The study and application of low permeability quaternary binary surfactant on-line injection technology in Nanpu oil field

Pointiong at the problems of high water injection、serious under injection、short term of validity of common acid in low permeability oil reservoir of Nanpu oil field. It is applied the on-line injection well stimulation technology of quaternary binary surfactant. It is indicated that the interfacial tension of crude oil can reach 10-2-10-3mN/m. It can change the rock strong water wet into weak water wet. and can prevent clay swelling. The experiments showed that the water drive depressurization rate can reach above 30%. The field application results of 24 wells showed that the field implementation efficiency was 94%, the initial injection pressure of water injection wells decreased by 9.5 MPa on average, the validity period was 200d, and the average enhanced injection of single well was more than 2×103 m3, which improved the water injection problem of Nanpu oil field low permeability reservoir.