Reserves parameters calculation for volcanic gas reservoirs in Xushen gas field

Due to the characteristics of lithologic diversities,strong heterogeneity and complex reservoir types of volcanic reservoirs,there are great difficulties in the reserves estimates.Hence,the accurate calculation of reserves parameters is important.In view of the uncertainty of volcanic framc parameters,through comprehensive analysis of cores,flakes,elements and logging data,the researches of volcanic lithology logging identification have been carried out by adopting many methods and with the thoughts of combining the composition with the structure and the conventional logging with the specific logging.The reserves parameters calculation model for the Xushen gas field in the Songliao Basin has been established through core analysis,logging data and gas testing results based on lithology identification,and then the values were taken by the comprehensive analysis method to reduce the risk of reserves calculation.With this method,the coincidence rate for volcanic lithology identification reached up to more than 85%,with the accuracy ratio of reserves parameters calculation over 80%,which can meet the reserves specification requirements,and thus will provide reference for the reserves evaluation of the volcanic oil and gas reservoirs.