As one of the biggest sedimentary basins in China, abundant oil reserves exist in the Ordos Basin. Compared with Bakken formation, the pressure of the study area is quite low, which may results in inefficient primary recovery.
The primary recovery in the study area has been studied through simulation. The results indicate that primary recovery is not efficient in such a low pressure reservoir. Water or gas should be injected to enhance the oil recovery. Compared with water, gas is more suitable for improving the oil recovery from the study area. Among all gases investigated, CH4 and separator gas are a better choice. The effects of heterogeneity have also been studied by reservoir simulation. As reservoir heterogeneity increases, oil recovery will decrease. However, gas injection can still highly improve the oil recovery. A geological model has been built to predict the gas injection performance in case studies.