Drill-In Fluid (DIF) Filter Cake Removal Process
The N-FLOW Systems are designed to clean up drill-in fluid (DIF) filter cake residue and near-wellbore formation damage in open-hole completions. Filter cake removal eliminates a major cause of restricted flow from the producing formation in sandstone and carbonate reservoirs. Draw down in high permeability formations may promote acceptable filter cake removal, but in horizontal wells where draw down is less, DIF filter cake clean up is more difficult to achieve.
There are N-FLOW formulations for water-based and synthetic oil-based DIFs. The controlled-reaction N-FLOW chemicals dissolve DIF filter cake components along the entire pay section and do not leave any hot spots. Unlike cleanup materials containing hydrochloric acid and corrosion inhibitors, the non-acidic nature of the system lowers the safety risk to personnel and the environment, and avoids corroding downhole hardware, including screens, packers and tubulars.
The cost-efficiency of the service perhaps is the most striking feature. Because the rate of DIF filter cake removal can be time delayed, the chemicals can be mixed with the carrier fluid in a gravel pack operation. This built-in compatibility eliminates a separate trip with the completion string for each operation.
After placing the N-FLOW filter cake breaker systems downhole, the well needs to be shut-in to allow the controlled-reaction chemicals time to attack the filter cake residue and near-wellbore damage. The shut-in period depends on the formulation, pay zone temperature and type of treatment selected.