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

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 facies-controlled 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.