Abstract
The heterogeneity of reservoirs in offshore oilfields, which causes low utilization of low-permeability reservoirs and poor exploitation of crude oil, is usually serious. Till date, fuzzy-ball fluids have been used to improve oil recovery of terrestrial heterogeneous reservoirs, but it is still uncertain whether it could enhance the recovery of offshore oilfields, because of high cost and special operating environment in offshore oilfields. To this end, laboratory core flooding experiments and field tests were conducted. The results of the feasibility analysis show that: (1) Fuzzy-ball fluid has good injection and plugging performance, which means fuzzy-ball fluid has great potential to be applied in enhancing recovery. (2) Fuzzy-ball fluid can greatly improve oil recovery, especially the recovery of low-permeability cores. Compared with polymer, surfactant and microsphere, fuzzy-ball fluid led to 30% higher recovery of low-permeability cores. (3) The application of fuzzy-ball fluid in enhancing recovery has good economic feasibility. The input-output ratio of fuzzy-ball fluid is 1:4.3. It is concluded that the use of fuzzy-ball fluid in the heterogeneous sandstone reservoirs for enhanced oil recovery is feasible.
