Bedrikovetski, P.Gladstone, P.Lopes Jr., R.Rosario, F.Bezerra, M.2009-02-032009-02-0320032003 SPE Latin American and Caribbean Petroleum Engineering Conference, Port-of-Spain, Trinidad, West Indies, 27–30 April 2003http://hdl.handle.net/2440/48997SPE paper 81128Barium sulphate scaling during waterflooding causes formation damage mostly near to production wells, because high velocity near to wellbore provokes intensive mixing and accelerated chemical reaction between barium and sulphate ions. The mathematical model for steady state oil-water flow towards producers accounting for chemical reaction is developed, and an analytical solution is found. It allows obtaining a productivity index formula for PI decline prediction. The main result of the work is proportionality between the inverse to productivity index and time.en(c) SPEConference paper00300013082009013017043410.2118/81128-MS2-s2.0-034699846365314Bedrikovetski, P. [0000-0002-4786-8275] [0000-0002-7100-3765] [0000-0003-2909-6731]