DOWNHOLE FILTER Russian patent published in 1997 - IPC

FIELD: oil and gas production. SUBSTANCE: invention deals with filters to filter products extracted from oil, water, and gas wells providing integrity of metal gauze with wire winding when sunk into inclined and horizontal wells, increased quality of product filtration, and smash resistance of filter under abnormally high pressures in deep wells. Filtration device includes perforated pipe with coupling and metal gauze embracing outer surface of perforated pipe. The latter, on its outer surface, has spirally arranged ribs. Height of rib (h_r, mm) is found from inequality: t_s<h_r≅(d_c-d_p)/2 where t_s is summary thickness of metal gauze and wire winding; d_c diameter of pipe coupling; and d_p diameter of perforated pipe. EFFECT: increased reliability. 3 cl, 2 dwg