Subsea Flexible Bag Separator for Produced Water
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Solution Overview
Problem
Offshore oil and gas platforms face challenges in efficiently separating and handling solid particles and hydrocarbons from produced water, as existing equipment often requires significant space and lacks systems for solid treatment, necessitating transportation to shore for further processing.
Innovation Solution
A method and system for subsea treatment of produced water using a collapsible flexible bag maintained by a protection structure, where produced water is operated at overpressure for gravitational separation of solids and hydrocarbons, allowing for continuous separation and controlled handling of fractions, with the option to replace the bag for solid collection and transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional topside processing equipment is used on offshore platforms, then produced water can be separated and cleaned, but platform space is consumed and solid fraction handling capability is limited
Solution Approach 1:
The invention moves the produced water treatment process from the topside platform environment to the subsea environment, effectively utilizing a different spatial dimension. The flexible bag separator is deployed below the sea surface, allowing platform space to be freed while maintaining treatment capability. This dimensional relocation resolves the contradiction between needing treatment equipment and limited platform space.
Solution Approach 2:
The invention employs a flexible bag made of flexible material that can be inflated to a predefined geometry and deflated for replacement. This flexible structure provides the necessary separation functionality while occupying minimal space when deflated, enabling efficient use of limited subsea space and facilitating easy replacement without requiring large platform accommodation facilities.
2Reliability
If produced water is transported to shore for solid treatment, then solids can be properly treated, but unnecessary transport is required
Solution Approach 1:
The flexible bag separator performs preliminary separation of solids from produced water at the subsea location, concentrating solids into a manageable form within the bag before retrieval. This preliminary action at the source eliminates the need for transporting large volumes of produced water to shore, saving time and resources while still enabling proper solid treatment.
Solution Approach 2:
The invention extracts and concentrates the solid fraction from the produced water stream within the flexible bag, separating it from the water phase. This extraction allows solids to be handled and treated separately at a later time, eliminating the need to transport the entire produced water stream to shore and reducing transport time and costs.
3Reliability
If a rigid separation vessel is used, then separation can be performed, but device complexity and installation difficulty increase
Solution Approach 1:
The invention replaces a rigid separation vessel with a flexible bag made of flexible material that can be inflated to the required geometry. This flexible structure achieves the same separation functionality through its configurable internal volume and shape, reducing structural complexity, weight, and installation difficulty compared to a rigid vessel while maintaining reliable separation performance.
4Shape
If the flexible bag is operated at high overpressure, then geometry is well-maintained, but energy consumption increases
Solution Approach 1:
The invention applies overpressure only to the extent necessary to maintain the predefined geometry and achieve effective separation, rather than using excessive pressure. The flexible bag is inflated to just sufficient pressure to maintain its functional shape and enable gravitational separation, optimizing energy consumption while ensuring proper operation.
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
Enables efficient subsea separation of water, hydrocarbon, and solid fractions, reducing the need for surface processing and transportation, allowing for environmentally adapted treatment of solids and controlled handling of hydrocarbons, with the potential for continuous operation and modular expansion.
Implementation Method 1
maintaining the produced water in the flexible bag to allow for gravitational separation of the solids fraction with a higher density than water in a lower section and optionally separation of the hydrocarbon fraction with a lower density than water in an upper section
Data Source
AI summary
Method and system for separation of produced water into a water fraction, a solids fraction and a hydrocarbon fraction, comprising feeding produced water into a collapsible flexible bag maintained subsea by a protection structure; operating the flexible bag at an overpressure and thereby providing a predefined geometry of the flexible bag; maintaining the produced water in the flexible bag to allow for gravitational separation of the solids fraction with a higher density than water in a lower section and optionally separation of the hydrocarbon fraction with a lower density than water in an upper section; removing the water fraction from a section above the lower section; optionally removing hydrocarbons from the upper section and replacing the flexible bag to remove the solids fraction.