摘要
Unlike previous theories with velocity and/or elastic modulus averaging, we use a three-phase porous rock physics model developed by Santos for analyzing the seismic response of two immiscible fluids in saturated porous media. Considering reservoir reference pressure and coupling drag of two fluids in pores, the effects of frequency, porosity, and gas saturation on the phase velocities of the P-and S-waves are discussed in detail under field conditions. The effects of porosity and gas saturation on Vp/Vs are also provided. The data for our numerical experiments are from a sample of deep volcanic rock from Daqing. The numerical results show that the frequency dispersion effect can be ignored for deep volcanic rocks with low porosity and low permeability. It is concluded that for deep volcanic rocks the effect of gas content in pores on Vp/Vs is negligible but the effect of porosity is significant when there is a certain amount of water contained in the pores. The accurate estimate of lithology and porosity in this case is relatively more important.
与以往利用速度或(和)弹性模量平均方法不同,本文基于Santos发展的三相孔隙介质岩石物理模型考察了两种不相混流体饱和的孔隙介质的地震响应。考虑到地层参考压力和孔隙中两种流体之间的牵引耦合作用,本文详细分析了地层条件下频率、孔隙度和含气饱和度对纵波和横波速度的影响。同时,孔隙度和含气饱和度对Vp/Vs的影响也给予了相应的讨论。用于本文数值研究的数据源自大庆探区深层火山岩样品。数值结果显示,对于低孔低渗的火山岩,纵波和横波的频散效应可被忽略。孔隙中气的含量变化对Vp/Vs的影响较小,但在含水饱和度一定条件下孔隙度的影响相对显著。在这种情况下,准确估计岩性和孔隙度对于深层火山岩来说显得更加重要。
