{HEAD ~ The procedure} by which the viscosity reduction of the heavy crude oil is achieved includes {TAIL ~ the use} of water or brine with an alkaline chemical additive such as sodium hydroxide, calcium hydroxide, sodium silicates and other strong bases 
includes
{ HEAD ~ The procedure } by which the viscosity reduction of the heavy crude oil is achieved includes { TAIL ~ the use } of water or brine with an alkaline chemical additive such as sodium hydroxide , calcium hydroxide , sodium silicates and other strong bases
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