基于高分辨率层序地层的储层流动单元研究

基于岩心分析、测井及生产资料,针对马岭油田下侏罗统延9油层组辫状河储层纵横向相变快、非均质性强的特征,通过确定层序格架内储层及渗流屏障空间分布,优选参数将储层划分为E、G、M、P共4类流动单元,结合测井交会分析、岩相相序解剖及沉积过程分析结果,对层序格架内流动单元空间分布的控制因素进行研究。结果表明:超短期旋回中,储层颗粒的分选、粒度中值及杂基含量制约着延9储层的岩石物理性质与渗流能力,使不同类型岩石相中沉积组构的差异特征控制着该级次流动单元的空间分布;短期基准面旋回中的各类沉积微相内不同岩相的垂向组合影响着该级次流动单元的垂向差异分布;沉积微相的平面分布与短期旋回内流动单元区带有良好的对应关系,心滩、辫状河道沉积为E、G类优质流动单元分布优势区;中期基准面旋回通过控制相序和相组合的变化,使不同基准面位置处同类沉积微相呈现不同的砂体叠置样式及规模,进而影响着各类流动单元相对比例的层间差异。

Research on flow units based on high resolution stratigraphic sequence

The braided river reservoir of the 9th member of Yan ''an Formation in Maling Oilfield had features of fast variation and strong heterogeneity. On the basis of core analysis, logging and production data, the spatial distribution of reservoir and barriers were determined in sequence stratigraphic framework. The reservoir was divided into E, G, M, P four types of flow units by preferred parameters. The controlling mechanism of flow units were analyzed in sequence stratigraphic framework, with the analysis result of well logging intersection, petrographic anatomy and depositional process. The results indicate that the petrophysics property and flowing ability are dominated by sorting, median grain size and matrix content, which contribute to the different sedimentary fabrics in different lithofacies of super-short cycles. The lithofacies association in different microfacies controls the flow unit variations in the vertical profile of short cycles. In the horizontal profile, the distribution of microfacies has an intern relationship with flow units. For instance, the bar and braided channel are advantageous microfacies relating with E and G flow units. Sand body stacked patterns and scales of similar microfacies are controlled by the sequence and facies association variation in middle-term cycles, which makes the interlayer differences in proportion of various flow units.