未固结含气砂岩储层低频地震响应特征研究  

Studies on the characteristics of low frequency seismic response from unconsolidated gas-bearing sand reservoir

作　　者：刘兰锋[1] 曹思远[1] 李绪宣 王鲁 姜绍辉 陈宝书 汪小将 

机构地区：[1]中国石油大学(北京)资源与信息学院,北京102249 [2]中海石油研究中心,北京100080 [3]中国石油集团测井有限公司技术中心,陕西西安710021 [4]东方地球物理公司物探技术研究中心,河北涿州072751

出　　处：《石油地球物理勘探》2010年第6期873-878,共6页Oil Geophysical Prospecting

基　　金：国家科技重大专项课题(2008ZX05024-001)

摘　　要：针对浅层未固结砂岩储层,本文引入了White薄层状模型,并结合Biot孔隙弹性介质波动理论,对储层部分含气和完全含水两种情况下的低频地震反射特征进行了理论计算,并运用OASES波场数值模拟软件包对这两种情况进行了数值模拟分析。与完全含水情形相比,储层部分含气时由于气泡的存在,岩石孔隙内的流体相对岩石骨架运动增强,波的传播速度随着地震波频率的降低而减小,砂岩储层与上、下围岩阻抗之差变大,从而引起地震低频反射能量相对增强,表现为明显的低频速度频散和低频反射异常。实际地震资料的低频能量分析结果表明,当未固结砂岩储层阻抗低于上下围岩阻抗时,低频地震能量异常现象可以作为识别储层含气的重要标志。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.

关 键 词：未固结砂岩 含气储层 White模型 低频异常 速度频散 

分 类 号：P618.130.2[天文地球—矿床学]