融合地震结构信息与属性信息表征陆相湖盆沉积体系

Terrestrial lacustrine basin depositional system characterization with seismic structure and attribute information fusion

以测井标定为基础的地震相划分方法采用小时窗的地震单一属性、多属性、属性融合及波形分类等划分沉积微相,缺乏对沉积微相宏观约束的背景分析,容易引起微相划分的"窜相",最终得到的属性平面分布往往突显了某类沉积体而弱化了其他沉积体,从而影响沉积体系研究结果的整体性。为此,在前人工作的基础上,提出了融合地震结构信息与属性信息表征陆相湖盆沉积体系的方法,其中层位—储层两步标定、时窗尺寸选择、两段色标显示及依据隶属关系进行旋回匹配融合等4个方面是该方法的关键点,满足了面状沉积体对地震结构信息完整性描述和线性沉积体对属性横向变化细节刻画的不同要求。实例分析结果表明,利用结构信息与属性信息融合技术得到的融合属性平面图既描述了三角洲内前缘、外前缘、浅湖相等面状沉积体的结构特征,又突显了对常规地震属性敏感的河道、河口坝等线性沉积体,相序更加完整,不同级别相序发育层次合理,有效避免了"窜相",完整刻画了目的层系沉积体系的发育特征。

Seismic facies classification based on logging data calibration always uses seismic single attribute,multi-attributes,attribute fusion,and waveform classification within small time window.This kind of approaches focus on sedimentary microfa-cies but ignores background analysis of macro-constraints,and might likely lead to wrong microfacies determination.So attribute distribution results often highlight one type of depositional body and weaken other types,which may affect the overall research on depositional systems.Therefore we propose in this paper a method to characterize terrestrial lacustrine basin depositional systems with seismic structure and attribute information fusion.The two-step calibration of horizon-reservoir,time window size selection,two-phase color-coded display,and cycle matching fusion are the 4key points of this method.It meets seismic structure integrity required by planar depositional body and seismic attribute lateral changes required by linear depositional body.Our case study shows that the attribute distribution obtained by the proposed method can describe planar depositional body structural characteristics such as delta inner front,outer front,and shallow lake facies,and highlight linear depositional bodies such as channels and mouth bars.So the target sequence order is more complete,the sequence development of different levels is reasonable,and development characteristics of target depositional systems are fully depicted.