FILTER FOR WELL FLUID PURIFICATION Russian patent published in 2011 - IPC E21B43/08 

FIELD: oil and gas production.

SUBSTANCE: filter for purification of well fluid from impurities consists of perforated tube with mechanical filter and of gravitation filter element connected to mechanical filter. The gravitation filter element consists of internal and external pipes installed concentrically and forming a circular gap between them. Also, at least one orifice for inlet of fluid flow is made in an upper portion of the external pipe. There is provided supply of fluid flow into the circular gap or into the internal pipe. The mechanical and gravitation filters are arranged so, as to let an incoming flow of fluid into only one of filters; while resistance of the gravitation filter element is at least 1.5 times higher, than resistance of the mechanical filter. A container collecting separated mechanical impurities is attached to a lower part of the gravitation filter element.

EFFECT: upgraded fine purification of produced fluid and increased service life of immersion unit.

5 cl, 2 dwg