含天然气水合物沉积物的岩石物性模型与似海底反射层的AVA特征

PHYSICAL PROPERTY MODELS OF GAS HYDRATE-BEARING SEDIMENTS AND AVA CHARACTER OF BOTTOM SIMULATING REFLECTOR

研究含天然气水合物沉积物的岩石物性模型与似海底反射层的振幅随入射角变化 (AVA)特征 .基于时间平均 -Wood加权方程、三相介质波传播理论模型和弹性模量模型 ,计算并阐述含天然气水合物岩石弹性参数与水合物饱和度、含游离气岩石弹性参数与游离气饱和度的关系 ;给出不同模型AVA特征 .结果表明 ,不同天然气水合物饱和度、不同游离气饱和度的各种组合呈现形态相似但反射系数值不同的AVA特征 .

Physical property models of gas hydrate bearing sediments are studied and the amplitude versus angle (AVA) character of bottom simulating reflector are analysed. The relationships between elastic properties and gas hydrate/free gas concentration are presented based on the models of weighted time average wood's equation, seismic wave propagation in three phases effective medium and elastic modulus. The AVA character of different models are calculated and analyzed. The analysis of AVA character of BSR shows that different reflection coefficient values but similar configurations of AVA curves are given for various combinations of different concentrations of gas hydrate and free gas.