Patent ID: 8709982

Claim:
A method for increasing oil recovery from carbonate reservoirs having low permeability, comprising: preparing a solution and subsequently injecting the solution into a well comprising crude oil where the crude oil has an interfacial tension >10 mN/m and an acid number higher than 0.25to modify a wettability of a rock from an oil-wet condition to a water-wet condition without lowering a water-oil interfacial tension, wherein the solution comprises one or more quaternary polyamines having formula (I) wherein n >=1 R1 represents H, CH 3 , CH 2 CH 3 , C n H 2n+1 R2 represents H 2 CHOHCH 2 , CH 2 , CH 2 CH═CH 2 R3 represents CH 3 , CH 2 CH 3 , C n H 2n+1 R4 represents CH 2 , CH 2 CH═CH 2 wherein when R 2 and R 4 are allyl group, they optionally jointly form aliphatic cyclic structures, wherein a ratio between the carbon atoms and nitrogen atoms (C/N) ranges from 2 to 30, and wherein the solution comprises the one or more quaternary polyamines at a concentration in a range of from 0.01% to 20% by weight with respect to the total weight of the solution, and wherein the one or more quaternary polyamines in the solution complex one or more acid components present in the crude oil absorbed on rock forming the carbonate reservoir thereby removing the acid components from the rock.