Although waterflooding has significantly improved recovery efficiencies in many reservoirs worldwide, there are several important issues for additional consideration.

First, the average ultimate oil recovery by primary production and a subsequent waterflood is only 33% of oil originally in place (OOIP). In many solution gas drive reservoirs and/or fields with viscous oil, water flood efficiency is significantly less than 33%.

Second, water injection alone can be very inefficient in many situations. For example, heterogeneous reservoirs significantly decrease waterflood efficiency. Advances in technology have convinced us that most reservoirs are in fact much more heterogeneous than previously believed.

Third, even very efficient waterfloods require many years to reach maximum economic recovery. If the present value of money is considered, long-life waterfloods become less attractive. For example, at a 10% discount rate, $1.00 received five years from now is worth about $0.62 and $1.00 received ten years from now is worth only about $0.38. Clearly accelerating oil revenues can have a tremendous impact on the value of a property.

Finally, waterfloods tend to produce oil at high water oil ratios (WORs). In today’s price environment, reducing water handling costs is more important than ever.

Chemically enhanced waterfloods seek to enhance sweep efficiency by improving mobility and altering rock permeability. Specific approaches tend to fall under the areas of Volumetric Sweep Improvement, Mobility Control, Water Shutoff, Permanent Clay Stabilization, Alkaline-Surfactant Polymer Residual Oil Recovery, and Injectivity Improvement.

Often opportunities exist to further improve recovery through a combination of approaches. In the fracture reservoirs in the Permian Basin in West Texas, for example, TIORCO believes opportunities exist to move beyond MARCIT^SM treatments to further improve recovery through the use of injectivity improvement chemicals, such as surfactants, wettability altering agents or alkaline surfactant agents that would help inject water in matrix rock. We are also seeing the need to consider the use of colloidal dispersion gel technology as a follow-up to MARCIT^SM treatments at water injection wells in the Permian basin to further improve waterflood sweep efficiency.

TIORCO Project Data Worksheet