【摘要】 针对浅层气具有埋藏浅、成因复杂、储量小、丰度低、类型多和分布广的特点,提出了一种改进的AVO识别方法来预测浅层气的分布范围。该方法是在常规AVO识别技术的基础上,用扫描的方法来确定一个道集内的角度范围,优选出能有效反映浅层信息的角度道集。由于受到是否含气的影响,不同角度下地震振幅幅度不同。据此计算不同角度下的能量包络差剖面,进而找出有利的含气区。该方法的优点是:①由于是优选的针对浅层的角度道集,所以更能反映浅层的信息;②采用的是能量包络差的方式,可以反映出不同角度下的地震能量细微的变化,使识别的分辨率更高;③减小了系统误差。应用该方法在大庆长垣南部葡南油田黑帝庙油层进行了天然气检测,取得了令人满意的成果。更多还原

【Abstract】 In view of the characteristics of shallow-layer gas, such as shallow burial depth, complex genesis, small reserves, low abundance, many types and wide distribution, an improved AVO identification method is presented to predict the range of distribution of shallow-layer gas. This method is to determine the scope of angles in a gather through scanning and select an angle gather that can effectively reflect the nature of the shallow layers on the basis of conventional AVO identification technologies. The scopes of amplitudes with different angles are not the same due to the impacts of whether containing gas or not. Energy envelope differential profiles at different angles are generated to indicate favorable gas-bearing areas. The advantages of this method include: the angle gathers are selected aiming at shallow layers, thus can better reflect the nature of the shallow layers; ② the application of energy envelope difference can reflect the small changes of seismic energy at different angles, resulting in a higher resolution; ③ the systematic error is lowered. It is successfully applied to detect gas in Heidimiao reservoir of Punan oilfield in the southern Changyuan, Daqing.更多还原