Method for modifying shale oil

The invention discloses a method for modifying shale oil, which comprises the following steps: selecting a shale oil block to be modified, the shale oil block to be modified comprising a shale oil layer and a brittle stratum sandwiched in the shale oil layer; carrying out horizontal drilling on the brittle formation; hydraulic fracturing and carbon dioxide fracturing are conducted on the brittle formation through the horizontal drilling well, so that the brittle formation is fractured, and fractures and matrix pores of the brittle formation are filled with water used in the hydraulic fracturing process and carbon dioxide fracturing fluid used in the carbon dioxide fracturing process; the carbon dioxide fracturing fluid carries a set amount of magnesium metal particles or aluminum metal particles. Magnesium/aluminum metal particles react with water in the stratum to generate high-temperature gas and dissipate a large amount of heat, and the high-temperature gas and the heat enter cracks and matrix pores in the