METHOD OF MONITORING OF ANNULAR SEALING Russian patent published in 2001 - IPC

FIELD: construction and operation of oil and gas wells, particularly, monitoring of sealing of annular space in development, exploratory, observation and other wells. SUBSTANCE: method is based on gamma-ray logging with use of radioisotopes in form of long-lived gaseous chemically inert radioactive isotope with monochromatic gamma radiation. This radioisotope is introduced directly into grouting mortar. Moment of starting of annular-space overflow is determined by comparison of reference gamma logging values with background gamma logging values after formation of cement stone. Radioisotope may be used in form of inert gas krypton-85. Problem of method consists in detection of moment of beginning of cement stone failure. EFFECT: higher efficiency of method. 2 cl, 1 ex