Abstract: As oilfield production progresses into the middle and late stages,the comprehensive water cut gradually increases,leading to a year-on-year rise in produced water treatment volumes. Consequently,the operational pressure on gas flotation systems intensifies. During primary oil recovery via gas flotation,suboptimal oil separation efficiency was observed,resulting in prolonged secondary oil recovery time and elevated oil content in the gas flotation effluent. This caused a sudden surge in treatment pressure on downstream water treatment equipment,ultimately leading to non-compliant treated water quality and adversely affecting injection water quality for reservoir pressure maintenance. To ensure compliance with water injection quality standards,maintain formation properties,and guarantee stable and high oil production in the oilfield,it is urgent to retrofit the primary air flotation oil recovery system. This retrofitting will effectively improve the treatment efficiency of the system and provide strong support for the continuous and stable production of the oilfield.

Key words: gas flotation, oil recovery system, optimization and retrofitting, injection water quality