Subsurface Water Treatment System for EOR

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Solution Overview

Problem

Conventional water treatment systems for subsea oil field operations face challenges in producing low salinity water for enhanced oil recovery (EOR) due to high costs and limited space on topside platforms, and the harsh subsurface environment, which limits the operational time of existing subsurface water treatment systems.

Innovation Solution

A subsurface water treatment system incorporating ultrafiltration membrane units, an electrochemical unit to produce hypohalous acid species for fouling prevention, and a backwash unit to maintain membrane cleanliness, along with nanofiltration and reverse osmosis units to achieve the desired water quality, is proposed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a subsurface water treatment system is installed adjacent to the injection well on the sea floor, then the need for high cost piping and limited platform space is eliminated, but the high concentration of particulate matter in the subsurface environment severely limits the operational time without maintenance

Engineering Contradiction:

Improvecost and space efficiencyVSAvoidoperational time without maintenance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The system performs preliminary cleaning actions by continuously producing purified water that prevents particulate accumulation on membrane surfaces during normal operation, rather than waiting for fouling to occur and then performing maintenance

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous production of purified water for EOR operations while simultaneously maintaining membrane cleanliness through the integrated electrochemical cleaning mechanism, eliminating the need for shutdown maintenance periods

Inventive Principle:

Principle #20Continuity of useful action

2Manufacturing precision

If conventional filtration is used in subsurface environments, then particles are removed from injection water, but the high concentration of particulate matter causes frequent membrane fouling and requires frequent maintenance

Engineering Contradiction:

Improveparticle removal efficiencyVSAvoidmaintenance frequency

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The electrochemical unit generates hypohalous acid species (strong oxidants) that actively clean particulate matter from membrane surfaces, preventing fouling accumulation and extending the time between maintenance operations

Inventive Principle:

Principle #38Strong oxidants (Accelerated oxidation)

Solution Approach 2:

The system replaces purely mechanical filtration with an integrated electrochemical cleaning mechanism that uses chemical oxidation to remove fouling, reducing the frequency of manual maintenance interventions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively produces purified water with reduced solid particulates and sulfate levels, enhancing EOR efficiency and reducing maintenance needs, thereby improving hydrocarbon yields and operational reliability in subsea environments.

Implementation Method 1

one or more ultrafiltration membrane units configured to use ambient water as a source fluid and to produce therefrom an ultrafiltrate substantially free of solid particulates having a largest dimension greater than 0.1 microns

Methodology Applied

Scientific EffectUltrafiltration: Filter (physical)

Implementation Method 2

an electrochemical unit in fluid communication with at least one ultrafiltration membrane unit and configured to provide an aqueous solution comprising one or more hypohalous acid species

Methodology Applied

Scientific EffectElectrochemical reaction: Electrolysis

Implementation Method 3

a backwash unit configured to deliver an ultrafiltrate-rich backwash fluid and at least a portion of the aqueous solution comprising one or more hypohalous acid species to at least one non-producing ultrafiltration membrane unit during a backwash cycle

Methodology Applied

Scientific EffectBackwash:

Implementation Method 4

a nanofiltration membrane unit configured to receive the ultrafiltrate and produce therefrom a nanofiltrate containing less than 100 parts per million sulfate species

Methodology Applied

Scientific EffectNanofiltration: Filter (physical)

Data Source

PatentEP3283195B1Subsurface water treatment system

Publication Date: 2022.08.24 GENERAL ELECTRIC CO

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AI summary

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.