Subsea Sampling Separation Module for Multiphase Fluids
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Solution Overview
Problem
Multiphase fluid flow in oil and gas wells presents challenges in sampling individual phases due to complex flow conditions, separation, and accumulation, especially in sub-sea environments with varying Gas Volume Fraction (GVF) and Water Liquid Ratio (WLR), and diverse sampling port configurations.
Innovation Solution
A system and method for separating and sampling multiphase fluids using a separation chamber with inlet and outlet ports, a pumping system with reciprocating pistons, and sensors to control fluid circulation and phase detection, allowing for efficient accumulation and storage of desired fluid phases in a sub-sea setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a separation chamber with circulation is used to accumulate desired fluid phase, then sampling efficiency and phase separation are improved, but device complexity increases
Solution Approach 1:
The separation chamber is divided into distinct regions with inlet and outlet ports positioned at different locations to facilitate phase separation. The pumping system is segmented into reciprocating pistons within tilted cylinders, creating modular functional units that improve sampling efficiency while maintaining manageable complexity.
Solution Approach 2:
The reciprocating pistons in the tilted cylinders perform preliminary separation of phases before fluid enters the main separation chamber. This pre-separation action reduces the burden on the main separation system and improves overall sampling efficiency by preparing the multiphase fluid in advance.
2Manufacturing precision
If reciprocating pistons in tilted cylinders are used for pre-separation, then phase separation efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The cylinders are tilted from the horizontal plane at a specific angle, creating an asymmetric configuration that enhances phase separation efficiency. This asymmetric design allows heavier phases to settle more effectively during the reciprocating motion, improving separation precision while the tilted angle can be optimized for manufacturing feasibility.
3Measurement precision
If multiple sensors and valves are used for phase detection and flow control, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Sensors are positioned to detect multiple phases (gas, oil, water) at different locations within the separation chamber. The same sensor system serves dual purposes: monitoring phase content for measurement precision and providing feedback for controlling the pumping and valve operations, thereby reducing the need for separate dedicated components.
Solution Approach 2:
Sensors continuously monitor phase content and provide feedback signals that automatically control the pumping system and valves. This feedback mechanism improves measurement precision by enabling real-time detection and adjustment, while reducing device complexity by eliminating the need for separate manual control systems.
4Loss of time
If fluid circulation through separation chamber is implemented, then accumulation time is reduced, but energy consumption increases
Solution Approach 1:
The reciprocating pistons create periodic circulation of fluid through the separation chamber, accumulating desired phases more rapidly than continuous flow would allow. The periodic reciprocating motion creates alternating phases of injection and withdrawal, enhancing separation efficiency and reducing accumulation time while the periodic nature allows for energy recovery opportunities.
Solution Approach 2:
The pumping system uses dynamic reciprocating motion rather than static continuous flow, allowing the system to adapt circulation patterns to the specific phase composition. This dynamic approach optimizes energy usage by adjusting pump intensity based on real-time phase content, reducing overall energy consumption while maintaining rapid accumulation speeds.
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 robust and efficient sampling of oil, water, and gas across a wide range of flow conditions, reducing total accumulation time and maintaining sample integrity by using phase enrichment at consistent temperature and pressure, with fault-tolerant architecture for sensor failures and adaptable sampling sequences.
Implementation Method 1
The pumping system can include reciprocating pistons within two cylinders that are tilted from a horizontal plane such that a degree of pre-separation of the phase can occur within the cylinders
Implementation Method 2
When the desired fluid phase is the gas phase, the fluid is allowed to exit the separation chamber at the lower outlet port until the onset of the gas phase exiting the lower port is sensed, indicating the separation chamber is at least nearly full of the gas phase
Implementation Method 3
When the desired fluid phase is the water phase or the oil phase, the fluid is allowed to exit the separation chamber at the upper outlet port until the onset of the water phase exiting the upper port is sensed, indicating the separation chamber is at least nearly full of the water phase
Data Source
AI summary
The disclosure describes a system to segregate, enrich and capture oil, water and gas samples from a multiphase flow. The system can be used in a subsea location, on the surface or in any other condition where it is connected to a flow of different phases of gas and/or liquid. The samples obtained are representative in composition of the phases flowing at well head conditions in terms of both pressure and temperature. Additionally, a relatively small volume of each phase is used in obtaining the samples. The system connects and disconnects to ports installed at the sampling location nearby the wellhead or the production line. The sampling flow is controlled by means of a pump. The collected samples are separated in mono (or nearly mono)—phase samples (oil, water and gas) and stored in individual bottles.