【摘要】 在碳酸盐岩地区的油气勘探中,溶洞地震响应特征的识别面临着很大挑战,关键问题在于对溶洞的形态、大小及充填物变化引起的地震波变化规律及地震响应特征的认识。为此,针对碳酸盐岩储层的地质特点,抽象出3类(不同形态、不同尺度及不同充填物)溶洞物理模型,利用地震物理模拟技术开展了模拟实验。结果显示,小尺度的溶洞(d(?)λ),地震波到达溶洞后,散射现象占主导,缝洞绕射波振幅与偏移距有近似解析关系。大尺度溶洞的形态对绕射波的振幅具有强烈影响,在菲涅耳带半径内,线体能量最强,片、柱、椭球、球型体绕射信号逐渐减弱。均匀充填溶洞的绕射波能量最强,波形简单,剖面信噪比高,反射成像收敛的"串珠"能量强,对称拖尾较短;非均匀充填溶洞的绕射波能量较弱,剖面信噪比低,非均质性越强其成像"串珠"形态畸变越大、拖尾越长。更多还原

【Abstract】 In the hydrocarbon exploration at carbonate area,the recognition of carven seismic response characteristics is confronted serious challenge;the key is about the recognition of seismic wave alterna- tion rules and seismic response characteristics caused by the changes on shape,size and fillings of caves.Therefore,aiming at the geologic characteristics of carbonate reservoir,three types of carven geophysical models were extracted,including different shape,different size and different fillings.Then seismic physical simulation technique was used to study the models.The result indicates that for small-scale cave(d<<λ),the seismic wave is mainly of scattered wave when it arrives at the cave,the diffraction wave amplitude of the cave has approximately analytical relationship to offset. Meanwhile,the shape of large-scale cave has strong impact on the amplitude of diffraction wave,in the Fesnel zone radius,the energy of the cave with linear shape is strongest,and is followed by flaky shape,cylinder,ellipsoid and sphere.The caves with uniform fillings have strong refraction energy,simple waveform and high S/N seismic section;its string reflection is characterized by strong energy, symmetry and short tailing.The caves with nonuniform fillings have weak energy,low S/N seismic section;stronger homogeneity causes larger string aberrance and longer tailing.更多还原