Split Flow Pipe Separator with Sand Cyclone
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Solution Overview
Problem
Subsea separation of multiphase fluids into oil, water, and gas phases is challenging at depths greater than 1500 meters due to increased pressure and vessel size constraints, which limits the effectiveness of traditional separation methods and requires innovative solutions for efficient oil-water separation and sand removal.
Innovation Solution
A compact subsea multiphase separation system that splits the multiphase fluid into parallel pipe separator lines with a control volume and sand boot, allowing for efficient separation of oil, water, and solid phases, and includes a polishing section to regulate flow rates and remove sand, enabling effective separation and flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional gravity separation vessels are used at water depths greater than 1500 meters, then separation effectiveness is maintained, but wall thickness and vessel weight increase to such an extent that fabrication becomes challenging and project economics are negatively impacted
Solution Approach 1:
The invention divides the separation system into multiple functional sections within a compact vessel: a gas separation section using cyclonic separators, an oil-water separation section using coalescing elements and gravity separation, and a water treatment section. This segmentation allows each function to be optimized independently while maintaining overall separation effectiveness in a compact configuration suitable for deep water applications.
Solution Approach 2:
The patent implements nested functional elements within the separation vessel, including inserting cyclonic separators, coalescing elements, and baffle plates within the same compact vessel space. The oil-water separator section is nested within the same vessel as the gas separation section, with each component arranged to maximize space utilization while maintaining separation performance.
2Reliability
If large diameter separators are used to maintain separation effectiveness, then separation performance is improved, but the added material and weight impact project economics and vessel availability for maintenance
Solution Approach 1:
The separation vessel is divided into multiple functional zones: an upper gas separation zone with cyclonic separators, a middle oil-water separation zone with coalescing plates and gravity separation chambers, and a lower water treatment zone. This segmentation enables high separation performance in a compact overall vessel diameter by optimizing each zone's function independently.
Solution Approach 2:
The patent replaces traditional large-scale mechanical gravity separation with a combination of cyclonic separation (using centrifugal force generated by swirling flow) and electrostatic coalescence. This substitution allows effective separation in a compact vessel by using fluid dynamics and electrical fields rather than relying solely on large vessel volume for gravity separation.
3Device complexity
If sand accumulation is allowed in the pipe separator, then device complexity is reduced, but flow restrictions and corrosion risks increase
Solution Approach 1:
The patent incorporates a sand trap at the inlet of the separation vessel and periodic purging mechanisms that actively remove sand accumulations before they can cause flow restrictions or corrosion. Sand removal cyclones and mechanical scrapers are positioned to prevent sand buildup in critical separation zones, maintaining flow assurance without requiring overly complex continuous cleaning systems.
Solution Approach 2:
The separation vessel includes self-cleaning features such as sand traps that automatically collect and remove sand through periodic purging operations, and design features that promote sand settlement in designated areas away from critical flow paths. The system maintains its own reliability through these self-service sand management capabilities without requiring external intervention.
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 achieves efficient separation of oil and water phases while reducing the risk of flow restrictions and corrosion, allowing for increased production and cost savings by using single-phase pumps and reducing the need for extensive topside facilities.
Implementation Method 1
Each sand trap includes a sand cyclone configured to separate sand in the multiphase fluid stream
Implementation Method 2
the sand cyclone is configured to separate sand in the multiphase fluid stream
Implementation Method 3
the divide splits the inlet line into two or more separate lines of similar diameter that are substantially parallel to one another, and are configured to separate components of a multiphase fluid
Implementation Method 4
The control volume has a diameter greater than the separate lines of similar diameter, and the control volume includes one or more outlet lines. The outlet lines are configured to flow substantially oil from an upper outlet line and substantially water from a lower outlet line
Data Source
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AI summary
The current disclosure relates to multiphase fluid separation via a multiphase separation system. The multiphase separation system is configured to feed a multiphase fluid into an inlet line (204) within the separation system. The multiphase fluid is configured to flow through a divide (206) and be split into separate lines (208, 210) of similar diameter. A control volume (214) is also connected at the end of the separate lines (208, 210), and the control volume (214) has a diameter greater than the separate lines (208, 210) of similar diameter. The control volume (214) includes outlet lines (216, 218), and is configured to adjust fluid flow rate at an outlet line. Also included in the current disclosure is a sand boot (212) connected to the separate lines (208, 210) that is oriented vertically with respect to the separate lines (208, 210), and is configured to collect and remove sand accumulated in the multiphase separation system.