Fine Logging Evaluation Study On Water-flooded Zone Of 7th Block West,Gudong Oilfield

After many years of exploration and development,the sandstone in the upper part of7^th Block west,Gudong Oilfield has entered a very high water cut period,and its oil,water movement,and remaining oil distribution are very complicated.The accuracy of the original interpretation models cannot meet the requirements of oilfield development.It has brought about difficulties in follow-up production and further research,and it is also an unfavorable factor in the study of the remaining oil distribution.In order to evaluate the status and problems of flooded reservoirs in the study zone,the sandstone flooding patterns and characteristics of the study zone were analyzed.The fine evaluation of the flooded sandstone layers in the studied zone were conducted.Firstly,it is cleared that the study zone is a high-porosity,high-permeability,unconsolidated sandstone reservoir dominated by fine sandstone and silt.Through statistical analysis,the characteristics of the reservoir before and after flood is concluded.Combined with core data and well logging data,the flooding degree of the target reservoir in the study area is identified,and qualitative identification charts and standards for different lithologic flooded layers is established.Then the conventional logging interpretation method based on lithofacies and the BP neural network logging interpretation method are used to complete the interpretation of porosity,permeability,water saturation,and irreducible water saturation.On the basis of the above research,combined with well logging data and production data in the study area,a comprehensive interpretation and evaluation of well logs was performed.