Carbon dioxide injection in tight oil reservoirs

Tight oil reservoirs, which contain huge reserve volumes, suffer from low recovery factor. The horizontal drilling and hydraulic fracturing techniques are beneficial but not sufficient enough to boost ultimate oil recovery. Therefore, there is a vital need for an enhanced oil recovery (EOR) technique to bring much oil volume to the surface. Carbon dioxide (CO2) injection, as a proven method for EOR, can be beneficial not only in increasing the oil recovery but also in the reduction of greenhouse gases by the storage of CO2. This chapter first presents active mechanisms during CO2-EOR and then available methods for CO2 injection. Next, the affecting parameters, such as reservoir parameters, fracturing parameters, and operational parameters are discussed. As optimization means a lot in an EOR process, it is reviewed in the next step. The last topic covered in this chapter is the application of molecular dynamic simulation for the CO2-EOR process in tight oil reservoirs.