Energy & Fuels, Vol.27, No.6, 3499-3507, 2013
Performances of Different Recovery Methods for Orinoco Belt Heavy Oil after Solution Gas Drive
Although foamy oil can improve the performance of solution gas drive in heavy oil, only about 5-15% original oil in place (OOIP) can be recovered under primary production. In this study, a series of micromodel flood experiments and sandpack flood tests were performed to evaluate the performances of water flooding, surfactant flooding, gas flooding, and foam flooding for enhancing the recovery of Orinoco Belt heavy oil after solution gas drive. Water flooding tests show that the sweep efficiency of water flooding was low as a result of the adverse mobility ratio caused by gas bubbles dispersed in the oil; about 10.57% OOIP was obtained in the sandpack study. Surfactant flooding tests indicate that the penetration of the surfactant solution into the heavy oil and the subsequent formation of gas bubbles and emulsified oil droplets in surfactant solution could reduce the mobility of water phase, thereby improving sweep efficiency, and oil recovery of 15.09% OOIP was recovered in the sandpack. Because of the viscous fingering, only 4.57% OOIP was obtained in the gas flooding test. The micromodel test of foam flooding shows that gas bubbles could reduce the mobility of the gas phase and the residual oil droplets could be pulled into oil threads by the viscoelasticity of gas bubbles, thereby reducing the residual oil saturation of foam flooding. The sandpack flood result shows that the oil recovery of foam flooding can reach 23.92% OOIP.