西湖凹陷平湖斜坡带平湖组煤系地层储层逐级预测OA

To identify hydrocarbon-bearing sandstones under the influence of thin coal seams,by integrating loc-al drilling and seismic data,we performed a progressive reservoir prediction workflow from our geological under-standing.The workflow included the identification of sand-rich zones → delineation of composite sandbodies →characterization of individual sand bodies.First,based on the slope-trough composite structural background of the study area,a slope-break controlled sand deposition model was established.Taking the advantages of structural seismic attributes such as gradient tensor,dip,and curvature,fine identification of flexural slope breaks was car-ried out.The overlap of slope-break zones and low-potential geomorphic areas indicated favorable sand-rich zones.Secondly,in the sand-rich zones,pre-stack seismic data with reduced coal influence were obtained through a method involving"seismic-scale coal-seam identification,filtering,and coal removal".Pre-stack inversion based on processed data effectively eliminated coal-induced artifacts in the inversion results,achieving accurate delineation of composite sandbodies.Finally,constrained by the composite sandbodies,the advantages of multi-attribute well and seismic data were utilized to delineate the boundaries of individual sandbodies from composite ones.The research strategy of"Inversion for sand identification,instantaneous attributes(frequency,phase,amp-litude)for boundary definition"was proposed,enabling detailed characterization of individual sandbodies.This method could effectively address the challenges of poor reliability and low resolution in reservoir prediction in coal-bearing strata of the Xihu Sag,and improved the prediction accuracy by 23%,showing importance for the progressive exploration and potential tapping of structural-lithological reservoirs in the study area.