天然气水合物沉积层的AVA特征

本文首先分析了天然气水合物沉积的三种微观模式,根据其不同的岩石物理模型特点,研究了弹性参数随水合物饱和度的变化规律;以精确Zoepprize方程为基础,研究随饱和度变化的AVA特征;最后,利用不同的理论模型模拟了BSR现象,分析BSR产生的三种客观条件以及调谐作用对BSR的影响。研究结果表明:天然气水合物饱和度、下伏层游离气的存在与否与水合物沉积层孔隙的变化是影响BSR特征的重要因素。本文的研究结果可为天然气水合物的深度研究提供一种思路。

AVA characters on gas hydrate-bearing sedimentary deposit

Gas hydrate-bearing deposit usually has obvious features on seismic reflection.For example,bottom simulating reflector(BSR) is commonly used as gas hydrate direct indication,but this reflection characteristic does not always mean the presence of gas hydrate.So the background of BSR phenomenon is the base of researches.In this paper,we first analyze three microscopic models of gas hydrate-bearing sedimentary deposit.According to the petrophysical model,we study the variation rule of elastic parameters.Then we discuss the AVA character for the saturation variation based on accurate zoepprize function.At last,we simulate BSR phenomenon using different theoretical model,and at the same time we analyze three external conditions for BSR,and study the tuning effect of gas hydrate-bearing sedimentary deposit.The research result indicates that gas hydrate saturation,free gas and sedimentary deposit’s porosity are the important factors for BSR character.So this paper could provide some conclusions for further research of gas hydrate.