METHOD FOR DETERMINATION OF PRODUCTIVE FORMATION STATUS BY PULSED NEUTRON METHOD Russian patent published in 2014 - IPC G01V5/10 

FIELD: oil and gas industry.

SUBSTANCE: logging device is moved along the borehole, a repetitively-pulsed fast neutron flux is generated in the well, a time analysis of the thermal neutrons flux rate is carried out for each quantum of the formation depth, values of baseline decrements are determined for the drop in the thermal neutrons flux rate. A chemical solution containing compounds with anomalously high macro cross-section of nonfission neutron absorption is pumped into the well under pressure, then values of baseline decrements are determined for the drop in the thermal neutrons flux rate repeatedly, ultrasonic radiation is generated in the well and the formation is impacted by this radiation, thereafter values of baseline decrements are determined for the drop in the thermal neutrons flux rate for satisfaction of the respective system of inequalities containing values of decrements obtained at all three stages of measurements. Against satisfaction of these inequalities a judgement is made about potential maintenance of the well flow rate at the operational level with periodical impact on the formation by a longitudinal acoustic pressure wave.

EFFECT: possible identification of productive formations where usage of acoustic impact on the formation to maintain the well flow rate gives positive result.

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