Polyacrylamide “EOR-1” is an anionic copolymer of polyacrylamide and sodium acrylate with molecular-weight average, it is very soluble in water, and it has no chemical interaction with hydrocarbons and porous medium. “EOR-1” is used for maintenance and workovers of oil and gas wells, in the technologies of oil recovery enhancement, where it ensures prolonged effect during polymer flooding, due to its retention of basic viscosity properties and capability to reduce water relative permeability of formation. The reagent is also used while carrying out water shut-off jobs in the form of viscoelastic compound cross-linked with the Cr3+ molecules.
According to conventional technology of polymer flooding, a chemical plug of the solution of the “EOR-1” polymer is injected into formation with permanent concentration, the chemical solution plug, in its turn, is moved within the formation with brine water of the formation pressure maintenance system. The polymer content in the solution and the volume of the chemical plug may vary within a wide range.
When preparing cross-linked compounds, depending on set goals, a water solution of “EOR-1” of the 0.01-1% concentration is injected into a well, with the crosslinker (chromium acetate or chromium potassium sulphate) entered into it, with concentration of 0.005 to 0.1%.
Due to selected concentration of the polymer and crosslinker it is possible to regulate the time of gel formation of the system and obtain the crosslinked system at a set point.