塔里木盆地牙哈断裂构造带寒武系白云岩潜山储层预测

塔里木盆地牙哈断裂构造带寒武系潜山地层剥蚀严重,由上寒武统、中寒武统和下寒武统白云岩组成。寒武系潜山储层主要分布在潜山风化壳,厚度不超过100 m,总体上属于裂缝-孔洞型复合型储层,储层孔缝洞级别较小,地震响应特征不明显,储层横向非均质性较强,基于模型的储层反演结果不能真实反映潜山储层横向展布规律,利用保幅的三维地震纯波数据进行地震属性储层预测结果较为可信。通过属性相关性分析,选取了均方根振幅、反射强度斜率和弧长3种属性进行聚类分析,分析结果表明寒武系潜山白云岩储层主要发育在构造高部位和北部斜坡区,呈星点状而非片状分布,与钻井结果相吻合。

Prediction of dolomite reservoirs for the Cambrian buried hills in the Yaha fault structural belt,the Tarim Basin

Severely eroded Cambrian buried hill in the Yaha fault structural belt of Tarim Basin consists of the Upper,the Middle,and the Lower Cambrian dolomites.The Cambrian buried hill reservoirs are mainly distributed in the weathering crust and have a thickness of less than 100 m.They as a whole belong to fractured-vuggy reservoirs,with the characteristics of relatively small pores,fractures and vuggies,undistinguished seismic responses and strong lateral heterogeneity.The results of model-based reservoir inversion can not reveal the real lateral distribution of buried hill reservoirs,but that of seismic attribute-based reservoir prediction with amplitude-preserved 3D seismic pure wave data are more reliable.According to the analysis of seismic attribute coherence,RMS amplitude,reflection strength slope and arc length attributes were selected to perform a multi-seismic cluster analysis.The results show that the dolomite reservoirs in the Cambrian buried hills mainly occur in the structural high and nor-thern slope area and are in patchy distribution.These predictions are consistent with the drilling results.