Studies on the characteristics of low frequency seismic response from unconsolidated gas-bearing sand reservoir
Liu Lang-feng1, Cao Si-yuan1, Li Xu-xuan2, Wang Lu3, Jiang Shao-Hui4, Chen Bao-shu2, Wang Xiao-jiang2
1. Faculty of Geo-resources and Information,China University of Petroleum,Beijing City,102249,China;
2. Petroleum Research Centre of CNOOC,Beijing City,100080,China;
3. Well Logging Instrument Plant,Welling Logging Company Ltd.of CNPC,Xi'an City,Shaanxi Province,710021,China;
4. Geophysical Technology Research Centre,BGP Inc.of CNPC,Zhuozhou City,Hebei Province,072751,China
Abstract：Regarding the shallow unconsolidated sand reservoir,the White thin layered model was introduced in this paper,by integrating with porous elastic medium wave theory the theoretical calculation of low frequency seismic reflection characteristics for partially gas bearing reservoir condition and total water-bearing rock condition were conducted,and then OASES wavefield numerical simulation software package was used to conduct numerical simulation analysis for the two conditions.Compared with totally water-bearing condition,the fluid in the pores of the partial gas-bearing reservoir could flow faster due to existence of bubbles in the fluid,then the wave propagation velocity decreases with the seismic wave frequency lowing down,as a result the impedance difference between the reservoir and the surrounding rocks will increase,so the final seismic low frequency reflection energy was relatively increased with obvious low frequency velocity frequency dispersion and low frequency reflection anomaly.The low frequency energy analysis for the field seismic data show that when the impedance of the unconsolidated sand reservoir is lower than that of the surrounding rocks,the low frequency energy anomaly can be regarded as an important indicator to identify a gas-bearing reservoir.
刘兰锋, 曹思远, 李绪宣, 王鲁, 姜绍辉, 陈宝书, 汪小将. 未固结含气砂岩储层低频地震响应特征研究[J]. 石油地球物理勘探, 2010, 45(6): 873-878.
Liu Lang-feng, Cao Si-yuan, Li Xu-xuan, Wang Lu, Jiang Shao-Hui, Chen Bao-shu, Wang Xiao-jiang. Studies on the characteristics of low frequency seismic response from unconsolidated gas-bearing sand reservoir. OGP, 2010, 45(6): 873-878.
