As an effective energy-saving measure, green roofs significantly improve the thermal environment of buildings by covering the roof with vegetation and soil. This paper compares the thermal transfer performance of concrete roofs and green roofs under different temperature conditions. First, a uniaxial compression discrete element method (DEM) was used to calibrate the mesoscopic parameters of concrete, ensuring an accurate representation of concrete properties. The results indicate that green roofs have significant insulation effects under high-temperature conditions in summer. After being exposed to high temperatures for 5 h, the temperature of the green roof was 23.4 degrees Celsius lower than that of the ordinary concrete roof. In addition, different initial temperatures of the model also have a certain impact on heat transfer. The higher the initial temperature, the slower the temperature increase under high-temperature conditions. In winter, the green roof significantly delays the cooling at the top of the building, demonstrating excellent thermal insulation performance. The maximum temperature difference compared with the concrete roof is 8 degrees C. Finally, there is an exponential relationship between the thermal resistivity of the green roof and the temperature. In conclusion, green roofs have significant energy-saving and environmental protection value.

Recently, conventional viscosifiers exhibit limited effectiveness under deep formations due to their poor salt tolerance and low thermal resistance. To address the limitations, a thermo-responsive macromonomer (DAM) consisting of N,N-diethylacrylamide and N,N'-methylenebisacrylamide was copolymerized with 2-acrylamido-2-methylpropane sulfonate and chemically modified nano-silica (N-np) to obtain an effective thermo-thickening/Nano-SiO2 polymer composite (N-DPAM) via in-situ polymerization under optimal conditions. The molecular structure of N-DPAM was analyzed by FTIR and H-1 NMR, while rheological and rheometric responses under high temperature, salt dosages, and shear resistance were investigated. The rheometric results demonstrated that DPAM exhibits a viscosity increase of 235% from 65 to 160 degrees C, but rapidly decreased at 180 degrees C, whereas N-DPAM displayed stabilized thickening responses of 218% above 160 degrees C due to intercalation and self-assembly of N-np within the polymer matrix as temperature increases. The viscosity retention rate (VRR) at a high shear rate of 1021 s(-1) and 200 degrees C indicated that the solution viscosity of N-DPAM was observed at 55 mPa s, which is 13 times higher compared to DPAM solution at 4 mPa s. From the rheological results, the VRR of N-DPAM fluid observed at 68% was slightly lower than that of HE300 at 73%, a commercially available viscosity additive in a salt-free environment at 200 degrees C, but three times higher (63%) than HE300 (25%) in the salt-saturated environment (20% NaCl). Additionally, a study of N-DPAM fluid contaminated by shaly soil from Dagang Oilfield demonstrated excellent compatibility with a filtration control agent to control the viscosity and filtration volumes (< 10 mL) at 200 degrees C.