METHODS FOR PERFORMING FRACTURING AND ENHANCED OIL RECOVERY IN TIGHT OIL RESERVOIRS

摘要

A method of recovering oil from a reservoir is described herein. The method includes introducing CO2 through a well bore into the reservoir, the well bore having a bottom-hole pressure greater than a fracture pressure of the reservoir to produce fractures within the reservoir and greater than a minimum miscibility pressure between the CO2 and the oil to produce a miscible zone; stopping the introduction of CO2 through the well bore for a first period of time to reduce the bottom-hole pressure to be less than the fracture pressure and greater than the minimum miscibility pressure; re- introducing the CO2 to maintain the bottom-hole pressure to be less than the fracture pressure and greater than the minimum miscibility pressure to maintain the miscible zone; shutting in the well bore to promote displacement of the CO2 through the reservoir in a direction away from the well bore; and recovering the oil from the reservoir.