putting into production, it is found that the formation water in the block is affected by structure and lithology respectively. The water injection policies of “strengthening water injection at high position and restraining water injection at low position” and “strengthening water injection at main layer and restraining water injection at communication layer” are adopted to restrain formation water energy from plane and interlayer and reduce water cut in horizontal wells. Based on the theoretical analysis of fracture effect and water breakthrough characteristics of horizontal wells, the theoretical water breakthrough strength and theoretical hydraulic conductivity strength of fractures are calculated respectively, and the chart is drawn. According to the chart, the adjustment idea of “classification cycle water injection, zonal determination of parameters” is implemented, so that the determination of cycle water injection parameters is changed from “fixed strength, fixed cycle water quantity” to “fixed water quantity, fixed cycle water strength”, and further improved The improvement of water injection policy can provide reference for the development characteristics research and water injection adjustment of horizontal wells in the same type of oilfield in the future.
Research on Reasonable Drilling Parameters of Hydraulic Reaming in Soft and Thick Coal Seam and Its Application in Field
Authors: Li Shengzhou
Published: February 2021

In view of the fact that the outburst disaster of the soft 3# coal seam in the Sangshuping Coal Mine is mainly caused by in-situ stress, it is proposed to use hydraulic reaming, pressure relief and anti-reflection technology to remove some of the high geostress in the coal seam and improve gas drainage efficiency. Numerical simulation software was used to analyze the distribution of plastic failure and stress distribution of the coal body after reaming under the three-hole spacings of 4m, 6m, and 8m. The results show that the radius of the plastic failure zone around the borehole is about 2.2m when the rate of expanded coal chips is 3%; the width of the pressure relief area of a single reamed hole is about 3.2m. When the drilling hole spacing is 6m, it has a good pressure relief effect and reasonable amount of drilling work. After the reaming, the drainage concentration and flow rate are both improved. After reaming, the extraction concentration and flow rate have been improved. The hydraulic reaming technology can effectively solve the problem of outburst prevention in the thick seam of soft outburst dominated by ground stress in Sangshuping Coal Mine.
Discussion on comprehensive adjustment technology of weak alkali ASP flooding in stage development of second-class reservoir
Authors: Zhu Yueyan
Published: February 2021

The application of ASP flooding development by stages and comprehensive adjustment technology plays a very important role in the development of the second-class reservoir, which is directly related to the development effect of the second-class reservoir and also improves the development effect of the reservoir to a certain extent. In this paper, the author analyzes and studies the comprehensive adjustment technology of ASP flooding in different stages. Taking SD block as an example, the development of the second-class reservoir is expounded, and the weak alkali ASP flooding technology is applied in different stages of the development of the second-class reservoir in SD block.
Application of water drive characteristic curve in oil field development planning index prediction
Authors: Liu Baolai
Published: February 2021

In the prediction of water drive development index in oilfield development planning, we often use constant liquid method to calculate production, injection-production balance prediction, water drive characteristic curve and exponential decline. At different development stages, various forecasting methods are constantly improving. However, after oilfield development enters the declining stage, many forecasting methods are no longer suitable for the current development index prediction. However, there is a certain correlation among all kinds of forecasting methods. To a certain extent, it can make up for their own shortcomings to predict various development indicators through the joint solution of parameters among different forecasting methods, which has good practicability in the prediction of development indicators in oilfield development planning.
Theoretical Analysis of Proppant Embedment and Fracture Conductivity in Fractured Reservoir
Authors: Wan Youyu , Hou Tengfei , Cheng Changkun , Lin Hai , Yang Xiangtong , Liu Shiduo , Xiong Tingsong , Zhang Yang , Ye Yu , Feng Xinyuan
Published: February 2021

Proppant embedment mainly accounts for diminishing fracture aperture and conductivity. The conductivity decrease could greatly restrict fluid flow, thereby affecting the well performance. In this paper, new mathematical models are derived to calculate the proppant embedment and fracture conductivity after hydraulic fracturing. These models take three crucial factors into consideration, including proppant instantaneous elastic deformation, the conductivity change over time, and effective fracture geometry and corresponding proppants amount. Fitting correction is performed for the new theoretical model based on the experimental data. The results show that the theoretical model proposed matches well with the experimental data. The fracture conductivity is in proportion to proppant viscosity, elastic modulus of proppant and in inverse proportion to closure pressure, while elastic modulus of rock and large value of formation rock viscosity have slight impact on fracture conductivity. Moreover, with the increase of proppant viscosity, it takes longer for the conductivity to come to the steady state. These new mathematical models can provide some insights for proppant size selection and sand ratio optimization of fracturing treatment, and it is also a good method to predict the proppant embedment and the fracture conductivity.
Analysis of Water Resources Change and Water Use Structure in Shaanxi Province
Authors: Liu Zhe , Cao Shiliu
Published: February 2021

This article analyzes the changes in water resources, water consumption, and water structure in Shaanxi Province, China from 2004 to 2018, based on the water resources bulletin data of Shaanxi Province. The results show that the inter-annual differences in the amount of water resources in Shaanxi Province in the past 15 years are obvious, and the change process of the amount of surface water resources is basically the same as that of the total amount of water resources. The amount of water resources varies greatly around 2012; the total amount of water used in Shaanxi Province and various types of water consumption have shown a significant upward trend. Among all types of water consumption, agricultural water consumption has the largest increase, with a linear trend rate of 38 million m3/a. The proportion of agricultural water used in various types of water shows a significant downward trend, and the proportion of domestic water and ecological water shows a significant upward trend.
Synthesis and evaluation of new slickwater fracturing fluid for drag reduction
Authors: Guo Hao
Published: February 2021

Currently, slip water fracturing fluid is widely used as a fracturing fluid for shale reservoirs. Non-ionic hydrophobic modified polyacrylamide (HM-PAM), partially hydrolyzed water-soluble hydrophobic associating polyacrylamide (HMWSP) and partially hydrolyzed anionic polyacrylamide (HPAM) solutions were modeled by molecular simulation software Materials Studio. The radius of gyration (Rg) and mean square displacement (MSD) of HPAM and HMWSP at different NaCl concentrations were calculated. From the simulation results, compared with HPAM and HM-PAM, HMWSP had a larger radius of gyration, a larger intrinsic viscosity number, and a larger hydrodynamic size, which would produce better drag reduction effects. Using acrylamide (AM), acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid (AMPS) as basic raw materials, a hydrophobic associative drag reducer (HMWSP) was prepared by an inverse emulsion method. Infrared spectroscopy (FIIR) was used to characterize the synthesized products, and fluorescence chromatography was used to test the association of polymer solutions. Using a friction tester to test the drag reduction performance of the drag reducer, HMWSP has good resistance to salt reduction. HMWSP had good resistance reducing salt performance.
Application of the large-diameter and extra-long rotary bored pile in the thick sand layer area
Authors: Liu Wenbin
Published: February 2021

The large-diameter and extra-long rotary bored pile is a common foundation used in civil structures, while the sand layer may influence the quality of the rotary bored pile. This paper analysed the forming of the rotary bored pile in the sand layer based on an engineering case. The testing data of the practical pile forming process were recorded, and the difficulties and key points are highlighted to provide experience for other cases.
Research on Profile Control Technology of Chengdao Oilfield
Authors: Qi Yuanqiu , Li Mingzhong , Bai Zhifeng
Published: February 2021

Chengdao Oilfield in Shengli was seriously submerged at the later stage of waterflood development, and its water content reached 85%. In view of the high water content of Chengdao Oilfield and the prominent contradictions with reservoirs, this paper studies the difficulties existing in offshore oilfield profile control and the profile control agent system for Chengdao Oilfield history. At the same time, the profile control effects of YG103 gel system, HST gel system, self-crosslinking gel system and DQG gel system used for profile control of Chengdao Oilfield were evaluated. According to the statistical data, the average production increment of YG103 jelly system per well group is 2137.8t, HST-1 jelly system per well group is 1924t, self-crosslinking jelly system per well group is 526t, DQG jelly system per well group is 182t. This paper analyzes the reasons why the profile control and production increasing effect of Chengdao Oilfield gradually becomes worse. Based on the research results, suggestions for improvement were put forward.
Evaluation model of coal mine emergency rescue resource allocation based on weight optimization TOPSIS method
Authors: Li Xiao , Shi Yongkui , Pang Chuming , Li Huitong , Lin Jiahui
Published: February 2021

In order to solve the problems of unreasonable allocation and low efficiency of emergency rescue resources in coal mine accidents, it is necessary to establish a coal mine emergency rescue resource allocation model by using comprehensive weight-approximation ideal solution (TOPSIS method).This paper takes rock burst in a coal mine as an example by extending this designed emergency rescue plan. Firstly, calculated the weight of the evaluation index affecting the emergency rescue is selected by AHP method and entropy weight method respectively. Then weight optimization is inspired by comprehensive weight method. Finally, the optimal scheme is selected by TOPSIS method, and the model is verified by AHP method approaching ideal solution and entropy weight method approaching ideal solution. The results shows that: (1) There are two influencing factors have great effect on the evaluation of coal mine emergency rescue model, which are rescue time and advance of rescue channel; (2) The optimal scheme is program 5 through comprehensive weight approaching ideal solution, which is consistent with the actual situation of the project, indicating that the model has high reliability.