川东北毛坝场构造飞仙关组三段裂缝预测

Fracture prediction in Maobachang structure in northeastern Sichuan Basin

对川东北毛坝地区的钻井资料进行研究发现,该区飞仙关组三段含气裂缝储层横向上呈不均匀分布,井位设计论证困难较大。通过对该区三维地震资料进行研究,得知该区断层发育,并对飞仙关组三段的裂缝发育有较大影响。飞三段岩性组合也使其容易产生裂缝。对此,首先利用井资料进行岩石物理正演模型研究,得到了飞仙关组三段裂缝含气储层的AVO响应特征;其次基于地震波在地下介质中传播所表现的各向异性,从叠前地震属性随方位角变化关系分析入手,表征和描述了研究区飞仙关组三段裂缝储层的分布特征,以此预测飞仙关组三段裂缝型储层发育情况。裂缝储层预测结果与钻井结果对应较好。

The well-drilling data from Maoba area in northeastern Sichuan Basin reveal that the gas-bearing fractured reservoirs in the third member of Feixianguan Formation are horizontally irregularly distributed,which leads to great difficulty in deployment of wells.3-D seismic data also imply that either the development of faults or the lithologic association has great influences on the development of fractures in the third member of Feixianguan Formation.A fracture predication method has been proposed.Firstly,the AVO responses of the reservoirs are obtained from rock physical modeling using well data.Secondly,the fractured reservoirs in the third member of Feixianguan Formation are characterized based on the analysis of the anisotropy of seismic waves and the variations of prestack seismic attributes with azimuths.The predicted result matches well with the drilling data.