METHOD OF FREEZING PREVENTION OF WATER-INJECTION WELL MOUTH Russian patent published in 2003 - IPC

FIELD: oil producing industry; methods of maintaining of wellhead equipment of water- injection wells in serviceable state under conditions of subzero temperatures in scheduled and emergency stopping of water injection and also with reduced water level in well accessories, or in drop of well injectivity. SUBSTANCE: method makes use of low-temperature heat of ground. For this purpose, connections of wellhead of water-injection well are made in form of closed circuit. In this case, left-hand upper and lower arms of circuit are located at angle to well axis, and left-hand lower arm is laid in ground and introduced into water- supplying water line at angle to axis of water line. Heating elements are installed on right-hand and left-hand arms of connection circuit from lower boundary of ground freezing up to central gate valve of water line (for right- hand arm) and up to day surface (for left-hand arm). Hydrophobic polyethylene foam with expansion factor of 5 to 30 is applied to surface equipment of well down to lower boundary of ground freezing. EFFECT: higher efficiency. 3 cl, 1 dwg