川北阆中地区茅口组生屑滩识别

川北阆中地区茅口组生屑滩厚度小、多期叠置、内部地震反射结构复杂多变，常规地震解释及预测方法难以适用于生屑滩识别及内部结构精细刻画。为此，以单井相序组合为基础，结合钻井资料和地震资料精细标定、划分生屑滩发育期次，确定不同期次生屑滩地震反射特征，并通过正演模拟分析生屑滩内部反射特征的主要影响因素；然后利用层序地层全局自动扫描解释技术精细刻画生屑滩内部反射结构；最后筛选能表征生屑滩分布特征的地震属性，结合地震相确定生屑滩发育区，并根据等时地层切片属性分析不同期次生屑滩沉积演化过程，直观展示多期生屑滩空间展布特征。研究结果表明：茅口组主要发育三期生屑滩，总体表现为“叠置、斜交、杂乱、弱振幅”反射特征，平面上呈NW-SE向展布，纵向上由研究区北东向南西方向披覆加积沉积，白云岩储层主要发育在第Ⅲ期生屑滩内部。该结果与实钻相吻合，可为下一步油气勘探提供参考。

Identification of bioclastic beach,Maokou Formation of Langzhong area,northern Sichuan Basin

Due to multi-stage superposition, small thickness, and complex and varied seismic reflection structures of bioclastic beaches in Maokou Formation of Langzhong area, northern Sichuan Basin, conventional seismic interpretation and prediction methods are not suitable for the identification of bioclastic beaches and the fine characterization of their internal structures. Therefore, with the facies-sequence combination of a single well as the basis, drilling and seismic data are combined to finely calibrate and divide the development stages of bioclastic beaches and determine the seismic reflection characteristics of bioclastic beaches at different stages. The main factors affecting the internal reflection characteristics of bioclastic beaches are analyzed by forward modeling. The global automatic scanning interpretation technique based on sequence stratigraphy is used to accurately depict the internal reflection structure of bioclastic beaches. The seismic attributes that can characterize the distribution characteristics of the bioclastic beaches are selected and combined with the seismic facies to determine the development zone of bioclastic beaches. The sedimentary evolution of clastic beaches at different stages is analyzed in combination with isochronous stratigraphic slicing properties, and the spatial distribution of multi-stage bioclastic beaches is intuitively displayed. The results show that three stages of bioclastic beaches are mainly deve-loped, manifested with "superposed, oblique, cluttered, and weak-amplitude" reflection characteristics. Horizontally, they are distributed in the NW-SE direction;vertically, they are deposited by coating and aggradation from the northeast to the southwest direction in the study area. Dolomite reservoirs are mainly developed in the stage-Ⅲ bioclastic beach. The above results are consistent with the actual drilling results and can provide a basis for future oil and gas exploration.