Nanosilica Based Fluid System for Water Shut-Off

Excessive water production from hydrocarbon-producing wells can adversely affect the economic life of the well. It was estimated that an average 3.0 barrels of water is produced for each barrel of oil worldwide. Unwanted water production can unfavorably affect well economics owing to handling of the produced water, reduction of hydrocarbon production, and environmental concerns. Naturally, fluids tend to follow in paths of least resistance which, are often created by the heterogeneous nature of the rock. The use of nanosilica based fluid system was developed for water shut-off application. Two sets of experiments were conducted to examine nanosilica treatment process and its ability to withstand an elevated temperature. A core flooding tests were conducted to evaluate the efficiency of this chemical system using super-K, fractured and wormholed cores plugs. An analytical study, (ESEM) and X-Ray techniques were applied to characterize untreated and chemically treated core plugs. The core flow testes indicate significant drops in water production for all core plugs including: High permeability, fractured and wormholed formation. When chemical treatments were placed, the Nanosilica system was able to withstand the differential pressures at 300°F and did not allow the flow of water in wormholed core, high permeability core and fractured core. The ESEM results showed the presence of SiO-rich compounds filling the secondary porosity. This suggests that the chemical treatment of the core plugs is resulted in some of the used nanosilica product is blocking fractures and pores. Nanosilica system expected to control water production through high permeability streaks and large pore openings. This system can be injected in porous media without plugging tendency due to their low viscosity. Nanosilica can enter deeper inside formation matrix before it gelled up. This work provides significant insight using nanosilica as an alternative chemical treatments intended for use in large openings.