COMPLEX TECHNOLOGY OF CLEANING OF BOTTOM-HOLE ZONE Russian patent published in 2000 - IPC

FIELD: oil and gas producing industry. SUBSTANCE: complex technology includes lowering into well of pipes, injection of reagents into interval of treatment and their holding for reaction, cleaning of formation and lifting of pipes. Cleaning of bottom-hole zone is carried out in several stages during one round-trip operation. At the first stage, injected into well is 10% aqueous solution of sodium carbonate with additions of sodium silicate in amount of 2% of sodium carbonate volume in terms of 0.8 cu.m per running meter of formation effective thickness. Then, formation is cleaned. At the second stage, injected into well is 10% aqueous solution of sodium bisulfate in terms of 0.5 cu.m per running meter of formation effective thickness. At the third stage, pipes are lifted after several cleanings of formation, attaining preset inflow and determination of pressure recovery curve. EFFECT: higher efficiency of cleaning of bottom-hole. 2 dwg