Full Field Offshore Surfactant-Polymer Flooding in Bohai Bay China

Abstract

Abstract This paper presents full field offshoresurfactant-polymer (SP) floodingapplied in JZ 9–3 Oilfield, Bohai Bay, China. Followed by 3-year polymer flooding which produced 4% incremental oil, the field turned to surfactant-polymer flooding. In the first stage, SP flooding was implemented in 4 injection wells. Then full field SP flooding was conducted in 8 injectors and 23 correspondent producers were involved. The injection scheme is designed as a slug of 0.23 pore volume (PV) of polymer solution at 0.120% polyacrylamide and second slug of 0.3 PV mixture of 0.20–0.24% of HDS surfactant and 0.12–0.15% of 3640C polymer and third slug of 0.035 PV of 0.12% 3640C polymer solution. By monitoring injection characteristics, oil increasing and water content decreasing, and development index, the results show significant effect in incremental oil recovery compared to polymer flooding since 2010 when the SP flooding started.By 1st, Dec, 2014, the SP flooding has been improving oil production for 42 million tons with composite water cut 73.5% which declined by about 6.5%. There are 11 wells in 23 producers has obviously responded. The daily oil production of the center correspondent producer was doubled and water content decreased from 81% to 42%. The SP flooding effects lasted for about 2 years and could be extended further. This paper presents the feasibility of SP flooding in offshore environment.