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This study aims to explore microbial activity evidence, composition of archaeal communities, and environmental constraints in coalbed-produced waters from the Hancheng Block, a representative region for coalbed methane development on the eastern margin of Ordos Basin, China. The investigation involves analyzing microbial community composition using 16S rRNA sequencing analysis as well as examining hydrogeochemical parameters. The results indicate that Euryarchaeota and Thaumarchaeota are predominant phyla within archaeal communities present in coalbed-produced water from the Hancheng Block. Among these communities, Methanobacterium is identified as the most abundant genus, followed by Methanothrix and Methanoregula. Moreover, a positive correlation is observed between the abundance of Methanobacterium and the levels of total dissolved solids as well as Mn; conversely, there is a negative correlation with dissolved organic carbon, Zn concentrations, and pH. The abundance of Co and Ni primarily influence Methanothrix while pH and Zn play significant roles in controlling Methanoregula. Additionally, No. 5 coal seam waters exhibit greater species diversity in the archaeal community compared to No. 11 counterparts. The higher abundance of archaea in the No. 5 coal seam promotes biogas generation due to the correlation between bicarbonate and dissolved inorganic carbon isotope. These research findings hold scientific significance in guiding the exploration and development of biogas within coal seams. [ABSTRACT FROM AUTHOR]

This paper researched the rheological properties of activated rubber powder–modified asphalt after aging. However, current aging methods only consider the aging of asphalt binder itself, ignoring the effect of asphalt mixture's performance and morphology. Hence, this paper proposes a new approach by conducting short-term aging of rubber asphalt from a different perspective. By utilizing the rotating flask method, coating activated rubber asphalt, grafting activated rubber asphalt, and rubber asphalt were recovered from short-term aged rubber asphalt mixtures. A temperature scanning test, multistress recovery creep test, and bending beam rheometer test were used in the study. The aging resistance of rubber asphalts was quantified by infrared spectroscopy test, and the microstructure of aged rubber asphalts was analyzed by utilizing a scanning electron microscope. The results showed that the activation could alleviate the negative impact of aging on the properties of rubber asphalt, especially the grafting activation. The activation could enhance the surface energy of rubber powder, allowing it to continuously swell during the aging process, absorb more light components, and reduce the oxidizable components of rubber asphalts. In addition, grafting activation rubber powder could react with the asphalt, and this reaction made the molecular chain of rubber asphalt fully expanded, limiting the flow of rubber asphalt. The area of contact between the rubber asphalt and air was reduced, and the aging degree was further alleviated. A stable structure was developed inside the activated rubber asphalts, enhancing the antiaging ability. [ABSTRACT FROM AUTHOR]

With advancements in the exploration and development of deep and ultra-deep oil and gas resources, the number of ultra-deep wells continues to rise globally. This trend places higher demands on testing technology. The combined perforating and testing technique, an established method for deep and ultra-deep wells, faces challenges. Frequent test operation failures due to perforation detonation failure increase down-hole complexity, restricting the timeliness of testing operations. Current methods use mechanical calibration software to calculate the minimum safety factor of the tubing string for safety assessments. However, without a thorough understanding of perforation detonation failure theory, existing mechanical analysis software remains unreliable for assessing well safety during operations. Simply using the safety factor method lacks reliability and cannot explain the causes of perforation detonation failure. This paper examines an ultra-deep well, referred to as TW1, to analyze perforation detonation failure mechanisms. Through metal microstructure examinations, chemical composition analysis, electron microscope scanning, and numerical simulation, the study yields the following insights: (1) The packer mandrel of Well TW1 fractured due to overstress from the detonation waves. (2) Detonation wave propagation patterns along the tubing string during perforation become apparent. (3) Simulation methods reconstruct the perforation detonation process, calculating effective stress at different tubing string positions over time. (4) It introduces an innovative approach for assessing perforation detonation failure mechanisms through a combination of laboratory testing and simulation modeling. [ABSTRACT FROM AUTHOR]