准噶尔盆地玛西地区致密砂砾岩优质薄储层预测

摘要

准噶尔盆地玛湖西斜坡区三叠系百口泉组储层为扇三角洲致密砂砾岩，具有低孔、低渗、储层薄的特征，水下中等孔隙度的灰绿色砂砾岩为优质储层。由于地震资料主频低（25～30 Hz），储层薄（10 m左右），而且优质储层与致密层阻抗叠置，目前常用的叠后波阻抗反演、叠前同时反演等方法都满足不了该地区优质薄储层预测的要求。笔者基于取芯、测井、试油等资料开展岩石物理分析，利用纵波阻抗和纵横波速度比建立岩石物理图版，确定该区的优质储层参数特征。在此基础上，开展叠前地质统计学反演，综合叠前同时反演与地质统计学反演技术的优点，实现砂砾岩优质薄储层的预测。反演结果表明，叠前地质统计学反演结果可以明显提高储层纵向预测的分辨率，较好地解决该地区致密砂砾岩优质薄储层预测的问题，为该区下步勘探开发提供依据。%The reservoir of Triassic Baikouquan Formation on Mahu slope in Junggar Basin is characterized by low porosity,low permea⁃bility,and thin tight conglomerate,with only the subaqueous grayish green conglomerate with medium porosity being the high⁃quality res⁃ervoir. Because central frequency of seismic data is low (25~30 Hz),the thickness of the thin layer is about 10 m,and the impedances of high⁃quality reservoir and tight layers are overlapped in these reservoirs,the commonly used post⁃stack impedance inversion and pre⁃stack simultaneous inversion are not very effective in prediction of high⁃quality and thin reservoirs.In this paper,based on core,logging and test data,the authors carried out the petrophysical analysis and established the petrophysical chart by using P⁃impedance and vp/vs , and then identified the parameter of the effective reservoir of this area.Finally,the authors conducted the pre⁃stack geo⁃statistic inversion that combines the advantages of the simultaneous inversion and geo⁃statistics inversion,and predicted the high⁃quality and thin conglom⁃erate reservoir.The result of inversion indicates that the pre⁃stack geo⁃statistics inversion can effectively identify the high⁃quality and thin conglomerate reservoir and provide reliable basis for further exploration and development.