Many reservoirs contain low permeability areas where water injectivity is limited. TIORCO utilized technology developed by the Bureau of Mines in the 1960’s to increase the imbibition of water into tighter formations. TIORCO® 535 is a TIORCO proprietary product that promotes imbibition to injected fluids into oil-bearing pore spaces by reducing the contact angle of water. Oil is swept to producers that otherwise would not be produced with straight water injection. TIORCO® 535 also has a water treating benefit of preventing scale precipitation and sequestering iron.

The TIORCO® 535 process can follow sweep improvement technologies or TIOR-KOH treatments in low permeability, clay-filled reservoirs. The first use of TIORCO® 535 was in 1970.

Water injectivity can also be increased in low permeability reservoirs through injection of alkaline agents, surfactants or both. The laboratory screening and design is similar to that done for an ASP process. By reducing residual oil in the near wellbore of an injection well, relative permeability of water is increased which gives more water injection at lower injection pressures.