SUBSEA SYSTEM FOR INJECTION OF SEAWATER BY MEANS OF A SUBMERGED CENTRIFUGAL PUMP

摘要

Subsea system for injection of seawater by means of a submerged centrifugal pump, more especially relating to a subsea system for injection of water into aquifers of petroleum or gas reservoirs requiring a secondary recovery method using water injection. The system is formed by a capture tube (2) that includes and keeps longitudinally aligned the pumping unit formed by a submerged centrifugal pump (1), a motor (11), a screen (3) or filters (6) and (8) or (9) and a flow measuring device (14). The stream of water is filtered through the screen (3) or filter (6) and then through the filter (8) or (9), and then flows towards the suction side of the submerged centrifugal pump (1). The suction side of the submerged centrifugal pump (1) is isolated from the discharge by means of a discharge pipe (12) or by means of a jacket (10). The capture tube (2) is able to float by means of a flotation device (4) and tethers (7) or is connected to/mounted directly onto the subsea tree (22); an ROV panel (19) is provided for connection of power cables and hoses for injection of chemicals, where necessary, and also comprises interfaces for valve operation. The speed of the motor (11), and consequently the flow and discharge pressure thereof are controlled by means of a speed-varying device (20) arranged externally to the capture tube (2). The present invention is mainly intended for use in injector wells where the injection of untreated seawater does not cause undesirable damage to the formation. The application thereof is directly linked to a reduction in water-injection plants installed on floating units.