The sand?carrying migration law of slick water in fractures is of great guiding significance to the practice of slick water fracturing.Sand transport profiles with different injection parameter combinations were tested by a visual parallel plate fracture simulator.The results show that the sand?carrying capacity of the slick water is favorable under the combination of slick water for fracturing +70~140 mesh proppant +8% sand ratio.In this case,no sand banks are observed at the fracture inlets,and the proppant does not fill the fractures adequately,under the combinations of low?viscosity slick water +40~70 mesh proppant +10% sand ratio and high?viscosity slick water +20~40 mesh proppant +20% sand ratio, the amount of sand filling fractures is large, and the sand banks in deep fractures are high,while the filling at fracture inlets is poor.With the increase in construction displacement, the various combination modes all exhibit growing positions of the front edges of the sand banks, decreasing heights of front edges, and insignificant changes in balance heights. Injection combination is an important aspect affecting the sand bank pattern. The sand bank patterns and characterization parameters corresponding to different injection parameter combination modes vary greatly. Therefore, the combination mode needs to be optimized on site to improve the conductivity of fractures at the inlet.

Cu?Cr modified activated carbon adsorbent was prepared by equal volume impregnation method.Using simulated coke oven gas as testing material,the effects of different transition metal active components and their loadings,different additives and loadings,calcination temperature on the removal activity of COS were investigated.The Cu?Cr modified adsorbent was characterized by X?Ray Diffraction (XRD), specific surface area (BET) and scanning electron microscope (SEM). The results show that the activated carbon modified simultaneously by Cu and Cr has the best adsorption performance of COS for coke oven gas, and the optimized preparation conditions of Cu?Cr modified activated carbon adsorbent are as follows: Cu and Cr loading is 5.0%, and 1.5% respectively, calcination temperature is 400 ℃. When the reaction temperature is 10 ℃, the breakthrough sulfur capacity of the modified activated carbon adsorbent is 1.47%, and the Cu?Cr modified activated carbon adsorbent shows good recycling performance. The characterization results indicate that CuO and Cr₂O₃ metal oxides are uniformly loaded on the activated carbon, and the specific area and pore volume of the adsorbent decrease after deactivation.