蚂蚁追踪与分频融合技术在低序级断层解释中的应用--以中台山须家河组致密砂岩气藏为例

An integrating technology of ant tracking and frequency division and its application to interpretation on low-order fault:Examples from Xujiahe tight sandstone gas reservoirs,Zhongtaishan area,Sichuan Basin

四川盆地上三叠统须家河组致密气藏烃源富集、河道砂岩储层发育且稳定分布,断裂发育是钻井获得高产的主控因素之一。中台山地区地表地腹构造相对平缓,小断层发育,断、储配置模式复杂,相干、曲率等常规断层解释技术存在解释精度不高、细节不足等问题,可能会导致井位钻探失利。采用蚂蚁自动追踪算法增强小断层或大尺度裂缝地震响应特征,进一步利用分频混色属性突出各单频体上断裂特征再进行多尺度融合,能够降低单一属性的多解性,该技术在中台山地区须家河组低序级断层地震解释中具有较好的应用效果,与相干、曲率相比较,反映的断裂细节更丰富,断裂空间分布及平面组合形态更清晰,提高了断裂地震刻画精度。新解释通源断裂3条,部署井位目标2口,证实断裂地震检测可靠度高,测试均获得高产工业气流,无阻流量最高410×10^(4)m^(3),对后续井位目标优选和精细开发具有重要的支撑作用。

There are rich source rocks in tight gas reservoirs of Upper Triassic Xujiahe Formation,Sichuan Basin,which are featured by stable distribution of channel sandstone reservoirs.Moreover,drilling practices show the developed fault as one of the main factors affecting high yield.In Zhongtaishan area,due to relatively flat surface and hinterland structures,developed small faults,and a complex fault-reservoirs configuration mode,it is hard to get accurate and fine interpretation on these small faults while using conventional coherence and curvature methods,bringing about failure in drilling.So,an automatic ant-tracking algorithm was applied to enhancing seismic response to small faults or large fractures,and frequency division of mixing attributes was used to highlight certain fracture characteristics at single frequency band.And then,to integrate ant tracking and frequency division might reduce multiple solutions induced by single attribute.Applied to Xujiahe Formation,Zhongtaishan area,this integrating technology may provide better seismic interpretation on the low-order faults than coherence and curvature methods.For these faults,the interpreted structural detail is more abundant and the spatial distribution and plane polygon is clearer,and the description accuracy is improved.Both newly interpreted 3 source-connecting faults and 2 deployed wells by this technology also illustrate highly reliable seismic interpretation.As a result,the open gas flow was even up to 410×10^(4)m^(3),showing the importance for future well location and fine development.