OIL FIELD DEVELOPMENT Russian patent published in 2008 - IPC E21B43/18 

FIELD: oil production, particularly to develop oil field at later stage.

SUBSTANCE: method involves extracting fluid from producing wells; injecting working agent through injection wells; performing periodic depression in producing wells without submersed downhole pumping equipment stoppage and performing periodical equilibrium filtration state recovery. Injection wells have two downhole pumps having different deliveries. Low-delivery pump is arranged upwards at working depth characterized by equilibrium filtration state. High-delivery pump is located from below at working depth characterized by depression regime. Equilibrium filtration state is provided by low-delivery pump operation with switched-off high-delivery pump. Depression regime is provided by high-delivery pump operation with switched-off low-delivery pump and with well fluid level reduction up to level less than working depth characterized by equilibrium filtration state. In going from depression regime to equilibrium filtration regime upper pump is switched-on as low-delivery pump reaches well fluid level with well fluid flow retention in well. Downhole pumps may be arranged in two flow strings.

EFFECT: increased oil field recovery.

2 cl, 2 ex