Subsea Conduit Heating Layout for Full-Length Plug Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Subsea conduits are prone to hydrate and wax plug formation during temporary well shutdowns in cold, deep-sea environments, leading to blockages that are difficult and costly to clear, and existing Direct Electric Heating systems can damage sensitive equipment with stray currents, making it impractical to heat the entire conduit length.
Innovation Solution
An extended Direct Electric Heating system combining a conductive conduit section for primary heating with resistive heating elements in sensitive areas, using separate power supplies to prevent stray current interference and ensure continuous heating along the entire conduit length without additional chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If Direct Electric Heating is applied along the entire conduit length, then heating coverage is improved, but sensitive equipment may be damaged by stray currents
Solution Approach 1:
The conduit is divided into two distinct heating sections: a Direct Electric Heating section for the majority of the conduit length, and a resistive heating section for areas where DEH is not suitable (near sensitive equipment). This segmentation allows each section to use the appropriate heating method, achieving complete heating coverage while protecting sensitive equipment from stray currents.
Solution Approach 2:
Different heating methods are applied to different locations along the conduit based on local requirements. The Direct Electric Heating system is used in areas where it is effective, while resistive heating elements are used in areas near sensitive equipment where DEH would cause harmful stray currents. This local differentiation resolves the contradiction between heating coverage and equipment protection.
2Productivity
If Direct Electric Heating is used for the majority of conduit length, then heating efficiency is improved, but unheated sections remain prone to plugging
Solution Approach 1:
The heating system is segmented into a main Direct Electric Heating section and additional resistive heating sections at strategic locations. This ensures that the high-efficiency DEH method covers the majority of the conduit while supplementary heating zones prevent plugging in areas where DEH cannot be applied, thereby maintaining both efficiency and reliability.
Solution Approach 2:
The combined heating system ensures continuous heating action along the entire conduit length without interruption. The DEH section provides continuous heating for the majority of the conduit, while the resistive heating sections fill in the gaps near sensitive equipment, ensuring that no section is left unheated and prone to plugging.
3Object-affected harmful factors
If resistive heating elements are used in sensitive areas, then equipment protection is improved, but heating coverage is reduced
Solution Approach 1:
The conduit heating system is segmented into a main Direct Electric Heating section that provides extensive heating coverage, and localized resistive heating sections placed only in areas where equipment protection is critical. This segmentation allows the system to maintain broad heating coverage while adding targeted protection zones where needed.
Solution Approach 2:
The system merges two different heating methods (Direct Electric Heating and resistive heating) into a single integrated heating system. The DEH system provides the primary heating coverage for the majority of the conduit, while resistive heating elements are merged in at specific locations near sensitive equipment to provide additional protection without significantly reducing overall heating coverage.
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 effectively prevents hydrate and wax plug formation along the entire conduit length, reducing production delays and costs while protecting sensitive subsea equipment from stray currents by using separate power supplies for each heating section.
Implementation Method 1
A section of the subsea conduit comprises a cable strapped to its outside, a so-called piggyback cable, extending between two ends of the section. The piggyback cable is electrically connected at a near end (nearer to the topside) and at a far end (nearer to the subsea well) of the conduit, thus forming a circuit. As electrical current is circulated in the circuit, the resistance of the metal conduit converts the electric energy to heat which is passed on to the well fluid inside the conduit.
Implementation Method 2
one or more resistive heating elements along a section or sections of the conduit where Direct Electric Heating is not suitable
Implementation Method 3
at least one thermally insulating layer arranged to cover the fluid transport pipe and the at least one heating cable
Data Source
AI summary
An extended Direct Electric Heating system includes a conduit arrangement for transporting fluid from at least one subsea well apparatus to a topside or onshore location/The conduit arrangement has at least one Direct Electric Heating conduit section arranged adjacent to at least one heat traced conduit section in a longitudinal direction of the conduit sections between a subsea connection point and the at least one subsea well apparatus.