柴达木盆地红柳泉地区致密油储层地震预测方法

柴达木盆地红柳泉地区下干柴沟组下段顶部I层组泥灰岩发育,具有较强的非均质性,孔隙度为5 %~12 %,渗透率为0.05~1.0 mD,属于低孔、特低渗储层,其分布具有单层厚度薄、层数多、纵向相互叠置、横向范围广的特征,常规地震属性分析或反演由于分辨率较低,难以精确地预测其有利储层分布。为此,针对这种薄层致密碳酸盐岩储层,通过工区实际井资料的地震正演模拟分析,明确了致密储层地震响应特征,进而探索性地将地震分频成像、90°相位转换、分频属性优化等技术有效结合,较好地预测了泥灰岩分布范围及有利储层发育区,且与实钻井吻合度较高,有效地指导了该区致密油的勘探工作,对整个柴西地区致密油储层预测具有借鉴意义。

Seismic prediction method for tight oil reservoir in Hongliuquan area of Qaidam Basin

Well developed in I-set at the top of the lower member of Xiaganchaigou Formation in Hongliuquan area, Qaidam Basin, the tight marl reservoir has strong heterogeneity, with low porosity of 5 % -12 % and extra-low permeability of 0.05-1.0 mD. Its distribution has the characteristics of thin single layer, multi-layer, longitudinal overlap and wide horizontal range. Because of low resolution, it is difficult to accurately predict the distribution of favorable reservoirs using conventional seismic attribute analysis or inversion. Thus, as to the thin layer of tight carbonate reservoir, its seismic response characteristics can be identified through analysis of the actual well in work area using seismic forward modeling method. Further, it is exploratory to adopt the effective technical combination of seismic frequency-divided imaging, 90° phase rotation and frequency division attribute optimization, which can better predict the distribution of micrite and favorable reservoir development zone. Moreover, the results are highly consistent with the actual drilling data, thus effectively guiding the tight oil exploration in this area and also providing a reference for prediction of tight oil reservoirs in the entire western Qaidam Basin.