摘要
初始模型构建和反演算法是影响反演可靠性与精度的两个关键因素。针对勘探程度低、钻井少且井距大带来的低频模型构建不合理、储层与围岩反射系数差异小所造成的反演预测精度低的问题,建立了基于目标最优双向建模的柯西约束反演方法。该方法基于地震反演预测目标,在利用岩相统计分析敏感地震属性的基础上将岩石物理垂向低频趋势与敏感地震属性的横向变化相结合,提高低频模型指示砂体横向边界的能力,实现了更加符合区域地质认识的目标最优双向初始模型构建;结合目标最优双向初始模型,采用三参数柯西先验分布对反演参数进行正则化约束,利用柯西分布长尾巴特征保护弱反射信息,提高薄层反演的垂向预测精度。XH凹陷A区块中深层勘探的实际资料应用结果表明,基于目标最优双向建模的柯西约束反演结果与研究区潮坪、三角洲的沉积环境特征吻合,并通过提高储层预测的纵、横向分辨能力有效指导了A区块的勘探实践。
The initial model construction and the inversion algorithm are two key factors that affect the reliability and accuracy of inversion.Due to less drilling and large well spacing in the middle and deep layers of low exploration areas,the construction of low-frequency models in these areas is unreasonable.Additionally,the difference in reflection coefficient between reservoirs and surrounding rock is small,resulting in low inversion prediction accuracy.Thus,a Cauchy constrained inversion method based on target optimal bidirectional modeling was established.Based on the target of seismic inversion prediction,the sensitive seismic attributes were analyzed through lithofacies analysis.The vertical low-frequency trend of rock physics combined with the transverse variation of sensitive seismic attributes improve the ability of low-frequency models to identify the transverse boundary of sand bodies,and enable the construction of a target optimal two-way initial model that is more in line with the regional geology.Combined with objective-optimal bidirectional modeling,the three-parameter Cauchy distribution is used to regularize the inversion parameters,and the long tail feature of Cauchy distribution is used to protect the weak reflection information to improve the vertical prediction accuracy of thin layer inversion.The practical application in an area of XH sag shows that the inversion results based on the technique are consistent with the sedimentary environment characteristics of tidal flats and deltas in the study area.Thus,these results effectively guide the exploration practice by improving the vertical and lateral resolution of reservoir prediction.
作者
姜勇
俞伟哲
刘庆文
胡伟
JIANG Yong;YU Weizhe;LIU Qingwen;HU Wei(CNOOC(China)Co.,Ltd.,Shanghai Branch,Shanghai 200335,China)
出处
《石油物探》
CSCD
北大核心
2023年第1期142-153,共12页
Geophysical Prospecting For Petroleum
基金
国家科技重大专项课题(2016ZX05027-002)资助。
关键词
目标最优双向建模
三参数柯西分布
弱反射系数
正则化约束
薄层反演
objective-optimal bidirectional modeling
three-parameter Cauchy distribution
weak reflection coefficient
regularization constraint
thin layer inversion
