Abstract: A system according to the invention includes a working well head 1 whose producing head is connected by a rigid or flexible pipe to at least one underwater degasifier tank. A pump 4 for lifting the product from the well or wells 1 is regulated by a control valve which responds to the discharge flow of liquids and/or variations in weight and/or buoyancy of the degasifier tank 3. A valve for regulating the flow of product from the well 1 is controlled by a second control means. The second control means may modulate the gas sealing pressure by pinching a stream of gas at some point in the piping in response to the relative buoyancy of said underwater degasification tank. Combinations of the various systems disclosed in the invention make it possible to increase the recovery of desired product fluids from an underwater deposit.