The objective of this project is to identify single chemical agents that exhibit a desirable rheological property whereby if such a chemical is dissolved in salt water it increases the solution viscosity significantly with time. We term that behavior as "self-thickening" and have nicknamed this as "T85 technology". As detailed in the original project proposal, such single chemical products can be applied to advantage as agents for selectively slowing or blocking high flow water channels in

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... rface oil reservoirs. The net effect is a decrease in water and an increase in oil flow and production. The initial testing has focused on five different synthetic co-polymers that have two or more chemical groups. These chemicals were dissolved at a concentration of 2500 ppm into different salt solutions (sodium chloride, potassium chloride, and calcium chloride) that encompass a range of dissolved salt concentrations. For the sodium chloride and potassium chloride solutions the salt concentration ranged from 1 -5 wt%. The calcium chloride dihydrate sample concentrations ranged from 0.1 -1 wt%. One set of samples being aged at 25 o C and a second set at 50 o C. Viscosity measurements versus aging time show two of these agents may exhibit apparent self-thickening behavior under certain salinity and temperature conditions. Generally the effect is greater in lower salinity NaCl brines and at 25 C. Preliminary flow experiments confirm that the aged fluids exhibit increased effective viscosity while flowing through a porous medium (sand pack). These flow tests include the case of the chemical fluid being aged on the bench before injection into a sand pack, and also a second series of sand packs where fresh chemical fluid is injected and allowed to age in-situ. Thus, the results of the static ageing tests together with the flow tests are a technical validation of the T85 concept.