Modular Subsea Gravity Separator for Crude Oil Phase Separation
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Solution Overview
Problem
Existing liquid/liquid separation devices for crude oil in deep-sea oil production face challenges in adapting to varying gas-oil ratios and water-cut proportions over time, requiring modifications in operating parameters and structure, while also needing to be cost-effective and resistant to high pressures.
Innovation Solution
A modular horizontal liquid/liquid gravity separation device with multiple modules anchored to the seafloor, featuring a bent tubular connection system that allows for flexible configuration and easy addition or removal of modules to adjust to changing fluid compositions and flow rates, using standard subsea pipes that can withstand pressure without excessive length, which reduces pressure drop differentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a horizontal gravity separator is installed at the bottom of the sea at great depth, then liquid/liquid separation can be performed, but the separator must resist implosion under high pressure which requires thick walls and makes the device delicate and expensive to produce and install
Solution Approach 1:
The separator is divided into multiple modular sections (first separator module, second separator module, etc.) that can be independently manufactured and assembled. Each module contains its own separation elements and can be connected to form a complete separation system, reducing the complexity of manufacturing a single large pressure-resistant vessel
Solution Approach 2:
The invention transitions from a traditional horizontal cylindrical separator to a vertical arrangement of modular separation units connected in series. This dimensional change allows the system to achieve the required separation length without requiring a large-diameter pressure vessel, thereby reducing the implosion resistance requirements
2Ease of manufacture
If the diameter and thickness of the separator are reduced to standard subsea pipe dimensions, then production costs are reduced, but the length of the separator must be increased to separate sufficient fluid which creates pressure drop differentials between phases
Solution Approach 1:
The separation system is segmented into multiple modules connected in series, each contributing to the overall separation length. This allows the use of standard pipe dimensions while achieving sufficient total separation length through modular repetition rather than a single long pipe
Solution Approach 2:
The modular design allows for dynamic adjustment of the number of separation modules based on flow rate and separation requirements. This enables optimization of the pressure drop differential by adjusting system configuration to match actual operating conditions
3Quantity of substance
If multiple small oil discoveries are located 15-30km from the FPSO, then new production sources are available, but the existing FPSO crude processing equipment is used at full capacity and cannot process the surplus
Solution Approach 1:
The separation system is designed as modular units that can be added or removed based on production volume requirements. This allows the satellite wells to be connected to the existing FPSO infrastructure with minimal modification, adding processing capacity in discrete modular increments
Solution Approach 2:
The modular separation modules are designed to be universally applicable to different well configurations and production rates. The same module design can serve both satellite wells and main FPSO processing, providing versatility in handling different production scenarios
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 and adaptable separation of crude oil phases at great depths, allowing for increased treatment capacity and flexibility in responding to changes in oil well production characteristics, while maintaining operational stability and reducing costs by using standard pipe materials.
Implementation Method 1
at least one gravity separation pipe extending in an axial longitudinal direction (X2 X2)... the separation of an upper oily phase 10-1 and a lower aqueous phase 11-1
Implementation Method 2
liquid/liquid gravity separation of two liquid phases of different densities of a liquid fluid
Data Source
Figure 1~2
Figure 1A~1B
Figure 3~6B
AI summary
The present invention relates to a modular device for the liquid/liquid gravity separation of the aqueous phases (11-1) and oil phase (10-1) of crude oil at the seabed (30), including a plurality of separation modules (1a) connected to a common collecting device (1b). Each separation module (1a) includes a fluid flow line (6) connected to at least one gravity separation pipe (7) by a tubular device (8) having an elbow. The common collecting device (1b) includes a first tank (3) to which crude oil is supplied by a supply pipe resting on the seabed (5) via a first inlet (3-1) thereof, a plurality of first outlets (3a) supplying crude oil to said flow lines (6). Two aqueous and oil phases are separated within separation pipes (7) before being discharged into a second tank (4) via second inlets (4a) of said second tank to which the separation pipes (7) are connected. The oil phase (10-1) is conveyed to the surface from the second tank (4) via a first discharge pipe (10). The aqueous phase (11-1) is conveyed to the seabed.