Research on formation mechanism of long-term water flooding high-permeability channel in loosely packed sandstone reservoirs
The high-permeability channel development is a prominent feature in the loosely packed sandstone reservoirs of A oilfield due to long-term water flooding.The size and structure of pore throat influence the selection of plugging agents,thus understanding the characteristics of channel development is of great significance for water control and oil stabi-lization in the oilfield.In this study,long-term water flooding experiments were conducted using natural sandstone cores provided by A oilfield,aiming to investigate the changes in reservoir properties and microstructure of pore throats under the long-term action of fluid shear stress.The results indicate that during the long-term water flooding process,clay min-erals are prone to migration,leading to the gradual disappearance of smaller pore throats and further enlargement of larger pore throats.The pore throat ratio decreases and the reservoir wettability tends to become water-wet,resulting in enhanced microscopic heterogeneity of the reservoir and changes in reservoir properties.Eventually,the inefficient circulation of injected water becomes increasingly severe,forming high-permeability channels.
high-permeability channelsreservoir propertiesclay mineralssize distribu-tionmicrostructure of pore throats
万方数据
维普
