The application of density baseline differences correction- Taking the pre-stack inversion in the PL9-1 oilfield as an example

The buried hill of the PL9?1 oilfield is a Mesozoic granite buried hill,which is characterized by shallow buried depth,strong weathering degree and great lateral variation of fractured reservoirs.On the basis of fine rock physical analysis,the density can better recognize the fractured reservoirs in the buried hill of this oilfield.Nevertheless,in this buried hill,the density baselines between wells show differences,which leads to different density measurements in describing the reservoirs. This is a challenge to predicting fractured reservoirs between wells.This study successfully solved the problem of density baseline differences between wells by using the method of density baseline differential correction,combined with verifying the feasibility of pre?stack inversion by the forward model analysis of AVO.The corrected density volume was achieved by pre?stack inversion.Furthermore,taking advantage of the good relationship between the corrected density and total porosity of the fractured reservoirs,the authors used the corrected density volume to describe the distribu?tion of fractured reservoirs in the buried hill and further reflect the development degree of fractured reservoir porosity horizontally. The result was proved by actual drilled wells. The successful application of this technology will provide important reference for the similar fractured reservoir studies of buried hill in future.