基于模糊数学的滨里海盆地东南油气储层评价

哈萨克斯坦滨里海盆地地处东欧地台东南部边缘,为克拉通边缘前陆盆地,是里海地区的主要含油气区之一。滨里海盆地东南部三叠系-侏罗系广泛发育陆源碎屑岩地层。储集层岩性主要为浅海陆棚、海滩砂坝及三角洲沉积相的砂岩和粉砂岩,储层物性特征总体表现为中孔-中渗型。测井结果显示储层物性和孔隙结构变化较大,储层非均质性强。采用基于模糊数学的评价方法,通过多元回归分析、最小二乘法优化地质要素,确定孔隙度、渗透率、含油饱和度、砂岩厚度作为关键地质因素,建立了模糊数学关系模型,克服了常规的储层含油气性评价过程中诸多不确定因素带来的复杂化和主观性问题。通过多个模型比较,作出判断,确定了J₂Ⅱ和TⅡ储层为本区优势储层,为该区进一步油气开发提供参考依据。

Fuzzy mathematics-based reservoir evaluation in the southeastern Pre-Caspian Basin

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 J₂Ⅱ and TⅡ.