Application of VIKIZ in Recognition of Annulus with Low Resistivity

During drilling,the mud filtrate may invade reservoirs,in some cases it causes low resistivity annular zone(annulus).The formation of annulus is an evidence that the reservoir bears movable oil.VIKIZ has the ability to detect the annulus.This paper first describes the phenomenon of mud invasion,and further discusses annulus formation mechanism.Based on the analysis of VIKIZ detection characteristics,the paper analyzes VIKIZ's unique property in comparison with the traditional induction logging instrument.Logging cases demonstrate VIKIZ's unique advantages in evaluation of oil and gas by using annulus.