METHOD FOR DETERMINATION OF LEAKAGE AND CUT-OFF PLACE OF EXTRACTING COLUMN Russian patent published in 2009 - IPC E21B47/00 E21B47/10 

FIELD: gas and oil production.

SUBSTANCE: invention refers to development of oil fields, particularly to operating well technical condition control. The method for determination of leakage and cut-off place of extracting column includes measurement of earth material natural gamma radiation along well bore - gamma-ray logging - and recording change in magnetic conductance of boring casing and oil-well tubing metal due to disruption of their leak tightness by collar locator. Readings of all exploration methods performed in well are linked by depth to geological section. Curves on gamma-ray logging and collar locator diagrams are compared. Collar connection locations on superposed diagrams are fixed. Interval coincidences of positive abnormal values on gamma-ray logging and collar locator diagrams (from which collar connections leak tightness is determined) are identified. And from interval coincidences of positive abnormal values on gamma-ray logging and collar locator diagrams in segments between collar connections with increase in interval of abnormal values of curves on gamma-ray logging diagrams of 3 metres and more cut-off place of extracting column is determined.

EFFECT: improvement of reliability and accuracy of extracting column disruption determination, lowering material expenses and time for search, determination of disruption type and recovery after disruption.

1 dwg, 1 ex