Subsea Multiphase Separation System Using Segmented Compartments
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Solution Overview
Problem
Subsea separation of production fluids into gases and liquids becomes impractical at depths greater than 1500 meters due to increased external pressure, making traditional large diameter separators unsuitable due to size and weight constraints, which complicates oil and gas recovery.
Innovation Solution
A compact subsea multiphase separation system that separates production fluids into gas, oil, and aqueous phases, allowing for the use of single-phase pumps and reducing the need for bulky vessels, while incorporating slug catchers to manage flow fluctuations and contaminants, thus enabling efficient bulk water removal and reducing hydrostatic head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional large diameter separators are used for subsea separation, then effective gas-liquid separation can be achieved, but the wall thickness and weight increase excessively at depths greater than 1500 meters due to hydrostatic pressure
Solution Approach 1:
The separator is divided into multiple compartments separated by vertical partitions. Each compartment functions as an independent separation unit, allowing the overall system to achieve effective separation without requiring a single large-diameter vessel with excessive wall thickness. This segmentation enables the use of smaller, lighter components that can be deployed at great depths.
2Reliability
If traditional large diameter separators are used for subsea separation, then effective gas-liquid separation can be achieved, but the vessel becomes difficult to fabricate and impacts project economics
Solution Approach 1:
By dividing the separator into multiple smaller compartments with standard wall thicknesses, the system avoids the need to fabricate and handle extremely thick-walled large-diameter vessels. Each compartment can be manufactured using conventional techniques and assembled on-site, significantly improving ease of fabrication and reducing project costs.
3Reliability
If traditional large diameter separators are used for subsea separation, then separation capacity is sufficient, but the added material and weight reduce availability for maintenance
Solution Approach 1:
The compartmentalized design allows individual sections to be accessed, removed, or maintained independently without requiring the entire large-diameter vessel to be brought to the surface. This modular approach maintains adequate separation capacity while significantly improving maintenance availability by enabling targeted interventions on specific compartments.
4Weight of stationary object
If compact separation systems are used to reduce size and weight, then deployment at depths greater than 1500 meters becomes feasible, but managing flow fluctuations and contaminants becomes more challenging
Solution Approach 1:
Different compartments are assigned specific functions: some optimized for gas-liquid separation, others for contaminant removal, and additional sections for damping flow fluctuations. This functional segmentation within the compact structure manages flow complexity through dedicated zones rather than requiring a single complex system.
Solution Approach 2:
The system combines multiple separation functions (gas-liquid separation, contaminant removal, flow damping) into a single integrated compact unit. By merging these functions into one multifunctional device, the system achieves the benefits of compactness while managing flow complexity through combined operations rather than separate systems.
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
This solution enhances subsea well production by reducing flow assurance concerns, lowering the risk of hydrate formation and corrosion, decreasing infrastructure needs, and increasing reservoir drive and production efficiency.
Implementation Method 1
subsea separation at water depths greater 1500 meters becomes especially challenging due to the environmental conditions. As water depth increases, the external pressure on a vessel created by the hydrostatic head increases
Implementation Method 2
Each pipe may include an expansion zone configured to lower a pressure of the multiphase fluid
Data Source
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AI summary
A system and method for separation of liquids and gases within a multiphase fluid are provided herein. The method includes flowing a multiphase fluid into a number of divisions within a multiphase separation system, wherein the divisions are configured to lower a velocity of the multiphase fluid. The method also includes separating the multiphase fluid among a number of lower pipes and a number of upper pipes, wherein each lower pipe includes an expansion zone configured to lower a pressure within the lower pipe to allow entrained liquids to drain from a corresponding upper pipe via a downcomer.