Applicability and Modified Application of Common Empirical Models for the Production Prediction of Shale Oil in Yanchang Oilfield

Abstract The development characteristics of continental shale oil wells exhibit distinct differences compared to marine shale oil and gas reservoirs. To evaluate the applicability of empirical models for production forecasting in horizontal wells targeting the Chang 7 continental shale oil within the Yanchang Oilfield, fitting effects of Arps decline model (0 ⩽n ⩽1), YM-SEPD model and Duong model were compared respectively, The results showed that Arps was not suitable for shale oil production prediction, while YM-SEPD and Duong models were greatly affected by the fluctuation of monthly oil rate data, which lead to poor fitting effects. Thus, by defining a new intermediate variable, and correcting the linear relationship between cumulative production and the intermediate variable, the second step of the Duong model is modified to the fitting of cumulative production and related intermediate variables, and the subsequent fitting process is optimized. By comparing the fitting results of the above methods with the numerical simulation method for a shale well, it is found the modified model can reduce the influence of monthly oil rate data fluctuation and has the highest fitting accuracy. The proposed model provides reliable production fitting and forecasting capabilities for Chang 7 shale oil horizontal wells, offering practical insights for optimizing shale oil development strategies.