The Temporary Sealing Formula for Fractured-Vuggy Carbonate Reservoir

Temporary sealing is a new technical trend in loss control in fractured-vuggy reservoir,which has the characteristics of widely ranged particle sizes,fast bridging of solid particle,compact seal,bi-directional bearing pressure and so on.Fractured-vuggy core was made through choosing excellent temporary sealing materials for fracture width of 150 μm.Three factors and three levels of orthogonal experiments including bridging particle size,bridging particle quantities,and deformed particle quantities were performed.The results showed that the compound with particles and the fractured width of 1∶1,bridging particle concentration of 2%,and deformed particle concentration of 1.5% are the optimal testing index.Dynamic damage evaluation test and acid-solution cake removal test were carried out using two kinds of fractured-vuggy cores with fracture width of 150 μm,one end fracture and the other end vugs.The test shows that the optimized formulation can all formed cakes in 3 minutes with temporary plugging rate of 99.999 9%,the pressure-resistance no less than 12 MPa,natural flowback recovery rate over 65%,acid cleanup recovery rate over 85%,the temporary sealing is realized.