成像测井在川西碎屑岩解释中的应用

Application of Imaging Logging interpretation in West Sichuan Detrital Rock

介绍了成像测井解释在川西碎屑岩沉积微相分析、地层应力分析、裂缝识别中的运用。对分流河道、河口沙坝微相的纵向沉积构造变化规律进行了解剖,在此基础上,对川西须家河组沉积微相特征进行了分析。通过对层理分布统计分析,研究了沉积时古水流方向。利用井眼崩落方向以及诱导裂缝走向特征开展了地层应力研究,结果显示,各井的主压应力方向总体上较为接近,为近东西向。利用裂缝走向与主压应力方向间关系开展了裂缝有效性研究,把倾角大于30°、走向与现今最大应力方向交角小于30°的裂缝定义为有效裂缝,其它产状的裂缝定义为无效裂缝,从而把裂缝分为有效裂缝和无效裂缝,对所有拾取的裂缝有效性进行了甄别。

Introduces the imaging logging interpretati on applied in West Sichuan detrital deposit microfacies analysis, terra stress ana lysis and crack identification. Analyses the changing rule of vertical sedimenta ry structure of distributed riverway ,outfall sand dam microfacies, based on whi ch analyses the deposit microfacies attribute of Xujiahe group in West Sichuan. Through the bedding distribution statistical analysis, studies the palaeocurrent during sedimentation. Uses the borehole avalanche direction and induced fractur e trend to estimate the terra stress, the result of which shows each well's main pressure stress orientation is rather approximate as a whole, i.e., it is east west direction. Uses the relation between fracture strikes and pressure stress direction to study the fractures availability, from which defines the fractures as available one with obliquity bigger than 30 degree and the cross angle small er than 30 degree between the strikes and current maximum stress direction, othe r cracks are defined as nonavailable cracks, consequently classifying cracks a s available ones and nonavailable ones. Discriminates all the picked cracks av ailability.