摘要:
针对四川盆地兴隆气田长兴组隐蔽海相生物礁气藏空间形态及有利储层预测难的问题,首先建立生物礁体地震正演模型,揭示生物礁体独特的"外形上凸、内部波形杂乱、反射波组增多、频率降低"地震响应模式,指导优选地震几何形态类、波组统计类、频率类属性开展分析,并通过多属性聚类融合刻画生物礁相储层边界形态;然后应用中子拟声波约束模型迭代反演方法预测储层厚度;进一步开展纵波速度与孔隙度交会分析,应用非线性方程转换速度反演成果预测储层孔隙度;最终通过计算储能系数,探寻储层厚度与孔隙度最优匹配特征,定量预测礁相有利储层分布特征.该预测方法揭示了生物礁储层空间展布特征,提高了预测精度,对礁相储层预测研究具有一定的借鉴意义.
Abstract:
In order to solve the difficult problem of reservoir spatial form and favorable prediction of subtle marine reef reservoir in the Changxing Formation of the Xinglong gas field in Sichuan basin,the authors first built the reef seismic forward modeling to reveal the unique seismic response pattern as "up-convex shape,internal event messiness,reflective events increase and frequency decrease".On the basis of the reservoir seismic characteristics,optimization analysis is processed for the multiple seismic attributes, including geometric shape class,wave group statistics class and frequency class.The boundary shape characterization of reef reservoir is studied by multiple attribute clustering.Secondly,neutron pseudo-acoustic curve is selected to constrain model-based iteration inversion method to predict reservoir thickness.The nonlinear equation method is adopted to convert velocity inverse result to porosity of the reservoir.Finally,the storage factor is obtained to explore the optimal matching of reservoir thickness and porosity characteristics.And the reef reservoir spatial distribution features are quantitatively predicted.This prediction method reveals spatial distribution characteristics of reef reservoir,improves prediction accuracy, and provides certain references for reef reservoir prediction research.
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