METHOD FOR DETERMINATION OF TECHNICAL CONDITION OF WELLS Russian patent published in 2010 - IPC E21B47/10 E21B47/12 G01V5/10 

FIELD: oil and gas production.

SUBSTANCE: method includes lowering radioactive survey tools down to well bottomhole, recording curve of distribution of natural gamma-activity from bottomhole to wellhead, radiation with neutron flux with the help of tools of pulse neutron-neutron survey. Curve of induced gamma-activity is recorded. Curves of distribution of natural and induced gamma-activity are compared along the well axis. At the same time geophysical surveys are carried out in operating well via lubricator. Radiation with neutrons flux is carried out in the intervals higher and lower than perforation holes. Recording natural and induced gamma-activity is done with the help of additional sensor installed on product line at wellhead. At the same time gamma-activity is registered before radiation of borehole annulus, after radiation of well bore interval arranged below interval of perforation and higher than specified interval in zone of occurrence of water-bearing reservoirs. Sources of water invasion of well products are determined by shape of curves of induced gamma activity, single-humped shape demonstrates underlay of bottom water, and double-humped - water supply from overlying reservoirs.

EFFECT: improved validity of wells cementing quality determination, detection of defects of cement ring behind operation string, intervals of borehole annulus untightness, sources of water supply and water invasion into well products.

1 dwg