METHOD OF INVESTIGATING INJECTION WELLS (VERSIONS) Russian patent published in 1998 - IPC

FIELD: methods for detection of leaky points of tubing and flow strings. SUBSTANCE: temperature is measured along well bore in 0.5-5 h after changing over from conditions of quasi-stationary distribution of temperature in tubing in the course of injection to withdrawal of fluid through tubing. In each interval of detected temperature anomaly, two temperature measurements are made. The first measurement is carried out after not more than 2 min and the second measurement, after 5-12 min after changing over from injection to withdrawal of fluid through tubing at which subject to registration in tubing is 0.1 Δ To, where Δ To = Ta - Tt; and Tm and Tt are temperatures in annular space and in tubing before withdrawal of fluid form well. Disturbed sealing of tubing is detected by the form of temperature anomaly during the first measurement and disturbed sealing of flow string is detected by absence of anomaly during the first measurement and by presence of anomaly during the second measurement. The second version of the claimed method includes performance in each detected interval of temperature anomaly of the second and third measurements fro 2 min and 5-12 min, respectively, after changing over from injection to withdrawal. Disturbance of sealing of tubing is detected by absence of anomaly in the first measurement, and by the presence of anomaly in the second measurement. Disturbance of sealing of flow string is detected by absence of anomaly of temperature in the first and second measurements, and by presence of temperature anomaly in the third measurement. EFFECT: higher accuracy in detection of points of disturbance of sealing of tuning and flow strings. 3 cl, 4 dwg