分频高阶扩展AVO技术在低孔低渗储层中的应用——以准噶尔盆地前哨地区三工河组二段为例

Application of frequency division high-order extended AVO technology in low porosity and low permeability reservoirs:a case study from the second member of Sangonghe Formation in the Qianshao Area,Junggar Basin

以叠前角道集、测井和试油资料为基础,利用广义S变换时频分析技术确定储层优势频带,在优势频带的约束下,利用高阶Aki-Richards近似方程拟合AVO曲线,求取更准确的截距和梯度;利用扩展弹性阻抗技术的坐标旋转方法,获得流体区分能力最优的AVO属性,结合试油结果进行有利区预测。结果表明:前哨地区三工河组二段储层的优势频段为33~68 Hz,进行AVO分析可以提高有利储层的预测精度。经分频高阶扩展AVO技术处理,有利储层的符合率由69%提高到94%。气层有利区主要集中于QS2—QS4、QS7井区及未钻探的QS1井西区域,其中未钻探面积为6.5 km^(2),是前哨地区天然气增储上产的重点潜力区。该结果为前哨地区天然气勘探部署提供技术支持。

Based on prestack gather,logging and oil testing data,the dominant frequency band of the reservoir was determined by using generalized S-transform time-frequency analysis technology.Under the constraint of the dominant frequency band,higher order Aki-Richards approximate equation was used to fit the AVO curve to obtain more accurate intercept and gradient.The AVO attribute with the best fluid discrimination ability was obtained by expanding the coordinate rotation technology of extended elastic impedance,and the favorable area was predicted by combining the oil testing results.The results showed that the dominant frequency band of the second member of Sangonghe Formation was 3368 Hz,and AVO analysis within the dominant frequency band was helpful to improve the prediction accuracy of favorable reservoirs in the Qianshao Area.After processing by frequency division high-order extended AVO technology,the verification coincidence rate of favorable reservoir was increased from 69%to 94%.The favorable areas of gas reservoirs in the Qianshao Area were mainly concentrated in the QS2 QS4,QS7 well areas and the area to the west of the undrilled QS1 well,of which the undrilled area was 6.5 km^(2),which was the key potential area for the increase of natural gas reserves and production in the Qianshao Area.The research result provided technical support for natural gas exploration and deployment in Qianshao Area.