Subsea Pipe Emptying via Submersible Pump and Gas Injection
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Solution Overview
Problem
Current methods for emptying undersea hydrocarbon transport pipes at great depths require bulky and voluminous high-pressure compressed air equipment, occupying large surface areas and facing challenges with hose durability under hydrostatic pressure, limiting operational efficiency and space utilization.
Innovation Solution
A method utilizing a submersible pump unit connected to the pipe to remove water, with gas injection under pressure from a higher point to compensate for volume loss, allowing for compact and efficient emptying operations without the need for extensive surface structures, using either low-pressure compressors on a surface structure or submersible high-pressure cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-pressure compressed air equipment is used to empty undersea pipes at great depths, then the emptying operation can be performed, but the equipment occupies large surface area and is voluminous
Solution Approach 1:
The system divides the emptying function into two independent parts: a submersible pump unit deployed at the pipe location that performs the actual water removal, and a separate gas injection system that can be positioned at the surface or intermediate locations. This segmentation allows the bulky high-pressure equipment to be replaced with a compact submersible pump while using readily available gas supply points.
Solution Approach 2:
The patent introduces an intermediary gas injection mechanism that compensates for volume loss during pumping without requiring direct high-pressure air injection from the surface. Gas is injected at intermediate points (such as from the high point of the pipe or from submersible cylinders) to maintain pressure balance, acting as a mediator between the pump and the deep-sea environment.
2Productivity
If high-pressure compressed air equipment is used for emptying, then water can be expelled from deep pipes, but the hose durability is compromised under hydrostatic pressure
Solution Approach 1:
Instead of injecting compressed air from the surface to push water out (which requires long, pressure-resistant hoses), the system reverses the approach by using a submersible pump to actively suction water out at the pipe location. The gas injection then compensates for volume loss, eliminating the need for long hoses to withstand extreme hydrostatic pressure.
Solution Approach 2:
The patent extracts the pumping function from the surface equipment and places it directly at the pipe location via a submersible pump unit. This removes the vulnerable hose connection from the high-pressure environment, as the pump operates independently at depth and only requires electrical power delivery rather than fluid pressure delivery through long hoses.
3Power
If surface structures are used for emptying operations, then compressed air can be generated, but the space available is greatly limited
Solution Approach 1:
The submersible pump unit is equipped with its own power and control systems, allowing it to operate autonomously at the pipe location without requiring extensive surface infrastructure. The pump performs the emptying function independently, and gas compensation can be provided from existing surface gas supplies or from submersible gas cylinders, eliminating the need for dedicated large-scale compressed air generation equipment on surface vessels.
4Productivity
If the speed of advance of scrapers is restricted due to equipment dimensions, then organized scheduling is affected, but high-pressure equipment is required for deep pipes
Solution Approach 1:
The patent replaces the mechanical scraper-pushing system with a submersible pump that actively removes water. Instead of relying on compressed air to mechanically push scrapers through the pipe at restricted speeds, the pump creates a vacuum effect that draws water and debris out efficiently, enabling faster and more flexible operation regardless of pipe depth.
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 approach reduces the required surface area for equipment to 100-150 square meters, enables efficient emptying with lower pressure gas injection (up to 50 bars), and ensures hose durability, facilitating faster and more organized pipe emptying operations even at great depths.
Implementation Method 1
pumping out at least a portion of the water present inside the submerged pipe by means of a submersible pump unit connected to a point of the pipe
Implementation Method 2
the volume of water pumped out from the inside of the pipe being compensated by a gas injected under pressure into the submerged pipe
Data Source
AI summary
A method of emptying an undersea fluid transport pipe (2) that is submerged and full of water, by pumping out at least a portion of the water present inside the submerged pipe using a submersible pump unit (6) connected to a point of the pipe, the volume of water pumped out from the inside of the pipe being compensated by a gas injected under pressure into the submerged pipe from a point (18) thereof that is situated higher than the connection point (12; 14) to the submersible pump unit. The invention also provides an installation for performing such a method.