METHOD OF ASSESSEMENT OF RESERVOIRS WITH ABNORMALLY HIGH PERMEABILITY Russian patent published in 2009 - IPC E21B47/10 G01V5/04 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to geo-physical methods of well survey, particularly to determination of reservoir-bed in prospect, producing and for other purposes wells. Gamma-survey is carried out with implementation of radio-active substances. Also to determine reservoirs with abnormally high permeability a gaseous chemically inert isotope is used; this survey is performed in an un-cased borehole; then the same isotope is introduced directly into a back-filling solution into the interval of the preceding survey. Then gamma-survey is made. Reservoirs with abnormally high permeability are determined on results of comparison of a concrete control gamma-survey with a background one made after formation of zone of indicator penetrating into reservoir beds and after washing the borehole off indicator liquid. Further gamma-survey is carried out directly after well cementing and after formation of cement stone; then after comparing permeability past the first gamma-survey with permeability obtained at gamma-survey after cementing, reservoirs with abnormally high permeability are selected.

EFFECT: determination of reservoirs with abnormally high permeability due to different permeability of drilling and back-filling agent into permeable reservoirs of surveyed interval.