Reservoir Logging Saturation Evaluation Method Of Moliqing

Yitong basin located in the eastern part of Jilin province, the rate of basin subsidence is large, on both sides of basin sediment source is adequate, deposition rate and phase change rate are both fast. The major research block Moliqing fault depression is a secondary tectonic units located in Yitong basin with special sedimentary environment and complex lithology.Underwater fan is the main types of sand body development in Moliqing fault depression, Its lithology shows as coarse particle size is difficult to separat, the lithology is relatively single,midfan with better pore structure is mainly consis of glutenite, conglomeratic sandstone and siltstone. Small particles, high shale content, low permeability and porosity obvious reservoir characteristics of containing mud or calcium powder sandstone.This paper based on core logging data, on the basis of comprehensive demarcate on conventional logging data, dividing the study area by crossplot analysis of 5 kinds of lithologic property and oiliness analysis. At the same time completed logging response analysis on typical lithologic, studied the logging response characteristics of various curve. To the ability to respond to and change trend of different strata, through five big rock physical properties and oiliness analysis,then combined with logging curve values which are mainly influence of lithologic identification. By crossplot analysis, bayesian clustering discriminant analysis technology, established a discriminant function, completed logging data lithologic identification of five main lithology, and get a high coincidence rate of recognition.Because the lithology of reservoir in Moliqing rift is complex.And resistivity of rock skeleton in gravel reservoir is high.The oil and water layers are shown as high apparent resistivity.Siltstone reservoir are shown as high calcium, high shale content, strong heterogeneity.So it is very difficult to get a good result to calculate water saturation by using Archie’s formula in the traditional sense.In order to solve the above problems,the formula of the relationship between the formation factor and the effective porosity of the strata is established by the lithology and establish the relationship between lithology coefficient and porosity index value and the coefficient of water saturation and resistivity increase.The relationship between the saturation exponent n and the average pore throat radius is formed.The correlation between the two is high.Finally, the method is verified by using the saturation analysis data of the closed coring wells.The results can meet the production requirements.