<p>China is rich in unconventional oil and gas resources, and the Jimushar Depression in the eastern uplift of Junggar Basin has a large longitudinal span and a wide planar distribution, with abundant shale oil resources, and the large-scale development has been carried out in a comprehensive manner. The shale oil in the Jimushar Depression has the characteristics of overall consistency and poor fluidity, etc. At present, the reasons for the emulsification of crude oil and the influencing factors have not been clarified, which greatly affects the extraction of crude oil. In this paper, the interaction between crude oil and formation water is simulated by different conditions such as water content, mineralisation, water quality, guanidine gel concentration, alkali concentration, etc. The causes of crude oil emulsification and the influencing factors of emulsion stability in M horizontal wells are investigated, so as to provide a basis for the smooth extraction of shale oil. The results show that the lower the water content of crude oil is, the stronger the stability of emulsion is, and the mineralisation degree plays a key role in the emulsification of crude oil. Under the condition of the same guanidinium gel concentration, the higher the guanidinium gel concentration, the more unfavourable to the crude oil emulsification; when the guanidinium gel concentration is 0.2% or less, the crude oil has good emulsification and stability; when the guanidinium gel concentration is 0.3%, the crude oil breaks the emulsion quickly; the concentration of 0.2% sodium hydroxide solution has strong emulsion breakage for the emulsion, and the strong alkali is unsuitable for the on-site application.</p>