【摘要】 目前,我国油气地震勘探正在由大尺度构造油气藏转向小尺度(薄互层)岩性油气藏,高分辨率和高保真成像是此类油气藏勘探需要解决的核心问题之一。与(角度)反射系数成像相比,宽带波阻抗成像更有利于岩性油气藏的(定量)精细描述。常规窄带、窄方位的地震数据采集只能进行窄带反射系数的估计,甚至只能实现构造的准确定位。基于单点高密度、宽带、宽方位的地震数据采集,精确估计背景(偏移)速度和宽带反射系数,结合来自测井数据的密度建模进行合理的深度域反演,得到背景速度和宽带反射系数融合的宽带波阻抗成像结果,是今后进行精确油气藏描述的重要技术发展方向。为此,分析了"两宽一高"地震数据对宽带地震勘探的贡献、宽带反射系数估计的影响因素、地震子波和低频成分在宽带波阻抗建模中的重要意义,提出了宽带波阻抗估计的方法及宽带波阻抗建模的关键技术,指出"两宽一高"地震数据下的宽带波阻抗建模能有效提高油藏描述的精度,进而提高油气地震勘探效益。更多还原

【Abstract】 Currently the goal of oil and gas seismic exploration is shifting from large-scale structural reservoir to small-scale(thin interbed)lithologic reservoir.High-resolution and high-fidelity imaging is essential for this type of reservoir exploration.Compared with the angular reflectivity imaging,broadband impedance imaging is more favorable for detailed(quantitative)description of lithologic reservoir.Conventional seismic data from narrow-band and narrow-azimuth seismic data acquisition can only estimate the narrow-band reflection coefficient and accurate structural positioning.The point source/receiver high density,broadband and wideazimuth seismic data acquisition provides data for accurate background(migration)velocity estimation and broadband reflectivity estimation.Combined with density model from the well log data,reasonable depth domain inversion method can be proposed to merge the background velocity and broadband reflectivity into broadband impedance results,which is an important technical direction for accurate oil and gas reservoir description.This paper also analyzed the goal of broadband seismic exploration,contributions of the broadband,wide-azimuth,and high-density seismic data to broadband seismic exploration,influence factors of broadband reflectivity estimation and the importance of low frequency components for broadband impedance modeling.The strategy and process of broadband impedance modeling are presented and the key technology for broadband impedance modeling is analyzed.The broadband impedance modelling based on the broadband,wide-azimuth,and high-density seismic data can effectively improve the accuracy of reservoir description and the exploration benefit.更多还原