Abstract: The porosity of a clastic reservoir can be calculated by the absolute velocities (synthetic acoustic logging)derived from seismic inversion. In ordinary usage, however, there are some problems which are difficult to eliminate: e.g., time average equation on a dual-phase media fails to compute the porosities of a muddy sand reservoir, and it is impossible to gain the to exact porosity by triple-phase medium time average equation under the condition without bore hole data or even in an area with sparse well control.The extended time average equation, a combined model introduced in this paper, can predict the porosities of muddy sand reservoirs only by absolute seismic velocities before exploratory drilling, and provide reliable quatitative information for an integrated evaluation of clastic reservoir quality.

摘要： 根据地震反演获取的绝对速度即合成声波测井速度,可以估算储层的孔隙度.本文提出的扩展时间平均方程组合模型,能够在钻井之前仅根据地震绝对速度,预测出泥质砂岩储层的孔隙度,为储层性能的综合评价提供有力的依据.

关键词: 时间平均方程, 泥质含量, 储集层, 孔隙度