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In order to reveal the correlation between H2S concentration and the concentration of CO, H2 and other reducing atmosphere near the water wall of the boiler, a multi-component synchronous test of reducing atmosphere adjacent to water wall was carried out on a 300 MW high temperature corrosion boiler. It is found that when CO volume fraction is between 3.5% and 13%, there is a strong positive correlation between CO concentration and H2S, H2 concentration. The correlation is negative between CO concentration and CO2 concentration. In addition, the positive correlation between CO concentration and H2S concentration is related to the location of the measuring point. With the increase of furnace height, the positive correlation between the two gradually decreases. In the reducing atmosphere, in addition to CO, a large amount of H2 is also observed, with the maximum H2 volume fraction of 4.7%. There is also a strong positive correlation between H2S concentration and H2 concentration. Finally, according to the results of synchronous test, the correlation equations between CO concentration and H2S, H2 concentration were given respectively, which could be used as a reference for operators.

A smart response fluid was designed and developed to overcome the challenges of gas channeling during CO2 flooding in low-permeability, tight oil reservoirs. The fluid is based on Gemini surfactant with self-assembly capabilities, and the tertiary amine group serves as the response component. The responsive characteristics and corresponding mechanism of the smart fluid during the interaction with CO2/oil were studied, followed by the shear characteristics of the thickened aggregates obtained by the smart fluid responding to CO2. The temperature and salt resistance of the smart fluid and the aggregates were evaluated, and their feasibility and effectiveness in sweep-controlling during the CO2 flooding were confirmed. This research reveals: (1) Thickened aggregates could be assembled since the smart fluid interacted with CO2. When the mass fraction of the smart fluid ranged from 0.05% to 2.50%, the thickening ratio changed from 9 to 246, with viscosity reaching 13 to 3100 mPa·s. As a result, the sweep efficiency in low-permeability core models could be increased in our experiments. (2) When the smart fluid (0.5% to 1.0%) was exposed to simulated oil, the oil/fluid interfacial tension decreased to the level of 1×10−2 mN/m. Furthermore, the vesicle-like micelles in the smart fluid completely transformed into spherical micelles when the fluid was exposed to simulated oil with the saturation greater than 10%. As a result, the smart fluid could maintain low oil/fluid interfacial tension, and would not be thickened after oil exposure. (3) When the smart fluid interacted with CO2, the aggregates showed self-healing properties in terms of shear-thinning, static-thickening, and structural integrity after several shear-static cycles. Therefore, this fluid is safe to be placed in deep reservoirs. (4) The long-term temperature and salt resistance of the smart fluid and thickened aggregates have been confirmed.

Background Neonatal necrotizing enterocolitis (NEC) adversely affects the long-term neurodevelopmental outcomes of preterm infants. However, few studies concerning the risk factors for neurodevelopmental outcomes in preterm infants with NEC have been conducted. Objective To investigate the risk factors for adverse neurodevelopmental outcomes of NEC in preterm infants. Methods Preterm infants diagnosed with stageⅡ toⅢ NEC in Department of Neonatology, the Third Affiliated Hospital of Zhengzhou University from January 2019 to June 2020 were included. General conditions and neonatal complications of the infants, as well as pregnancy-related complications of the mothers were obtained. All infants were followed up to a corrected age of 12 months, at which the neurodevelopmental outcome was evaluated by the Bayley Scales of Infant Development Ⅲ (BSID-Ⅲ) , and in accordance with the evaluation results, the infants were divided into a normal group and an adverse neurodevelopment outcome group. Multivariate Logistic regression analysis was performed to investigate the risk factors for adverse neurodevelopmental outcomes. Results Of the 236 infants included, 23 died, and 13 were lost to follow up, the other 200 cases who completed the follow-up were finally included for analysis, including 21 (10.5%) with neurodevelopmental disorders (adverse neurodevelopmental outcome group) , and 179 (89.5%) with normal neurodevelopmental outcome (normal group) . Compared with infants with normal neurodevelopmental outcome, those with neurodevelopmental disorders had lower mean birth weight, and higher incidence of sepsis, intestinal perforation, and short bowel syndrome (P

Abstract: Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solution polymerization and applied in the field with a new secondary temporary plugging technique. The optimization and performance evaluation of thermo-sensitive temporary plugging agent were carried out through laboratory experiments. The optimized formula is as follows: (6% − 8%) acrylamide + (0.08% − 0.12%) ammonium persulfate + (1.5% − 2.0%) sepiolite + (0.5% − 0.8%) polyethylene glycol diacrylate. The thermo-sensitive temporary plugging agent is suitable for formation temperatures of 70−90 °C, it has high temporary plugging strength (5−40 kPa), controllable degradation time (1−15 d), the apparent viscosity after degradation of less than 100 mPa(S and the permeability recovery value of simulated cores of more than 95%. Based on the research results, secondary temporary plugging technique was used in a horizontal well in the Jidong Oilfield. After treament, the well saw a drop of water cut to 27%, and now it has a water cut of 67%, its daily increased oil production was 4.8 t, and the cumulative oil increment was 750 t, demonstrating that the technique worked well in controlling water production and increasing oil production. Key words: bull-heading water control technique, thermo-sensitive temporary plugging agent, secondary temporary plugging technique, thermal degradation property, reservoir protection

Compressed Sensing (CS) has been proved to be effective in Synthetic Aperture Radar (SAR) imaging. Previous CS-SAR imaging algorithms are very time consuming, especially for producing high-resolution images. In this study, we propose a new CS-SAR imaging method based on the well-known omega-K algorithm, which is precise and convenient to use in SAR imaging. First, we derive an inverse omega-K algorithm to directly obtain echoes without any convolution between the transmitted signal and scene. Then, we formulate the SAR imaging problem into a sparse regularization problem and solve it using an iterative thresholding algorithm. With our derived inverse omega-K algorithm, we can save significant amounts of computation time and computer memory usage. Simulation results show that the proposed method can effectively recover SAR images with much less data than that required by the Nyquist rate.

The inorganic gel coating diverting agent, which is non-toxic and environmentally friendly, is developed for in-depth water diversion to improve water flooding effect. After being injected into the formation, the agent reacts with the formation water and forms inorganic silicate gel with a density approximating to formation water. The gel suspends in water as a bulk or particulates, scales and forms inorganic gel coating on rock surface by way of adsorption. The dominant channels of deep formation water are narrowed, forming flowing resistance and forcing flow diverting of the subsequent fluid so as to improve water flooding effect. This agent features fast solution, temperature resistance, salt resistance, environmentally friendly, and long-acting. It has been used in different reservoirs with different temperatures and salinity conditions, such as the Lunnan Oilfield of the Tarim Basin, the Yuejin oil region of the Qaidam Basin, and the Dagang Oilfield for in-depth flow profile control. The field applications involve single well group and whole block, with success ratio up to 100%, average injection pressure of well group increasing by 2–3 MPa, and the effective rate of oil production increase and water-cut decrease of producers are over 80%. Key words: in-depth profile control, diverting agent, inorganic gel, coating, field test, effect analysis

Macromolecule networks were introduced into the networks of normal sopping swelling materials by redesigning the materials molecule structure, and thus forming materials with the characteristics of retarding swelling, high strength and the structure of interpenetrating networks. The microscopic structure of the materials was analyzed by TEM and SEM, and the homogeneous structure of interpenetrating networks was observed from TEM and SEM images. Its static water absorption performance and mechanical performance after water absorption indicate that the total swelling time of the retarding swelling particles, which can be suspended and dispersed in water, is more than 20 days. After swelling, the modulus of elasticity (G′) of the sample is over 104 Pa, higher than that of the general swellable particle diversion agent. The excellent deep part injection and plugging performances were confirmed by physical simulation experiments. These performances overcome the shortcomings of quick swelling, low strength and less placement depth. Key words: retarding swelling particles, swelling, strength, deep profile control, fluid diversion agent

Objective: To establish a microbial limit test method for compound miconazole nitrate ointment. Methods: According to the Pharmacopoeia of the People's Republic of China and considering the physical and chemical characteristics of the ointment, the test product was treated by isopropyl tetradecanoate and bacteria free sodium chloride (pH 7.0 )-peptone buffer which contained 10% poly sorbitate 80, and the membrane filtration method was applied in microbial count test. At the same time, the control bacteria of Pseudomonas aeruginosa was detected by routine method, and the control bacteria of Staphy-lococcus aureus was tested by the culture medium dilution method combined with membrane filtration method. Results: In the microbial counting part, each test bacterium was 0.5-2. At the same time, the control bacteria of Pseudomonas aeruginosa could be detected by routine method and the control bacteria of Staphylococcus aureus could be tested by the culture medium dilution method combined with the membrane filtration method. Conclusion: Appropriate pretreatment methods for test products might thoroughly remove the antibacterial properties of ointment and solve the problem of difficult filtering of samples. This method is reliable for microbial limit test. [ABSTRACT FROM AUTHOR]

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Water production from gas wells affects gas production. Though water shut-off is an effective method to cure water production on gas wells, the research and development on water shut-off technique has little progress, because of difficulty and risk of the treating operation, and it still locates at indoor research stage. The paper firstly analyzed the reason of high difficulty and high risk of gas well water shut-off, which is the demand of selective water shut-off treatment. Furthermore, based on the absorbing and referencing of the current research progress at home and abroad, from the view point of water shut-off principles, three novel types of water shut-off methods are formed. The first principle is that the water shut-off agent itself has gas-water selection capacity after injected into reservoirs; the second one is that the agent changes wettability of rock surface into more hydrophobic after getting into water beard gas formations, resulting in gas relative permeability increase and water relative permeability decrease; the third one is that the agent has some physical or chemical reactions when contacting water, such as expansion, assembling, or precipitation, to plug water flow, but no reaction when contacting gas. Furthermore, the paper proposed an integrated water treatment method from the whole gas reservoir point of view. [ABSTRACT FROM AUTHOR]