DEVICE FOR CLEANING OF INTERNAL SURFACE OF DOWNHOLE PIPES Russian patent published in 1999 - IPC

FIELD: oil and gas industry, particularly, cleaning of internal surface of pipes and annular spaces of wells drilled in permafrost zones from asphalt-resin-paraffin and hydrate deposits. SUBSTANCE: device working end part is made in the form of body accommodated together with all body in shell made of highly heat-conducting material. Exterior part of shell is of various configuration that promotes extension of service potentialities of device. Body is made tight and current conducting. Located inside body, coaxially to it, by means of centralizer, is insulated electrode in the form of rod with pointed cone immersed in electrolyte. Working chamber is communicated with body upper hollow. Rod is assembled and secured in centralizer by means of bushing for motion of its pointed end with respect to bottom of working chamber. Device is used in wells with pressure up to 50 MPa and drilled with inclination to horizon for removal of drain valve of wells with oil recovery by electric pumps. EFFECT: extended service potentialities, higher efficiency of operation with minimum consumption of power and reduced overall dimensions. 4 cl, 5 dwg