Kazakhstan Pre-Caspian Basin is a craton marginal foreland basin located in the southeast edge of East European Platform and is one of the main petroliferous regions in Caspian Sea.Terrigenous clastic rocks were widely developed during the Triassic-Jurassic in southeastern Pre-Caspian Basin.The reservoirs are dominated by sandstone and siltstone of shallow marine shelf facies

shoals facies and delta facies.The poroperm characteristics of the reservoirs are medium porosity and moderate permeability as a whole.The well logging interpretation shows that the reservoirs physical properties and pore texture are of strong heterogeneity.Based on fuzzy mathematics evaluation

this paper optimized the geological factors through multiple regression analysis and smallest secondary multiplication

recognized porosity

permeability

oil saturation and sand thickness as the key geological factors

and established fuzzy mathematical model.The new model overcomes the complexity and subjectivity caused by various uncertainties that are common in traditional reservoir evaluation.Multiple model comparison reveals that the favorable reservoirs in this area are J

2

Ⅱ and TⅡ.