【摘要】 珠江口盆地白云凹陷深水区A气田ZJ210气层为珠江组SB21层序界面之上的深水浊积水道化朵叶体砂岩,储层物性好。砂岩含气后表现为明显的亮点特征和第3类AVO异常。位于A气田北断层下降盘的E构造的ZJ210层由于没有亮点显示,一直被认为不含气。经过岩石物理分析认为,当砂岩储层埋深(从海底算起)超过2000m时,应用纵波阻抗无法识别储层及含气性,进而提出利用密度识别储层、λρ属性及第2类AVO异常识别含气性的新观点,并明确λρ小于25GPa·g/cm3为该区含气砂岩识别的量板值。针对深水区钻井少,建模低频缺失的特点,还利用地震速度体与井数据联合建立反演初始模型的新方法有效解决了初始模型低频缺失的问题,并通过叠前反演、AVO综合分析,预测E构造ZJ210层有较高含气性,且得到钻探证实。更多还原

【Abstract】 Being high porous lobe body sandstone overlying SB21,the Member ZJ210 of Zhujiang Formation in deep water areas,Gasfield Baiyun shows bright spots and third AVO anomaly on seismic sections.But Member ZJ210 of Structure E in the same area is not considered as gas bearing sand as it does not shows bright spots on seismic sections.Based on series of rock physics analysis,we believe that the density,λρand the second AVO anomaly can be used to identify gas-bearing sand reservoir when sand reservoir burial depth is greater than2000 meters,while acoustic impedance cannot.Whenλρis less than 25G Pa·g/cm3,sand reservoir can be interpreted as gas bearing sand.Initial model for inversion is built on both seismic velocity volume and well data to solve lack of low frequency data.We have predicted Member ZJ210 of Structure E as gas-bearing sand reservoir based on prestack inversion and AVO comprehensive analysis.Later drilling result proves our prediction.更多还原