复杂水动力环境下的相控迭代反演技术

FACIES-CONTROLLED ITERATIVE INVERSION TECHNIQUE AND ITS APPLICATION IN COMPLEX HYDRODYNAMIC ENVIRONMENT

西湖凹陷花港组水动力环境复杂,沉积过程中伴生有多种砂体发育模式。巨厚的大型辫状河叠置砂体与较薄的三角洲水下分流河道砂体在纵、横向上共生,导致储层横向展布和纵向厚度变化剧烈,而埋藏深度大导致地震资料信噪比低、频带窄,降低了常规储层预测的纵、横向分辨能力。提出了基于相控约束体的相控分频迭代反演方法,利用沉积和岩性信息构建模型进行正、反演研究,重构对岩性敏感的地震属性信息,建立相控约束体并实现空间上的相控建模,提高了低频模型的横向合理性。在此基础上,通过分频迭代反演保护低频信息,在低信噪比、窄频带地震数据和稀疏钻井条件下,提高了中深层复杂水动力环境下多沉积类型砂体边界识别及厚度刻画的精度。

The Huagang Formation in the Xihu Sag is complex in terms of its hydrodynamic environment.There are several types of sand bodies.Thick massive braided river sand bodies prevail in the north part,and the thin deltaic submarine distributary channel sand bodies in the middle part,that resulted in the dramatic changes of reservoirs in both vertical and lateral dimensions.At the same time,seismic SNR turns lower and frequency band becomes narrower due to deeper buried depth that reduces the horizontal and longitudinal precision of normal reservoir prediction.In this paper,the faciescontrolled frequency-divided iterative inversion method is proposed based on the facts of facies-control and constrain.Forward and inversion studies are carried out for the sedimentation and lithological information so as to rebuild the litholgic sensitive attributes and improve the horizontal pattern of the low frequency model.Based on the above,facies-controlled iterative inversion in complex hydrodynamics environment is formed,that may improve the precision of the boundaries and thicknesses of multiple sand bodies of different origin,based on less wells and seismic data with low SNR and narrow frequency band.