摘要
在陆相断陷盆地陡坡带砂砾岩中,广泛沉积的粒径不等的砾石是影响其速度变化特征的关键因素,基于均匀介质建立的岩石物理模型具有明显的不适用性。为准确计算砂砾岩的纵横波速度并分析其影响因素,通过对东营凹陷北部陡坡带10口取心井100余块超声波岩心样品的选取、测定及实验数据分析,构建包含多岩石组分参数的砂砾岩扩展时间平均方程。利用岩心砾石图像扫描技术确定砾石含量,通过岩石薄片鉴定得到砂级碎屑颗粒、杂基、胶结物以及孔隙流体等岩石组分含量,借助岩心样品的实验室超声波测试得到不同岩石组分的纵横波速度,并代入已构建的扩展时间平均方程得到砂砾岩的纵横波速度。模型检验与实际应用结果表明,利用扩展时间平均方程计算的砂砾岩纵横波速度比Wyllie时间平均方程计算结果的精度提高10%以上,也表明在砂砾岩发育的地层,利用扩展时间平均方程计算的纵横波速度比基于均匀介质建立的岩石物理模型更加准确合理。
Gravels,with different granularities and compositions,are widely developed in continental faulted basin,which is the key factor that influences the velocity change of sandy conglomerate. It is not suitable to use rock physical model based on homogeneous medium. In order to accurately calculate compressional and shear wave velocities and analyze its influence factors,an extended time-average equation was established considering variable parameters through selecting 100 core samples from 10 wells in the northern steep slope of Dongying sag for ultrasonic measurement and data analysis. The contents of gravel,sand-sized clastic particle,matrix,cement and pore fluid were obtained through rock slice identification,and then compressional and shear wave velocities,obtained through ultrasonic test of core samples in the laboratory,were put into the extended time-average equation to obtain the compressional and shear wave velocities of sandy conglomerate. Model test and actual applications indicate that the calculation accuracy of compressional and shear wave velocities of sandy conglomerate derived from the extended time-average equation is 10% higher than that from Wyllie time-average equation,and the compressional and shear wave velocities derived from the extended time-average equation are more accu-rate than those derived from petrophysical model based on homogeneous medium.
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2015年第6期55-60,共6页
Petroleum Geology and Recovery Efficiency
基金
国家科技重大专项"深层油气
非常规天然气成藏规律与有利勘探区评价技术"(2011ZX05008-004)
关键词
砂砾岩
岩石组分砾石含量
扩展时间平均方程
岩石物理测试
sandy conglomerates
rock components
gravel content
extended time-average equation
petrophysical test
