Correction Model Of Reservior Fluid Saturation And Application Of Yanchang Formation In Wuding Area

At present,in most fields,fluid saturations measured in the laboratory have varying degrees of loss,and there are many recovery methods,most of which are recovered using experimental methods,but there are few batch correction methods for mass fluid saturation analysis results.This article takes the Yanchang Formation in Wuding area of Ordos Basin as the research object.Firstly,on the basis of investigation of fluid saturation analysis,carried out the on-site sampling,indoor sample saturation analysis,rock sample volatilization,fluid sample volatilization,crude oil high-pressure physical property test,and water washing simulated experiments and showering simulated experiments,systematically studied the factors affecting fluid saturation.Secondly,we established a fluid saturation correction mathematical model based on the affecting factors,and used the model to correct reservoir fluid saturation.Then,verified the results of the calibration model using NMR three measurements,and the result is reliable with a error within 5%.Finally,combined with the test data,we have determined the value of oil limit after reservoir correction,and studied the distribution law and control factors of oil saturation after correction of reservoir fluids.The results show that the loss of reservoir fluid saturation is serious in Wuding area.The main reasons are related to the nature of crude oil,water content of crude oil,environmental humidity,systematic errors,and degree of reservoir cementation.Among them,the nature of crude oil and the extent of reservoir cementation have a great influence.The oil saturation distribution is mainly affected by the physical properties of the reservoir,the sedimentary facies,and the distribution of the source rock,the migration mode,the fault cracks and the microcracking.Therefore,when obtain cores in different reserviors,the coring time should be different depending on the nature of the reservoir.By studying the correction method of fluid saturation in Wuding area,it is of theoretical significance to study reservoir fluid saturation in similar areas.