As the society and economy move forward, energy and environmental problems have attracted extensive attention. Hydrogen energy is considered the ideal clean energy in the 21st century due to its high energy density, pollution?free attribute, abundant reserves, and wide application. As a clean production technology, hydrogen production by water electrolysis has developed vigorously under the goals of carbon peak and carbon neutrality. The key challenge lies in the development of high?performance electrocatalysts for the hydrogen evolution reaction (HER) to reduce the overpotential of water splitting. This paper reviewed the current mainstream hydrogen production technologies by water electrolysis in detail and analyzed the characteristics and advantages and disadvantages of each technology. Moreover,it summarized the research progress of HER catalysts and predicted the development directions of the hydrogen production technology by water electrolysis and its electrocatalysts.

The spherical hexagonal phase tungsten oxide (h?WO₃) was synthesized by precipitation method. Then a series of hexagonal/monoclinic WO₃(h/m?WO₃) phase junction photocatalysts were controllable fabricated by regulating the phase transition process from hexagonal to monoclinic phase. The crystal phase structure and phase composition, particle size and specific surface area of these WO₃ catalysts were characterized by X?ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area (BET). The experimental results of photocatalytic O₂ evolution show that compared with the pure hexagonal phase WO₃, the h/m?WO₃ with suitable crystal phase composition exhibits remarkable photocatalytic performance. Based on the band positions of hexagonal and monoclinic phases, the surface photovoltage (SPV) characterization results show that the formation of h/m?WO₃ phase junction significantly promotes the efficient separation of photogenerated electrons and holes on the surface of the catalyst, and then improves the photocatalytic activity of WO₃ catalyst.

Bohai L oilfield has undergone multiple adjustments since it was exploited, such as well pattern internal infilling, changing well patterns, and reversing lines. The scattered distribution of remaining oil on the flat and extremely complicated vertical flooding law resulted in difficulty for tapping the remaining oil. Based on the data of core, well logging, seismic, production dynamic and other results, the thick reservoir can be comprehensively characterized, so as to guide the remaining oil fine characterization and potential development. The results show that the plane contact styles of single sand body is mainly in butt type, and the vertical overlap mainly in cut type. The remaining oil of the southern vertical accretion type leaf body is mainly concentrated near the vicinity of the fault, the buried hill area and the sand?body deposition margin, which can be tapped using directional wells. The remaining oil of the central prophase frond is mainly concentrated in the top of the thick sand body and the lower part of the thin interbe, which can be tapped using horizontal wells.

Serious well collapse in the 2h well horizontal section of a CFD oilfield took place during drilling in carbonaceous mudstone before landing. In order to satisfy the requirements of drilling the rest wells, the analysis of drilling collapse and the research on anticollapse countermeasures were carried out. By investigating the correlation between drilling fluid performance and wellbore collapse,bedding structure and clay minerals, the low drilling mud density, and the poor performance of plugging and anti?swelling were determined to the main factors leading to the well collapse. From the point of view of mechanical countermeasures, the relationship curve between well deviation and collapse pressure were established based on the strength anisotropy model, for the future selection of mud density. In view of chemical countermeasures, 1% inhibitor along with 5% calcium carbonate and 1% nano?materials as plugging agents were added in the drilling fluid. The results show that the cuttings roller recovery using optimized drilling fluid could reach to 91.39%, the dynamic HTHP filtrate loss performance be decreased by 22.41%. The point load strength of the optimized drilling fluid is only 13.60%, which is superior to the original one of 32.45%.The research results can provide reference for solving the problem of lack of physical data and urgent need of anti?sloughing measures.