Abstract: Fractured leakage and cavern leakage occurred during the second spud of Xiangye-1 Well.To improve the pressure-bearing capacity of the thief zone and ensure the cementing quality,expandable low-density slurry plugging technique was adopted to plug or seal the thief zone.Due to long section of loss with multiple leaking points,expandable low-density plugging slurries with different performances were prepared for different lost circulation types.The plugging operation was conducted three times to raise bearing capacity of the formation higher than 1 MPa,thereafter no lost circulation occurred during drilling,running casing and cementing.The application shows that expandable low-density plugging slurry features such advantages as good flowing performance and high pressure sealing capacity.This type of slurry is easy to be prepared and adjusted with no demand for special equipment,and it has such advantages as advanced and safe operation technique,high safety factor and excellent pressure sealing effect,so it provides new technological supports for plugging and sealing the Carboniferous formation of Xiangzhong Depression.