Study on Shale Oil Heating Development Based on Embedded Discrete Fracture Model

Abstract

Heating development has become the main development mode of medium- to low-maturity shale oil. In this study, the thermodynamic mathematical models of flow and heating development of organic matter, inorganic matter, hydraulic fracture, and natural fracture are established based on the embedded discrete fracture model (EDFM). A model for calculating the apparent permeability is established based on the fractal theory considering the effect of adsorption and slippage of fluid in shale pores. The mathematical model is solved by the finite volume method. The results show that improving formation temperature can increase the shale oil production. When the temperature increases from 338 K to 500 K, the cumulative production of shale oil can increase by 40.34%. The more natural fractures are, the greater the cumulative production of shale oil is. As the half-length of hydraulic fracture increases, the cumulative production of shale oil increases. When there is greater thermal conductivity and a decrease in the heat capacity of the matrix, the formation area affected by the thermal effect is enlarged and the cumulative oil production increases. There is a negative correlation between the shale oil production and the proportion of pore volume of organic matter. Through the study of the influencing factors of shale oil heating development, characteristics of shale oil production under different fracture and matrix parameters are clarified, and the optimal parameters under different influencing factors are obtained and a significant theoretical basis for shale oil heating development is achieved.