Reservoir Sand Body Prediction Of Putaohua Reservoir In Zhao9 Block Of Xujiaweizi Syncline

The Putaohua oil layer in Xujiaweizi Oilfield is developed in a delta front sedimentary environment.The overall development characteristics of the reservoir sand body are thin single layer thickness,poor continuity,and scattered distribution.Therefore,how to effectively identify and accurately predict the type of reservoir sand body and clarify the distribution pattern of reservoir sand body has become a key issue for further exploration and development of the oilfield.Therefore,this paper takes Putaohua oil layer in Zhao9 block of Xujiaweizi oilfield as the research target,comprehensively uses seismic,drilling,logging and other related data,combines sedimentary stratigraphy,geology,seismic sedimentology and other theories,and through well seismic joint interpretation,seismic attribute analysis,seismic inversion and other reservoir fine prediction methods,deeply carries out the research on the distribution of sand bodies in Putaohua oil layer in Zhao9 block.The results indicate that:（1）Based on the method of well seismic joint,the maximum amplitude attribute is selected from the extracted seismic attributes.（2）Qualitative prediction based on single seismic attribute and multi attribute fusion attribute shows that the northwest sand body is well developed,while the southeast is poorly developed,with a distribution pattern of mostly mudstone.（3）Quantitative prediction of sand bodies was carried out through seismic statistical inversion,and the accuracy of the inversion prediction for sandstone thickness was 75.8%.By analyzing the sandstone thickness histogram,it was found that the sand body thickness of each sedimentary unit is mainly distributed between 0m-2m,with a maximum thickness of 3.8m.（4）Based on the vertical analysis of resistivity inversion profile,the content of sand bodies in the upper part of PI is relatively low,while the content of mudstone is relatively high,and the connectivity is poor;The sandstone content in the middle of PI is relatively high and thick,with well-developed sand bodies.The sandstone on both sides is relatively thin and has good connectivity;The development of some sand bodies under PI is poor,and the sand bodies exhibit intermittent characteristics with poor continuity.However,the bottom layer of sand bodies is not developed,and they are all mudstone.Overall,they exhibit the distribution characteristics of mudstone sandstone mudstone.（5）From the analysis of the inversion sandstone thickness prediction map,it can be concluded that the sand bodies of PI1₁,PI1₂,PI2₁,PI7,PI8,and PI9 sedimentary units are almost undeveloped,with a pattern of mostly mudstone.However,the sand bodies of PI2₂,PI3,PI4₁,PI4₂,PI5₁,PI5₂,and PI6 sedimentary units are well developed,showing a distribution pattern of good development of sand bodies in the northwest and southeast,and poor development of sand bodies in the southwest and northeast.The overall performance is characterized by thicker sand bodies in the north and thinner sand bodies in the south,with a wide distribution of sand bodies;Based on the sandstone thickness map of sedimentary units PI9 to PI1₁,it can be seen that the distribution pattern of sand bodies from lower to upper Portugal is from thin to thick and then to thin.The achievements and understanding achieved in this research have important guiding significance for the exploration and development of oil fields.