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Salinization of reservoir will affect domestic water, agricultural irrigation and sustainable utilization of water. Previous research focused on the salt release of sediment. There are few researches on the influence of groundwater on salinization of reservoir. This study took Beidagang Reservoir in Tianjin as the research area and conducted the indoor column experiment using reservoir water at different sampling points. This study analyzed the vertical dynamic change law of TDS, Cl- and hydrogeochemical changes to reveal the mechanism of salinization of reservoir. The results show that TDS and Cl- went through three periods: the resting periods, the rising periods and the dynamic equilibrium periods. In the first week after the injection of groundwater, there are no significant changes in TDS and Cl- concentration. After one week, it went through the rapid rising period about 30 days and reached the dynamic equilibrium period at a later stage. There was a concentration gradient in the vertical direction with the highest concentration of TDS and Cl- in the bottom layer. There was a diffusion boundary layer and the concentration in the boundary layer changes more than that outside the boundary layer. The TDS concentrations at 10cm depth are 13.59 ρ0 and 4.52 ρ0, and those at 30cm depth are 6.82 ρ0 and 1.97 ρ0. The release fluxes of TDS and Cl- went through three stages: fluctuation stage(1~14 d), rising stage (15~44 d) and descent stage(45~106 d). The ions ratio indicated that hydrochemical component derived from evaporite, carbonate rock and sulfate minerals. [ABSTRACT FROM AUTHOR]

The Hongjiang—Qianshan fault has abundant medium-low temperature geothermal resources. However, the excessive fluorine concentration in geothermal groundwater restricts the development and utilization of geothermal resources. 20 samples were collected in this region for identifying the genetic mechanism of medium-low temperature of fluoride-enriched geothermal resources. The hydrochemical results indicate that the hydrochemical characteristic of high fluoride geothermal groundwater is HCO3-Na. The groundwater environment is alkaline and weakly alkaline. The fluoride concentration in geothermal groundwater is 2−12 times greater than the upper limited value, while those in the surface water and shallow groundwater are within the permittable threshold range. The isotopic results reveal that the recharge elevations and circulation depth are 797−2186m and 893−1893m, respectively. Quartz provides the most reliable estimations of reservoir temperatures, ranging from 79.4℃ to 113.1℃. The fluoride in geothermal groundwater originates from the rock weathering and mineral dissolution. Cation exchange and alkaline condition are the main influence factors for fluorine enrichment. [ABSTRACT FROM AUTHOR]

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In order to find a general corrosive treatment scheme suitable for underground structures in Foshan area, based on the geotechnical investigation of the Phase I project of Foshan Metro Line 4, this study adopted the method of literature research and comparative analysis of specifications to conduct in-depth analysis of the corrosion resistance requirements in different specifications. Furthermore, the existing problems in the GB/T 50476-2019 Durability Design Standard for Concrete Structures were discussed, and combined with the actual situation of the existing Foshan Metro Line 3 and Guangzhou Metro Line 7 West Extension to Shunde section, a set of groundwater corrosion prevention and control design standards suitable for subway structures in Foshan area were carried out. The application results in the early construction site of Foshan Metro Line 4 show that when executed according to the above design standards, the relevant performance indicators meet the regulatory requirements. [ABSTRACT FROM AUTHOR]

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The issue of water salinity in Beidagang Reservoir is prominent, and the phenomenon of groundwater salinity also exists. By collecting water and shallow groundwater samples from Beidagang Reservoir, this study explored the hydrogeochemical mechanism of shallow groundwater salinization in Beidagang Reservoir by means of hydrochemical characteristic analysis, principal component analysis and ion proportion analysis. The results show that the water body of Beidagang Reservoir and the surrounding shallow groundwater are affected by evaporation and crystallization. The distribution of ions in the water of each reservoir is relatively uniform, and the spatial distribution of ion concentration in the shallow groundwater varies greatly. The contents of Na+ and Cl- in the water of Beidagang Reservoir and the shallow ground- water near the reservoir area are very high, and Mg2+ and SO42- in the groundwater near Bohai Sea play a dominant role in the contents of each ion Ion ratio analysis shows that Na+ and K+ of water and groundwater in Beidagang Reservoir mainly come from the dissolution of salt rock, while Ca2+ and Mg2+ come from the dissolution of carbonate and sulfate. The dissolution and precipitation of rock salt, carbonate and magnesium salt is the main reason of salinization of reservoir water, and the groundwater is also affected by sulfate and potassium salt. [ABSTRACT FROM AUTHOR]

Stable CO2 foam is prepared under the conditions of high temperature and high pressure(HTHP) and the presence of foam stabilizer. The effects of the mass fraction of surfactant, salinity and shear rate on the viscosity of CO2 foam are investigated. The results show that the mass fraction of surfactant and salinity have a significant impact on the power law index(K, n). The flow consistency index(K) shows a quadratic function relationship with the mass fraction of surfactant, while the flow behavior index(n) shows a linear relationship with the mass fraction of surfactant. K and n are quadratic functions of salinity. The revised power function model is applicable under the conditions of surfactant mass fraction of 0.25%~1%, salinity of 0.5%~8%, and shear rate of 10~500 s-1, and has a high matching degree between experimental and predicted values. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to improve the survival rate of Litopenaeus vannamei during transportation with water after carbon dioxide (CO2) anesthesia, the effects ofCO2 flow rates (anesthesia stage), soaking time (soaking stage), water type and salinity (recovery stage) on the survival rate were studied. The experiment set four factors:CO2 flow rates (3 L/min, 5 L/min and 7 L/min), soaking time (0 min, 1 min and 5 min), water type (tap water, supernatant of aquaculture water and aquaculture water) and salinity (3, 7 and 11). The single factor experiment was carried out, and the L9(34) orthogonal experiment and verification experiment were carried out based on the single factor experimental results. The results showed that in the single factor experiment, the bestCO2 flow rates was 7 L/min, the best soaking time was 0 min, the best water type was tap water and the best salinity was 7. The results of orthogonal experiment of transportation within 2 hours showed that the primary and secondary relationship of the four factors was:soaking time > water type > salinity >CO2 flow rates, and the best combination wasCO2 flow rates of 8 L/min, the water type of tap water, the salinity of 7 and the soaking time of 0 min. The results of orthogonal experiment of transportation within 4 hours showed that the primary and secondary relationship of the four factors was soaking time >CO2 flow rates > water type > salinity, and the best combination wasCO2 flow rates of 7 L/min, the water type of tap water, the salinity of 7 and the soaking time of 0 min. The results of orthogonal experiment of transportation within 6 hours showed that the primary and secondary relationship of the four factors was soaking time >CO2 flow rates > salinity > water type, and the best combination wasCO2 flow rates of 6 L/min, the water type of tap water, the salinity of 7 and the soaking time of 0 min. The experimental results show that the recovery rate of Litopenaeus vannamei under different transportation time conditions can be improved by adjusting the levels of four factors:CO2 flow rates, soaking time, water type and salinity, which provides a new idea for shrimp keep-alive transportation. [ABSTRACT FROM AUTHOR]

Exploring the seawater intrusion mechanism in coastal aquifer with horizontal double fractures is critical for understanding the seawater intrusion mechanism in coastal region. Sand- tank experiments and numerical simulation based on discrete fracture matrix model were performed. The effects of horizontal double fractures with different spatial distribution on the seawater intrusion were analyzed in terms of the saltwater wedge and mixing zone. Results showed that: ① The development of saltwater wedge and mixing zone can be enhanced significantly by the horizontal double fractures. The seawater-freshwater mixing between the fractures is more pronounced. The individual effects of the two fractures are limited to each other. The effects are more significant for the fracture that is horizontally close to the offshore and vertically more close to the middle of the aquifer. ② A higher offshore-side fracture can exacerbate the development of the saltwater wedge and the mixing between fractures. However, the height of land-side fracture has a significant influence only on the tail of the saltwater wedge. ③ When the upper or lower fracture is horizontally closer to the inland, the saltwater wedge becomes wider with the total volume being shrank. However, once they are distributed so far to the inland that being out of the range of the saltwater wedge, the mixing zone area and the width of the saltwater wedge can drop sharply. [ABSTRACT FROM AUTHOR]

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The complex hydrogeological conditions in karst areas lead to frequent water seepage and water gushing disasters in tunnels, which often require supporting drainage systems to prevent and control water hazards. When the karst groundwater with high salinity enters the tunnel drainage pipe, the solubility of soluble salt ions in water changes with the variation of external temperature and pressure conditions, forming saturated solution. Ions crystallize and precipitate, sticking to the inner wall of the drainage pipe, which will contribute to decreasing its flow area. If not treated, in the long run, the drainage pipe will be blocked, resulting in the increase of water pressure in the tunnel lining. Consequently, it is likely to occur a series of tunnel water hazards such as water leakage, water gushing, mud outburst, lining damage, etc., which may seriously threaten the safety of tunnel construction and operation. For quantitative research on the crystallization blocking process of tunnel drainage system, we constructed the blocking model of karst water crystallization in drainage pipes for the first time, coupling with the pipeline hydrodynamic field, the concentration field and the chemical reaction field. Meanwhile, with methods of dynamic mesh and level set, we quantitatively expounded the crystallization blocking process in the tunnel drainage system. We also carried out a comparative study on different simulation technologies to analyze the influence of such factors as temperature, velocity, solute concentration, etc. on the blocking of crystallization. The results show that: (1) Both of the two methods can simulate and predict the crystallizing process, among which the dynamic mesh method is simpler and its solving accuracy is relatively higher, and the level set method can be used to simulate the further deposition after the topological shape has been changed (i.e., completely blocked). (2) Crystallization blocking mainly occurs in the transverse tube, where more crystalline precipitates are developed, because the flow velocity in the longitudinal tube is generally higher than that in the transverse tube, and the CaCO3 crystal concentration in the transverse tube is higher than that in the longitudinal tube. (3) Temperatures and solution concentrations are positively correlated with the crystallization rate, while the flow rate is negatively correlated with it. (4) Given the coupling of hydrodynamic reaction with chemical reactions, the numerical model of crystallization blocking can provide technical support for the early identification and safety evaluation of geological hazards of karst tunnels. [ABSTRACT FROM AUTHOR]

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A Soil and Water Assessment Tool (SWAT) model was selected to simulate the dynamic changes of water and fertilizer migration, and crop yields under different tillage modes and soil salinization levels. The Hetao Irrigation District with the complex spatial variability of soil salinity were taken as the research object, where three areas were divided: Jiefangzha, Yongji, and Yichang irrigation area. Some parameters were utilized for the simulation and verification of the model, including eight runoff and seven nitrate-nitrogen variables. At the same time, five parameters of crop growth were selected using the existing research. Finally, the specific values of each variable were measured at the outlets of irrigation areas. The soil types were also the cumulic anthrosols and mollic solonchaks in the study area. Four salinity levels were set under the two soil types, according to the grades of non-salinized soil (S1), lightly salinized soil (S2), moderately salinized soil (S3), and heavily salinized soil (S4). At the same time, five farming treatments were selected in the long-term farming mode: no-tillage management (CK), no tillage (T1), less tillage (T2), conventional spring tillage (T3), and template plowing (T4). A systematic investigation was then made on the effects of tillage modes and soil salinization on water production, crop nitrogen uptake, nitrate-nitrogen leaching and transportation, as well as the crop yields in the irrigation areas. As such, the salinized soil was be adjusted to reduce environmental pollution, while promoting the grain production, and the sustainable development of agriculture. The results show that the SWAT model with the calibrated parameters performed better than before to directly verify the runoff and nitrate nitrogen, where the determination coefficient R², and the efficiency coefficient were not less than 0.69 and 0.58, respectively, while the absolute value of the Relative Error (RE) was less than 10%. The simulated and measured crop yields were basically distributed near the 1:1 line, where the efficiency coefficient and R² values in the calibration and validation period were not less than 0.93 and 0.94, respectively, and the RE absolute value was less than 4%. The validated SWAT model presented an excellent performance to simulate the water production, nitrate-nitrogen transport, and crop yield in the irrigation areas. There were some significant effects of tillage modes and soil salinity on the total regional water production, crop nitrogen uptake, nitrate-nitrogen leaching, nitrate-nitrogen transport, and crop yield (P<0.05). Among them, the regional water production, nitrate-nitrogen leaching, nitrate-nitrogen transport run in different hydrological paths, whereas, the wheat yield gradually decreased, with the increase of tillage mixing depth and efficiency. The amount of nitrogen uptake by crops and the yield of corn and sunflower gradually increased, with the increase of mixing depth and efficiency. The nitrogen uptake of template plowing crops increased by 11.78% on average, and the nitrate-nitrogen leached volume was reduced by 16.5% on average, indicating an effective reduction in the soil nutrient loss and groundwater pollution. In addition, the output of maize and sunflower increased but the output of wheat decreased, compared with no-tillage treatment. The increase in the soil salinity significantly increased the total regional water production, and nitrate-nitrogen leaching (except for the Mollic Solonchaks). The effective water holding capacity of the soil layer greatly contributed to reducingthe underground nitrate nitrogen transport, as well as the amount of crop nitrogen uptake and crop yield. The yields of wheat, maize, and sunflower in the treatment of heavily saline soil were significantly reduced by 19.15%, 27.31%, and 26% on average (P<0.05), compared with non-salinized soil. There was a more significant impact of soil salinity on the regional water production, soil nutrients, and crop yields, compared with the tillage modes. Therefore, a strong recommendation can be addressed to focus on the prevention, control, and treatment of regional soil salinization, in order to better manage the serious pollution in the irrigation areas and crop yields. This finding can also provide a theoretical basis for the sustainable development of agriculture in the Hetao Irrigation District. [ABSTRACT FROM AUTHOR]

Using high-salinity oilfield water as the annulus protection liquid base fluid can easily increase the risk of corrosion and cracking of tubing and casing steel. Therefore, it is necessary to evaluate the corrosion risk of P110 S steel in the oilfield water annulus protection liquid. Firstly, the chemical components of oil field water and P110 S steel were analyzed. Then, the field conditions were simulated by using a high-temperature autoclave. The weightlessness corrosion and four-point bending experiments were carried out under the temperature of 200 ℃, CO2 partial pressure of 10 MPa and H2S partial pressure of 2 MPa, and the morphology and composition of corrosion products was analyzed by using SEM and EDS. Finally, the cross-section of the sample was analyzed. The results show that P110 S steel does not suffer from stress corrosion failure under high temperature and highacid conditions. The corrosion rate is 0.098 5 mm/a, severe pitting and local corrosion can be observed on the surface of the sample. Cross-sectional analysis shows that the thickness of corrosion product film on the sample surface is 63 μm, and the metal matrix is corroded seriously. P110 S tubing and casing steel faces a greater risk of corrosion failure under this working condition. In order to suppress the corrosion damage of the pipes, it is recommended to use fresh water or low-salinity well site water as the annulus protection liquid base fluid. [ABSTRACT FROM AUTHOR]

A micro-sprinkling hose has been a promising type of equipment for water-saving irrigation, due to the cheap, easy to lay and pack up when working. The performance of the micro-sprinkling hose depends on the kinetic energy in the process of field irrigation. Correspondingly, the intensity of kinetic energy can be determined by the droplet distribution of spraying water in the air, where the irrigation water is sprayed from the thin pipe within regular orifices. There is also a different tolerance of various plant organs to the kinetic energy of droplets sprayed from the micro-sprinkling hose. Particularly, the plant height and the canopy coverage of crops vary greatly in each growth period. In this study, an indoor irrigation experiment was carried out to explore the influence of spraying angle and pressure on the droplet distribution of micro-sprinkling hose. An N44-5 micro-sprinkling hose was used, where “44” was defined as the folding diameter of 44 mm, and “5” was represented a group of five orifices on the pipe wall of the micro-sprinkling hoes. Four working pressures were set, including 20, 24, 28, and 32 kPa, expressed as P20, P24, P28, and P32. Three spraying angles were also set, including 40°, 60°, and two-angle combinations, expressed as A40, A60, and A4060. A total of 12 working conditions was completed in the entire experiment. The measuring points were arranged in the wet area of the micro-sprinkling hose. Then, the irrigation water was sprayed from the single or two holes of the micro-sprinkling hose under different conditions, where the spraying water droplets were passed through the measuring area of the instrument. An LPM instrument was developed to measure the droplet number, diameter, velocity, and irrigation intensity of the spraying water. The results showed that: 1) The irrigation intensity at A40 was relatively stable, with the production of working pressure, where the intensity was 17.9-23.0 mm/h. Meanwhile, the irrigation intensity decreased gradually, with the increase of the working pressure at A60. When the two angles were combined for the irrigation, the irrigation intensity of the micro-sprinkling hose presented an outstanding increase trend, where two peaks of irrigation intensity were generated. 2) The droplet diameter decreased under the same spraying angle, with the increase of working pressure. However, the diameter of single-hole spraying droplets in the micro-sprinkling hose decreased under the same working pressure with the increase of spraying angle. 3) Both spraying angle and working pressure posed great influences on the spatial velocity and droplet diameter distribution of the single hole spraying droplets in the micro-sprinkling hose. The diameter range of the droplet was 0-2.5 mm for the single hole with the micro-sprinkling hose, where the droplet diameter was concentrated in the range of 0.45-1.25 mm. This finding can provide promising theoretical support to design the micro-sprinkling hose. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To deeply understand the mechanism responsible for lowering interfacial tension (IFT) of extended surfactant, the interfacial tension between extended surfactant and n-alkanes has been investigated by spinning drop method. The effects of temperature on the ability of extended surfactant to reduce interfacial tensions under different salinity was investigated. The experimental results show that the size of hydrophobic group of extended surfactant molecule becomes larger because of containing polypropylene oxide(PO) groups, and its ability to reduce interfacial tension is strong,which results in its IFTs with octane reaches 0.01 mN/m order of magnitude. Under the condition of low salinity, an increase of temperature generally causes an increase in the size of hydrophobic group, which results in a decrease of IFT and IFT values reduce an order of magnitude when temperature increases from 30 °C to 90 °C. The extended surfactant can lower interfacial tension to ultra-low value against oil phase with optimum carbon number under high salinity because a rise in salinity usually results in a decrease in the size of head group. In this case, the increase of temperature will adjust the hydrophilic-lipophilic balance of the extended surfactant, which has little effect on the minimum value of the interfacial tension. [ABSTRACT FROM AUTHOR]

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Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the fluid inclusion study on the Jiangjiatun and Lanjiagou Mo deposits, two distinctive ore-forming fluids were identified. Fluid inclusions in the Jiangjiatun Mo deposit are characterized by type I two-phase aqueous inclusions, with homogenization temperatures from 163 to 234°C and salinity values from 3. 06% to 6. 01 % . It indicates that ore-forming fluids are moderate-low homogenization temperature and salinity. Fluid inclusions in the Lanjiagou Mo deposit are featured by type II CO2-bearing fluid inclusions, indicating a deep formation environment. Microthermometric data in the Lanjiagou Mo deposit show homogenization temperatures from 200 to 283°C for type I inclusions and from 281 to 346°C for type II inclusions, and salinities from 2. 74% to 7. 3 1 % for type I inclusions and from 3.52% to 4.80% for type II inclusions. In view of the above research results, it is believed that the discovered ore bodies in the Jiangjiatun deposit were formed in a much shallower environment with lower homogenization temperature and salinity than the Lanjiagou Mo deposit. It indicates that it is possible to find Mo orebodies at depth beneath the exposed ore bodies. [ABSTRACT FROM AUTHOR]

The natural gas in Yuanba gas field contains high H2S and CO2. With the increase of water output and the increase of mineralization, the corrosion environment of surface system becomes more and more complex. In order to find out the main control factors that can affect the ground system corrosion of Yuanba gas field, this article establishes a grey correlation analysis method which takes CO2 partial pressure, H2S partial pressure, liquid-gas ratio, pH value, salinity, Cl- concentration, and corrosion inhibitor residual concentration as independent variables, and corrosion rate as dependent variable. The influence degree of various factors on corrosion is analyzed by data. The results show that the main control factors of the ground system corrosion in Yuanba gas field are CO2 partial pressure, H2S partial pressure and liquid-gas ratio. Therefore, it is possible to appropriately optimize the corrosion inhibitor addition program, adjust the batch operation cycle, and reasonably reduce the cost of corrosion inhibitor pigging operation. The research results provide a technical basis for the integrity management of the ground system in Yuanba gas field [ABSTRACT FROM AUTHOR]

The calculation formulas for water inflow of a circular foundation pit with different insertion depths of waterproof curtain are proposed based on the principle of seepage continuity of groundwater and Darcy’s law, The analytical solution of ground subsidence outside the foundation pit with different insertion depths of waterproof curtain is proposed according to the method of resistance coefficient widely used in ship engineering in China, Finally, an applicable procedure of dewatering of foundation pit with waterproof curtain partially penetrating aquifers was developed, in which water control cost is set as the target, and ground subsidence and groundwater inflow are set as the constraints conditions considering both safety and economy of foundation pit design. The proposed optimization method for water control was applied in a project site in Tongzhou district, Beijing. [ABSTRACT FROM AUTHOR]

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Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil fertility decline is caused by loss of fertile top soil due to water or wind erosion. The decreasing of cultivated land may be caused by urbanization, industrialization, land abuse, soil pollution, salinization and improper agricultural cultivation. The deterioration of soil in the cultivated land has posed a serious threat on the productivity of the land and the food security. The control of soil erosion in the cultivated land is strongly related to the agricultural, environmental, economic and social concerns. New technologies are highly demanding to develop for the control of soil erosion in cultivated land. In the present, chemical measures represented by soil anti-erosion material are the focus of current research. However, the ecological benefits of previous materials are not enough to meet the requirements in the environmentally sensitive areas, such as cultivated land. Seeking new feasible materials with excellent soil anti-erosion and ecological benefits has become the great issue in the key investigation of soil anti-erosion materials. As endogenous substances in soil, the soil polysaccharides have excellent ecological benefits, indicating perfect needs of cultivated land. In this study, a novel kind of soil polysaccharide-based material was added into the soil, thereby to investigate the influence on soil strength and water cycle, with emphasis on its application possibility to prevent and control soil erosion in the sloping farmland. The material was also cheap easy to be industrial produced. The direct shear, disintegration, and permeability tests were selected to explore the relationship between addition amount, curing age, shear strength, permeability, and anti-disintegration effect in soil. The results indicated that the material can be used to enhance the cohesion, indicating that the cohesion was positively correlated with the amount of material addition under the same curing time. At the same addition amount, the cohesion increased with the curing age, where the increase was mainly distributed in the early stage of curing. The internal friction angle increased slightly after the application of materials under different addition amount and curing time, where the increasing of internal friction angle ranged between 5.42% to 7.29%. The anti-disintegration effect was improved with the increase of addition amount, indicating that a small amount addition can achieve excellent performance. The disintegration rate of 0.25% concentration treated group decreased 66.1% of control group after 1-hour curing, and the 1% concentration treated group had no disintegration during 30 min test. The permeability of soil samples first increased and then decreased, with the increasing of material application concentration. The permeability coefficient of soil samples was achieved the maximum at 0.25% concentration treated group (2.86×10-5 cm/s), the minimum at 1% concentration treated group (0.91×10-5 cm/s). All the samples belonged to the medium permeable layer, where to ensure the exchange of water and air for the crop growth. Furthermore, all the experiments demonstrated that the short-term and simple curing can be used to achieve excellent anti-corrosion effect after the application of materials, while, the easy application suitable for the sloping farmland. The Scanning Electron Microscopy (SEM) images showed the materials can form the hydrogel on soil particles surfaces and pores, indicating that the materials can wrap the soil particles in the form of a hydrogel network structure, thereby to enhance resistance to soil corrosion. [ABSTRACT FROM AUTHOR]

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Slick water volume fracturing technology is one of the main technologies for the development of high temperature and compact carbonate reservoirs in 'Western China at present. Slick water complex acid is mainly used to form volume acid fracturing fractures to improve the stimulation effect. However, at the present stage of field construction in Western China, high salinity groundwater is used to distribute fluids, while formation temperature is high, the performance of conventional friction reducer is seriously reduced, so it is necessary to develop targeted high- performance polymer friction reducer. Through the optimization of fracturing fluid additives, free radical aqueous solution copolymerization was carried out by using one or more hydrophilic monomers and temperature/salt resistant monomers. In order to optimize the modified monomers and their dosage, infrared spectroscopy, nuclear magnetic resonance and differential scanning calorimetry are used to analyze the newly synthesized polymers. Finally a kind of modified monomers is developed, which has good temperature resistance, fast dissolution rate under high salinity conditions, excellent friction reduction, swelling properties, low formation damage, and the flow-back treatment is simple. It can tolerate high temperature o f 14() °C. • and rapidly dissolve under the salinity of "100,000 mg/L, the resistance reductio n rate is abou t 70%. A new type o f temperature-resistant and salt-resistant slick water fracturing fluid system act as a theoretical foundation and technical support for the development o f ultradeep carbonate rocks [ABSTRACT FROM AUTHOR]

In order to quantitatively analyze the relationship between the phreatic evaporation and water surface evaporation of different soil textures in bare soil area, soils with different texture and sand samples were taken from the test site in Hefei University of Technology. After pretreatment such as drying and particles sieving, 4 types of homogeneous test materials were selected including coarse sand, fine sand, loam and sand soil. Then, a self-made phreatic evaporation measurement device was made with diameters of 60 and 25 mm and a height of 42 mm. It can easily solve the problem of automatic water replenishment during the evaporation process, so that the groundwater depth can always be 0. Based on the self-designed device, a total of 5 groups of comparative test schemes were constructed, including coarse sand, fine sand, loam, sandy soil and water in bare soil area. Under the same environmental conditions, daily phreatic evaporation of the 4 different soil textures and water surface evaporation were observed for a total of 127 days from December 24, 2018 to April 29, 2019. By analyzing the relationship between phreatic evaporation and water surface evaporation for soils with different textures, linear mathematical equations were established. The results revealed that the change trend of phreatic evaporation and water surface evaporation was basically the same during the experiment. The high air temperature would lead to larger soil evaporation. However, the phreatic evaporation of the 4 different soil textures was not equal to the water surface evaporation, and the difference between them was more significant as the air temperature was increased. The determination coefficients between phreatic evaporation value of different soil textures and the water surface evaporation were all greater than 0.97. Especially for fine sand, the correlation coefficient reached 0.99, which indicated that there was a significant correlation between phreatic evaporation and water surface evaporation (P<0.05). And the conversion coefficients were achieved between them according to the linear mathematical equations. Generally, in soil bare areas with similar climatic conditions in Hefei, the conversion coefficient of coarse sand was 0.94, and the coefficients of fine sand, loam and sand are 1.04, 1.14 and 1.19, respectively. The phreatic evaporation value of coarse sand was less than the evaporation of water surface. The phreatic evaporation values of fine sand, loam and sand were greater than water evaporation. Under bare soil conditions, this conversion coefficient was only related to soil texture. In addition, the loam and sandy soil evaporation in the Wudaogou test site of Anhui Province, China was selected to verify the rationality of the conversion coefficient obtained above. The results showed that when the groundwater depth was 0.4 m, the relative error of the loam evaporation calculated by the substitution method and the phreatic evaporation coefficient method were -10.30% and 2.25%, respectively. Moreover, the sand evaporation calculated by the substitution method was 5.11 mm smaller than the measured value with a relative error of -17.79%, while the sand evaporation calculated using the phreatic evaporation coefficient method was only less than the measured value of 0.56 mm, and the relative error was reduced to -1.94%. Therefore, when calculating the phreatic evaporation at different groundwater depths, directly replacing phreatic evaporation with water surface evaporation would inevitably cause larger relative errors. However, the relative error of the calculation result obtained from the phreatic evaporation coefficient method was smaller, and the calculated value was much closer to the measured value. The coefficient method proposed in this paper would significantly improve the reliability and accuracy of the calculation results of phreatic evaporation. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)