US 11,867,039 B2
Alternating microsphere and smartwater injection for enhanced oil recovery
Subhash Chandrabose Ayirala, Dhahran (SA); Dongqing Cao, Beijing (CN); Ming Han, Dhahran (SA); Saleh Hamad Al-Salah, Dhahran (SA); and Ali Yousef, Dhahran (SA)
Assigned to Saudi Arabian Oil Company, Dhahran (SA)
Filed by Saudi Arabian Oil Company, Dhahran (SA)
Filed on Jan. 7, 2022, as Appl. No. 17/571,257.
Prior Publication US 2023/0220754 A1, Jul. 13, 2023
Int. Cl. E21B 43/20 (2006.01); C09K 8/588 (2006.01); E21B 43/16 (2006.01)
CPC E21B 43/20 (2013.01) [C09K 8/588 (2013.01); E21B 43/162 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method for enhanced oil recovery in a reservoir, comprising:
injecting a microsphere suspension, comprising polymeric microspheres dispersed in seawater, into an injection well in the reservoir, wherein the polymeric microspheres are between about 10 nm and about 100 nm;
injecting SmartWater into the injection well in the reservoir to swell the polymeric microspheres diverting flow of the SmartWater into unswept regions of the reservoir;
injecting saltwater into the injection well to shrink the polymeric microspheres and move the polymeric microspheres in the reservoir;
injecting a second slug of Smartwater into the injection well to swell the polymeric microspheres and diverting flow into another unswept region in the reservoir; and
producing oil from a production well in the reservoir.