岩石物理 RockPhysics.ppt

Example: Lithology prediction in carbonates 例子：碳酸岩环境下的岩性预测 Lithology and porosity both vary in reef/margin settings 在珊瑚礁及其边缘环境下，岩性和孔隙度都可能变换 Similar P-wave impedances between porous dolomite and tight limestone, marl, or shale 有孔隙的白云岩和无孔隙的石灰岩、泥灰岩、泥岩具有相似的纵波阻抗 Costly exploration mistakes are often made drilling into “porosity events” 高费用的勘探错误经常发生在所谓的地震“孔隙显示”上钻井 Example: Lithology prediction in carbonates Impedance ratio is a good indicator of lithology and porosity in carbonate rocks波阻抗比可用来区分岩性和孔隙 P-P Seismic Vp/Vs 2.0 1.5 1.0 Using Vp/Vs= (2*TintPS/TintPP) - 1 : Example: Porosity and solid bitumen 例子：孔隙度与固体沥青 Solid bitumen is a big problem in a giant carbonate reservoir. It reduces effective porosity, whereas seismic waves “see” the total porosity 在一个很大的碳酸岩油田中，固体沥青是一个大问题 By comparing seismic properties with those of “clean” carbonate, the amount of shift on the porosity axis gives the approximate bitumen content 通过与不含沥青碳酸岩的比较，孔隙度轴的移动量大体就是沥青的含量 Example: Porosity and solid bitumen The derived bitumen content compares reasonably well with the laboratory measured values 导出的沥青含量与实验室直接测量的大致吻合 It seems that S-wave is better for bitumen content prediction 看起来在预测沥青是，横波要比纵波好 Effect of pore fluids and saturation孔隙流体及其饱和的影响 Rocks with less compressible pore fluids show higher P-wave impedances and velocities 带有非可压流体的岩石具有较高的波阻和波速 S-wave properties are hardly affected by pore fluids 横波基本不受流体的影响 Rocks with less compressible pore fluids show higher Vp/Vs ratio 带有非可压流体的岩石具有较高的纵横波比 Gas Light oil Heavier oil Fresh water Saline water Compressibility 可压性 Bulk modulus Gas 0.01-0.2 GPa Condensate 0.2-0.6 GPa Light oil 0.6-1.4 GPa Heavier oil 1.4-2.2 GPa Fresh water 2.25 GPa Saline water 2.3-3.5 GPa Effect of pore fluids and saturation Fluid effect is the key to 4D, AVO/DHI, and oil-water contacts 流体效应在AVO，直接找油、和油水接触面中起主要作用 However, fluid effect is “shadowed” or complicated by rock properties: Softer rocks show larger fluid effect 但是，流体效应往往被岩石本身特性遮盖或复杂化：软的岩石显示较大