Flow control apparatus and method

Claim 1

Apparatus for use in transporting an aqueous solution of a polyacrylamide to be used as a drive fluid and/or mobility buffer in the secondary or tertiary recovery of oil from an oil-bearing subterranean formation, said apparatus including a polymerization reactor for polymerizing an aqueous solution of an acrylamide monomer and a hydrolysis reactor in communication with the polymerization reactor for hydrolyzing the polyacrylamide produced in the polymerization reactor, and dilution means in communication with a source of water, said dilution means having an inlet in communication with the hydrolysis reactor and an outlet, the improvement comprising: conduit means in communication with the outlet of the dilution means for conveying diluted aqueous hydrolyzed polyacrylamide solution from the dilution means to storage means or to an input well of an oil-bearing subterranean formation; and flow control means in said conduit means and across which a substantial fluid pressure differential exists in said conduit means, said flow control means being located downstream with relation to the dilution means and upstream with relation to said storage means or said input well of the oil-bearing subterranean formation, said flow control means including a needle valve-like fluid flow control element which is movable to a substantially fluid flow limiting position and to a fluid flow open position, said needle valve-like fluid flow control element in its fluid flow open position enabling the diluted aqueous hydrolyzed polyacrylamide solution from the dilution means to undergo, a substantial lowering in fluid pressure as it flows across the flow control means while at the same time substantially preventing shear degradation of the hydrolyzed polyacrylamide comprising said diluted aqueous hydrolyzed polyacrylamide solution.