Subsea Fluid Phase Separation System for Slugging Control
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Solution Overview
Problem
Deep-water hydrocarbon recovery is limited by pressure drops across pipelines and risers, and the complexity of subsea fluid phase separation is exacerbated by slugging, which reduces hydrocarbon recovery and increases operational challenges, especially in mature fields with high water production.
Innovation Solution
A subsea fluid phase separation system comprising vertical and horizontal gas-liquid separation modules, pumps, and a control system to manage fluid flow and pressure, along with multi-stage hydrocyclones for efficient water treatment and re-injection, which includes a control system to optimize valve and pump operations and handle slugging effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If subsea fluid phase separation is performed, then hydrocarbon recovery is improved, but slugging occurs which complicates operation
Solution Approach 1:
The separation system is divided into multiple stages: a first separation stage for gas-liquid separation and a second separation stage for liquid-liquid separation. This segmentation allows each stage to handle specific phase separation tasks independently, preventing slugging by ensuring complete separation before fluid reaches the next stage, thereby improving operational ease while maintaining high hydrocarbon recovery
Solution Approach 2:
The system performs preliminary gas-liquid separation before liquid-liquid separation. By removing gas phase first in the first separation stage, the system prevents gas-induced slugging in subsequent stages. This preliminary action ensures that only properly separated liquid phases proceed to the second stage, simplifying operation while maximizing recovery
2Productivity
If pressure drop across pipelines is reduced, then flow is improved, but separation equipment capacity is exceeded
Solution Approach 1:
The separation process is segmented into two sequential stages with distinct functions. The first stage handles gas-liquid separation under high flow conditions, while the second stage handles liquid-liquid separation under controlled conditions. This segmentation allows the system to maintain high flow with reduced pressure drop without overloading any single separation equipment, as each stage is optimized for its specific function
Solution Approach 2:
The first separation stage acts as an intermediary between the wellhead and the second separation stage. It pre-separates gas from liquid, reducing the load on the second stage and the topside processing equipment. This intermediary function allows the system to handle high flow rates while keeping individual equipment capacities within acceptable limits
3Productivity
If water production increases, then hydrocarbon recovery is reduced, but pressure drop increases
Solution Approach 1:
The system extracts and removes water phase through the liquid-liquid separation stage. By using a second separation stage specifically for liquid-liquid separation, the system can effectively remove water from the hydrocarbon stream, preventing water-induced pressure drops and maintaining hydrocarbon recovery even in high water production conditions
Solution Approach 2:
The system maintains continuous phase separation through both stages operating in sequence. The first stage continuously separates gas from liquid, and the second stage continuously separates water from hydrocarbons. This continuous action ensures that pressure drop is consistently managed and hydrocarbon recovery is maintained, even as water production varies
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 enhances hydrocarbon recovery by reducing pressure drops, improving flow assurance, and efficiently separating fluid phases, thereby optimizing subsea operations and extending equipment lifespan.
Implementation Method 1
vertical and horizontal gas-liquid separation modules
Implementation Method 2
multi-stage hydrocyclones for efficient water treatment
Implementation Method 3
one or more pumps to provide fluid flow out of the vertical and horizontal gas-liquid separation modules
Implementation Method 4
the configuration of hydrocyclones assist in breaking solids-stabilized emulsion particles and increase overall efficiency of solids removal from the water
Data Source
AI summary
Systems and methods for subsea fluid phase separation. A two phase embodiment of the subsea fluid separation system separates a multiphase flow into gas and liquid phases. A three phase embodiment of the subsea fluid separation system separates multiphase flow into gas, oil, and water phases. The subsea fluid separation systems include a wellhead desander system to remove solids from the multiphase flow, a vertical gas-liquid separation module having associated valves disposed in series with a horizontal gas-liquid separation module having associated valves, one or more pumps to provide fluid flow to the vertical and horizontal separators, and a control system to control operation of the valves and pumps. The three phase embodiment further includes oil-water separators and multi-stage hydrocyclones for produced water treatment in a subsea environment.