小波分析在王官屯油田王26井枣Ⅴ油层组沉积微相研究中的应用

Application of wavelet analysis in study of sedimentary micro-facies of ZaoⅤ reservoir group in Well 26,Wangguantun Oilfield

由测井相解释与岩芯观察,结合前人分析资料得知,王26井枣Ⅴ油层组主要沉积冲积扇相扇中亚相。测井相解释的多解性与岩芯资料的不完整局限了精细分析沉积微相特征。借助小波理论、结合测井曲线、岩芯观察,共同分析王26井枣Ⅴ油层组的沉积微相特征。提取了自然电位、自然伽马、电阻率3种测井曲线,经过Daubechies小波分解后重构的第三层细节信号d3,以高分辨率层序地层学为理论指导,着重对该层段的沉积旋回特征进行分析,借此解释其沉积微相及组合特征。研究结果表明,小波分析、测井相、岩芯资料的结合不仅能识别沉积微相类别——辫状河道及河道内部心滩与河道间沼泽,而且能在纵向上精确地反映其沉积微相组合特征——辫状河道的正旋回特征、河道心滩的反旋回特征、辫状河道连续叠加特征。

Based on the previous analysis of other experts, in combination with the interpretation of well logging facies and core observation, the authors found that Zao V reservoir group in Wang 26 well mainly belonged to the sediments of middle fan of alluvial fan. In order to accurately analyze the features of sedimentary facies, the authors utilized wavelet analysis together with well logging curves and core observation to analysis micro-facies features. When Daubechies wavelet was analyzed, the authors extracted three detailed signals of SP, GR, R4 well logs. With high-resolution sequence stratigraphy as theoretical guidance, the detailed signals of Daubechies wavelet were used to explain the sedimentation of micro-facies and assemblage characters. And the results showed that the combination of wavelet analysis, logging facies, and core data could identify the type of micro-facies-braided river channel, channel bar and the swamp within river beaches, meanwhile vertically assemblage features of microfacies also were precisely reflected-upwards sequence of braided river channels, backwards sequence of channel bar, and continuous superposition of braided river channels.