基于部分叠加角道集属性的含油薄层砂体预测

Sandstone prediction of the oil-bearing thin-layers based on seismic attributes from partial stack angle gathers

针对在调谐背景下直接利用叠后属性识别预测薄层砂体多解性强的问题,研究并提出了塔中北坡S1井区目标储层基于部分叠加角道集属性的含油薄层砂体预测方法。首先,以现有井资料为基础,开展薄层地震反射波随入射角变化规律的正演分析,认为研究区含油薄层反射的视AVA效应是敏感且可检测的;其次,在对原始CRP道集资料提高储层成像精度预处理的基础上,利用部分道集叠加的方式进一步增强薄层反射视AVA效应的规律性;然后,结合正演模拟取得的认识和实钻井目的层油气显示结果,进行基于部分叠加角道集数据的属性随入射角变化规律分析,认为在调谐背景下目的层最大波峰振幅和最大波峰主频属性是检测薄层砂体含流体性质的敏感地震属性,据此提出了相应的油气检测因子,预测了研究区目的层含油薄层砂岩有利分布区。

In the target reservoirs of S1 well area at the north slope of Tazhong Uplift,the tuning effect will cause multi-solution in the thin-layer sandstone prediction.Therefore,we studied and proposed an oil-bearing thin-layer sandstone prediction method based on seismic attributes from partial stack angle gathers.Firstly,the seismic reflection variation versus incident angle is studied by forward modeling,which indicates that the apparent AVA effect of the reflection from the oil-bearing thin-layers is sensitive and detectable.Secondly,on the basis of preprocessing on the CRP gathers for improving the reservoir imaging precision,partial stack angle gathers are used to enhance the regularity for apparent AVA effect of the reflection from the oil-bearing thin-layers.Thirdly,the achievements from forward modeling and the drilling results are jointed to analyze the variation of seismic attributes versus accident angle for the intervals based on partial stack angle gathers,which demonstrates that the maximum peak amplitude and maximum peak dominant frequency are sensitive to the fluid properties.Based on the recognition,we proposed corresponding hydrocarbon detection factor,which is used to successfully predict the potential zone for oil-bearing sandstone in the area.