TOOL FOR CONSTRUCTION OF FILTERED WELL Russian patent published in 2003 - IPC

FIELD: mining, particularly, devices for construction of wells for production of water and other fluids, applicable in well completion in process of drilling or in well repair operations involved in control of sand carrying-out from slightly cemented and loose producing formations. SUBSTANCE: tool includes main filter connected with additional filter, washing pipe with valve and blocking means in lower part. Blocking means is made with washing holes. Main filter has settler in which check valve is secured. Washing pipe may be disconnected from settler check valve. Washing pipe is provided with additional blocking means and additional check valve located between blocking means. Upper-blocking means has washing holes. Additional filter has sealing cap in which washing pipe is movably installed. EFFECT: optimal distribution of gravel over entire filter zone, provided full cleaning from drillings and formation sand, and formation of natural filter due to carrying-out of fine fractions. 4 cl, 2 dwg