Application of spectral decomposition in deep tight conglomerate reservoir prediction
Song Xiaowen1, Ma Shizhong1, Qin Qiuhan1, Shu Ping2, Wen Huijian1, Zhai Shengnan2, Wang Tao2
1. College of Geosciences,Northeast Petroleum University,Daqing,Heilongjiang 163318,China;
2. Exploration and Development Research Institute,Daqing Oilfield Co.Ltd.,Daqing,Heilongjiang 163712,China
Abstract：Gas reservoirs from the Member 4 of Yingcheng Formation in Xujiaweizi Depression were developed in early Cretaceous lacustrine rift basin and they are characterized by low porosity and low permeability,high thickness variation and high heterogeneity.Therefore they post a challenge on exploration and exploitation.In the study area,the Member 4 of Yingcheng Formation was penetrated by 96 boreholes,and DST was conducted in 21 wells.Analysis of seismic data shows the attenuation of frequency spectrum for the gas bearing conglomerate reservoir in the Member 4 of Yingcheng Formation.With spectral decomposition,gas saturation in the tight conglomerate reservoir in the Member 4 of Yingcheng Formation has been tested.Furthermore a classification is made based on different characteristics in spectral attenuation,and a positive correlation is found between spectral attenuation angle and gas production.This method has been applied to the Member 4 of Yingcheng Formation in the places where no well data is available,and the predicted distribution of favorable reservoir zone coincides with other geological evidences observed,e.g.high gas production rate agrees with high secondary dissolution high-porosity zones.
