Abstract: The invention concerns a subsea water processing system comprising an electrochemical unit that uses raw or treated seawater to generate high pH and low pH solutions that are used to clean at least one subsea process apparatus during a cleaning cycle by circulation through the at least one subsea process apparatus via acid or base flow lines connecting the electrochemical unit with the subsea process apparatus on-site.

Abstract: A water treatment subsea installation and method are disclosed, adapted for scaling prevention and treatment of raw seawater into process water suitable for use in subsea hydrocarbon production. The water treatment installation comprises a seawater inlet to a primary filtration unit wherein a filtration membrane separates a receiving chamber from a permeate chamber having an outlet for treated water. A pump is installed in fluid flow communication with the treated water outlet, a recirculation loop feeding a portion of the treated water via a subsea electro-chlorinator back to the water stream upstream or downstream of the membrane of the primary filtration unit, and a secondary filtration unit is installed in the treated water stream between the primary filtration unit and the electro-chlorinator.

Abstract: A subsea water processing system and associated methods are disclosed. The subsea water processing system includes a microfiltration unit, an ultrafiltration unit, and an electrochemical unit. The microfiltration unit includes an oil-tolerant microfiltration membrane and is configured to receive a stream of produced water and to produce a first treated stream of water. The ultrafiltration unit is fluidly connected downstream of the microfiltration unit, includes an oil-rejecting ultrafiltration membrane, and is configured to receive the first treated stream of water and to produce a second treated stream of water. The electrochemical unit is fluidly connected to at least one of the microfiltration unit or the ultrafiltration unit, and is configured to produce an acid and a base, and to deliver the acid, the base, or both the acid and the base to the at least one of the microfiltration unit or the ultrafiltration unit during a cleaning cycle.

Abstract: A water treatment subsea installation and method are disclosed, adapted for scaling prevention and treatment of raw seawater into process water suitable for use in subsea hydrocarbon production. The water treatment installation comprises a seawater inlet to a primary filtration unit wherein a filtration membrane separates a receiving chamber from a permeate chamber having an outlet for treated water. A pump is installed in fluid flow communication with the treated water outlet, a recirculation loop feeding a portion of the treated water via a subsea electro-chlorinator back to the water stream upstream or downstream of the membrane of the primary filtration unit, and a secondary filtration unit is installed in the treated water stream between the primary filtration unit and the electro-chlorinator.

Abstract: A method of producing purified water in a subsurface environment is provided in which ambient subsurface source water is introduced into and through one or more ultrafiltration membrane units of a subsurface water treatment system and producing thereby an ultrafiltrate substantially free of solid particulates having a largest dimension greater than 0.1 microns. An electrochemical unit in fluid communication with at least one ultrafiltration membrane unit provides an antifoulant solution. An ultrafiltrate-rich backwash fluid and at least a portion of the antifoulant solution are delivered to at least one non-producing ultrafiltration membrane unit during a backwash cycle. A flux of source fluid through each of the ultrafiltration membrane units of less than thirty gallons per square foot per day limits the need for backwash cycles. A reduction in the number of backwash cycles enhances system autonomy and useful life, and limits the need for intervention for maintenance and component replacement.

Abstract: An active rotating separator is disclosed, comprising a separator drum arranged to receive multiphase fluid via an upstream end and to deliver separated fluid phases from a downstream end of the drum. An electric motor is installed in the flow through the drum, the motor operable to generate rotation in the fluid flow that passes through the drum, the motor comprising an open rotor permitting through-flow of fluid through the motor.

Abstract: A subsurface water treatment system is provided which may be used to produce purified water using ambient subsurface water as a source fluid. The system includes one or more ultrafiltration membrane units which use ambient water as the source fluid and to produce therefrom an ultrafiltrate substantially free of solid particulates having a largest dimension greater than 0.1 microns. An electrochemical unit provides an antifoulant solution comprising hypohalous acid species. A backwash unit allows periodic cleaning and defouling of a non-producing ultrafiltration membrane unit. The system may also include a nanofiltration unit and a reverse osmosis membrane unit which may be used to produce purified water having any of a wide range desired total dissolved solids content. The novel systems and methods described may be used to stimulate the production of hydrocarbon fluids from a hydrocarbon reservoir.

Abstract: A method of producing purified water in a subsurface environment is provided in which ambient subsurface source water is introduced into and through one or more ultrafiltration membrane units of a subsurface water treatment system and producing thereby an ultrafiltrate substantially free of solid particulates having a largest dimension greater than 0.1 microns. An electrochemical unit in fluid communication with at least one ultrafiltration membrane unit provides an antifoulant solution. An ultrafiltrate-rich backwash fluid and at least a portion of the antifoulant solution are delivered to at least one non-producing ultrafiltration membrane unit during a backwash cycle. A flux of source fluid through each of the ultrafiltration membrane units of less than thirty gallons per square foot per day limits the need for backwash cycles. A reduction in the number of backwash cycles enhances system autonomy and useful life, and limits the need for intervention for maintenance and component replacement.