Study On Correction Method Of Annulus Fluid For RPM Logging And Its Application

Nowadays the proportion of oilfield water injection well is very high,so looking for remaining oil to increase production of old oil fields has become an important goal.As a cased hole technology,carbon oxygen ratio logging is not affected by salinity of formation water and the high accuracy oil saturation calculation makes it more and more widely used in the evaluation of remaining oil saturation.While during well logging,the screen tube add to the pipe column makes the structure complex,also effect the measuring result of carbon and oxygen ratio;the oil between tubing and casing has caused the measurement of carbon oxygen ratio value very high,then the oil saturation calculation result is relatively large even higher than 100%.For the column structure of complicated pipes,we use Monte Carlo simulation to establish carbon oxygen ratio logging response charts under the condition of complex pipe column structure,then we get different carbon and oxygen ratio oil saturation interpretation model that can be suitable for different pipe string structure;for ring empty oil,which influence the measure carbon oxygen ratio,through Monte Carlo simulation,we establish the far,nearly detectors for the measurement of carbon oxygen ratio with the variation of porosity and saturation under different oil holdup.Then establish far and near carbon oxygen ratio correction method of ring air fluid and process the measured well data,which improve the accuracy of oil saturation obviously.Based on Forward platform,the Fortran language is used to compile the carbon oxygen ratio logging interpretation software and to deal with the measured data,which has achieved good results.Research shows through the establishment of complex pipe column interpretation model and annular fluid correction,carbon and oxygen ratio logging interpretation have high accuracy,formed a set of suitable carbon and oxygen saturation evaluation method for offshore well logging under the condition of complex string and the annulus oil fluid.