Search

In this study, a novel high‐temperature and high‐pressure foam evaluator with variable diameters inner cell and cylinder flip function was designed on our own, which can solve the problems such as difficulties in foam generation and inaccurate determination of various foam parameters by the same type of instruments, through which the foaming performance of more than 10 betaine surfactants was evaluated. The results show that: (1) the higher the pressure, the higher the foaming rate of the foaming agent and the more stable the foam, but the foam stability of the foamers at low and high pressures, and low and high temperatures do not correspond exactly, and the foaming agent used needs to be screened under simulated reservoir conditions. (2) The comprehensive foaming performance of different types of foamers with different molecular structures found that hydroxy sulfobetaine with longer carbon chains has a relatively better foaming performance. Therefore, for the reservoir conditions of temperature 130°C, pressure 30 MPa, and salinity 22 × 104 mg/L, hydroxy sulfobetaine, which does not contain an amide group in the molecule, can be considered preferentially as a foaming agent. The results can guide the selection of foaming agents for high‐temperature and high‐salinity reservoirs. [ABSTRACT FROM AUTHOR]

Polymer gels are the most commonly used materials in the petroleum industry for reservoir conformance control and resolving excessive water production problems. In this study, high-temperature gels were prepared with HPAM or AM/AMPS as the gel-forming agent, methyl etherified melamineformaldehyde resin (MEMFR) as the crosslinker, and nano-silica as the stabilizer, and their properties were evaluated. The results showed that HPAM-MEMFR gels were unstable at 110°C in a brine of 20665 mg/L. AM/AMPS-MEMFR gels are stable at 110°C, with gelation time ranging from 15 h to 92 h and storage modulus ranging from 3.6 Pa to 50 Pa. AM/AMPS-MEMFR gel has less than 10% dehydration after aging at 110°C for 90 days, almost no shrinkage in volume, and a significant increase in strength, making it suitable as a gel material for enhanced oil recovery.

For the high temperature (130 °C), high pressure (30 MPa), and high salinity (2.5 × 105 mg/L) of formation water conditions in the target block of the Tarim Basin Oilfield in northwest China, dodecyl hydroxy sulfobetaine surfactant was evaluated for its foaming performance, thermal stability, adsorption performance. The evaluation results showed that the surfactant exhibited good foaming ability and thermal stability than the general carboxy betaine under the above harsh conditions. The static adsorption of the surfactant on the surface of quartz sand particles was less than 1 mg/g with a concentration of less than 0.4%, which met the requirement for foaming agent adsorption. Moreover, the results of core displacement experiments indicated that, when simultaneously injecting 0.4% foaming agent and gas at a volume ratio of 3:7 into the cores of 38 mD, 161.4 mD, and 478.7 mD, foam with low mobility of less than 2 mD/cP could be generated; in the 57.3 mD Berea core, the resistance factor of foam generated by 8 cycles of injecting gas-liquid alternately with gas-liquid volume ratio ranging from 0.2:0.1 to 0.4:0.1 was nearly 20, and the residual resistance factor was greater than 5 after 5 PV of continuous gas injection. The results of the study can guide the selection of foaming agents for gas mobility control in high-temperature and high-salinity sandstone reservoirs. [ABSTRACT FROM AUTHOR]

For the automation of cigar appearance inspection, a cigar appearance inspection device was developed, and a cigar appearance inspection model based on machine vision technology and deep learning was established. The images of defects of the cylindrical surface of cigars were captured by a test device. The captured images were equilibrated and augmented by random panning and flipping to create a data set. The K-means clustering algorithm was used to generate appropriate anchors for the cigar defect dataset. The YOLOv5 model was trained and verified. The optimal threshold was obtained using the OTSU method to segment the images of loose end cigars. The loose end defect was identified by statistically computing the proportion of tobacco loss from the cigar end. The results showed that: 1) Using the YOLOv5 model to identify the defects of cylindrical surface, the mean average precision(MAP) reached 87.7% and the time for going through a single image was 13.1 ms. The YOLOv5 model featured strong anti-interference and advantages over other models in terms of inspection accuracy and efficiency. 2) The YOLOv5 model was able to accurately identify and locate multi-size, multi-category and densely distributed defects with strong generalization ability and robustness. 3) The loose end defect could be identified under different luminance lighting environments. This method supports the promotion of cigar quality. [ABSTRACT FROM AUTHOR]

Foam properties and surface dilational rheology of single and mixed LHSB (lauramidopropyl hydroxyl sulfobetaine)-OAB (oleic amide propyl betaine) surfactants were measured to investigate the synergism between the two components. Experimental results showed obvious synergistic effects in foam stability, dilational modulus, and phase angle between LHSB and OAB. Moreover, interaction parameters were calculated to quantitatively characterize the synergism. The negative interaction parameters between LHSB and OAB demonstrated that there was an attractive interaction between LHSB and OAB, and the attractive interaction contributed to forming the dense surfactant layer at the liquid/air layer, which in turn improved foam stability. The negative values of parameters reached their maximum when the LHSB: OAB molar ratio ranged from 1:1 to 1:2, the same time the foam stability reached its maximum. The interaction between LHSB and OAB was confirmed by 2D NOSEY (two-dimensional nuclear overhauser enhancement spectroscopy) experiments, the interaction between LHSB and OAB could be attributed to the hydrogen bonding or the electrostatic interaction between the hydrophilic groups of the two surfactants. [ABSTRACT FROM AUTHOR]

Thromboangiitis obliterans (TAO) is a segmental nonatherosclerotic inflammatory vascular disease characterized by recurrent progressive inflammatory reactions and thrombosis in the small and medium-sized arteries and veins of the extremities. However, there are few bibliometric studies on TAO. Therefore, this study was employed to generalize the research status, hotspots and development trends of TAO-related research.Methods: The data from 1999 to 2022 were collected from the Web of Science core collection database, and analyzed through bibliometrics software. VOSviewer was utilized to carry out academic collaboration between different countries/regions, institutions, and authors, visualization map of co-cited authors, journals, reference, and co-occurring keywords. CiteSpace was used to analyze the dual-map of journals, keyword bursts, and timeline of keywords. Bar and pie charts in this study were statistically analyzed and graphed through Microsoft Excel 2021. Scimago Graphica was applied to map the academic collaboration between different countries/regions.Results: A total of 553 literatures were involved in this study. Japan at the leading global position not only in the number of publications, but also total citations, average citations and H-index. Institution with the major contribution to TAO research is Mashhad University of Medical Sciences, and Nagoya University. Annals of Vascular Surgery, Angiology, Journal of Vascular Surgery are the main publication channel for articles related to TAO. Fazeli, B., Iwai, T., and Kihara, Y. are major contributors in this field. The studies on TAO keywords could be grouped into four clusters: Etiology, Mechanism, Cell therapy and Clinical therapy.Conclusion: Although the number of TAO publications has fluctuated over the past 20 years, it has generally shown a steady upward trend. Etiology and treatment research on TAO and some keywords such as trail, therapy, outcome, management, stem cells, angioplasty, and activation will become a hot spot in the future. [ABSTRACT FROM AUTHOR]