Logging Recognition Method Research Of The CO₂Gas Layer In The Songliao Basin

Along with deeply exploration and development of the nature gas in Daqing oil field, theexactly recognizing and delicately estimating of the CO₂gas layer is very important fordetermining the reservoir’s output and judging the gas-water layer. However, the detectedresult of CO₂can not be judged delicately because of the undetermined source and simplemethods and other unknown factors. Though the detected result of CO₂could not match thereservoir’s output, and the recognition and judgment of the CO₂gas layer become moredifficultly, and the logging integration is very unideal. Therefore, the inevitable developingtrends of the geological log is that seeking more useful recognizing and judging methods ofthe CO₂layer and exactly exclude the involution of the drilling fluid system and exploringmore integrated interpretation and judgment system. Also, this is very desirability for theexploration development of Daqing oil field.Firstly, our work fully analyzed the spatial distribution of the CO₂of Songliao Basin inDaqing oil field, and deeply studied the main CO₂detecting methods and the principles of thethermal conductivity analyzer and the infra-red absorption analyzer. Secondly, we studiedadjustment methods of the environment factors to the CO₂detected results, through analyzinghow the CO₂enters the drilling system. Thirdly, we built up the methods to get the reservoirgas bearing factors and porosity through the integrated logging techniques. Finally, we builtup the recognition method which can determine the truthfulness and thickness of the CO₂layer and its relative content. We built up interpretation and judgment system of the CO₂gaslayer and make its appearance according to the output based on correction of the CO₂detectedresult combined with the experimental findings, log data, oil test data and effective judgmentfactors.This work got good purposes in the practical experiments, achieved the comparison withthe CO₂and hydrocarbon gas’s relative content, and the coincidence rate is up to90.9%. Theinterpretation plate of CO₂gas layer was completed and the coincidence rate of the old wells’reinterpretation is up to90.0%. The logging recognition and judgment of the CO₂gas layer isvery perspective in the exploration field of the deep nature gas.